Note: Descriptions are shown in the official language in which they were submitted.
13283~S
REFRIGERANT RECLAIM METHOD AND APPARATVS
This invention relates to a method and apparatus for
removing refrigerant from a refrigeration system during
repairs, confining it so as to avoid its escape to the
atmosphere, separating contaminants from the refrigerant and
cetucning the refrigerant to the repaired refrigeration system
or discharging it to a storage container. The invention is
particularly adapted for incorporation in a mobile unit of the
general type illustrated in U.S. Patent No.'s 3,232,070 and
4,4~6,68~.
~ackground of the Invention
A number of years ago when the refrigeration system
in an air conditioner, for example, required cepairs or when
the refrigerant, such as those sold under the trademark
"Freon", was contaminated sufficiently to affect the
2;effectiveness of refrigeration, it was the standard practice
to bleed the refrigerant to the atmosphere. This practice was
not only costly, but environmentally unsound.
In more recent times it has been the practice to
cemove the refrigecant with means which confines it while
30separating contaminants, liq~efies it and either returns it to
the refrigecation system or stores it. Two such reclaim
system~ are illustrated in U.S. Patents No.'s 4,476,6a~3 and
4,646,527. Each includes a compressor, the intake side of
which draws the refrigerant from the refrigeration system
3;through contaminant removal means into the compressor and
discharges the refrigerant into a condenser which liquefies it
and discharges it into storage means f rom which it may be
retucned to the refrigecation system, if desired.
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13283~
Prior art systems of this type have generally not
provided truly adequate means for making certain that
refrigerant entering the compressor is in a gaseous state,
which is necessary to avoid damaging the compressor. Nor do
the prior art systems provide means for cooling and
controlling the temperature of the liquid refrigerant while it
is held or stored in the reclaim system so that the
appropriate amount of refrigerant can easily be transferred
back to the refrigerator system. Often at the time the
refrigeration system of a repaired air conditioner is to be
recharged with refrigerant, the gases still within the system
are at an elevated temperature resulting in the pressure being
high enough that liquid refrigerant at room temperature cannot
enter, or can only slowly enter, the system by gravity flow. -
When refrigerant in the reclaim system has been cooled to a
temperature well below the temperature of gases within a
container to be charged, the cooler refriqerant will flow
partially into the warmer gas, cooling it in the process and
thus reducing the pressure of the gas and the resistance to
flow of the refrigerant.
It is known in the prior art to provide means for
repeatedly recycling the refrigerant through a standard
filter-dryer unit ducing the repair operations, to ensure
maximum removal of the acid and water vapor, one such
recycling loop being shown in U.S. Patent No. 4,476,688.
Without means to cool the recycling refrigerant, however, its
tempecature will inevitably rise and this will reduce the
effic~ency of standard filter-dryers and make it much more
3 difficult to discharge the refrigerant directly from the
reclaim system back into the repaired refrigeraeion system.
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132835~
73605-7
Summarv of the Invention
~ he present invention provides a method and means for
drawing refrigerant from a container, or a refrigeration system to
be repaired, heating the refrigerant sufficiently to maintain it
in a gaYeous state while it passes through an oil separator into
the intake of a compressor. Ccmpressed gaseous refrigerant is
discharged from the compressor and passed through a heat exchanger
to heat the incoming liquid refrigerant and then passe~ through a
condenser where it is liquefied. The liquefied refrigerant is
pa6sed from the condenser into a hold tank from the bottom of
which liquid refrigerant flows through a filter-dryer and an
expansion device for reconverting the liquid refrigerant to
gaseous form. From the expansion device the gaseous refrigerant
passe~ through a coil submerged in the liquid in the hold tank and
then is passed back to the intake of the compressor. The
temperature of the liquid in the hold tank is lowered by the
chilling effect of the expanding gaseous refrigerant passing
through the coil ~ubmerged in the liquid and because of this
chilling effect the hold tank is referred to as a "chill tank.
The refrigerant can be repeatedly passed from the chill tank
through the filter-dryer, expansion device, cooling coil,
compressor, heat exchanger, condenser and back to the chill tank
so as not only progre6sively to lower its temperature in the chill
tank but also repeatedly, and thus more completely, to remove acid
and water from it.
According to one aspect, the present invention provides
in an apparatus for reclaiming refrigerant, means for removing
refrigerant from a container and ~eparating oil from the
refrigerant, comprising a heat exchanger having a hot side and a
cold ~ide, means connecting the cold side of the heat exchanger to
the refrigerant container, means for connecting the hot side of
the heat exchanger to a source of hot gaseous refrigerant, means
for causing refrigerant from the container to flow through the
cold æide of the heat exchanger, means for passing heated gaseous
refrigerant from the heat exchanger into the lower portion of an
elongated vertically extending separator tank, baffle means in the
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1328355
73605-7
upper portion of the separator tank for interrupting the flow of
riiing expanding hot gaseoui refrigerant, the periphery of the
baffle means prov~ding a narrow openlng between the baffle and the
lnner wall of the tank to permlt escape of ga~eous refrigerant
around the baffle and a fluld condult havlng an lnlet above the
baffle for removlng gaseous refrigerant from the separator tank.
According to another a~pect, the present invention
provides in an apparatus for reclalming refrlgerant, an oll
separator compriciing an elongated tank oriented with its
longitudinal axis extending vertically, baffle means mounted in
the upper portion of the interior of the tank, ~aid baffle mean~
including a central plate having attached to lts perlphery a
downwardly and outwardly extendlng sklrt, there belng a narrow
openlng between the lower extremlty of the skirt and the interior
wall of the tank, mean~ above the baffle havlng an opening
permitting gaseous refrigerant to leave the tank, means in the
lower portlon of the tank permltting entry of gaseous refrlgerant
lnto the tank and means for wlthdrawlng oil from the bottom of the
tank.
According to another aspect, the present lnvention
provides in an apparatus for reclaiming refrigerant, mean~ for
holding refrigerant wlthin the apparatus whlle repeatedly cleaning
and cooling the refrigerant, said means comprisingl a compressor
for compressing and dlscharglng gaseous refr~gerant, mean~ for
condensing the gaseous refrigerant to a llquid, mean~ for
conducting the llquid refrlgerant lnto a closed elongated chill
tank the longitudlnal axls of which extends vertlcally, means for
wlthdrawlng llquid refrlgerant from the bottom of the chlll tank
and pas~lng lt succe~sively through a fllter-drler, an expansion
device and a fluld conduit within the chill tank extending
upwardly from the lower portion of the chill tank, and mean~
outside the chill tank for connecting the fluid condult in fluid
communication with the intake of the compressor.
According to another aspect, the present invention
provides a refrigerant recovery and purification system
comprising~ a refrigerant compres~or~ means including evaporator
r 3a
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73605-7
means for connecting said compreEisor to a container fro~ whlch a
refrigerant i8 to be recovered; condenser means ln fluid
communication with said compressor and in heat exchange relation
to Eiaid evaporator means; refrigerant storage means; means for
feeding liquid refrigerant from sald condenser means to said
refrigerant storage means; means for selectively circulating
refrigerant in a clo~ed path from sald refrlgerant storage means
through said compressor and back to said refrigerant storage
means .
Accordlng to another aspect, the present lnven~ion
provides a refrigerant recovery and purlficatlon system
comprlsing. a compressor within said recovery and purlflcatlon
system and apart from a contalner or refrigerant sy~tem from which
refrigerant is to be recovered; means for connecting sald
compressor to the container or refrigerant sy~item from which a
refrigerant is to be recovered; refrigerant holdlng means within
said recovery and puriflcation system and in fluid communicatlon
with said compresEior for holding the refrlgerant recovered fro~
said container or refrlgerant sy~tem; and means for selectlvely
clrculatlng the recovered refrlgerant in a closed path from siald
refrlgerant holding means through said compreseor and bac~ to sald
refrlgerant holding means.
Accordlng to another aspect, the present inventlon
provldes a method for reclalmlng refrlgerant comprising,
compre~islng gaseous refrlgerant, condensing the refrigerant to a
llquid, discharglng the llquid lnto a pool of the llquld,
wlthdrawing llquld from the bottom of the pool, filtering and :-
drying the liquid, pas~lng the liquid through a narrow passage
into a larger passage to convert the llquid into a gaseous state
and causing the gaseous refriqerant to expand in a pa~isage
extending through the pool of liquid thereby cooling the liquid ::
and repeatedly performing the steps of compressing, condensing, ~ -
filtering-drylng, and coollng with the same body of refrlgerant. - :-
Accordlng to another aspect, the present lnventlon
G :-`
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13283~ -
73605-7
provides a method for reclaiming refrigerant comprising drawing
refrigerant to be reclaimed from its container, heating the
refrigerant to a gaseous state, separating oil from the gaseous
stream, compressing the gaseous refrigerant, heating the
refrigerant as it is withdrawn from the contalner by passlng the
compressed gaseous refrlgerant in thermally conductlve contact
with the withdrawn refrigerant, condensing the compressed gaseous
refrigerant to a liquid, discharging the liquid into a pool of the
liquid, withdrawing llquid from the bottom of the pool, filtering
and drying the liquid, passing the liquid through a narrow passage
into a larger passage to convert the liquld into a gaseous state
and causing the gaseous refrigerant to expand in a passage
extending through the pool of liquid thereby cooling the liquid,
combining the expanding gaseous refrigerant with the gaseous
refrigerant from which oil has been separated and compressing the
combined gaseous refrigerant.
According to another aspect, the present inven$ion
provides a method for reclalming refrigerant comprising2 drawing
refrigerant to be reclaimed from lts container; heatlng the
refrigerant to a gaseous state with heat exchange means for
transferring heat energy; separating oil from the gaseous stream;
compressing the gaseous refrigerant; cooling the gaseous
compressed refrigerant with said heat exchange means; condensing
the compressed gaseous refrigerant to a llquid; discharging the
liquld into a chamber of liquid refrigerant; withdrawing
refrigerant from said chamber; passing said refrigerant through a
filter; and returning said refrigerant to said chamber.
According to another aspect, the present invention
provides a method for reclaiming refrigerant comprising. drawing
refrigerant to be reclaimed from its container; heating the
refrigerant to a gaseous state; separating oil from the gaseous
stream; compressing the gaseous refrigerant; heating the
refrigerant as it is withdrawn from the container by passing the
compres ed gaseous refrigerant in thermally conductive contact
with the withdrawn refrigerant; condenslng the compressed gaseous
refrigerant to a liquid; discharging the liquid into a chamber;
G 3c
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~ ' ' ,. ' "' ' ," ' ' ' '. ' : ' . ' : '. ', ,, .', ' ': . ". ' . :
1328355
73605-7
withdrawing refrigerant from the chamber; passing the refrigerant
through a filter; and returning the refrigerant to the chamber.
The invention can be more fully understood when the
detailed description which follows is read wlth reference to the
accompanying drawing.
The Drawina
The drawing is a schematlc illustratlon of the lnvention
in which the parts illustrated are either ctandard
3d
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132835~
;
items which can be purchased or are disclosed in sufficient
detail when viewed in conjunction with the description so as
to teach those skilled in this art how to practice this
invention.
O
~he Detailed Descri~tion
As illustrated in the drawing, the reclaim system of
this invention includes a heat exchanger 10, one portion of
which is in fluid communication with a refrigerant intake
fluid conduit 11 controlled by solenoid valve 12. The conduit
11 is in fluid communication with conduit 13 which constitutes
the cold side of heat exchanger 10. The conduit 13 is
illustrated as being joined to conduit 15 by thermally
conductive weld 14. Conduit 15 constitutes the hot side of
20heat exchanger 10. The heat exchanger arrangement shown in
the drawing is for illustration purposes only. In practice it
is preferred that intake 11 be in fluid communication with a
conduit with a spiral fin, or ridge and groove arrangement,
facilitating its beinq mounted within a conduit to form a so-
2-called tube-within-a-tube heat exchanger. Preferably also the
tube-within-a-tube construction is in the form of a coil so as
to provide greater length in a smaller space than would be
possible with a straight tube-within-a-tube construction. The
coiled tube-within-a-tube is a standard item well known in the
30heat exchange art, and it will be apparent that the inner tube
should be the cold side and the outer tube the hot side of the
heat exchanger.
Conduit 16 constitutes the outlet from the cold side
of heat exchanger 10 and is in fluid communication with oil
3 separator 20 through the conduit 21. The oil separator 20 is
preferably an elongated pressure cylinder with partially
spherical ends mounted so that its longitudinal axis extends
vertically. The fluid conduit 21 extends through the outer
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132835~
wall of the oil separator tank 20 somewhat above the lower end
of the tank and extends inwardly so that its open end is near
the axis of the tank. Another fluid conduit 22 has its open
end fixed near the inner surface of the rounded top of the
tank. This fluid conduit extends downwardly and supports a
circular baffle 23 composed of a disc-like portion 24 and a
downwardly extending partially cone-shaped skirt 25. Conduit
22 is arranged to extend along the axis of the tank and is
connected to fluid conduits 26 and 31 controlled by a low
pressure activated electrical control device 27 having a
pressure gauge indicator associated with it. The control 27
will automatically shut down compressor 30 when the pressure
in conduit 31 drops to virtually zero PSIG. Oil from the
bottom of oil separator 20 can be discharged through fluid
conduit 28 controlled by solenoid valve 29.
Fluid conduit 31 extends through the outer wall of
compressor 30 and a short distance into its interior as
illustrated. Compressor 30 is provided with a fluid csnduit
outlet 32 and an oil sight gauge and oil supply device 33.
Outlet conduit 32 has a high pressure activated electrical - :-
control device 34 associated with it and is in fluid
communication with conduit 15 of heat exchanger 10 and is thus -
in fluid communication with conduit 41, which in turn is in
fluid communication with a condenser 40 through condenser
inlet conduit 42. If preseure in conduit 32 is too high,
control 3q acts automatically to shut down compressor 30.
Outlet conduit 43 connects condenser 40 in fluid
communication with chill tank 50, which as illustrated is an
elongated, cylindrical pressure tank arranged with its
longitudinal axis extending vertically and having upper and -
lower ends of partially spherical shape. Outlet end 51 of
fluid conduit 43 is located substantially on the axis of chill
_5_
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13283~5
tank S0. At the bottom of the chill tank 50 there is a fluid
conduit 52 controlled by solenoid valve 53 and arranged in
fluid communication with the interior of chill tank 50. At
the upper end of chill tlnk 50 there is an air outlet conduit
' 54 controlled by solenoid valve 55 having a pressure gauge
indicator associated with it. Conduit 54 is v-nted to the
atmosphere through a small orifice to prevent an explosive
discharge of air. Fluid conduits 52 and 54 open into the
interior of chill tank S0 at points preferably on the
longitudinal axis of the tank. Also located at the upper end
of chill tank 50 is a high pressure activated safety valve 56.
~ ocated partially within and partially outside chill
tank S0 is a cooling and recycling system 60 composed of a
conduit 61 in fluid communication with conduit 52 and
20 controlled by solenoid valve 62. The fluid conduit 61 is in
fluid communication with filter-dryer 63, which in turn is
connected in fluid communication with an expansion device 64,
illustrated in the drawing as being a capillary tube. The
expansion device 64 is in fluid communication with conduit 65
arranged in the form of a coil within chill tank 50. The
cooling coil 65 is in fluid communication with conduit 66,
which in turn is in fluid communication with inlet conduit 31
of compressor 30.
All the elements of the reclaim system of this
invention can be mounted within a mobile cabinet (not shown
having a control panel in one outer surface and casters
underneath it.
T,he control panel includes a power on-off switch
which, depending on the positions o~ various valves and the
pressures at various points in the system, energizes the
compressor 30 and the valves 12, 29, 55, 53 and 62. Since
controls 27 and 3q shut down or start up compressor 30
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1328355
automatically when power is on, and since relief valve 56
responds automatically to pressure, the control panel need not
include switches ~or manually activating these devices. Hence
the control panel need include only, in addition to the power
10 on-off switch, switches for valve 12 (refrigerant in), valve
29 (oil out), valve 53 (refrigerant out), valve 55 (air out)
and valve 62 (control for cooling and recycling system 60), or
a total of six switches. The control panel also includes two
pressure gauge indicators, one for displaying the pressure
15 entering conduit 31 and the other for displaying the pressure
at valve 55 and the upper portion of chill tank 50. Details
of the circuitry for electrically connecting switches,
controls, valves and gauges will be apparent to those skilled
in this art.
Chill tank 50, being the largest element of the
reclaim system, and being about 40 inches in height, the
cabinet should be about 62 inches in height including the
height of the casters. The cabinet can be about 23 inches in
width and 24 inches in depth if the cabinet contains the
system illustrated in the drawing which has only one chill
tank 50. As will be apparent to those skilled in the art, if
the cooling effect from one chill tank 50 is insufficient, one
or more additional chill tanks can be provided and connected
to run in parallel with the first chill tank 50. Each chill
tank is preferably about 6 inches in diameter, has a capacity
B to store or hold 45 lbs. of refrigerant such as*"Freon" 12, 22
or 502 and meets ASME and Underwriters Laboratory
specifications for pressure tanks. The tank for oil separator
20 preferably meets the same specifications and is 36 inches
long and 6 inches in diameter. Compressor 30 is of a type in
which a combination sight gauge and oil inlet cap 33 can be
provided for maintaining proper lubrication in compressor 30.
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132835~
The following is a compilation of the items which are standard
devices which can be purshased, together with an
identification of these items:
10 Item Description Manufacturer ~dentification No.
Compressor ~0 Copeland Corp. SSC4-0200
Condenser 40 Snow Coil Co. 585aM736
Heat Exchanger 10 Packless Industries AES001672
Control 34 Ranco Inc. 016-42
Control 27 Penn Corp. P70AB-2
1- Solenoid val~es 12,
62, 55, 53 & 29 Sporelan Valve Co. E 35-130
Safety Valve 56 superior 3014-400
Gauges on control
panel Ashcroft Laboratory quality
1377-AS
Filter-Drier 63 Sporlan Valve Co. 384 cubic in.
A unit constructed as disclosed above weighs about 325 lbs.
When the system illustrated is utilized in repair of
the refrigerating system of an air conditioner, for example,
fluid conduit 11 is connected to a refrigerant outlet in the
2~ refrigeration system, the power is turned on and valve 12 is
o~ened. Control 27 at the inlet to the compressoc is
activated when it senses pressure in fluid conduit 31, and
with the power turned on compressor 30 begins to function.
~efrigerant from the refrigeration system is drawn into the
reclaim system through conduit 11. Normally the refrigerant
at this point will be a liquid, which has been illustrated in
the drawings by double cross hatching inside the fluid
conduit. At some point in fluid conduit 13 of heat exchanger
10 the refrigerant is converted to gaseous form by the heat
transferred to it from conduit 15 carrying the output of
compressor 30. The single cross hatching in fluid conduit 13
is illustrative of refrigerant in gaseous form. Throughout
-a-
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132835~
s
the drawing double cross-hatching indicates liquid and single
cross-hatching gas or ~apor. The refrigerant flows through
fluid conduits 15 and 21 into oil separator 20. It is at this
point relatively hot and is an expanding gas rising rapidly
10 within the tank of oil separator 20. The upward flow of gas is
abruptly interrupted by the baffle 23 causing oil to be
separated and to drop to the bottom of the tank. The gaseous
refrigerant passes around the outer (lower) edge of skirt 25
which is spaced from the interior wall of the surrounding tank
by an amount providing a total open area which is
approximately equal to the open area at the upper end of
conduit 22. The gaseous refrigerant passes around skirt 25
into the upper end of fluid conduit 22, then through fluid
conduit 26 into fluid conduit 31.
so long as there is sufficient pressure in fluid
conduit 31 to indicate that the refrigeration system of the
air conditioner has not been completely evacuated, compressor -
30 will continue to run. Refrigerant from fluid conduit 31
passes into the compressor, is compressed and discharged -
through fluid conduit 32 and passes through the heat exchanger
in fluid conduit 15 and then through fluid conduit 41 into
condenser 40 through condenser inlet 42. The gaseous
refrigerant entering the condenser is converted into a liquid
30at some point in the condenser such as 44.
Liquid refrigerant passes out of the condenser 40
into conduit 43 and through that conduit into the upper
portion of chill tank 50. At this point valves 53 and 62 are
closed and.the compressor will continue to withdraw
3 refrigerant from the refrigeration system of the air
conditioner, and to cause liquid refrigerant to be discharqed
into chill tank 50 until the pressure at the inlet to ..
compressor 30 drops to virtually zero PSIG indicating all of .- .
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132835~
the refrigerant has been removed from the refrigeration system
of the air conditioner. At this point control 27 will act to
shut down oompressor 30.
After waiting to see if pressure again will build up
in conduit 31 and cause the compressor to start up again, the
operator will close ~alve 12 (refrigerant intake) and open
valve 62 causing liquid refrigerant to leave the chill tank 50
through fluid conduit 52 and pass into the filter dryer 63
through fluid conduit 61. The liquid refrigerant then passes
through expansion device 64, where it is converted into a gas
and passes through coil 65 to cool the liquid refrigerant,
illustrated in the drawing as filling approximately 3/4 of
chill tank 50 and having the coil 65 submerged in it. When
20 expanding gas from coil 65 reaches the compressor inlet
conduit 31 via fluid conduit 66, there will be sufficient
pressure to actuate control 27, and the compressor will
automatically start running again.
With valve 12 closed, the cold side of heat exchanger
25 10 and the entirety of oil separator 20 are shut down. With
pressure in fluid conduit 31, the compressor continues to
operate and the gaseous refrigerant which entered the
compressor through conduits 66 and 31 is compressed and
discharged from the compressoc through fluid conduit 32 and
30 thence through the heat exchanger 10 and condenser 40 back
into the chill tank 50 and the cycle just described is
repeated again and again until the temperature of the liquid
refrigerant in chill tank 50 has been reduced to the desired ~-
level, normally about 38 to 45 degrees Fahrenheit.
3~ The repeated passing of liquid refrigerant through
filter dryer 63 removes substantially all acid and water from
the liquid refrigerant. During this recycling, normally a
certain amount of air will be separated from the refrigerant
.
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1328355
and collect in the upper portion of chill tank 50 causing the
pressure there to rise. Air can be re~oved from the reclaim
system by opening valve 55 so that the air escapes through
conduit 54. This is normally done when the pressure within
10 chill tank 50 reaches something in excess of 300 PSIG and is
done by activating a switch, preferably a push button, on the
control panel. In the event for some reason pressure should
reach a level of about 400 PSIG, safety valve 56 will be
actuated and gases in the system will be vented. -
Before any liqùid refrigerant is returned to the
refrigeration system of the air conditioning unit, which is
done by closing valve 62 and opening valve 53, any oil which
has been collected in the bottom of oil separator 20, as
schematically illustrated in the drawing, should be removed
through outlet 2B by opening valve 29. The amount of oil
removed should be measured so that an appropriate amount of
oil can be resupplied to the refrigeration system.
~ he refrigerant reclaim system of this invention can
be utilized to transfer refrigerant from one container to
another. This is done by connecting the fluid conduit 11 to
the container from which refrigerant is to be taken (the first
container~ and fluid conduit 52 to the receiving or second
container. Upon opening valve 12 and supplying power to
compressor 30, refr$gerant will be removed from the container
and p~s6ed through the heat exchanger 10, the oil remover 20,
the compressor 30, the condenser 40, and into chill tank 50.
Operation is continued in this mode until the pressure display
on the control panel indicates the first container has been
evacuated. As in other operations when all of the refrigerant
has bcen removed fro~ the first container, pressure in line 31
will drop to virtually zero PSIG, thus actuating control 27
and shutting off the compressor which will not begin to run
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132835~
s
again until there is pressure in line 31 from the gaseous
refrigerant exiting from the cooling device 60. Valve 12 is
then closed. Since it will facilitate discharging the
refrigerant into the receiving container, it is desirable that
valve 53 first be closed and valve 62 opened so that cooling
device 60 will be operative. Operation in this mode is
continued fot a sufficient period to reduce the liquid
refrigerant in chill tank 50 to the desired temperature. When
the desired temperature is reached, valve 62 is closed, valve
53 opened, and liquid refrigerant will flow from the chill
tank 50 into the receiving container by gravity, and any
pressure from gases in the upper portion of chill tank 50.
-12-
