Note: Descriptions are shown in the official language in which they were submitted.
CA 02211898 1997-07-30
WO 96!24827 PCTICA96/00083
LIQUID INJECTIO;;V DEVICE, SYSTEM AND METHOD
~ TECHNICAL FIELI)
- The invention relates to devices for injecting liquid into pressurized
systems. More
particularly, it relates to such devices for injecting liquids into air
conditional g systems.
BACKGROUND ART
Air conditioning systems often leak refrigerant. This is undesirable from an
economic
point of view as the system will not operate as efficiently with reduced
quantities of
refrigerant, and the refirigerant needs to be replaced. It is also undesirable
environmentally. '
Leak detection is generally performed by injecting a fluorescent dye into the
system.
Typically dyes used for this purpose fluoresce in the ultraviolet region, so
an ultraviolet
light is shone on the system. Wherever leaks occur the dye will escape the
system and
fluoresce under the light.
A number of injectors have been developed for getting liquids into an air
conditioning
system. US patent number 4,745,772 issued May 24, 1988 to Ferris describes a
chemical additive device. The device has a container that unscrews to allow
access to
the interior for pouring in the additive. The container is screwed back
together, the
device is connected to the air conditioning system and the additive is
injected under
. pressure into the system. Although there is no indication in the Ferris
patent of the
material used for the container, it is likely to be metal or some other
visually solid
material capable of withstanding the pressures used in air conditioning
systems.
I
CA 02211898 1997-07-30
WO 96!24827 PCTICA96/00083
US patent number 4,938,063 issued July 3, 1990 to Leighley discloses a mist
infuser for
infusing a fluorescent dye into an air conditioning system. The Leighley
nnfuser has two
concentric glass cylinders sandwiched between two circular end caps. Together
the end
caps and the small cylinder define a reservoir. One end cap has a circular
inlet through
its centre, while the other has an outlet. An inlet bore opens from the
outlet,
perpendicular to it, through the circumference of the outlet end cap.
Similarly, an outlet
bore opens to the inlet from the circumference of the inlet end cap. The bores
have
respective sealing caps.
In operation, the infuser is turned on its side and the sealing caps are
removed. The dye
is added through the inlet bore, while air escapes through the outlet bore.
The level of
the dye is visible through the glass cylinders.
The Leighley device has a number of drawbacks. It is expensive to manufacture
and
assemble due to the number of components and their specialized nature. The
device
must be filled on its side which is very cumbersome. The glass is susceptible
to being
broken. This is the likely reason for having two glass cylinders, one inside
the other, to
contain the dye in the event of breakage. Even if the glass is not broken, it
is susceptible
to being scratched, possibly, impairing sight to the interior.
Another problem in the art is the desire for different sized injectors.
Injectors can be
used not only for the injection of dye, but also refrigerant oil and other
liquids. Different
jobs will require different amounts of liquid to be injected. Typically small
amounts of
dye are injected, while larger amounts of oil are injected. However, the
amounts used
for each can vary from application to application. The use of many sizes of
injectors is
expensive. The use of an oversized injector is not always possible and, even
if it is
2
CA 02211898 2004-09-21
possible, it is wasteful of dye or oil. Also, in the leak detection process
there is typically
a desirable ratio of dye to refrigerant_ Adding more dye can decrease the
effectiveness of
the process and can contaminate the refrigerant in the system.
It is an object of the invention to address these or other problems with
devices for the
,.
injection of liquidslinto pressurized systems.
DISCLOSURE OF THE INVENTION
In a first aspect the invention provides an injector for use in injecting a
liquid into a pressurized system
using a charging system. The injector includes a body having a generally
tubular interior and
a non-opaque tube for being inserted into the interior of the body. The body
is for receiving fluid
connections at opposing ends of the body to the charging system and to the
pressurized system,
respectively. The injector further includes at least one opening through the
body, not at the opposing
ends, for viewing the liquid in the tube, and an end fill cap at one of the
opposing ends, the end fill cap
for connection to the charging system. The tube and body are in sealed
connection such that the liquid
will not escape through the at least one opening while under pressure. The
tube and body are for
receiving the liquid prior to injection into the pressurized system. The end
fill cap is manually
releasable from the body to provide interior access to the injector for
filling the tube with the liquid.
The tube may be translucent. The tube may be transparent. The tube may be
transparent and
uncoloured. The tube may be a glass tube. The glass may be clear borosilicate
glass.
The injector may further include a valve coupler at the other of the opposing
ends of the body for
connection to an on-off valve between the coupler and the pressurized system.
The liquid may be
poured into the injector through the interior access when the body is held
sufficiently upright to retain
the liquid. The injector may further include at least one additional opening,
the openings for viewing
into the tube and for allowing light to pass into the tube.
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CA 02211898 2004-09-21
The charging system may be a refi-igerant charging system, the liquid may
include a fluorescent dye for
leak detection, and the pressurized system may be an air conditioning system.
In a second aspect the invention provides a liquid injection system for
injecting a liquid, the injection
system including an injector, a pressurized system, and a charging system. The
injector is the injector
of the first aspect.
In a third aspect the invention provides a method for charging a pressurized
system with liquid using a
charging system. The method includes the steps of connecting an injector,
comprising a body with a
generally tubular interior and a non-opaque tube inserted into the interior of
the body, at opposing ends
of the body to the charging system and to the pressurized system,
respectively, while fluid connection
to the pressurized system is disabled; manually releasing an end fill cap at
one of the opposing ends to
provide interior access to the injector, the end fill cap for connection to
the charging system; filling the
tube and body in a generally upright position with the liquid; enabling fluid
connection to the
pressurized system; injecting the liquid into the pressurized system using the
charging system; and
viewing the tube through at least one opening in the tubular body, not at the
opposing ends, to
I 5 determine if sufficient amount of the liquid was propelled from the
injector by the charging system.
In a fourth aspect the invention provides an injector for use in injecting a
liquid into a pressurized
system using a charging system. The injector includes a body having a
generally tubular interior with a
longitudinal axis, the body having fill and coupling ends disposed at opposite
ends of the body and
about the longitudinal axis, and a non-opaque tube in the interior of the body
and co-axial with the
longitudinal axis of the body. The tube has fill and coupling ends at opposite
ends of the tube and
about the longitudinal axis. The injector further has at least one opening
through the body, not at the
opposing fill and coupling ends, for viewing the liquid in the tube, a fill
end cap removably coupled to
the fill end of the body, for filling the interior of the tube with the
liquid, sealing means disposed on an
3B
CA 02211898 2004-09-21
interior of the body between at least one the opening and the fill end of the
body such that the fill end
of the tube is sealed to the body even when the fill end cap is removed, and a
coupler end cap,
removably coupled to the coupler end of the body, for coupling the injector to
the pressurized system
when coupled to the body, and for sealing the tube between the coupler end cap
and the sealing means.
The tube may be'translucent. The tube may be transparent. The tube may be
transparent and
uncoloured. The tube may be a glass tube. The glass may be clear borosilicate
glass.
The coupler end cap may include a valve coupler for connection to an on-off
valve between the coupler
end cap and the pressurized system. The fill end cap may have a roughened
exterior surface. The fill
end cap may be manually releasable from the body to provide interior access to
the injector for filling
the tube with the liquid.
The injector may further include an on/off valve coupled to the coupler end
cap so that when the liquid
is poured into the injector through the fill end of the body when the body is
held upright, the liquid is
retained in the tube. The injector may further include at least two openings
in the body for viewing the
tube and for allowing light to pass into the tube.
The charging system may be a refrigerant charging system. The liquid may
include a fluorescent dye
for leak detection, and the pressurized system may be an air conditioning
system.
The sealing means may include an annular projection disposed on the inside of
the body adjacent the
body fill end. The injector may further include an annular seal disposed
between the tube and the
coupler end cap to prevent the liquid in the tube leaking at a periphery of
the coupler end cap.
In a fifth aspect the invention provides a liquid injection system for use
with a charging system and a
pressurized system, for injecting a liquid into the pressurized system. The
liquid injection system
includes a body having a generally tubular interior with a longitudinal axis.
The body has a fill end
about the axis for coupling the body to the charging system, and a coupler end
about the axis for
3C
CA 02211898 2004-09-21
coupling the body to the pressurized system. The system further includes a non-
opaque tube for being
inserted into the interior of the body and co-axial with the longitudinal
axis, and a removable fill end
cap, removably coupled between the body fill end and the charging system for
pouring the liquid into
the tube when the fill end cap is removed from the body. The system also
includes a coupler end cap,
removably coupled between the body coupler end and the_pressurized system, for
permitting the tube to
be removed from the body coupler end when the coupler end cap is removed from
the body, and at
least one opening through the tubular body, not at the opposing ends thereof,
for viewing the liquid in
the tube. The systems further includes sealing means coupled to an interior of
the body between at
least one the opening and the fill end of the body such that the tube is
sealed to the body even when the
fill end cap is removed from the body, and an on/off valve, coupled to the
coupler end cap, for allowing
the liquid to enter the pressurized system when the valve is on, and for
preventing the liquid from
entering the pressurized system when the valve is off:
The sealing means may include an annular projection integral with the interior
of the body adjacent the
fill end thereof. The system may include an annular seal disposed between the
annular projection and
1 S the tube to prevent the liquid in the tube from leaking about a periphery
of the fill end cap. The system
may include an annular seal disposed between the tube and the coupler end cap
to prevent the liquid in
the tube leaking at a periphery of the coupler end cap.
In a sixth aspect the invention provides a method for charging a pressurized
system with liquid using a
charging system. The method includes the steps of connecting an injector
including a body having a
generally tubular interior with a longitudinal axis, the body having fill and
coupling ends disposed at
opposite ends of the body and about the longitudinal axis; and a non-opaque
tube in the interior of the
body and co-axial with the longitudinal axis of the body, the tube having fill
and coupling ends at
opposite ends of the tube and about the longitudinal axis; at least one
opening through the body, not at
4
CA 02211898 2004-09-21
the opposing fill and coupling ends, for viewing the liquid in the tube; a
fill end cap, removably
coupled to the fill end of the body, for filling the interior of the tube with
the liquid; sealing means
disposed on an interior of the body between at least one the opening and the
fill end of the body such
that the fill end of the tube is sealed to the body when the fill end cap is
removed; and a coupler end
cap, removably coupled to the coupler end of the body, fo~r.coupling the
injector to the pressurized
system when coupled to the body, and for sealing the tube between the coupler
end cap and the sealing
means. The method further includes the steps of removing the fill end cap;
filling the tube with the
liquid while the body is held in a generally upright position; replacing the
fill end cap; enabling fluid
connection to the pressurized system through the coupler end cap; enabling
fluid connection to the
charging system through the fill end cap to inject the liquid into the
pressurized system using the
charging system; and viewing the tube through at Ieast one opening in the
tubular body to determine if
a sufficient amount of the liquid was propelled from the injector into the
pressurized system by the
charging system.
The method may further include a step of disposing the body so that the fill
end faces downward, to
ensure that the tube does not exit the fill end of the body.
The method may include the steps of disposing an on/off valve at the coupler
end cap to control flow of
liquid therethrough; closing the on/off valve prior to filling the tube with
the liquid; an opening the
on/off valve to enable the liquid to flow to the pressurized system.
BRIEF DESCRIPTION OF THE 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:
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CA 02211898 1997-07-30
WO 96/24827 PCT/CA96/00083
Figure 1 is a perspective exploded view of an injector according to the
preferred
embodiment of the present invention,
Figure 2 is a cross-section of the m~ector of Figure 1,
Figure 3 is a sketch of the injector of Figure 1 connected to a charging
system and
a pressurized system,
Figure 4 is an exploded perspective sketch of a supplemental reservoir
according
to the referred embodiment of the invention in combination with an inline
end fill injector,
Figure 5 is a cross-section of the combination of Figure 4, and
Figure 6 is an exploded perspective sketch of an adaptor set employing the
combination of Figure 4.
MODES FOR CARRYING OUT THE INVENTION
Referring to Figures 1 and 2, an injector 1 has a valve coupler 3, a valve
coupler seal 5, a
tube 7, a tube seal 9, a body 11, a fill cap seal 12, and a fill cap 13.
The coupler 3 has a conical nipple 15 with exterior thread 17, and a tubular
plug section
19 with exterior threads 21. Through the centre of the coupler 3 is a bore 23.
The valve coupler seal 5 is a flat ring seal for durability, while the tube
se~il 9 and the fill
cap seal 12 are O-ring seals. Neoprene O-rings are used as they tend to expand
outwardly as they are compressed thus providing additional sealing surface,
while they
rebound to their original position when compressive forces are removed thus
reducing
the tendency to stick to the surfaces that are compressing them. As well,
neoprene has
6
CA 02211898 2004-09-21
been found to be suitable for use with fluorescent dyes typical in automotive
air
conditioning applications. Those skilled in the art will recognize that other
seals and
sealing mechanisms may be used.
The tube 7 may be formed from any suitable materialrsuch as borosilicate
glass. The
material should be chosen for specific clarity, strength and compa~ibility
requirements of
a given application. Although the tube 7 and the body 12 do not have to be
tubular, this
is certainly the easiest configuration for manufacturing purposes.
The fill cap 13 has a tubular plug 25 with exterior threads 27. The cap 13 has
a grip
section 29 with a roughened surface 31. Inside the grip section 29 about the
centre of
the cap i3 is a reverse conical thread 33 (see Figure 2) into the cap 13. The
thread 33
corresponds to the tluead 17. Through the centre of the cap 13 is a bore 35.
The body 11 is tubular and has threads 37, 39 at opposing ends atiout its
interior.
Between the threads 37, 39 through the body, equally spaced about the axis of
the body
I 1, are three openings 41 (two openings 41 are evident in Figure 1, while
only one is
shown in FigutTr 2). Beyond the threads 37 moving into the body l l, the
internal
diameter of the body 11 is narrowed by an annular projection 43. ~ Between the
projection 43 and the threads 39, the internal diameter of the body 11 widens
to a
support surface 45.
The injector 1 is assembled by inserting seal 9 into the body 11 past the
threads 39 until
it meets the projection 43. The tube 7 is inserted in a similar manner. The
external
diameter of the tube 7 and the internal diameter of the support suiface 45 are
matched to
allow far expansion and contraction differences between the various materials
at the
temperatures likely to be encountered by the injector 1. A few thousands of an
inch
CA 02211898 1997-07-30
WO 96/24827 PCT/CA96100083
between the tube 7 and body 11 is usually sufficient at operating
temperatures. The seal
is then inserted into the injector 1 and the coupler 3 threaded into the body
11. The
coupler 3 squeezes the seals 5, 9 and creates a continuous surface from the
projection 43
through the internal diameters of the seal 9, the tube 7, the seal 5 and the
coupler 3.
5 To remove the tube 7, for cleaning, repair or replacement, the reverse
process is
followed.
The fill cap seal 12 is inserted to the opposite side of the projection 43 and
the fill cap 13
is threaded into the body 11 until the fill cap 13 squeezes the seal 12 and
creates a
continuous surface from the projection 43 through the internal diameters of
the seal 12
and the fill cap 13.
Referring to Figure 3, a charging system 49 has a high pressure side 51 and a
low
pressure side 53 and is connected to a source of refrigerant supply 55. A low
side hose
57 is connected from the charging system 49 and threaded into the threads 33
of the cap
13. The valve coupler 3 is threaded at the threads 17 into an on-off two way
ball valve
59. Another suitable valve could be used, however a two way is recommended in
case
the injector 1 is connected backwards. The valve 59 is connected through a
further low
side charging hose 61 to the low side 62 of an air conditioning system 63.
In operation, the valve 59 is closed, the fill cap 13 is manually unthreaded
from the body
11 at the threads 27 by gripping the roughened surface 31. The body 11 is held
vertically
and liquid to be injected into the air conditioning system 63 is poured into
the tube 7 up
0
to the threads for the fill cap 13. The fill cap is then re-threaded into the
body 11.
8
CA 02211898 2004-09-21
As is clear from Fig. 2, since tube 7 is sealed to body 11 via seal 9 and
projection 43, no liquid can
escape through holes 41. Accordingly, the fill end of the tube 7 is sealed to
body 11 even when the fill
end cap 13 is removed.
8A
CA 02211898 1997-07-30
WO 96/24827 PCTtCA96tU0083
Excess liquid is squeezed. out the threads 27 as the fill cap 13 is threaded.
This ensures
that a minimum of air is retained in the injector 1. Injecting air into an air
conditioning
system 63 could render the system 63 unstable and potentially dangerous.
The valve 59 is then opened to provide fluid connection to the air
conditioning system
63. The charging system 49 is activated using refrigerant to propel the liquid
from the
injector 1 into the system 63. Having the valve coupler 3 immediately adjacent
the valve
59 lessens the chance that air will be introduced between the injector 1 and
the valve 59
and injected into the pressurized system.
Examples of liquids that can be used are a fluorescent dye, refrigerant oil
combination
used to detect leaks from the system 63 as the dye escapes from the system 63
and is
made visible using an ultraviolet light. The dye has a distinctly different
colour from
refrigerant. The interior of the injector 1 can be viewed through one opening
41 and the
tube 7, while light flows in the other openings 41 and the tube 7 to
illuminate the interior.
In this way one can check that the dye has been fully propelled from the
injector 1.
The tube 7 must at a minimum be non-opaque to allow the user to determine if
sufficient
amounts of the liquid have been propelled. Determining a sufficient amount
will depend
on the particular applicavtion of the user. For better viewing it is
preferable to use a
transparent tube 7. The colour of the tube 7 must be compatible with the
contents to be
viewed. For example, some fluorescent dyes are yellow and refrigerant is clear
so the
use of a yellow tube 7 is not advisable. For the widest general use, the tube
7 will be
clear.
The body 11 shields the tube 7 as the injector 1 may be subject to a good deal
of
knocking about in a shop or repair environment. The body 11 can be machined
from
9
CA 02211898 1997-07-30
WO 96/24827 PCT/CA96/00083
aluminum or brass stock, with the valve coupler 3 and fill cap 13 separately
manufactured, preferably from the same material as the body for compatibility
purposes.
The body 11 can be formed from other materials of suitable strength that are
compatible
with the liquid.
The preferred embodiment has been described with reference to injection of dye
into an
air conditioning system 63. For use with automotive air conditioning systems
pressures
are typically in the range of 145 to 180 psi. It will be evident to those
skilled in the art
that the principles described herein can be extended for use in other
applications where
liquids are to be injected under pressure. For example, the injector could be
used to
inject refrigeration oil or to inject chemical additives as described in US
patent no.
4,745,772 issued May 24, 1988 to Ferris mentioned previously.
In another aspect, Figures 4 and 5 show a supplemental reservoir 401 used in
conjunction with an inline end fill injector 403. The injector 403 could be
the same as
the injector 1; however, it does not need to be. The injector 403 need only
separate
between an end cap 429 and a body 407. Like names are used for components that
are
similar in the Figures showing injector 403 to those in the Figures showing
the injector 1;
a detailed description will not be repeated. Although the injector 403 is
shown without a
window, such as opening 41 of injector l, a window would continue to be useful
for the
reasons discussed above with regard to the injector 1.
The reservoir 401 has a cylindrical adaptor 409 and a cylindrical base 411.
The adaptor
409 is enclosed at one end, except for an aperature 413. The aperature 413 is
surrounded by a cylindrical nipple 415 with threads 416. The threads 416
correspond to
threads 417 in a first opening at one end of the body 407. At the opposing
end, the
CA 02211898 1997-07-30
WO 96124827 PCTICA96100083
adaptor 409 has outside threads 418. The base 411 has interior threads 419 at
one end,
corresponding to threads 418. The opposing end of the base 411 is enclosed,
except for
an aperature 421 surrounded by threads 423 (see Figure 5).
The adaptor 409 and base 411 are threaded together to form a hollow receptacle
434
which encloses chamber .435 (see Figure 5). A liquid gasket, commonly referred
to as
"lock tight", not shown, i.s poured in the threads 419 and threads 418. This
seals the
adaptor 409 and base 41:1 for pressure applications and prevents them from
being
unthreaded by the user.
A two piece receptacle 434 formed from an adaptor 409, base 411 combination is
used
for manufacturing reasons. The receptacle 401 shown in the Figures is made
from metal
(aluminum) and it is easiest to hollow out the adaptor 409 and base 411 from
their open
ends. It is possible to make a single piece receptacle 401 using blow moulding
or other
such techniques. The manetial and dimensions of the receptacle 401 must be
selected to
withstand the pressures of the particular application; pressure of 1200 PSI
are ouside
design limits for a wide variety of air conditioning applications.
Threads 423 correspond to threads 425 on plug 427 of end cap 429. Threads 425
of the
end cap 429 also correspond to threads 417 of the injector 403 and are the
same as
threads 416 of the adaptor 409. Similarly, threads 423 are the same as threads
39 and
correspond to threads 41L6.
Seals 431, 433 are similar to seal 12 described previously.
In operation, as shown in Figure 5, seals 431, 433 are placed in the opening
to body 407
and the aperature 421. 'Che receptacle 401 is threaded to the injector body
403 and the
cap 429. In this way, th~r effective capacity of the injector 403 is
increased. Dye, oil or
11
CA 02211898 1997-07-30
WO 96/24827 PCT/CA96/00083
other liquids, not shown, can be added through the aperature 421 (when the cap
429 is
removed) until the injector 403 and receptacle 401 are filled. The cap 429 is
then
threaded to the receptacle 401 in the same manner that cap 13 is threaded to
injector 1.
The reservoir 401 saves having to use separate injectors for different desired
capacities.
Injectors are fairly expense components, particularly where a window is used.
Although
a reservoir 401 may be used for injecting dye, it is particularly useful for
injecting
refrigerant oil where larger amounts of liquid are typically used.
These advantages are multiplied by using a set of reservoirs 401 in different
capacities.
For example, reservoirs 401 with 2 ounce, 4 ounce and 6 ounce capacities would
allow
for 2, 3, 4, 5, 6, 7, and 9 ounce capacities when used alone or piggybacked by
threading
one reservoir 401 to another between the injector 403 and cap 429. Previously,
7
different injectors would be used to allow for each of these different
capacities. The
reservoirs 401 are not restricted simply to these sizes; these are examples
only. The
savings are particularly significant when greater capacity injectors are
desired.
As shown in Figure 6, different effective reservoir 401 sizes can be created
using base
411 and a set of different sized adaptors 409A, 409B and 409C. For example,
adaptor
409A when combined with base 411 may create a 2 ounce capacity chamber 435;
adaptor 409B and base 411 may create a 3 ounce capacity; and, adaptor 409C and
base
411 may create a 4 ounce capacity. Although only one base 411 is shown in
Figure 6, it
is understood that a base 411 would be provided for each adaptor 409 in this
application.
Larger permutations and combinations are possible with greater numbers of
adaptors 409
and bases 411, and greater variety in the sizes of the adaptors 409 and the
bases 411.
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WO 96/24527 PCTICA9GI00083
It is possible to provide reservoirs 401, adaptors 409, bases 41 l, and
injectors 403
separately or in sets. For pressure applications it may be desirable to
provide assembled
sealed reservoirs 401 ratter than require the user to perform the assembly or
permit the
user to use the reservoir ~401 without a proper seal between adaptor 409 and
base 411.
It will be understood by those skilled in the art that this description is
made with
reference to the preferred) embodiment 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.
13
