WO1991002932A1

WO1991002932A1 - Flexible gas salvage containers and process for use

Info

Publication number: WO1991002932A1
Application number: PCT/US1990/004218
Authority: WO
Inventors: David C. H. Grant
Original assignee: Ashland Oil, Inc.
Priority date: 1989-08-16
Filing date: 1990-07-27
Publication date: 1991-03-07
Also published as: AU6182190A; CA2042590A1

Abstract

Process and system for recovering refrigerant from refrigeration systems without substantial contamination of the atmosphere, said system comprising means for removing refrigerant from the system under the vapor pressure of the refrigerant or with aid from a compressor or other pump, conduit means for conveying the refrigerant from the system, and a collapsible bag constructed of a flexible material substantially impermeable to refrigerant and to air, having at least one inlet for introducing refrigerant to be salvaged and sealing means for sealing the inlet on the bag. After filling, the bag may be transported to a recovery system for recovering refrigerant from the bag so that the refrigerant may be purified and recovered for reuse.

Description

FLEXIBLE GAS SALVAGE CONTAINERS AND PROCESS FOR USE

This application is a continuation-in-part of UΞSN 394,594 filed August 16, 1989.

Cross Reference to Related Application

USSN 07/371,785 filed June 27, 1989 (RI-6346AUS) relates to the general field of recovery of refrigerants and names the same inventor as the present application and employs slack-sided accumulators which can be similar to the bags used in the present invention.

Background of Invention The loss of refrigerant such as R-12 refrigerant from refrigeration systems, particularly during servicing of automotive air conditioning systems is the subject of much public concern at this time. A refrigeration service mechanic in servicing the air conditioning system normally vents the same. During venting, a significant amount of R-12 vapor is lost from the air conditioning system. There is a need, therefore, to provide a practical, simple, effective and low cost refrigerant recovery and restoration system which will allow the mechanic to vent an automotive air conditioning system with full recovery of the vapor contained therein, to provide a system which at least in part is relatively transportable to the situs of the automotive or like air conditioning or refrigeration system, which produces reclaimed refrigerant of equal quality in comparison to virgin refrigerant, which is small in size, but which will be capable of operating with the volume of normal automotive air conditioning service operation.

Attempts have been made to produce an effective refrigerant recovery and/or disposal, purification and recharging system. Issued U.S. Patents representative ₃ of such known systems are: U.S. 3,232,070; 4,285,206;

₄ 4,363,222; 4,441,330; 4,476,688; 4,539,817; 4,554,792;

₅ 4,646,527; and 4,766,733.

6 η These patents disclose as aspects of such

₈ refrigerant recovery systems the employment of

9 components such as vacuum pumps, oil separators, _Q condensers, liquid refrigerant receivers and accumulators. Unfortunately, the systems identified 2 above are characterized by complexity and high pressure 3 operation and are plagued with maintenance problems due 4 particularly to the high pressure portions of the system. 6 7 It is therefore an object of the present invention 8 to provide an improved, low cost, simple, essentially 9 atmospheric pressure operated refrigerant recovery and 0 restoration system which operates primarily as a direct 1 condensation process, which has particular application 2 to servicing automotive air conditioning systems, but is 3 not limited thereto, and which may be advantageously 4 employed in servicing home refrigerators or systems 5 using R-12 as refrigerant, and which obviates the 6 problems discussed above with respect to the known prior 7 art. 8 9 All of the prior attempts to recover refrigerant

30 have suffered from the difficulty that they require

31 extensive apparatus to be brought to the site where the

32 refrigerant is to be salvaged, or that the refrigeration

33 unit being serviced has to be brought to a central

34 reclaiming system. The present invention, by its use of

35 approximately atmospheric pressure, bags which may be

36 either reusable or even disposable, permits a

37 refrigeration service engineer to fill a number of the

38 bags at various locations where refrigerant is to be

39 salvaged and, for example, at the end of his working

40 day, return these bags to a central refrigeration recovery system where the refrigerant may be condensed and purified for reuse.

Another method which was used in the past for recovering refrigerant was to fill small pressure vessels with the refrigerant by compressing the refrigerant into the pressure vessels through the action of the compressor on the refrigeration unit from which the refrigerant is being withdrawn or by action of a liquid pump or a vacuum pump. As anyone connected with liquified compresses gas handling knows, over-filling of any pressure vessel is always of concern. Pressure relief devices are not always reliable and may fail to open after years of hard handling in and out of trucks, contamination by grease and oil, corrosion, etc. Therefore, the possibility of hydrostatic rupture and even explosion is always present when a pressure vessel is being filled. This danger is greatly extenuated when the filling is being done in the field under adverse circumstances and generally without any weighing device, often by only modestly experienced personnel.

It is an object of the present invention to provide a safe, low cost, simple, essentially atmospheric pressure refrigerant recovery system which avoids the need for bringing expensive, bulky equipment to the location from which the refrigerant is to be salvaged. Another object is to provide a reclaiming system which is light and small which can be brought to the salvage site. Still another object is to avoid having a mechanical reclaiming system for each service mechanic or for small companies which may not be able to justify the purchase of reclaiming systems. Still another object is to avoid the difficulty of smaller reclaiming systems which may take too long to recover the refrigerant vapor which is being salvaged. A further object is to provide a simple, easy to use, lightweight system to capture refrigerant vapor at the service site; 2 to allow reclaiming at a later time without delaying the

. service work; and to allow a central reclaiming unit to

₅ reclaim refrigerant form a multiplicity of service men e each servicing a multiplicity of refrigeration units. η Another object is to avoid loss of CFC vapor to the g atmosphere by making practical reclaiming of vapor from

9 scrapped or disabled refrigerators, automobile air

10 conditioners and other refrigeration systems or those

H requiring servicing.

12 3 The present invention provides economic,

14 convenience, and safety advantages over the solutions

1 taught in the prior art because the bags used by the 5 present invention are cheap and disposable or reusable, 7 the bags take up virtually no space prior to their being

18 filled, and the bags, if somehow overfilled, will merely

19 rupture softly by tearing apart at the weld or

20 elsewhere, without any danger of explosion due to high

21 pressure rupture such as would be involved in the

22 failure of a pressure vessel.

23

24 Summary of the Invention

25 The present invention utilizes slack-sided bags

26 (bladders or balloons) to contain refrigerant vapor from

27 refrigeration units from which the refrigerant is to be

28 salvaged, e.g. refrigerators which need compressor

29 replacements, commercial cold display case units,

30 household and commercial heat pumps, automotive air

31 conditioners, and any other system which utilizes

32 halogenated hydrocarbons or other liquifiable gases as

33 refrigerants in connection with a compressor, condenser,

34 and evaporator.

35

36 The present invention embodies the recognition that

37 bags of a practical size can contain refrigerant vapor

38 from automobiles, home refrigerators, supermarket

39 display cases, etc. at substantially atmospheric

40 pressure. For example, a typical household refrigerator contains 0.5 pounds of refrigerant which is equivalent to approximately 1.6 cubic feet at atmospheric pressure and 90°F. The refrigerant vapor capture apparatus is shown.

Brief Description of the Drawings

Figure 1 is a schematic diagram of the overall system of the present invention showing the refrigeration system from which refrigerant is to be salvaged, the bag, and the refrigerant vapor capture system .

Figure 2 is a schematic diagram of an improved means to attach the bag to the refrigeration system for the purpose of transferring the refrigerant vapor from the refrigeration system being serviced to the bag using a convenient handle and commercially available double shut off quick disconnect coupling to connect to the conventional serviceman's refrigeration gauge set and connecting hose.

Figure 3 is a section diagram of a simple valve for withdrawing refrigerant from the bag at the inlet to the refrigerant reclaim system.

Figure 4 is a manifold which is connected to the refrigerant recovery/purification system.

Figures 5a and 5b are typical clips for sealing the bag of Figure 1.

Figure 6 is a schematic of a preferred flexible bag in a flexible sleeve with carrying handle.

Figure 7 shows the bag-sleeve assembly of Figure 6 in a rolled configuration. ~ Description of the Preferred Embodiments

. Referring to Figure 1, 10 is a typical home

₅ refrigeration system showing the evaporator 11, the

₆ accumulator 12, the compressor 13, the condenser 14, and η the capillary 15.

8

₉ A conventional piercing valve 16 is placed on the 0 low pressure side of the compressor and a conventional 1 piercing valve 17 is placed on the high pressure 2 discharge of the compressor. Hoses 19 and 19a lead 3 respectively from piercing valves 16 and 17 to 4 conventional refrigeration service gauge set 18 which 5 consists of a manifold with high and low pressure gauges connecting to hoses 19 and 19 . A third hose 20 leads 7 from the gauge set to inlet valve 25. This connection ₈ between gauge set 18 and inlet valve 25 can optionally 9 (not necessarily) be through a vacuum pump 21 with 0 appropriate valves 22 and 23 to evacuate the ₁ refrigeration system. This vacuum pump would be 2 particularly useful in salvaging refrigerant from an 3 automobile air conditioner. Valve 25' is shown in detail ₄ in Figure 2 and consists of a commercial double shut off 5 quick disconnect coupling, male part 25a and female part 6 25b, mechanically connected to aluminum handle 26, and ₇ discharging through a longitudinal hole 27 drilled in

28 the tapered end 28 of handle 26. A slack-sided bladder

29 or accumulator 30 has an outlet 31 which fits snugly

30 over the tapered end 28 of handle 26 and is further

31 sealed by an elastic band 40 which is stretched over the

32 bladder outlet 31 to compress it to the handle 26.

33

34 The handle 26 (or valve tip 62) has a tapered end

35 28 such that a bag connection 31 can be put onto or

36 removed from the handle without any significant loss of

37 refrigerant or entry of air. The connection 31 conforms

38 to the geometry of the tip 28 (or 62) which gradually

39 changes the shape of the bag connection 31 from two 40 ₃ sheets of film flat against each other to the condition

. where the film is wrapped around the handle 26 (or valve

_b. tip 62, as the case may be) as the tip 28 (or 62) is

₆ pushed into connection 31. The low pressure within the

₇ bag contributes to the desired conservation of o refrigerant vapor.

9 0 The accumulator assembly 50 is composed of: the 1 accumulator 30, a protective sleeve 51 which is similar 2 to an envelope open on three sides. The closed side has 3 a handle 52 for easy carrying of the accumulator 4 assembly 50, grommets 53 for easy hanging of the 5 assembly 50, closures 55 to hold the sides of the sleeve 6 51 around the accumulator 30 and a loop 56 for attaching 7 the seal clip 45 by means of cord 57. 8 9 Referring again to Figure 1, in operation, piercing 0 valves 16 and 17 are placed onto the tubing of 1 refrigeration system 10, a typical home refrigerator. 2 (Only one piercing valve is required, but using one on 3 the high side and one on the low side of the compressor 4 speeds the expelling of refrigerant.) Refrigerant flows 5 through tubes 19 and 19a into the refrigerant service

26 gauge set 18 through hose 20 and optional vacuum pump 21

27 into valve 25 and through handle 26 into slack-sided

28 accumulator 30. The slack-sided accumulator is flat

29 when the refrigerant begins to flow in, and gradually

30 expands to a plump pillow-like shape containing, in the

31 case of a home refrigerator, up to about 1.6 cubic feet

32 of refrigerant vapor (0.5 lbs at 90°F) or in the case of

33 a typical automotive air conditioner up to about 11.4

34 cubic feet (3.5 lbs at 90°F) of refrigerant vapor. When

35 flow stops (as is easily observed by noting that the

36 accumulator is no longer expanding) , the accumulator

37 outlet 31 is removed from the valve 25 by removing the

38 seal band 40 and sliding the accumulator outlet 31 off

39 the valve, closing the opening by flattening the

40 connection as it slides off the tapered end of the valve 25, rolling it up and compressing it with seal clip 45 shown in Figure 5a. The accumulator assembly 50 is easily carried or hung in a service truck by means of either the handle 52 or grommets 53 which are an integral part of the sleeve 51.

After the service engineer has completed his workday, acquiring about one or more filled slack-sided accumulators or bags, he simply returns to the home shop and leaves the bags for condensing and purification of the refrigerant to be salvaged.

The refrigeration and recovery system can be completely conventional as shown in the U.S. patents mentioned under background of the invention, or can be of the novel configuration shown in my copending U.S. patent application USSN 07/371,785 (RI-6346AUS) .

The bags can be readily reused after the refrigerant has been expelled into the recovery/purification unit. The refrigerant is, of course, recycled for use in conventional refrigeration systems.

Though the above preferred embodiments have been described in a refrigeration system which would commonly use refrigerant 12, the system is also adaptable to recovery of refrigerants 11, 22, 502, 500, 503, 113, 114, and similar halogenated hydrocarbons. Other refrigerants may be recovered with the system, but these are less preferred because of toxic and possible corrosive hazards and because they are less commonly encountered in smaller refrigeration systems.

Bags: The bags for use with the present invention are not narrowly critical. For convenience and economy, they will preferably be made of sheet materials, preferably 2 hot stamped and welded to shape. They may, of course,

₄ be of virtually any shape, though the rectangular

₅ configuration shown in the figures will be preferred.

₆ Tucks or gussets may be added to increase the volumetric η capacity of the bag. The bag should be substantially ₈ impermeable to the gases they are to hold and to air because cross-contamination is undesirable as is well 0 known in the refrigerant art. The bags can have 1 specially formed fittings attached to their outlets but 2 there is generally no need for this expense and 3 additional weight. Instead, the bag will have a simple 4 extension outlet long enough so that it may be folded 5 over and clipped to seal the bag and also long enough to 5 provide a good seal on the filling and withdraw valves 7 26 and 60 shown in the Figures 1, 4 and 5, respectively. 8 9 Referring to Figure 3, the manifold valve 60 is 0 composed of body 61, tip 62, valve stem 63, tip seal 64, 1 stem seal 65 and handle 66. The tip is inserted into 2 accumulator 30 connection such that the end of the 3 connection is in the area of the cylindrical portion of 4 the tip 67. Seal band 40 is used to make the seal by 5 compressing the connection against the tip. 6 7 The tip is long enough to extend several inches 8 into the interior of the accumulator bag. It has one or 9 more, preferably three or four, exterior grooves running 0 parallel with the long dimension of the tip connected to 1 holes 69 drilled into the central gas conduit ("core").

32 When vapor is extracted from the accumulator it is

33 possible for the bag to deform covering the central

34 inlet hole 70 making extraction of further vapor

35 impossible. The external grooves 68 and holes 69

36 provide an alternate path for the vapor to enter the tip

37 62, thus, until all vapor is extracted, the bag cannot

38 be sucked into the tip openings. 39

40 2 After the accumulator connection 31 is attached to

₄ the tip 62, the handle 66 is used to pull the valve stem c 63 down unsealing the seal 64 and opening the central

₆ core to the pipe connections 71. These connections 71

7 provide for interconnection of more than one valve 60 g and connection to the refrigerant reclaim system.

9 0 Referring to Figure 4, valves 60 are arranged such 1 that several accumulator assemblies 50 can be connected 2 to their respective valves 60. Pipe connections 72 and 3 a plug 73 are used to interconnect the valves 60 and 4 seal the blind end and connect to the reclaim system 74. 5 5 When the operator desires to recover vapor from a 7 given accumulator 50, he connects the accumulator 50 to 8 the valve 60 then pulls handle 66 connecting the bag to 9 the reclaim machine. One or more valves 60 may be open 0 a one time. When a given bag is empty, its valve may 1 be closed, isolating it from the system. That bag may 2 then be removed and replaced without affecting the other 3 bags that are being emptied into the reclaim system. 4 5 While the materials and construction of the bags 6 are not narrowly critical and may be adapted to suit 7 particular needs, particularly preferred bags are 8 constructed from plastic film, more preferably from 9 Mylar brand polyester film manufactured by DuPont, and 0 most preferably from Mylar 50XM860 or Mylar MMC 1 metallized polyester film for excellent gas carrier 2 properties.laminated to about 4 mils of polyethylene or

33 similar film such as polypropylene or polyamide (e.g.

34 "nylon") to impart toughness to the structure. Atlanta

35 Film Converting Company produces such film in widths up

36 to 39 inches. Also preferred is the use of silicon

37 coated polyester film as a substitute for Mylar 50XM860

38 or MMC or the use of metallized polyethylene film

39 producing excellent gas barrier results. 40 2 In general, it will be sufficient for the bag to

₄ prevent diffusion of substantial amounts of refrigerant

₅ gas within the 8-24 hour period in which the bags will

₆ commonly be stored before being brought to the salvage η unit.

8 g Convenient sizes of bags are those holding 8 ounces 0 by weight of refrigerant and those holding about 3-3 \ 1 pounds of refrigerant. 2 3 In a particularly preferred embodiment. Figure 6,

1₄ the bag is inserted into a sleeve 30 which may be rigid

15 or preferably flexible, and may be made of any material 15 suitable for protecting the bag from mechanical damage.

17 These various sleeves may be made from any material

18 having sufficient mechanical properties, but Tyvec brand i is particularly preferred because of its toughness,

20 light weight, strength, and low cost. Handles 50,

21 closures 71, e.g. Velcro brand closure materials,

22 zippers or snaps may be used in the design of the

23 sleeve.

24

25 In a particularly preferred embodiment. Figure 7,

26 the sleeve 30 and bag are adapted so that they may be

27 rolled, e.g. by placing a rigid longitudinal stiffener

28 in the sleeve in the sleeve so that the sleeve with the

29 bag inside may be rolled up around the longitudinal

30 stiffener 70. A suitable case for the rolled sleeve-bag

31 assembly can be provided. Rolling saves space and

32 additionally protects from mechanical damage, extending

33 the life of the reusable bags and sleeves.

34

35 The exact design of the bag is also not narrowly

36 critical, but the outlet is preferably a snout which is

37 most preferably parallel with the long dimension of the

38 bag so that a larger capacity bag can be fabricated from

39 a given width of film with less waste. The snout is

40 shown as element 40 in Figure 1, and element 31 in Figure 2. The snout design has the advantages of

3

4 eliminating hardware from the bag, simplifying bag 5 manufacture, reducing cost and permitting removal of the 6 valve without substantial loss of refrigerant. The bag

₇ can have cemented or heat-sealed seams which may be

Q double seamed. Bags fail safely under extreme g conditions by soft failure rather than exploding as do ₀ rigid containers. 1 2 Additional details can be found in my copending ₃ application identified above. 4 5 Modifications 6 Specific compositions, methods, or embodiments 7 discussed are intended to be only illustrative of the 8 invention disclosed by this specification. Variation on 9 these compositions, methods, or embodiments are readily 0 apparent to a person of skill in the art based upon the 1 teachings of this specification and are therefore 2 intended to be included as part of the inventions 3 disclosed herein. 4 5 6 7 What is claimed is : 8

29

30

31

32

33

34

35

36

37

38

39

40

Claims

ACTIVE CLAIMS IN CASE:

3

4

51. An improved apparatus for recovering refrigerant from

6 multiple refrigeration systems which are spaced some

7 distance apart, said apparatus comprising in 8 g combination: 0 1 a. valve means for removing refrigerant from said 2 3 system under the vapor pressure of the refrigerant 4 with or without aid by compressor and/or pump 5 means, without significant refrigerant vapor loss 6 7 or cross-contamination with air. 8 9 b. a collapsible bag, said bag being constructed of a 0 1 flexible material substantially impermeable to 2 refrigerant and air, said bag having at least one

23 small orifice for ingress and egress of refrigerant

24

25 to be salvaged;

26 27 28 c. sealing means for sealing the outlet on said bag; 29 30 d. a recovery system comprising means for pumping or

31

32 expelling refrigerant from said bag, pressurizing

33 said refrigerant above its vapor pressure to

34 condense said refrigerant to a liquid; 35 36 37 38 39 40 e. purification means connecting to said recovery means for purifying said condensed liquid refrigerant by removing air, oil, moisture, and other impurities;

whereby said refrigerant is collected from various dispersed refrigeration systems into said bags and wherein said bags are transported to said central recovery system for recovery and purification of said refrigerant.

2. A process for the recovery of refrigerant from refrigeration systems comprising in combination:

a. filling a bag which is substantially impervious to said refrigerant and to air with said refrigerant through an opening connected to said refrigeration system;

b. transporting said bag to a central recovery system for recovering said refrigerant;

c. expelling said refrigerant from said bag at said central recovery system and condensing said refrigerant to a liquid and thereafter purifying said refrigerant for reuse.

3. A process according to Claim 2 wherein said refrigerant is removed from said refrigeration system through an existing service connection or a puncture type valve which punctures said refrigeration system and conducts said refrigerant into said bag without substantial loss of said refrigerant to the atmosphere.

4. An apparatus of Claim 1 wherein said bag lies substantially flat when deflated and has a bursting strength of less than about 2 atmospheres absolute.

5. A process according to Claim 4 wherein said bag has a handle or other means for carrying or hanging said bag.

6. An apparatus according to Claim 1 wherein said bag is formed from two flat opposing faces of meltable plastic film by hot stamping or the like.

An apparatus accrding to Claim 1, wherein the collapsible bag is constructed of material comprising polyester or equivalent polymer.

8. An apparatus according to Claim 7, wherein the polyester or equivlent polymer is laminated to a polyolefin or polyamide film.

9. An apparatus according to Claim 7, wherein the polyester

3 or equivalent is aluminized and/or silica coated.

5 6 10. An apparatus according to Claim 1, wherein the collapsible bag is insertable into a sleeve which serves 8 g to protect the bag from mechanical injury. 0

11. An apparatus according to Claim 10, in which the 2 3 sleeve-bag combination is adapted to be rolled up to 4 reduce space and further protect from injury. 5 6 7

12. An apparatus according to Claim 1, wherein said orifice 8 is a snout projecting from the bag which can be folded 9 to seal the bag. 0 1 2

13. An apparatus according to Claim 12, wherein the snout of 3 the bag engages tapered connecting means to enable 5 insertion and extraction of the connecting means without 6 substantial loss of refrigerant or entry of air. 27

28

29 14. An apparatus according to Claim 1, wherein said

30 connecting means has at least one groove along the outer 31 portion of its length, said groove being in 32

33 communication with holes extending into an inner gas

34 conduit to prevent said snout from being sucked into and 35 blocking gas removal before said bag is empty. 36 37 38 39 40

15. In an improved ap^paratus for recovering refrigerant from refrigeration ε ems comprising valve means for removing refrigerant from said system with or without aid by compressor and/or pump means comprising, without substantial refrigerant vapor loss or cross contamination with air, and container means for receiving the refrigerant removed from said refrigeration system, the improvement comprising in combination:

a. said container means comprising a collapsible bag constructed of a flexible material substantially impermeable to refrigerant and air, said bag having at least one small orifice for ingress of refrigerant to be salvaged;

b. sealing means for sealing the orifice on said bag, said sealing means comprising a flexible conduit which can be sealed by folding.

16. The improvement according to Claim 15, wherein said orifice means comprises a flexible conduit projecting from said bag which can be folded to seal said bag.

17. The improvement according to Claim 15, wherein said bag with said sealing means are substantially planar.

18. The improvement according to Claim 16, wherein said projecting conduit is adapted to engage tapered connecting means to enable insertion and extraction of the connecting means for injecting and/or removing refrigerant gas from said bag without substantial loss of refrigerant or entry of air.

19. The improvement according to Claim 17, wherein said connecting means has at least one groove along the outer portion of its length, said groove being in communication with holes extending into an inner gas conduit within said connecting means, to prevent said bag from being sucked in so as to block gas removal before said bag is substantially empty.