Note: Descriptions are shown in the official language in which they were submitted.
CA 02736909 2011-03-10
WO 2010/028493 PCT/CA2009/001264
COMPOSITIONS AND METHODS FOR INJECTION OF SEALANTS AND/OR DRYING
AGENTS INTO AIR CONDITIONING AND REFRIGERATION SYSTEMS
[0001] The content of U.S. patent application Ser. No. 10/860,646 entitled
COMPOSITION AND METHODS FOR INJECTION OF SEALANTS INTO AIR
CONDITIONING AND REFRIGERATION SYSTEMS filed June 4, 2004 is hereby
incorporated by reference into the detailed description hereof. For the
purposes of US
prosecution, this application is a Continuation in Part of, and claims the
benefit of the filing date
of U.S. patent application Ser. No. 11/941,364, filed November 16, 2007 and
which, itself, is a
continuation of US patent application Ser. No. 10/860,646 entitled COMPOSITION
AND
METHODS FOR INJECTION OF SEALANTS INTO AIR CONDITIONING AND
REFRIGERATION SYSTEMS filed June 4, 2004. This application claims the benefit
of the
filing date of U.S. patent application ser No. 61/096,208, filed September 11,
2008, the contents
of which are incorporated by reference into the detailed description hereof.
BRIEF DESCRIPTION OF THE DRAWINGS
[0002] For a better understanding of the present invention and to show more
clearly how
it may be carried into effect, reference will now be made, by way of example,
to the
accompanying drawings which show the preferred embodiment of the present
invention and in
which:
[0003] FIG. 1 is a graphic representation of a sealant injection assembly in
accordance
with a preferred embodiment of the present invention in use with an air
conditioning or
refrigeration system 1,
[0004] FIG. 2 is a partially exploded perspective view of the assembly of FIG.
1,
[0005] FIG. 3 is an end view of a fitting and orifice used in the assembly of
FIG. 2, and
[0006] FIG. 4 is a cutaway view of a typical single cylinder hermetic
compressor.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0007] Referring to FIG. 1, a typical hermetically sealed air conditioning or
refrigeration
system 1 has an evaporator 3, compressor 5, condenser 7 and expansion device
9. The system 1
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WO 2010/028493 PCT/CA2009/001264
has a "low side" 10 consisting of the part of the system I between the
expansion device 9 (for
example, an orifice 9) and the suction line to the compressor 5. The
compressor 5 draws in low
pressure, low temperature refrigerant in a gaseous state from the "low side"
10. The compressor
compresses the gaseous refrigerant to a high pressure, high temperature
gaseous state that
5 flows to the condenser 7. The refrigerant passes through the condenser 7 and
is cooled to a
liquid state. The liquid refrigerant passes through the expansion valve 9,
which causes the
refrigerant to expand to a low pressure, low pressure temperature gas. The
evaporator 3 absorbs
heat from outside the system 1, and relatively low temperature, low pressure
gas is reintroduced
to the compressor 5.
[0008] For the test environment, the low side pressure was approx. 77 psig at -
the
compressor 5, and pressure on the high pressure side of the compressor (the
discharge 11) was
approx. 256 psig. The temperature at the evaporator 3 was approx. 45 F and at
the condenser
approx. 126 F. The ambient temperature was approx. 90 F. The temperature of
the gas between
the valve 9 and evaporator 3 was approx. 55 F. The temperature at the
compressor 5 discharge
11 was approx. 171 F. The valve 9 in the test environment had a diameter of
approx. 0.059
inches. The gas flow rate in the low side between the evaporator 3 and the
compressor 5 was
approximately 1596 ft/min. The diameter of pipe in the low side was nominal
3/4 inch, while the
inside diameter of pipe at the discharge was 3/8 inches. The test environment
was a single phase
2 ton compressor 5.
[0009] These are typical characteristics for an air conditioning system 1 or
the
environment about an air conditioning system 1. For larger and smaller systems
1, the particular
specifications may change. This a design choice. The particular parameters
under which sealant
is introduced into the system may vary accordingly.
[0010] In order to seal small leaks in the system 1 it is desirable to
introduce
organosilanes or other sealants into the system 1. Organosilanes cure when in
the presence of
moisture, such as would occur at the situs of a leak.
[0011] The use of organosilanes in non-hermetically sealed air conditioning or
refrigeration systems 1 is previously known, see for example, U.S. Patent No.
4,237,172 issued 2
December 1980 to Packo et al under title Sealing Leaks by Polymerization of
Volatilized
Aminosilane Monomers; United States Patent No. 4,304,805 issued 8 December
1981 to Packo
et al under title Sealing Leaks by Polymerization of Volatilized Aminosilane
Monomers; U.S.
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WO 2010/028493 PCT/CA2009/001264
Patent No. 4,331,722 issued 25 May 1982 to Packo et al under title Sealing
Leaks by
Polymerization of Volatilized Organosilane Monomers; and U.S. Patent No.
5,417,873 issued 23
May 1995 to Packo under title Sealant Containing Partially Hydrolized
Tetraalkoxy Silane, for
Air Conditioning and Refrigeration Circuits that describe mixtures for this
purpose. As
previously mentioned, the simple injection of an organosilane or mixture of
organosilanes into a
hermetically sealed system I will typically cause compressor 5 failure.
[0012] Referring to FIG. 2, an injection assembly 12 has a vessel 15
containing an
organosilane mixture. In the preferred embodiment the vessel 15 is a canister
15. The mixture is
selected for miscibility with the contents of the system 1. It is to be
recognized that, in addition
to- refrigerant, the system I contains a miscible lubricant for lubrication of
the compressor 5. The
system 1 may also have other contents, such as a fluorescent dye for leak
detection. It may also
contain a chemical dryer to remove moisture from the system 1.
[0013] The inventors have recognized that, in addition to liquid slugging, the
introduction of greater concentrations of organosilanes remove lubricants from
the compressor 5,
resulting in compressor 5 failure. The organosilane should be introduced in
sufficiently low
concentrations and be miscible with the system 1 lubricant to avoid liquid
slugging and to
maintain sufficient lubricant for proper operation of the compressor 5. The
organosilane is
introduced from vessel 15 to a low side port 17 between the evaporator 3 and
compressor 5.
[0014] The organosilane is introduced at a rate that allows the concentration
of the
organosilane to be diluted sufficiently by the other system 1 contents to
prevent liquid slugging
and to maintain sufficient concentration of lubricant for proper operation of
the compressor 5.
[0015] Referring to Fig. 4, controlled injection of the organosilane combined
with the
miscible lubricant is critical when injected at the low side port 17 because
of the close proximity
between the low-side charging port 17 and compressor 5. After the
organosilane/miscible
lubricant mixture enters the compressor 5 along with cool refrigerant vapor it
has to first pass by
outboard shaft bearing 18. This aids in replacing oil to the outboard bearing
which may have
been stripped by passing refrigerant. The mixture continues on flow path 19a
rushing over motor
windings (stator 19b, rotor 19c) removing heat from the electric motor. The
flow of refrigerant
vapor /mixture is then drawn over oil reservoir (sump) 19d into compressor
pump l9e where it is
compressed into a hot vapor and discharged. During this flow path the
importance of maintaining
a suitable viscosity is important for a continued oil barrier between metal
internals.
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CA 02736909 2011-03-10
approximately 60% of the refrigerant then turning on the system and adding
remaining
refrigerant.
The sealant mixture may have a viscosity above 7 est. when measured at 40 C.
The flow rate of
injection may be 6 cc/sec or less.
The viscosity for a particular lubricant/sealant mixture may be T1inj or
greater where 11iõ j is
determined by:
exp(xir,j.ln 11inj + xs,p.1n'nsump + C} > Fr . 11sU,p
where,
In is the natural logarithm and exp is the exponential,
xinj, is mole fraction of injected material in final sump mixture,
xsõmp is mole fraction of original sump oil in final sump mixture,
ili,j, rmsõmp are viscosities of the injected mixture and original sump oil
respectively,
and
Fr is a desired fraction of original sump oil viscosity to be maintained.
Fr may be equal to 0.9 or more. Where the calculated viscosity may be less
than 7 est., then the
minimum viscosity may be set at 7 est.
The step of allowing the sealant to enter the system may further include
allowing the sealant to
enter through an orifice having an opening within a range of from 0.020-0.06
inches diameter.
The step of connecting the vessel to the system may include connecting a hose
assembly between
the vessel and a low pressure side service port of the system. The hose
assembly may include a
first fitting for connection to the vessel and a second fitting for connection
to the port.
The step of providing fluid connection between the vessel and the system, and
the step of
allowing sealant mixture to enter the system, may include opening a valve in
the second fitting.
The vessel may be a sealed canister, and the step of providing a fluid
connection between the
canister and the system may include tapping the canister before opening the
valve in the second
fitting.
The second fitting may be a can-tapper. The method may also include
substantially evacuating
the hose assembly prior to connection to the system.
In a fourth aspect the invention provides a device for introducing sealant
into a hermetically
sealed air conditioning or refrigeration system. The device includes a sealed
vessel including an
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AMMED ST1 ET
CA 02736909 2011-03-10
r t
organosilane mixture of an organosilane and a miscible material, the mixture
having a viscosity
above 7 est. when measured at 40 C. In this aspect the organosilane is a
monomer or oligomer
capable of forming a solid polymer with itself or other chosen organosilanes
in the presence of
moisture, and is stable in the absence of moisture in the system, and does not
substantially
interference with the normal operation of contents of the system in selected
quantities.
The device may include a metering device for fluid connection with the sealed
vessel, and for
controlling fluid flow from the sealed vessel. The metering device may be an
orifice having an
opening within a range of from 0.020-0.06 inches.
The device may further include a fitting for sealed fluid connection to a low
side port of the
system, and the fluid flowing through the metering device also flows through
the fitting. The
device may also include a hose assembly with a first fitting for sealed fluid
connection to a low
side port of the system, and a sealed fluid connection to the sealed vessel.
The device may also include a metering device for controlling fluid flow from
the sealed vessel
through the hose assembly.
The fluid connection to the sealed vessel may be a second fitting. The second
fitting may include
a manually operable valve for providing fluid connection between the hose
assembly and the
sealed vessel. The second fitting may include a can-tapper for opening the
sealed vessel.
The device may include a filter is placed between the fitting connecting to
the system and the
'orifice, The orifice may have a diameter of 0.06 inches or less. The sealed
vessel maybe a
sealed canister.
The organosilane or components of the sealant mixture may include components
that can be
represented as (Rj)(R2)Si(R3)(Ra)
where,
Ri =is an alkyl radical of 1-4 carbon atoms or vinyl or -OH
R2 is Ri or-ORI or NH(RI) or-N(RI)2 or -RINHR1NH2.
R3 is RI or-ORI or NH(RI) or N(RI)2 or -RINHRINH2, and
R4 is RI or --ORI or NH(RI) or N(RI)z or -RINHRINH2.
A component of the sealant mixture may include components that can be
represented as
(R5)(Rs)(R7)Si-O-Si(R5)(R6)(R7)
R5, R6 or R7 are each any one of RI,R2,R3 or R4 where,
MEN S ET
CA 02736909 2011-03-10
R1 =is an alkyl radical of 1-4 carbon atoms or vinyl or -OH,
R2 is R1 or-OR1 or NH(R1) or-N(R1)2 or -RINHRINH2,
R3 is Rl or-OR, or NH(R1) or -N(R.02 or -R1NHR1NH2, and
R4 is R1 or-OR, or NH(RI) or -N(RI)2 or -RINHRINH2.
The sealant mixture may also include a lubricant miscible with the
organosilane and refrigerant
for use in the system. The miscible mixture may include a lubricant selected
from one or more
of a polyol ester, polyalkylene glycol, mineral oil, polyalphaolefin and
alkylbenzene. The
miscible mixture may include a lubricant further comprising additives to
enhance and-refresh the
performance of lubricant in the compressor.
The preferred embodiment of these and other aspects of the invention will be
described later
herein.
BRIEF DESCRIPTION OF TUB DRAWINGS
For a better understanding of the present invention and to show more clearly
how it may be
carried into effect, reference will now be made, by way of example, to the
accompanying
drawings which show the preferred embodiment of the present invention and in
which:
FIG. 1 is a graphic representation of a sealant injection assembly in
accordance with a preferred
embodiment of the present invention in use with an air conditioning or
refrigeration system 1,
FIG. 2 is a partially exploded perspective view of the assembly of FIG. 1,
FIG. 3 is an end view of a fitting and orifice used in the assembly of FIG. 2,
and
FIG. 4 is a cutaway view of a typical single cylinder hermetic compressor.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, a typical hermetically sealed air conditioning or
refrigeration system 1 has
an evaporator 3, compressor 5, condenser 7 and expansion device 9. The system
I has a "low
side" 10 consisting of the part of the system I between the expansion device 9
(far example, an
orifice 9) and the suction line to the compressor 5. The compressor 5 draws in
low pressure, low
temperature refrigerant in a gaseous state from the `low side" 10. The
compressor 5 compresses
the gaseous refrigerant to a high pressure, high temperature gaseous state
that flows to the
condenser 7. The refrigerant passes through the condenser 7 and is cooled to a
liquid state. The
liquid refrigerant passes through the expansion valve 9, which causes the
refrigerant to expand to
a low pressure, low pressure temperature gas. The evaporator 3 absorbs heat
from outside the
system 1, and relatively low temperature, low pressure gas is reintroduced to
the compressor 5.
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AMENDED SHEET
CA 02736909 2011-03-10
For the test environment, the low side pressure is 77 psig at the compressor
5, and pressure on
the high pressure side of the compressor (the discharge 11) is 256 prig. The
temperature at the
evaporator 3 is 45 F and at the condenser 126 F. The ambient temperature is 90
F. The
temperature of the gas.between the valve 9 and evaporator 3 is 55 F. The
temperature at the
compressor 5 discharge 11. is 171 F. The valve 9 in the test environment had a
diameter of 0.059
inches. The gas flow rate in the low side between the evaporator 3 and the
compressor 5 is 1596
ft/min. The diameter of pipe in the low side is nominal f inch, while the
inside diameter of pipe
at the discharge is 3/8 inches. This is for a single phase 2 ton compressor 5.
These are typical characteristics for an air conditioning system 1 or the
environment about an air
conditioning system 1. For larger and smaller systems 1, the particular
specifications may
change. This a design choice. The particular parameters under which sealant is
introduced into
the system may vary accordingly.
In order to seal small leaks in the system 1 it is desirable to introduce
organosilanes or other
sealants into the system 1. Organosilanes cure when in the presence of
moisture, such as would
occur at the sites of a leak.
The use of organosilanes in non-hermetically sealed air conditioning or
refrigeration systems I is
previously known, see for example, U.S. Patent No, 4,237,172 issued 2 December
1980 to Packo
et al under title Scaling Leaks by Polymerization of Volatilized Aminosilane
Monomers; United
States Patent No. 4,304,805 issued 8 December 1981 to Packo et al under title
Sealing Leaks by
Polymerization of Volatilized Aminosilane Monomers; U.S. Patent No. 4,331,722
issued 25 May
1982 to Packo et al under title Sealing Leaks by Polymerization of Volatilized
Organosilane
Monomers; and U.S. Patent No. 5,417,873 issued 23 May 1995 to Packo under
title Sealant
Containing Partially Hydrolized Tetraalkoxy Silane, for Air Conditioning and
Refrigeration
Circuits that describe mixtures for this purpose. As previously mentioned, the
simple injection
of an organosilane or mixture of organosilanes into a hermetically sealed
system 1 will typically
cause compressor 5 failure.
Referring to FIG. 2, an injection assembly 12 has a vessel 15 containing an
organosilane mixture.
In the preferred embodiment the vessel 15 is a canister 15. The mixture is
selected for
miscibility with the contents of the system 1. It is to be recognized that, in
addition to
refrigerant, the system I contains a miscible lubricant for lubrication of the
compressor S. The
system 1 may also have other contents, such as a fluorescent dye for leak
detection. It may also
contain a chemical dryer to remove moisture from the system 1.
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[0035] Other sealants, alternative to or in combination with organosilanes,
may also be
used. These sealants may consist of polymeric latexes, vinyl acetates,
acrylonitriles,epoxide or
methacrylates or some combination thereof. The sealant may include alkylene
glycol. The
sealant may contain a catalyst or accelerator. The catalyst may contain a
copper or cobalt
compound. The catalyst or accelerator may contain a solubilizer. The sealant
may contain a
filler. The filler may be graphite, carbon powder or a
polytetrafluoroethylene.
[0036] Preferred compositions of the lubricant/organosilane mixture, or the
lubricant/hydrolytic drying agent mixture, or the
lubricant/organosilane/hydrolytic drying agent
mixture are those providing viscosities above a viscosity of 7 cst. when
measured at 40 C. The
choice of this viscosity minimum was determined by experiment as illustrated
below in examples
4 to 7. The 40 C measurement point is used simply because this is the
temperature at which
compressor lubricants are typically characterized for viscosity.
[0037] The quantity of organosilane to be added depends on the size of the
refrigeration
or air conditioning system. This is not due to the size or number leaks in the
system. For small
leaks, say less than 1/16" in diameter, and a sealant plug 1/16" long, several
hundred seals would
easily require only an ounce of organosilane. The rapidity with which a leak
will seal depends
on delivering an effective quantity of the sealant to the situs of the leak.
This latter
consideration, experience in automotive applications, and general practical
considerations such
as the size of the injection apparatus, suggest that injections of between 1/8
and 1 oz. of
organosilanes are sufficient for most applications, with larger systems
requiring the larger
amount. In addition, it has been found that injections up to a maximum of 10%
of the lubricant
quantity in the system are recommended due to concerns with injection of
liquid into the low
side in proximity to the compressor 5.
[0038] In the preferred embodiment, organosilane is combined with a miscible
lubricant.
The quantity of lubricant mixed with the organosilane is determined by
considerations of first,
providing adequate lubrication as the fluid enters the compressor 5 as has
been previously
described and second, of producing limited effect on the final lubricant
viscosity, preferably no
more than 10% reduction, once the organosilane has been distributed throughout
the system.
[0039] The desired viscosity of the lubricant/organosilane mixture can be
achieved by
varying the ratio of the two or by adjusting the viscosity of the lubricant.
Organosilanes of
interest generally have very low viscosities (<1 cst. @ 40 C) while lubricants
of interest are
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CA 02736909 2011-03-10
of the organosilaane is introduced. Although this may allow for greater rates
of introduction, the
process would still be slow, and fine control is still required.
An alternative method of introducing the organosilane is to form an
organosilane mixture by pre-
diluting the organosilane in a material miscible with the system 1 contents
and with the
organosilane. This mixture is then introduced into the system 1 using one of
the methods
discussed above.
In the preferred embodiment, the organosilane is mixed with a lubricant to
form the organosilane
mixture. This has an additional benefit of maintaining lubricant in close
proximity to the
organosilane at'all times, For increased flow control the viscosity ofthe
organo'silane mixture
can be maintained within a selected range. Organosilane on its own has a very
low viscosity (for
example <1 cst, at 40 C). This in part results in difficulty in controlling
the flow of
organosilane.
An additional method of injection would include the use of a fluid injector
that can inject the
mixture into the working low side system of the unit in small increments, an
example include a
RevolverW sold by Cliplight Manufacturing Company of Toronto, Canada. The
Cliplight device
allows for approximately 0.04 of an ounce to be measured in at any one time.
Additional
amounts of the mixture depending on the system size could be accurately added.
This would be
an acceptable method of injection allowing only small amounts of the mixture
into the suction
gas path and thus preventing possible liquid slugging to the compressor 5.
Also, there are other modifications that could be made to an injection device.
For example, a
filter 16A could be added, as shown in FIG. 1, to the hose apparatus 16 to
filter out any particles
injected from the system 1 when charging the canister 15.
Further details of the preferred embodiment will be described.
Referring to the FIGS., the use of sealants based on organosilanes for
refrigeration and air
conditioning systems 1 is made possible by control of the rate of introduction
and viscosity of the
sealant mixture within certain ranges. An appropriate choice oforganosilane
sealant is made to
allow effective sealing of small pinhole size leaks in the air conditioning or
refrigeration system
1.
Preferably, the organosilane is chosen with several criteria in mind. The
organosilane is miscible
in the lubricant fluid; it is typically a monomer, but may contain oligomers,
capable of forming a
solid polymer with itself or other chosen organosilanes in the presence of
moisture under the
conditions of the particular application. The reaction rate of the
organosilane or mixture of
organosilanes is sufficient to form an effective seal at the sites of the
leak. The polymeric seal is
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CA 02736909 2011-03-10
chosen to be sufficiently strong to maintain an effective barrier to prevent
further leakage of
refrigerant from the system 1. Also, the organosilanes are chosen to be stable
in the absence of
moisture, be non-corrosive and otherwise inactive to the components of system
1 and be
generally environmentally acceptable. Further, the nature and injected
quantity of the
organosilanes is chosen, to the extent that it would interefere with the
refrigerant and/or
lubricant, so that such interference remains consistent with the normal
operation of the
refrigerant fluid e.g. vaporization and liquefaction characteristics.
The organosilane is combined with a miscible lubricant at particular ratios to
provide the proper
mixture viscosity for injection to the refrigerant system i to prevent bearing
seizure. Specific
orifice 20 (see FIG. 3) sizes are selected for an apparatus to ensure that the
mixture is injected at
flow rates required to prevent liquid slugging and subsequent compressor 5
shutdown or failure.
In addition, certain procedures are perfofined for effective introduction of
the mixture. Injection
procedures are also described that reduce risk of temporary or catastrophic
equipment shutdown.
These include allowing the sealant mixture to cool to ambient temperatures
before injection.
Cooling permits better control over the flow rate of the organosilane
component of the mixture.
Preferred components and compositions for the organosilane include those
described in U.S.
Patent No. 4,237,172 issued 2 December 1980 to Packo et al under title Sealing
Leaks by
Polmerization of Volatilized Aminosilane Monomers; United States Patent No.
4,304,805 issued
8 December 1981 to Packo at al under title Sealing Leaks by Polmerization of
Volatilized
Aminosilane Monomers; U.S. Patent No. 4,33 1,722 issued 25 May 1982 to Packo
at al under
title Sealing Leaks by Polymerization of Volatilized Organosilane Monomers ;
and U.S. Patent
No. 5,417,873 issued 23 May 1995 to Packo under title Sealant Containing
Partially Hydrolized
Tetraalkoxy Silane, for Air Conditioning and Refrigeration Circuits.
Particular compositions for the organosilane are dependent on the selected
criteria from those set
out above. However the general nature of the organosilane can be represented
as
(Rt)(R2)Si(R3)(R4) where the preferred nature of the radicals is that
RI is an alkyl radical of 1-4 carbon atoms or vinyl or -OH
R2 is R1 or-OR1 or NH(R1) or-N(Rt)2 or-R1NHRtNH2
R3 is R1 or -OR, or NH(R1) or N(Rlh or -R1NHR1NH2
R4 is R1 or-OR1 or NH(R1) or N(Rt)2 or-R1NHRjNH2
Other components which can be included are oligomers of the monomeric silanes
described.
One such example are the siloxanes:
AMENDED SHEET
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[0044] With the limit that the final sump viscosity should not be lowered more
than 10%
compared to the original sump viscosity, then based on Equation 2, this
amounts to a
requirement that:
exp(xinj.ln rlinj + xsõmp.ln 1lsump + C) > 0.91lsump (Equation 3)
Since the mole fraction of any component depends on the weight percent present
for that
component, then Equation 3 provides a basis for determining the desired
viscosity and quantity
limits on the injected material.
[0045] Of course, Equation 3 can be adjusted based on any selected limit on
final
viscosity other than the 90% of original sump viscosity used here.
exp(xinj=ln r1inj + xsump=ln rlsump + C) > Fr. rlsump (Equation 4)
where Fr is the desired fraction of the original sump oil viscosity to be
maintained.
[0046] Examples of these predicted effects using Equation 2 are shown for
various
situations in Table 2.
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TABLE 2
VISCOSITY EFFECTS OF LUBRICANT /ORGANOSILANE MIXTURES ON
REFRIGERATION SYSTEMS
1 2 3 4 5 6 7 8
Lubricant Lubricant System Volume Viscosity of Weight Weight % Final
Viscosity Viscosity Oil Injected Lubel % Organosilane Oil
in system injected Capacity Organosila Lubricant Injected Sump
(oz.) ne Injected Injected Viscosit
(est. @ (est. @ (oz.) y
40 C) 40 C) (est. @ 40
C) (est. @
40 C)
1 32 - 10 1 0.6 0 100 18.7
2 10 32 10 1 10 76 24 9.9
3 32 32 10 1 15.6 87.5 12.5 29.9
4 32 32 30 1 10 79 21 30.7
32 32 30 1 7 71 29 30.2
8 32 32 50 1 10 79 21 31.2
9 32 32 50 2 10 79 21 30.4
32 32 50 3 10 79 21 29.7
11 46 32 65 3 10 79 21 42.2
12 68 32 512 3 10 79 21 66.9
5
[0047] As seen in row 1 of Table 2, the injection of I oz. of these particular
organosilanes causes a drop in viscosity in a 10 oz. sump from 32 to below 19
cst. (all viscosities
will refer to 40 C). A maximum drop in sump viscosity of about 10% is
generally acceptable,
corresponding to 29 cst. limit for units designed for 32 cst. viscosity oils.
In such small systems,
10 our testing indicates that this low viscosity material would likely cause
bearing seizure. Rows 2
and 3 of Table 2 show that injection of organosilane blends with a 32 cst
lubricant can provide
satisfactory results. In row 2, it is indicated that 1 ounce of a mixture
containing about `/4 ounce
of an organosilane and 3/4 ounce of a POE lubricant having a viscosity of 32
cst. at 40 C combine
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CHARACTERISTICS OF TYPICAL REFRIGERATION AND AIR CONDITIONING
SYSTEMS
SYSTEM TYPICAL SUMP CAPACITY OIL VISCOSITY
CAPACITY APPLICATION (OZ) RECOMMENDATION
(TON/HR.)* (CST. @ 40 C)
300 -18,000 BTU/hr Residential 10 - 30 10 - 32
Commercial
refrigeration, air
conditioning
18,000 Residential 30 - 65 32, 46
- 60,000 BTU/hr Commercial
refrigeration, air
conditioning
60,000 BTU/hr Commercial, 65- 512 32,46, 68
(5 ton) - 25 industrial
refrigeration and
air conditioning
25 + Industrial 65 - 900 and greater 46, 68 up to 220
applications
*1 ton represents approximately 12,000BTU
Given the wide range of possibilities represented in Table 2, it was found to
be convenient to
evaluate the effect of various injected lubricant viscosities,
lubricant/organosilane ratios, oil
sump size and oil sump viscosity by calculation of these factors. This process
guides selection of
the preferred viscosity and quantity of the injected mixture. The following
serves to illustrate the
process only.
The viscosity of a binary mixture of similar materials is often related to the
viscosity of the
components by the relation:
In imix = xl.ln rll + x2.ln 112 + C (Equation 1)
where: In is the natural logarithm
r)miX is the viscosity of the mixture
ill, 112 are the viscosities of components 1 and 2 and
xl and x2 are the corresponding mole fractions
C is a constant dependent on the nature of the components.
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to a minimum viscosity injected of 17 cst. corresponding to just over 1/2 oz
of silane in a 3 oz.
total charge to maintain final viscosity above 61.2 cst.. Dropping the
injected charge to 2 oz.
actually yields little benefit in organosilane injected in this case and also
has a much lower
injected viscosity for the injected material at the minimum injected
viscosity.
TABLE 3
DEPENDENCY OF INJECTED VISCOSITY ON REFRIGERATION AND AIR
CONDITIONING SYSTEMS
Sump size (oz.) Lubricant Grade Injected Amount Minimum Maximum
in Sump oz * Viscosity organosilane
Injected ** injected (oz)
(cst. at 40 C)
32 1 12 0.175
30 32 3 12 0.525
65 46 3 8.2 0.81
65 68 3 17 0.51
65 68 2 7.6 0.6
* lubricant of 32 cst. at 40 C combined with organosilanes
* * to 90% viscosity limit in sump viscosity
10 [0050] It is not required that the viscosity of the injected lubricant be
the same as the
lubricating oils in the system, only that there be effective injection of the
sealant and non-
deleterious longer term effects. The effect of increasing the viscosity of the
injected mixture
using higher lubricant viscosity, however, is relatively small as seen in
Table 4 which shows the
effect of introducing an organosilane/polyolester (POE) lubricant mix into a
unit designed to
operate with a lubricant at 32 cst.
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TABLE 4
EFFECT OF VARYING LUBRICANT VISCOSITY OF INJECTED ORGANOSILANE
MIXTURE INTO SYSTEM USING 32 CST. POE LUBRICANT
POE Wt.% POE Wt. % Viscosity Final System
Viscosity Organosilane Injected Viscosity
(cst@40 C) Mixture (cst. @ 40 C)
(cst@40 C)
1 32 79 21 10 28.5
2 46 79 21 13 29.0
3 68 79 21 17 29.6
*10 oz. sump capacity, 1 oz. injected
[0051] The application of Equations 1-4 allows calculation of acceptable
mixtures of
lubricant and organosilane to be used for any specific situation in terms of
the size of the unit (oil
capacity) and viscosity of the sump oil. The minimum ratio of lubricant to
organosilane is
predetermined by the minimum allowable injected viscosity and the individual
viscosities of the
lubricant and organosilane in the injected mixture. The viscosity of mixtures
relate exponentially
to component viscosities and in ratios dependent on mole fractions rather than
simple weight
fractions. In addition, it is recognized that the molecular nature of the
lubricant affects the
relation between viscosity and molecular weight so that the examples presented
here are not to
be taken as representing the only possible trends.
[0052] These examples demonstrate that the application of the techniques
described
herein is not limited to fluids of a particular viscosity except as related to
effective injection and
longer term operation of the system particularly as related to the compressor.
[0053] Some systems operate with a lubricating subsystem that is independent
of the
refrigerant. In this case, organosilanes alone are injected into the
refrigerant circuit.
[0054] It is also possible to inject organosilanes alone in systems where the
lubricant is
carried by a miscible refrigerant. In this case, the organosilane alone, or in
a mix with lubricant,
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can be injected into the high side of a refrigeration system while the unit is
operating up to a
maximum of 6% per minute of the systems total oil content. For example, a
system with a 50 oz
oil capacity could be injected up to a rate of 3 oz/ min. of organosilanes.
The quantity injected
remains limited by the foregoing based on limits to reduction in sump
viscosity. After 6% is
exceeded, there will be a decreased level of compressor performance due to
higher discharge
temperature resulting in possible decreased oil return to the low side of
compressor eventually
damaging the shaft bearings. Injecting at a rate above 8% per minute of the
total oil system's
content will likely result in loss of effective heat transfer, decreased
bearing lubrication and
possible catastrophic compressor failure. It is recognized that the 6% and 8%
amounts are for
typical systems and there are likely systems that can exceed these thresholds
while falling within
the principles described herein.
[0055] These methods can be utilized regardless of the class of compressor.
[0056] In the preferred embodiment, injection of the lubricant/organosilane
mixture is
accomplished through the use of a sealed canister 15 and a coupling hose
assembly 16 that is
first fitted to the canister 15 and then to the inactive refrigeration system
1 through an injection
port 17 on the low-pressure side of the compressor 5.
[0057] The canister 15 can be pressurized before the canister 15 is sealed.
The pressure
in the canister 15 causes the sealant mixture to enter the system I when the
canister is opened,
there is fluid connection to the system 1, and the system 1 is running to
cause "low side" 10
pressures to drop. In test environment the canister 15 was not pre-pressurized
as will be
explained below; however, a charged pressure of 100 psig was found to be
acceptable for
allowing the sealant mixture to enter the system I in the test environment,
where the low side
pressure was 77 psig as mentioned previously.
[0058] Alternatively, the sealed canister 15 can have a pressure near, at or
below
ambient. The canister 15 can be charged (pressurized) using the system 1
pressure. First the
system I is turned off and pressure within the system 1 is allowed to
equalize. In the test
environment, this results in an overall system 1 pressure of approximately 100
psig. The canister
15 is then placed in fluid connection with the system 1. This causes the
canister 15 to be
pressurized to approximately 100 psig. The system 1 can then be run. This
causes the pressure
in the low side 10 to drop. The higher pressure within the canister 15 causes
the sealant mixture
to enter the system 1.
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[0059] Using a non-pressurized canister 15 as described above is preferred as
such
containers are less hazardous. This means, for example, that they are
transportable without
having to comply with the strict transportation regulations applicable to
pressurized containers.
[0060] More details of a preferred method used in the test environment will
now be
described. Before use, the canister 15 is at a pressure of about 20 inches of
mercury vacuum.
The vacuum is a result of packaging processes that ensure much of the air is
removed from the
canister 15 before it is sealed. Hose assembly 16 is evacuated and then the
canister 15 seal is
broken using a can-tapper 21 that is built into the hose assembly 16 in such a
way that refrigerant
mix from the system 1 is allowed into the canister 15 until pressures are
stabilized, and the
canister 15 is charged. The can-tapper 21 has a manually operated valve (see
valve handle 25
below) for fluid connection (open) and fluid disconnection (closed) of the
canister 15 from the
system 1. It also has a tapping pin (operation described below) for unsealing
the canister 15
(which is also required for fluid connection when the canister 15 is sealed).
The can-tapper 21 is
also a fitting for sealed fluid connection to the canister 15, typically by
way of compatible
threads in the can-tapper and on the canister 15, and corresponding seals,
such as a rubber gasket
or an o-ring.
[0061] The addition of canister 15 contents to the refrigerant system I is
controlled to a
maximum flow rate of about 6 cc/sec which in the preferred embodiment is
obtained through the
use of orifice 20 having a maximum diameter of about 0.06 in. One such
arrangement is shown
in Figure 2. Although there is no minimum flow rate required, the minimum
orifice size should
be about 0.02 inches in diameter to avoid orifice plugging due to
contamination from particles
from system I as the canister 15 is charged. This minimum restriction could be
removed by the
inclusion of a filter, such as filter 16A of FIG. 1, in the injection hose
between the fitting 22 and
the injection port 17.
[0062] The orifice 20 is located within fitting 22 of FIG. 2. In the test
environment an
orifice of 0.0292 inches diameter was successful. The hose assembly 16 has a
hose 23 between
the can-tapper 21 and the fitting 22.
[0063] Surprisingly, it has been found that the action of filling the canister
15 with
refrigerant upon tapping the canister 15 and opening a valve in the tapper 21
causes the canister
15 and its contents to heat to temperatures well above ambient. Temperatures
of 135 F were
encountered in tests. This may affect the flow rate of the organosilane as it
enters the system 1.
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In the preferred embodiment, the canister 15 is fluidly disconnected after
charging and the
system 1 is run. Then the canister 15 is again fluidly connected to the system
1. This allows the
system 1 to achieve full low side 10 pressure that will best allow the sealant
mixture to enter the
system 1.
[0064] As there is a period of time between disconnecting and re-connecting
the canister
15, the canister 15 should be allowed to cool to at or near ambient
temperature while still fluidly
connected to the non-running system 1. If not, then charge in the canister 15
may be lost as
pressure will drop with the temperature in a closed canister 15.
[0065] Also, the contents of the canister 15 should enter the cooler suction
gas stream
with as close to ambient temperature of the system 1 as possible so as not to
effect the volume of
the cooler gas going to the compressor 5. A compressor 5 generally requires at
least a four
percent return of oil to maintain adequate lubrication on metal-to-metal
surfaces. In practical
terms, a residential system 1 operating at a suction pressure of 70 psig will
typically have a
corresponding evaporator 3 saturation temperature of 41 degrees F. If the
system 1 is operating
satisfactorily then the actual suction line 10 temperature should be
approximately 51 degrees F.
This is due to an extra 10 degrees of superheat picked up during the
expansion. Elevating this
temperature momentarily could cause an erratic expansion of gas followed by
contraction
resulting in a cavitation effect on the compressor 5. Experiments show a
fluctuation in low-side
and high-side pressures when the product has not been sufficiently cooled.
Rapid changes of
pressure can damage compressor valves and discharge excess oil from the
compressor sump into
the high-side line. This excess oil will begin to' log and affect downstream
conditions such as
temporary high discharge pressures accompanied by temporary low- side
pressure. The
percentage of required oil to be carried back could lower to the point of not
supplying adequate
lubrication to metal-to-metal contact causing damage to the compressor 5
[0066] These and other steps in the procedure of the preferred embodiment are
described
in Table 5.
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enter the system 1 in the test environment, where the low side pressure was 77
psig as mentioned
previously.
Alternatively, the sealed canister 15 can have a pressure near, at or below
ambient. The canister
15 can be charged (pressurized) using the system 1 pressure. First the system
1 is turned off and
pressure within the system 1 is allowed to equalize. In the test environment,
this results in an.
overall system I pressure of approximately 100 psig. The canister 15 is then
placed in fluid
connection with the system 1. This causes the canister 15 to be pressurized to
approximately 100
psig. The system 1 can then be run. This causes the pressure in the low side
10 to drop. The
higher pressure within the canister IS causes the sealant mixture to enter the
system 1.
Using a non-pressurized canister 15 as described above is preferred as such
containers are less
hazardous. This means, for example, that they are transportable without having
to comply with
the strict transportation regulations applicable ,to pressurized containers.
More details of a preferred method used in the test environment will now be
described. Before
use, the canister 15 is at a pressure of about 20 inches of mercury vacuum.
The vacuum is a
result of packaging processes that ensure much of the air is removed from the
canister 15 before
it is sealed. Hose assembly 16 is evacuated and then the canister 15 seal is
broken using a can-
tapper 21 that is built into the hose assembly 16 in such a way that
refrigerant mix from the
system I is allowed into the canister 15 until pressures are stabilized, and
the canister 15 is
charged. The can-tapper 21 has a manually operated valve (see valve handle 25
below) for fluid
connection (open) and fluid disconnection (closed) of the canister` 15 from
the system 1.. It also
has a tapping pin (operation described below) for unsealing the canister 15
(which is also
required for fluid connection when the canister 15 is sealed). The can-tapper
21 is also a fitting
for sealed fluid connection to the canister 15, typically by way of.compatible
threads in the can-
tapper and on the canister 15, and corresponding seals, such as a rubber
gasket or an o-ring.
The addition of canister 15 contents to the refrigerant system 1 is controlled
to a maximum flow
rate of about 6 cc/sec which in the preferred embodiment is obtained through
the use of orifice
20 having a maximum diameter of about 0.06 in. One such arrangement is shown
in Figure 2.
Although there is no minimum flow rate required, the minimum orifice size
should be about 0.02
inches in diameter to avoid orifice plugging due to contamination from
particles from system 1
as the canister 15 is charged. This minimum restriction could be removed by
the inclusion of a
filter, such as filter 16A of FIG. 1, between the fitting 22 and the injection
port 17.
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assembly by changing position while under pressure. Having the gas first pass
through the mixture also helps to mix the contents of the mixture if possible
stratification occurred between the organosilane and the miscible lubricant.
9. Turn handle 25 clockwise until it stops, isolating charged canister 15 from
A/C or
R system 1.
10. While holding the canister 15 upside down turn on A/C system 1. Slowly
turn
handle 25 counter-clockwise gradually releasing sealant into the system 1.
This
should take approximately 3 to 5 minutes.
Releasing sealant too quickly could result in liquid slugging. Shake canister
15 gently
to determine when empty. If all of the contents in canister 15 are not emptied
after 5
minutes then turn canister 15 tapper 21 piercing handle 25 clockwise until it
stops.
Turn of A/C or R system 1 and repeat steps 8, 9 and 10.
11. Once canister 15 is empty remove female fitting 22 from low side service
port 17,
then shut down A/C system 1. Allow system 1 pressure to equalize. The A/C or R
system 1 should be left off for approx. 5 minutes. This procedure allows
product
to mix with systems 1 oil and when the system 1 is restarted will allow for
equal
distribution throughout system 1.
[0067] In typical experiments performed during the course of the current
development, a
canister was used with approximate dimensions of 5 cm. diameter and 10 cm
height and this
contained about 89 cc (3 oz.) of a lubricant/organosilane mix. With the
canister 15 filled with
refrigerant and inverted at ambient conditions, this would produce a lower
column of liquid
about 4.5 cm. high covered with a gaseous column of refrigerant 5.5 cm. in
height. The
pressure exerted by the refrigerant was around 120 psi and this was then
injected into a system
operating at 66 psi. Thus the driving force for injection of the liquid phase
into the system was
about 54 psi.
[0068] In an ideal situation the equation
Q=CdxAx(2xAP/p)'~2 (Equation5)
could be applied where
Q is flow rate
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Cd is the coefficient of discharge
AP is the differential pressure, and
p is the fluid density.
[0069] Experiments in transparent glass vessels showed the expected result
that the liquid
actually contained bubbles of refrigerant. Nevertheless, considering the ideal
one-phase flow
situation, equation 5 can be applied to obtain at least a model of the
injection process. For an
orifice of 0.029 inches in diameter, the canister was found to empty in about
90 sec. This
corresponds to a coefficient of discharge of 0.37. Experiments showed that
satisfactory
injections could be made using orifice sizes up to about 0.060 inches. This
corresponds to an
initial flow rate of 6 cc/sec and a final flow rate of 4 cc/sec for the last
fraction of the liquid.
[0070] Considerations of system size relate to the effect on viscosity of the
lubricant in
the system which tends to increase with the size of the system itself. System
size is typically
measured in tons - a measure if the cooling capacity of the system 1 (1 ton is
equivalent to the
delivery of 12,000 BTU cooling capacity per hour). General consideration of
these factors
provide "rules of thumb" to guide quantities of organosilane mixture to be
added. For example,
one scenario suggests for units above 5 tons capacity, a mixture about 7-8
est. @ 40 C is
appropriate and about 10 est. for smaller units. The actual total quantity of
lubricant/silane mix
is dependent on ensuring effective delivery of sealant material to the situs
of the leak. Typically,
units below 1 ton should require about 1/8 - 1/4oz. of organosilane and larger
units'/2 -1 oz. The
total quantities of the mixture will also depend on the practicality of the
details of the injection
system being used. The viscosity of the mixture and the quantity of
organosilane can be adjusted
within these general guidelines.
EXAMPLES
[0071] The principles described herein are further illustrated in the
following examples,
but the scope is not limited by these examples.
Test Methods
[0072] The general test apparatus is shown schematically in Figure 2 and
represents the
basic components of a typical refrigeration system 1. A refrigerant gas (R-22
was used in the
test environment; however, R134a and other refrigerants could also be used) is
circulated by
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means of a hermetically sealed electric motor and compressor 5. The gas is
condensed to liquid
by means of a condenser 7; the liquid passes through valve 9 and then through
an evaporator 3
where the liquid is regenerated to a gas accompanied by the desired cooling
effect. The gas then
returns to the compressor 5 for repeating cycles of the process.
[0073] Sealant and mixtures were added by the procedure represented in Table 1
to the
low pressure (suction) side of the compressor 5.
Sealant
[0074] In the base case, simple injection of the organosilane sealant in the
low side port
17 was shown not to be appropriate for hermetically sealed refrigerant
compressor 5 systems 1.
Example 1
[0075] In a laboratory test, a 2 ton vertical hermetic single phase
refrigeration system 1
with a full refrigerant load was loaded to simulate an ambient temperature
above 32 C. An
organosilane mixture was injected into the circuit and the compressor 5 failed
after only one
further hour of operation due to bearing seizure.
Example 2
[0076] In another set of tests, two 2 ton single phase piston type systems 1
were injected
with a mixture of commercial organosilane and immiscible lubricating oil.
Failure occurred in
one system I after 10 minutes and after 1 hour in the second case.
Example 3
[0077] Two small 10,000 BTU packaged refrigerant systems 1 were tested. Both
failed
within 10 hours. Subsequent examination of these systems 1 showed that failure
was due to lack
of oil to the upper sleeve bearing, referred to as the compressor 5 outboard
bearing.
Sealant Viscosity
[0078] The effect of sealant viscosity was investigated by varying the ratios
of
organosilane and lubricating oil in the sealant mixture.
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CA 02736909 2011-03-10
Experiments in transparent glass vessels showed the expected result that the
liquid
actually contained bubbles of refrigerant. Nevertheless, considering the ideal
one-phase
flow situation, equation 5 can be applied to obtain at least a model of the
injection
process. For an orifice of 0.029 inches in diameter, the canister was found to
empty in
about 90 sec. This corresponds to a coefficient of discharge of 0.37.
Experiments
showed that satisfactory injections could be made using orifice sizes up to
about 0.060
inches. This corresponds to an initial flow rate of 6 cclsee and a final flow
rate of 4
cc/sec for the last fraction of the liquid.
Considerations of system size relate to the effect on viscosity of the
lubricant in the system
which tends to increase with the size of the system itself: System size is
typically measured in
tons - a measure if the cooling capacity of the"system 1 (1 ton is equivalent
to the delivery of
12,000 BTU cooling capacity per hour). General consideration of these factors
provide "rules of
thumb" to guide quantities of organosilane mixture to be added. For example,
one scenario
suggests for units above 5 tons capacity, a mixture about 7-8 cat. a@ 40 C is
appropriate and
about 10 cst for smaller units. The actual total quantity of lubricant/silane
mix is dependent on
ensuring effective delivery of sealant material to the situs of the leak.
Typically, units below 1
ton should require about 1/8 -1/4oz. of organosilane and larger units V2 -1
oz. The total
quantities of the mixture will also depend on the practicality of the details
of the injection system
being used. The viscosity of the mixture and the quantity of organosilane can
be adjusted within
these general guidelines.
EXAMPLES
The principles described herein are further illustrated in the following
examples, but the scope is
not limited by these examples.
Test Methods
The general test apparatus is shown schematically in Figure 2 and represents
the basic
components of a typical refrigeration system 1. A refrigerant gas (R-22 was
used in the test
environment; however, R134a and other refrigerants could also be used) is
circulated by means
of a hermetically sealed electric motor and compressor 5. The gas is cooled to
liquid by means
of a condenser 7; the liquid passes through valve 9 and then through an
evaporator 3 where the
liquid is regenerated to a gas accompanied by the desired cooling effect. The
gas then returns to
the compressor 5 for repeating cycles of the process.
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Sealant and mixtures were added by the procedure represented in Table 1 to the
low pressure
(suction) side of the compressor 5.
Sealant
In the base case, simple injection of the organosilane sealant in the low side
port 17 was shown
not to be appropriate for hermetically sealed refrigerant compressor 5 systems
1.
Example 1
In a laboratory test, a 2 ton vertical hermetic single phase refrigeration
system 1 with a full
refrigerant load was loaded to simulate an ambient temperature above 32 C. An
organosilane
mixture was injected into the circuit and the compressor 5 failed after only
one further hour of
operation due to bearing seizure.
Example 2
In another set of tests, two. 2 ton single phase piston type systems 1 were
injected with =a mixture
of commercial organosilane and immiscible lubricating oil. Failure occurred in
one system 1
after 10 minutes and after 1 hour in the second case.
Example 3
Two small 10,000 BTU packaged refrigerant systems 1 were tested. Both failed
within 10 hours.
Subsequent examination of these systems I showed that failure was due to lack
of oil to the
upper sleeve bearing, referred to as the compressor 5 outboard bearing.
Sealant Viscosity
The effect of sealant viscosity was investigated by varying the ratios of
organosilane and
lubricating oil in the sealant mixture.
Example 4
Mixtures of organosilane sealant (viscosity < I cst@40 C) and immiscible
compressor 5 oil
(viscosity 6Scst. @ 40 C) caused bearing seizure in all five cases in Examples
1,2, and 3.
Example 5
Use of straight organosilane mixture caused compressor 5 bearing seizure
within one hour in a
test with the 2 ton system 1.
Example 6
A test was performed using a 0.029 in. orifice 20 to inject a 3 fl. oz.
mixture consisting of
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CA 02736909 2011-03-10
3 parts of a commercial polyolester refrigeration compressor 5 oil and 1 part
of an organosilane
sealant such that the mixture had a viscosity of 8 cst. @ 40 C. The oil
capacity of the single
phase hermetically sealed 2 ton system 1 was 55 oz. The system 1 was injected
with the
organosilane%oil mixture with no change in amperage of the motor, indicating
no liquid slugging.
The system 1 was run successfully for 12 days until shut down deliberately.
Example 7
A test was performed similar to that described in Example 6 except that the
mixture injected
consisted of 2 parts of the commercial polyolester refrigeration compressor 5
oil and I part of
the organosilane sealant to give a mixture viscosity of 11 cst. @ 40 C.
A start/stop test was run with 60 start/stops over a 3 1/2 hr. period. This is
a severe test due to the
surge of electricity required to start the spinning of the rotor of the motor
and also due, to some
initial loss of oil from the inboard bearing at each start. The test was
successful with no change
in operating variables and the system 1 ran for an additional 13 days with
excellent operation
until it was deliberately shut down.
Rate of Injection
Controlled rate of introduction of the organosilane/oil mix was investigated
as a variable. The
hose assembly shown in Figure 2 was used to introduce mixtures into a 2 ton
refrigeration
system 1 fitted with an oversized 2 % ton condenser 7. The can tapper 21 at
one end of the hose
seals and punctures a canister 15 containing the sealant. The fitting 22 at
the other end is
attached to the refrigeration system 1 and low side port 17 is opened to allow
the sealant mixture
to enter the refrigeration system 1 through an orifice 20. The size of this
orifice 20 affects the
injection rate of the sealant.
Example 8
Using an orifice 20 size of 0.094 in., it was found that the rate of addition
of the sealant/oil
mixture caused fluctuations in suction and discharge pressure of the system 1.
As previously
mentioned this upset condition can cause the compressor to momentarily
discharge from the
sump into the discharge line causing logging possibly affecting oil return to
the suction side of
the compressor and eventual bearing failure. Any needle valve associated with
the orifice 20
would not allow sufficient additional fine control to overcome this problem.
Example 9
A capillary tube was used to control introduction of the sealant. An orifice
20 size of
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Charge 1.59 ounces
Procedure : Bullet piercing valve installed
Conditions : Base of compressor - 90 F
.88 AMPS
Suction temp - 70F
Discharge temp - 102F
Inside - panel - freezer - 4F to 5F
Allow 3 min to fill
5 min cool down
Allow 5 min run then switch off
After stop time, put in operation
[0092] After 90 days, the system continued to run successfully.
Injection Procedures
[0093] As outlined in Table 1, the typical procedure used to inject mixtures
into the
refrigeration system 1 involves opening the canister 15 containing the
oil/organosilane mixture to
a low pressure port 17 just prior to the non-operating compressor 5. The
mixture is at a pressure
near 20 inches of mercury vacuum before opening to the refrigerant system 1
which is typically
near 100 psig. The entry of the refrigerant into the mixture in the canister
15 causes a heating
effect and raises the canister 15 and contents to about 25 C above ambient.
Single phase
systems I are particularly susceptible to this effect since entry of the hot
mixture into the
refrigeration system I would cause momentary heating of the suction vapor and
a decrease in the
vapor's density. This in turn affects the ability of the vapor to cool the
motor and other
mechanical parts.
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[0094] Therefore as part of the procedure to inject the mixture from the
canister 15, it is
important to allow the refrigerant/ sealant mixture to cool before
introduction into the
refrigeration system 1.
[0095] The use of orthoformates as hydrolyte drying agents has been discussed
above.
Example orthoesters (including orthoformates) may be one or some of
trimethylorthoformate
(TMOF), trimethylorthoacetate (TMOA), triethylorthoformate (TEOF),
triethylorthoacetate
(TEOA). Triisopropylorthoformate (TIPOF), or triisopropylorthoacetate (TIPOA).
As a further
example, other orthoformates with an aryl substituent such as
triethylorthobenzoate (TEOB) may
be used.
[0096] Several patents have described the general application of orthoformates
as drying
agents for refrigeration systems or with specific refrigerant base oil
compositions. US 5,300,245
issued April 5, 1994 by Sawada et al under the title "Working fluid
composition having ketone-
containing compound for use in refrigeration system" mentions the application
of orthoesters,
acetals etc. US 5,395,544 issued March 7, 1995 by Hagihara et al under the
title "Ester-
containing working fluid composition for refrigerating machine" describes a
similar potential
use of orthoesters apparently in the 2.5-15 wt% compositional range. US
5575944 issued
November 19, 1996 by Sawada et al under the title "Acetal-containing working
fluid
composition for refrigerating machine" similarly describes the use of
orthoesters and acetals as
drying agents. US 5720895 issued February 24, 1998, US 5,869,702 issued
February 9, 1999
and US 5922239 issued July 13, 1999 by Nakagawa et al under the title "Polyol
ether
derivatives and production methods therefore" mention the potential use of
orthoesters
apparently in the range of 0.5-50 wt% based on using refrigeration base oils
with particular
compositions.
[0097] These previous disclosures suggest the use of the refrigerant oil and
additives
such as orthoformates as initial system charges only - not to the addition of
orthoformates or
other orthoesters to charged, pressurized systems. Typically, this initial
charging of a system
involves injection of the oil and additives into the system, followed by
evacuation of the system
to remove volatile materials including water prior to addition of refrigerant.
The system is then
pressurized (typically using the compressor 5) to complete the charging
process. Orthoformates,
typically highly volatile, are removed by this evacuation procedure and
therefore may not be
present at levels to be effective as hydrolytic drying agents after system
start-up.
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[0098] The present methods describe a series of options in which the
orthoformate is
efficiently added after system charging to remove accumulated water during
operation of the
system. Addition of a refrigeration base oil/orthoformate composition as an
initial charge is
impractical. The presence of a minimum amount of base oil such as polyester is
required to
provide sufficient lubrication for the system. Replacing base oil on the
initial charge with
significant amounts of orthoester sacrifices the required lubrication
performance. Adding
ineffectually small amounts of the orthoester in an initial charge limits the
water reduction
performance of the orthoester component. The present methods of adding
orthoester and other
additives allow customized addition of hydrolyte to the particular system. The
present methods
also ensure that the orthoesters are mixed throughout the a/c or refrigeration
system and not
added only to the oil sump. This ensures reaction with water wherever it is
present throughout
the a/c or refrigeration system.
[0099] The orthoformate may be introduced into the a/c or refrigeration system
alone or
in combination with other additives by one of a variety of techniques such as
for example from a
vacuum packed canister, a pressurized refrigerant can, a syringe or piston
operating device, or
from an in-line canister, for example using the methods otherwise described
herein for. injection
of additives.
[00100] One method of introducing the orthoformate includes introducing the
orthoformate at a time prior to the injection of another additive that is
unstable in the presence of
moisture followed by injection of the other additive at a time before it is
known that the
orthoformate is fully reacted with moisture in the system. This can include
for example the
organosilane sealants previously described herein. It can also include dye and
dye mixtures
typically injected for use in leak detection as previously described herein.
Such dyes may
include perylene or napthalimide for example. The dye may be carried in a
lubricant, such as
those described previously, such lubricants can be reactive with moisture. As
an example,
polyolester is often utilized as a lubricant and can be unstable in the
presence of moisture.
[00101] It has been found that orthoformates generally react more quickly with
moisture
than organosilanes, and the dye and dye mixtures typically utilized in air
conditioning and
refrigerant systems. This allows the orthoester to be injected at the same
time. Thus, the
orthoesters can be included together with the other moisture reactive additive
(sealant) in a single
vessel for contemporaneous injection into the system. Since the orthoester
reacts with water
before the organosilane, the formation of deleterious silicone polymers within
the system is
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avoided. Alternatively, the orthoformate or other orthoester can be injected
into the system at a
time prior to the injection of the other additive followed by injection of the
other additive at a
time before it is known that the orthoformate is fully reacted with moisture
in the system.
Previously, it is typically recommended to run systems for a period of time
after injection of a
drying agent to ensure reaction of the agent with moisture prior to taking
other actions dependent
on the activity of the drying agent. This can be hours or a day for larger
systems. As an example
embodiment of the methods described herein the other additive can be injected
immediately after
or contemporaneously with the orthoformate. Where, for example, a technician
uses a hose
connected to the system to inject the orthoformate, the technician could use
the same hose for
injection of the other additive immediately thereafter while leaving the hose
connected to the
system. These methods can provide simple and quick methods of injecting a
moisture-reactive
hydrolytic drying agent that provides or remains a fluid, for example, an oil-
soluble fluid, upon
reaction with water. These methods can also provide effective performance of
the additive.
[00102] Undesired reaction of additives with moisture within an air
conditioning or
refrigeration system can be deleterious to the system for at least some of the
reasons discussed
previously. As an example, undesired reaction of an organosilane away from a
leak site can
reduce the effective amount of the sealant for reaction at a leak site. It has
been found that
sealant (such as organosilane) is often injected in amounts far greater than
are required for leak
sealing in a moisture-free system. This can be seen for example when sealant
is found in oil
sludge when a system is opened up for examination. In addition to requiring
additional sealant
undesired reactions of sealant with moisture can result in contamination of
the system, such as
might cause blockages and otherwise reduce the efficiency of the system.
Undesired reaction of
dye and/or carrying lubricant can cause the formation of crystal and gel-like
substances within
the system. Such substances can also cause blockages or otherwise negatively
affect the
operation of the system.
[00103] When orthoformates or other orthoesters react with moisture the result
is typically
a liquid that is soluble in oil typically found in air conditioning and
refrigeration systems. Some
non-orthoformate drying agents that have been used in air conditioning systems
can themselves
react with moisture to form globs that trap particulate and can lead to
blockages.
[00104] If a leak exists within the system then the amount of drying agent at
the leak situs
will be overcome by incoming moisture, immediately or over time, and the
sealant will react
with the moisture at the situs to repair the leak. Thus, the sealant can
operate to seal the leak
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more effectively. Contamination from the sealant is less likely. It is
possible that less sealant
can be used. Dye will flow through any remaining leak in the system for use in
known external
leak detection methods, for example involving ultraviolet lights.
[00105] Similar viscosity and time of injection requirements, as described
above for the
organosilane sealing agents above, can be applied to the addition of
orthoesters and other drying
agents that provide or remain fluid after reaction with water. These
requirements can also be
applied to the addition of mixtures of orthoesters and sealing agents, or
mixtures of orthoesters,
sealing agents, and other desired additives such as indicator dyes. For
example, an orthoformate,
or a mix of orthoformate and organosilane, or a mix of orthoformate,
organosilane, and indicator
dye,can be mixed with an ISO 32 grade refrigeration compressor oil, for
example, in a ratio to
maintain a total mixture viscosity above 7 cSt. Compressor oils of other
viscosity grades may be
used and the composition of the oil may be mineral, polyalkylene glycol,
polyolester, or
polyalpholefin subject only to the requirement that the orthoester is soluble
in the compressor oil
at the selected ratio.
[00106] Depending on the mechanism of injection selected, the orthoester may
be injected
as a pure compound or as a solution in the presence of other useful additives.
[00107] As an example, the orthoester can be included with compressor oil and
organosilane sealant compounds as discussed previously. The mixture ratios can
be such that the
injected materials have a viscosity minimum of 7 cSt at 40 C and the mixture
is of a single phase.
[00108] Orthoesters may be selected subject to the requirements above.
Preferred
orthoesters may be one or some of trimethylorthoformate (TMOF),
trimethylorthoacetate
(TMOA), triethylorthoformate (TEOF), triethylorthoacetate (TEOA).
Triisopropylorthoformate
(TIPOF), or triisopropylorthoacetate (TIPOA). Alternatively, other
orthoformates with an aryl
substituent such as triethylorthobenzoate (TEOB) may be used.
[00109] Catalytic effects can be useful in improving the amount of water
consumed by a
given orthoformate, although it is typically not necessary to use a catalyst.
As an example an
sulfonated macroreticular solid acid catalyst can be used. This may be used by
including the
catalyst in a canister in line with the circulating refrigerant medium or as a
side-stream.
Further Examples
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General Test Procedure
[00110] Samples were prepared in approximately 40 gram batches by measuring
the
desired amount of water into a vial, adding compressor oils and then adding
the orthoformate and
any additional chemicals. Typically 1 wt % water was used since this amount is
insoluble in
compressor oils and represents a severe test of the invention. Samples were
shaken periodically
over several days with observations made on the reaction mixtures over this
time period. At the
end of the test period, water content of the solution or mixture determination
by the Karl-Fischer
method, ASTM D6304.
[00111] Orthoesters were obtained from Sigma-Aldrich Chemicals. Deionized
water was
used throughout except as noted.
[00112] Results pertinent to the examples below are summarized in Table 6.
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Table 6
Reactions of Orthoesters with Water
WT %
OTHER Final Water
EXPERIMENT ADDITION WT % WT % WATER/ESTER Water REDUCTI
NO. ESTER S WATER ESTER MOLE RATIO wt % ON
1 TMOF None 1.00 5 1.18 0.27 73
2 TEOF None 1.00 8.25 1.00 0.08 92
3 TEOF None 1.00 4.10 2.01 0.51 49
4 TEOA None 1.00 4.52 1.99 0.10 90
TEOF DMSA 1.00 4.10 2.01 0.54 46
Amberlyst
6 TEOF 15 TM 1.00 4.13 1.99 0.02 98
7 TEOA None 1.00 4.52 1.99 0.10 90
0.798 21
8 TEOB None 1.00 6.25 1.99 2
0.664 33
9 TEOB IN KOH 1.00 4.13 3.02 8
Amberlyst 53
15TM 0.465
TEOB (DRY) 1.00 4.15 3.00 5
11 0.0001N 0.533 47
TEOF KOH 1.00 4.10 2.01 4
0.320 68
12 TIPOF None 1.00 3.52 3.00 2
Amberlyst 0.511 49
13 TEOF A-26 TM 1.00 4.13 1.99 0
5 Amberlyst 15TM: sulfonated macroreticular solid acid catalyst
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Example 13
[00113] As shown by experiments 1 and 2 of Table 6, addition of TMOF or TEOF
to a
mixture of water and mineral oil such that the molar ratio of the water to
orthoformates was near
1: 1, resulted in a significant reduction of water content.
Example 14
[00114] As shown by experiments 2 and 3 of Table 6, doubling the molar
quantity of
water relative to TEOF shows the same relative reaction with TEOF. One mole of
reaction
between water and TEOF would reduce the amount of water by 50%, in agreement
with the
experimentally observed quantity of 49%.
Example 15
[00115] As shown by experiments 3 and 4 of Table 6, using TEOA in place of
TEOF
results in nearly doubling the amount of reaction with water. At a molar ratio
of 2:1 of water
with orthoester, the TEOF reduced the amount of water by 90 wt % compared to
the lesser
reduction of 49 wt % with TEOF.
Example 16
[00116] As shown by experiments 3, 5 and 6 of Table 6, the addition of
catalytic amounts
of a solid methanesulphonic acid catalyst in an in-line drying/filtering
canister to the 2:1 molar
ratio of water:TEOF had little effect on the amount of reaction with water.
The reduction in the
presence of methanesulphonic acid was 46 wt %, effectively the same as the 49
% reduction
observed in the absence of the acid. Use of the acid ion exchange catalyst,
Amberlyst 15, in an
in-line drying/filtering canister gave a doubling of the amount of reaction
with water, producing
a 98 wt % reduction in water content. A side-stream canister of catalyst would
also work.
Example 17
[00117] As shown by in experiment 12 of Table 6, TIPOF in the absence of acid
catalysis
gave a reduction of 68% in water content of a sample when water was present
initially at 1 wt %
and the molar ratio of water:TIPOF was 3:1. This corresponds to twice the
expected water
reduction of 33 wt % in the presence of acid catalyst.
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Example 18
[00118] As shown in experiments 3 and 13 of Table 6, the introduction of
Amberlyst 26, a
basic ion exchange catalyst, does not deleteriously affect the ability of TEOF
to reduce water
content in the presence of mineral compressor oil.
[00119] Tests have shown that TEOF is particularly well suited as the
orthoformate.
Example 19
[00120] A 5200 BTU window style air conditioner was modified to include a16
cu.in.
sealed liquid line drier and isolation valves with bypass piping for on line
change outs. Two
liquid moisture indicators were integrated into the circuit for observing
moisture levels as low,
medium or high as shown by colour changes from pink through green. The unit
was put into
service under constant load at an ambient temperature of 70F/21.1 C. Normal
operating
conditions for the unit typically result in 68 psig suction pressure and a 220
discharge pressure.
The following procedures demonstrated the efficacy of orthoesters in water
removal from this
unit.
1) An injection of 1.25 ml of demineralized water resulted in a rise of
discharge pressure
from 220 psig to 230 psig - a gain of 5 psig. There was no change in the
suction pressure.
The liquid moisture indicator showed evidence of moisture contamination.
2) After operation for 24 hours at constant load, the liquid line drier had
absorbed system
moisture as shown by the moisture indicator.
3) A further 2.5 mL of demineralized water was injected and this resulted in
wet condition
by the moisture indicator. After 24 hours of operating service at constant
load, the liquid
moisture indicator had not changed and still showed a wet system. At this
point in the
experiment the liquid line drier had absorbed water to its full capacity no
further water
removal could be accomplished.
4) The unit was shut down and system pressure was allowed to equalize. On
start up, the
unit exhibited fluctuating pressures of 5 to 10 psig on both low side and high
side
pressures with an accumulation of frosting at the suction line drier. Such
fluctuations are
characteristic of free moving particulates or a partial blockage with oil
logging or in this
case moisture intermittently forming at the expansion device.
5) An injection of 29.6 ml of TEOF was administered. Almost immediately the
frosting on
the suction line drier disappeared. After 1 hour of run time under constant
load, the high
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and low side pressures began noticeably to stabilize with fluctuations
decreased to 2 to 4
psig with longer times between the swings compared to the startup.
6) After a further four hours of run time under constant load both the high
and low side
pressure had stabilized and with 65 psig suction and 210 psig discharge. After
a total
time from startup of 24 hours, the liquid moisture indicator continued to
display a dry
system condition.
7) The unit was again shut down and system pressure was allowed to equalize.
On
restarting, there was no sign of frosting at the suction line drier. Low side
pressure
stabilized at 69psig while high side pressure returned to 225 psig and
operation was
normal.
[00121] It has been found that four different canister content configurations
are
particularly well suited example embodiments to address the needs of most air
conditioning and
refrigeration systems to utilize in association with the drying agent
injection methods described
herein. It is recognized that the canister content configurations may also be
usable with other
injection methods as desired.
[00122] For example, a canister may contain simply a drying agent such as
TEOF. The
size of the canister may be variable. It has been found that a canister
containing about 29.6 ml
(about 1 ounce) of TEOF is appropriate for 300-18,000 BTU systems of Table I
to remove up to
2 ml of moisture. For larger systems having potentially more moisture more
than one canister
can be used, if desired.
[00123] As a further example a canister for a 300-18,000 BTU system can
include 29.6 ml
of total contents made up of 21 ml of TEOF, 7.4 ml of lubricant and
organosilane sealant
mixture, and 1.2 ml of leak detection dye mixture, such as for example a
napthalmide and
polyolester oil mixture. An example sealant mixture is sold as HVACR TM by
Cliplight
Manufacturing Company of Toronto, Canada. An example dye mixture is sold as
Cliplight AC
Universal TM dye by Cliplight Manufacturing Company of Toronto, Canada.
[00124] As another example a canister for a 18,000-60,000 BTU system can
include 88.6
ml of total contents made up of 29.6 ml of TEOF, 56.6 ml of lubricant and
organosilane sealant
mixture, and 2.4 ml of leak detection dye mixture, such as for example a
napthalmide and
polyolester oil mixture. An example sealant mixture is sold as HVACR TM by
Cliplight
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Manufacturing Company of Toronto, Canada. An example dye mixture is sold as
Cliplight AC
Universal TM dye by Cliplight Manufacturing Company of Toronto, Canada.
[00125] As an additional example for automotive air conditioning systems a
canister can
include 44.30 ml of total contents made up of 14.7 ml of TEOF, 28.4 ml of
lubricant and
organosilane sealant mixture, and 1.2 ml of leak detection dye mixture, such
as for example a
napthalmide and polyolester oil mixture. An example sealant mixture is sold as
SUPERSEAL
TM by Cliplight Manufacturing Company of Toronto, Canada. An example dye
mixture is sold
as Cliplight AC Universal TM dye by Cliplight Manufacturing Company of
Toronto, Canada.
[00126] A canister can be sold as a kit, either with instructions for use, or
in combination
with a hose for attaching the canister to the refrigerant stream of an air
conditioning or
refrigeration system.
[00127] Again, the above combinations are example embodiments only. The above
combinations are example embodiments of a "total" solution in that a hydrolyte
drying agent is
provided in combination with an organosilane sealant and a leak detection dye.
The hydrolyte
drying agent is used to dry the system to improve system operation generally
in addition to
preparing it for improved effectiveness of the sealant and the dye.
[00128] As further examples, an orthoformate hydrolyte drying agent could also
be
provided together with a dye or dye mixture or, alternatively, with a sealant
mixture.
[00129] An orthoformate hydrolyte drying agent can be mixed with a dye or dye
mixture,
or with a sealant mixture, to stabilize the dye and dye mixture, and the
sealant mixture, for
storage prior to injection into a system. Dyes and dye mixtures containing
components that react
with moisture have been found in some circumstances to react over time in
storage. In this case,
where it is desired to stabilize the dye, dye mixture or sealant mixture only
for storage purposes a
relatively small amount of an orthoformate can be utilized in the container.
The amount need
only be enough to react with any possible amount of anticipated moisture in
the dye, dye mixture
or sealant mixture. Again, the orthoformate drying agent will react more
quickly with moisture
than the dye, dye mixture or sealant mixture.
[00130] As can be seen the above methods and devices involving the utilization
of
orthoesters can increase performance and stability of organosilane mixtures
when used
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separately or combined with dyes, such as for example perylene and
naphthalimide dyes and
lubricants by reducing air conditioning and refrigeration system moisture
content. A lesser, or
optimized, amount of organosilane, or dye can be used in an air conditioning
and refrigeration
system while allowing greater potential for chemical productivity performance
and stability
while on route to its intended target. Increased chemical reaction can result
in more work done
because of decreased reaction with internal residual moisture as is the case
of chemical solutions
which form a solid polymer, gels or crystallize when coming in contact with
water.
[00131] Moisture laden air can enter systems in manufacturing or when being
serviced or
when loss of system refrigerant creates a lower than atmospheric condition on
the suction side of
the compressor which results in drawing air containing a moisture content into
the system while
in operation. In the case of organosilanes where the intended purpose is to
react with atmospheric
moisture externally at the point of a refrigerant leak forming a solid polymer
the performance of
the reaction can be affected by internal moisture contents within the system
away from the leak
situs. The volume of organosilanes has been found to be increased to offset
premature reaction
with internal system moisture. The pre polymerization has been found to reduce
the amount of
chemical performance reaching the intended purpose while possibly leaving
residual polymer
particulate as in the case of a high system moisture content internally
causing a potential
blockage and mechanical breakdown. When moisture reactive dyes, such as
perylene and
naphthalimide, are used for the detection of refrigerant leaks a simulate
reaction to internal
moisture occurs. The dyes when coming in contact with internal system moisture
will begin to
form gels and in some cases will solidify forming a crystallized substance.
This by product of the
reaction to internal system moisture will also as in the case of the
organosilanes cause a blockage
to refrigerant flow and eventually result in a mechanical breakdown. Critical
blockages will
usually form at the expansion valves and in capillary tubes, reducing
refrigeration effect and
ultimately causing a catastrophic mechanical failure.
[00132] When moisture in the form of water vapor is present in an air
conditioning or
refrigeration system for an extended time, it combines with refrigerant gases
to form acids
which cause corrosion of system components, copper plating, and the
deterioration of motor
insulation leading to system failure. Refrigerants such as HCFC22 and HFC
134a, which contain
fluorine, are hydrolyzed to form hydrofluoric acid. This acid forms a solution
with water and
causes oil degradation to form organic acids and subsequent metal corrosion
and formation of
sludge. The sludge and corrosion particles restrict refrigerant flow in
regulators, filters and
strainers which impairs efficient operation of the system.
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[00133] The introduction of organosilanes for the purpose of sealing
refrigerant leaks or as
in the case of dyes for locating refrigerant leaks compounds the affect of
system degradation
forming increased particulate and sludge contamination.
[00134] The recommended procedure for water removal from air conditioning and
refrigeration systems is by refrigerant gas removal and evacuation of the
system with a vacuum
pump to pressures below 0.05 Pa.
[00135] Liquid line driers can also be installed to help remove small amounts
of moisture.
The primary objective of these driers is to help with the removal of
particulate and sludge.
[00136] Installation of driers or evacuation by vacuum pump requires system
shutdown
and downtime with subsequent losses of time and money.
[00137] Embodiments of the methods and devices described herein can provide an
alternative method for water removal by chemically reacting with water to
transform it to a more
benign product. Such a chemical reactant reduces water content in the system
without requiring
removal of refrigerant or application of a deep vacuum.
[00138] The approach of combining a chemical reactant to an organosilane
separately or
within a specified mixture of lubricating oil and refrigerant dye allows a one
step procedure to
remove moisture, seal micro refrigerant leakage and expose larger points of
leakage with a dye
stain so that an efficient and economical repair can be exercised. Benefits of
a chemical
reactant mixture involving Organosilane separately and or including Perylene,
Naphthalimide
dye and lubricating oils can include:
1) Reduced service time
2) Extended unit life
3) Increased efficiency and therefore reduced energy consumption
4) Improved application of chemical sealants.
[00139] Thus, embodiments of the methods and devices described herein can be
used to
enhance the ability of chemicals which react to water for a specific purpose
or become unstable
when in contact with water by including orthoformates for the removal of water
from air
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conditioning or refrigeration systems to enhance the potential of
organosilanes and dyes, such as
for example perylene and naphthalimide, lubricating oils, or the combination
of them as a
mixture. As appropriate, these applications can be introduced to a system at
the time of
manufacturing or servicing of a refrigerant free system or to operating
refrigeration or air
conditioning systems which have absorbed water from the environment.
[00140] Some embodiments can include the introduction of orthoformates in a
non-acidic
environment into a refrigeration or air conditioning system with subsequent
reduction of water
content through hydrolysis. Some embodiments provide for the use of specific
catalytic media
and specific orthoformates to provide up to enhance the reduction of the
amount of water. Thhis
may include the use of acidic or basic macroreticular ion exchange resins,
such as acid ion
exchange resins to enhance the reactivity of water with orthoformates beyond a
1:1 molar ratio
of water and orthoformate. The resins may be all or part of a filtering device
as part of the a/c or
refrigeration system. Neutralizing media may be introduced into air
conditioning and
refrigeration systems with said orthoformates.
[00141] Some embodiments provide for introduction of orthoformates into
refrigeration
and air conditioning systems in combination with refrigerant compressor oils.
Some
embodiments provide a method to remove reaction products from the resultant
mixture after
reaction of the water. Removal of reaction products of orthoformates and water
by partial or full
recovery of the system refrigerant can be performed for example by a) shutting
down the system
to allow pressure in the a/c or refrigeration system to equalize and
sufficient time for the
compressor oil to migrate back to the sump, and b) using a small positive
displacement pump or
vacuumed vessel attached to the suction charging valve to remove the lighter
reaction products
from the sump.
[00142] Some embodiments can be applied when orthoformates are part of the
refrigeration oil/refrigerant composition originally installed in the air
conditioning or
refrigeration system or as part of a retrofit process during system service.
In this latter case,
injection of the orthoformate alone or in useful mixtures with other additives
can, for example,
be accomplished by one of several methods such as introduction from a vacuum
packed can into
the low side charging valve of the system while in operation, introduction of
the contents from a
pressurized refrigerant can into the low or high side charging valve,
introduction of the contents
from a vacuum packed can into the high or low side charging valve on a system
which has had
the refrigerant recovered and is in vacuum, injection of contents from a
syringe or piston
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operating device (vessel) utilizing modulated positive displacement into low
or high side
charging valve when the machine is operating or not operating, inject of the
contents using an
inline canister into the high or low side charging ports.
[00143] According to one aspect is provided a method of maintaining an air
conditioning
or refrigeration system charged and pressurized with a system fluid comprising
a refrigerant, the
method comprising: (a) introducing into the system fluid, a maintenance fluid
containing a
hydrolytic drying agent which maintains a fluid form upon hydrolytic reaction
with water, and
having a maintenance fluid viscosity; and (b) causing the system to distribute
said maintenance
fluid throughout the system fluid.
[00144] According to another aspect, the method further comprises c)
determining if the
system fluid continues to indicate the existence of water in the system, and,
if so, then repeating
a), b), and c).
[00145] According to one aspect, the hydrolytic drying agent is introduced
into the system
fluid at a controlled rate.
[00146] According to another aspect, the hydrolytic drying agent forms or
maintains an
oil-soluble form after reacting with water.
[00147] According to one aspect, the hydrolytic drying agent is an orthoester.
In certain
embodiments, the orthoester is selected from the group consisting of
trimethylorthoformate,
trimethylorthoacetate, triethylorthoformate, triethylorthoacetate,
triisopropylorthoformate,
triisopropylorthoacetate, and triethylorthobenzoate.
[00148] According to one aspect, the maintenance fluid viscosity is selected
such that,
after said maintenance fluid is introduced, a sump viscosity of a sump mixture
of the air
conditioning or refrigeration system is affected by less than a 10% reduction.
[00149] According to a further aspect, a controlled rate of introduction of
the maintenance
fluid is selected to avoid liquid slugging and to maintain sufficient
lubricant for proper operation
of the compressor.
[00150] According to a further aspect, the controlled rate is less than 6% (by
volume) of a
total oil content of the system per minute.
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[00151] According to a further aspect, the controlled rate is less than
6cc/second.
[00152] According to yet a further aspect, the maintenance fluid viscosity is
selected such
that, when said maintenance fluid is introduced, a sump viscosity of a sump
mixture of the air
conditioning or refrigeration system does not fall below 29 cst at 40 C.
[00153] In another embodiment, the maintenance fluid viscosity is not less
than 7 cst at
40 C.
[00154] In yet another embodiment, the maintenance fluid further comprises a
sealant.
[00155] In another embodiment, the sealant is an organosilane.
[00156] In yet a further embodiment, the maintenance fluid further comprises a
refrigerant.
[00157] In yet a further embodiment, the maintenance fluid further comprises
an indicator
dye.
[00158] In another embodiment, the indicator dye is a fluorescent dye.
[00159] In yet another aspect, the method further comprises (c) introducing
into the
system fluid, simultaneously with step (a) or (b), shortly after step (a), or
shortly after step (b), a
sealant fluid comprising a sealant and having a sealant fluid viscosity; and
(d) causing the system
to distribute said sealant fluid throughout the system fluid.
[00160] According to a further aspect, the sealant fluid is introduced at a
second controlled
rate.
[00161] According to a further aspect, the maintenance fluid viscosity and the
sealant fluid
viscosity are selected such that, when said sealant fluid is introduced, a sum
viscosity of a sump
mixture of the air conditioning or refrigeration system is affected by less
than a 10% reduction.
[00162] According to yet a further aspect, a controlled rate of introduction
of the
maintenance fluid and a second controlled rate of introduction of the sealant
fluid are selected to
avoid liquid slugging and to maintain sufficient lubricant for proper
operation of the compressor.
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[00163] According to yet a further aspect, the controlled rate and the second
controlled
rate combine to less than 6% (by volume) of a total oil content of the system
per minute.
[00164] According to yet a further aspect, the controlled rate and the second
controlled
rate combine to less than 6cc/second.
[00165] According to yet a further aspect, the maintenance fluid viscosity and
the sealant
fluid viscosity are selected such that, when said sealant fluid is introduced,
a sump viscosity of a
sump mixture of the air conditioning or refrigeration system does not decrease
below 29 cst at
40 C.
[00166] According to a further aspect, the sealant fluid viscosity is not less
than 7 cst at
40 C.
[00167] In certain embodiments, the method further comprises (c) passing said
hydrolytic
drying agent through a filter/dryer comprising a solid catalyst.
[00168] In a further aspect, the solid catalyst is selected from the group
consisting of a
solid acid catalyst and a solid basic catalyst.
[00169] In yet a further embodiment, the solid catalyst is a macroreticular
ion exchange
resin.
[00170] In yet a further embodiment, the macroreticular ion exchange resin is
Amberlyst
15.
[00171] According to a further aspect, the filter/dryer also contains a filter
drying medium.
[00172] In one embodiment, the filter drying medium is selected from the group
consisting of any one or more of alumina, charcoal and molecular sieves,
either in separate layers
or admixed with said ion exchange resin.
[00173] According to one aspect is provided a device for use in maintaining an
air
conditioning or refrigeration system, the device comprising: (a) a sealed
vessel adapted to
receive a hose assembly forming, at a proximal end, a sealed fluid connection
to a refrigerant
fluid of the system, and having at a distal end, a receiving unit for the
vessel, and (b) in the
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sealed vessel: : (i) a fluid containing a hydrolytic drying agent which
maintains a fluid form upon
reaction with water, and (ii) a sealant.
[00174] In a further embodiment, the hydrolytic drying agent is an orthoester.
[00175] In a further embodiment, the orthoester is selected from the group
consisting of
trimethylorthoformate, trimethylorthoacetate, triethylorthoformate,
triethylorthoacetate,
triisopropylorthoformate, triisopropylorthoacetate, and triethylorthobenzoate.
[00176] In yet a further embodiment, the sealant is an organosilane.
[00177] In yet a further embodiment, the fluid has a viscosity of not less
than 7 cst. At
40 C.
[00178] In a further embodiment, the fluid further comprises an indicator dye.
[00179] In yet a further embodiment, the indicator dye is a fluorescent dye.
[00180] According to another aspect, is provided a charged, pressurized air
conditioning
or refrigeration system, having: a compressor, a high side, a low side, and a
refrigerant fluid
having a refrigerant and travelling from the high side to the low side and
back; a canister,
containing a maintenance fluid comprising a hydrolytic drying agent which
maintains a fluid
form upon reaction with water; a hose assembly having a manually operated
valve, and forming,
at a proximal end, a sealed fluid connection to the refrigerant fluid, and
having, at a distal end, a
receiving unit for the canister; said distal end capable of puncturing or
otherwise opening said
canister to form a fluid connection between the maintenance fluid and the
refrigerant fluid.
[00181] In a further embodiment, the hydrolytic drying agent is an orthoester.
[00182] In yet a further embodiment, the orthoester is selected from the group
consisting
of trimethylorthoformate, trimethylorthoacetate, triethylorthoformate,
triethylorthoacetate,
triisopropylorthoformate, triisopropylorthoacetate, and triethylorthobenzoate.
[00183] In a further embodiment, the maintenance fluid also comprises a
sealant.
[00184] In a further embodiment, the sealant is an organosilane.
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[00185] In a further embodiment, the air conditioning or refrigeration system
further
comprises a can tapper for puncturing or otherwise opening said canister.
[00186] In a further embodiment, the air conditioning or refrigeration system
further
comprises a flow rate controller which controls or restricts the maximum flow
rate of the
maintenance fluid into the refrigerant fluid.
[00187] In yet a further embodiment, the flow rate controller is an orifice.
[00188] In a further embodiment, the fluid connection is formed between the
maintenance
fluid and the refrigerant fluid, the maintenance fluid flows into the
maintenance fluid at a
maximum flow rate of 6 cc/second.
[00189] In a further embodiment, the air conditioning or refrigeration system
further
comprises a filter/dryer canister, comprising a solid catalyst, through which
the refrigerant fluid
travels.
[00190] In yet another embodiment, the solid catalyst is selected from the
group consisting
of a solid acidic catalyst and a solid basic catalyst.
[00191] In a further embodiment, the solid catalyst is a macroreticular ion
exchange resin.
[00192] In a further embodiment, the resin is Amberlyst 15.
[00193] In yet a further embodiment, the filter/dryer canister also contains a
filter drying
medium.
[00194] In yet a further embodiment, the filter drying medium is selected from
the group
consisting of any one or more of alumina, charcoal, and molecular sieves,
either in separate
layers or admixed with said catalyst.
[00195] In a further embodiment is provided a kit comprising: the device of
claim 31; a
hose assembly capable of forming, at a proximal end, a sealed fluid connection
between an
inside of the hose assembly and a refrigerant fluid in an air conditioning or
refrigeration system,
and capable of attaching, at a distal end, to the vessel, said distal end
capable of puncturing or
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otherwise opening said vessel to form a fluid connection between the inside of
the hose and the
fluid.
[00196] Further variations and modifications can be made without departing
from the
spirit of this invention. It should be understood that the form of the
embodiments described
above, including the Figures and Tables, is illustrative only and is not
intended to limit the scope
of the present invention.
[00197] It will be understood by those skilled in the art that this
description is made with
reference to the illustrative embodiments and that it is possible to make
other embodiments
employing-the principles of the invention which fall within its spirit and
scope as defined by the
following claims.
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