EP0666456B1 - Refrigerant receiver/drier - Google Patents

Description

BACKGROUND OF THE DISCLOSURE
• The present invention relates to drying, filtering, and collecting liquidrefrigerant in the high pressure side of a liquid vapor recirculating refrigerationsystem. Typically, in such systems, a device is interposed in the refrigerant linebetween the condenser and the thermal expansion valve or capillary tube for thepurpose of removing moisture and foreign matter which could cause freezingand/or blocking of the flow upon expansion through the valve or capillary.
• Heretofore, in providing receiver/driers for automotive air conditioningsystems, it has been the practice to employ desiccant beads on the order of1/16 inch (1.6 mm) diameter in a container such that the refrigerant flowsthrough the desiccant beads into a collecting chamber and then is dischargedfrom the collecting chamber by flow through a standpipe. The construction ofthe receiver/drier, which is typically formed in a cylindrical configuration ofmetal material has proven to be troublesome. Where it is desired to provide afiltering function in addition to the drying function, it has been required toprovide filtering media adjacent the ports in the desiccant container in order tofilter all of the liquid refrigerant passing through the desiccant material.Because of the relatively high pressures on the order of 350 psi (2415 KPa),substantial forces are created across the desiccant and filter material, which hasresulted in blockage of the flow openings in the desiccant container, and alsoincreased weight due to the additional material required in the desiccantcontainer to withstand such forces.
• The additional forces created by the large pressure drop across the filtermaterial has rendered the construction, assembly, and attachment of thedesiccant container to the header or attachment plate a problem area in massproduction. It has also been desired to find a way or means of containing thedesiccant during assembly in a manner which prevents the beads from spillingfrom the container during the assembly operations.
• US patent 5 038 582 discloses areceiver/drier comprising features (a), (b) and (c) to (e) of claim 1, as well as a closure header with inlet and outlet port.The receivercomprises a desiccant charging portion 6 (inner shell) utilizing a steppedportion in a tank body (outer shell). The stepped portion acts to assuredlysupport the desiccant charging portion for the purpose ofpreventing it from being displaced by the pressure of therefrigerant which is introduced through a refrigerant inletportion. The desiccant charging portion comprises an uppersupport.
SUMMARY OF THE INVENTION
• The present invention provides a novel and improved construction for arefrigerant receiver/drier having filters therein as defined in claim 1. This construction employs a thinwall container cup for the desiccant beads with flow ports formed as louveredslots in the closed end of the cup in a manner which stiffens the closed end ofthe cup to resist the pressure forces on the filter material disposed adjacent theopenings. The closed end of the cup has a central opening, enabling the cup tobe assembled over the standpipe and the desiccant beads loaded into the cup.A cup closure plate having similarly formed louvered slots is assembled over theupper end of the standpipe and into the cup, thus closely containing thedesiccant beads therein. The assembly of the standpipe, desiccant, filter, andplate is then assembled onto a header and the sides of the cup are deformedthereover to attach the cup to the header. The outer shell is then received overthe assembly thus far formed in the shell, and is sealed and retained on theheader by weldment.
BRIEF DESCRIPTION OF THE DRAWING
• The invention is illustrated in cross-section taken along the longitudinalaxis thereof.
DETAILED DESCRIPTION
• Referring to the drawing, the receiver/drier of the present invention isindicated generally at 10 and comprises a header orattachment block 12 whichhas formed therein aninlet port 14 and anoutlet port 16 centrally located in theheader, and which has attached thereto, preferably by press-fitting therein, astandpipe 18. The standpipe passes centrally through a generally cup-shapedinner shell 20, which is filled with desiccant material in the form ofbeads 22and theshell 20 is closed at its upper end by acover plate 24 through whichthestandpipe 18 passes. The bottom or closed end ofshell 20 has formedtherein a plurality of spacedopenings 26 which are preferably formed aslouvered slits with thelouvers 27 formed integrally in the bottom of theinner shell 20. Similarly, theclosure plate 24 has a plurality of spacedopenings 28formed therein which are also preferably formed as louvered slits by integrallystampedlouvers 29.
• In the present practice of the invention, the layer offilter material 30 isdisposed adjacent theopenings 28 in the cover plate; and, similarly, a layer offilter material 32 is disposed adjacent theopenings 26 in the bottom of theinner shell 20. In the present practice, it has been found satisfactory to employfibrous glass material for thefilter layers 30,32; and, the material may bewoven or in wool-like arrangement of the fibers. Thedesiccant beads 22 in thepresent practice of the invention are beads on the order of 1/16 inch (1.6 mm)and a material described as a molecular sieve and bearing manufacturer'sdesignation XH-7, obtainable from UOP, Incorporated, 2511 Country Club Blvd.,North Olmsted, Ohio 47070, has been utilized. Theheader 12,standpipe 18,desiccant container 20, andcover plate 28 are preferably formed of aluminummaterial for light weight and ease of fabrication.
• At assembly, thelower filter layer 32 is installed in the container cup orinner shell 20, and thestandpipe 18 inserted through the central openingtherein. The desired amount ofdesiccant beads 22 is then loaded into theinnershell 20. Theupper filter layer 30 is then received over the standpipe and theclosure plate 24 is likewise received over the standpipe and inner periphery oftheinner shell 20 to retain thefilter 30 anddesiccant beads 22 therein in asubassembly.
• Theheader 12 is formed with aperipheral groove 34 in a reduceddiameter portion 36 thereof. The open end of the inner cup orinner shell 20 isreceived over the lip ofgroove 34. Portions of the wall of theshell 20 aredeformed inwardly as, for example, with a punch to retain theinner shell 20onto theheader 12; and, these deformed portions are denoted byreferencenumeral 38 in the drawing. The standpipe is then press-fitted into theoutletport 16 in theheader 12.
• An outer shell orcasing 40 is then received over thediameter 36 of theheader and secured thereon. In the present practice of the invention, theoutershell 40 is formed of an aluminum alloy similar to that ofheader 12; and, the outer shell is secured to theheader 12 by weldment as indicated byreferencenumeral 42.
• The receiver/drier of the present invention is constructed of lightweightmaterial, and has the desiccant beads thereof contained in a cup-shaped innershell received over the standpipe with a cover plate also received over thestandpipe and received in the open end of the cup-shaped shell to retain thedesiccant material therein. The closed end of the container cup and the coverplate have spaced flow openings therein which are formed as louvered slits,which stiffen the material thereof against the forces of the fluid pressureresulting from the flow restriction created by the pressure drop across the filtermaterial disposed adjacent the flow openings. The present invention permitsthe inner shell or cup-shaped material to be assembled as a subassembly overthe standpipe in a manner which reduces spillage of the desiccant material andhandling problems during assembly.
• Also it should be noted that said desiccant comprises according to oneembodiment of the invention glass bead material.
• Although the invention has hereinabove been described with respect tothe embodiment illustrated in the drawing, it will be understood that theinvention is capable of modification and variation, and is limited only by thefollowing claims.

Claims (12)

1. A receiver/drier for refrigerant comprising:

   (a) a generally cup-shaped outer shell (40);

   (b) a generally cup-shaped inner shell (20) having formed in the closed endtherein a plurality of spaced openings (26), said inner shell (20) disposed within said outer shell (40);

   (c) a closure header (12) attached to the open end of said outer shell (40), saidheader (12) having an inlet port (14) therein and an outlet port (16) with astandpipe (18) attached thereover, wherein portions (38) of the wall of the inner shell (40) are deformed to retain the inner shell (40) onto the closure header (12);

   (d) desiccant material disposed in said inner shell (20); and,

   (e) a closure plate (24) secured to said inner shell (20) at the open end thereof,said closure plate (24) having formed therein a plurality of spacedopenings (28), wherein said standpipe (18) extends through said closureplate (24), said desiccant and said closed end of said inner shell (20) forcommunicating said outlet port (16) with the interior region of saidouter shell (40) between the closed end thereof and the closed end ofsaid inner shell.
2. The receiver/drier defined in claim 1, further comprising first filter means (32)disposed adjacent said openings (26) in said inner shell and a secondfilter means (30) disposed adjacent said openings (28) in said closureplate (24).
3. The receiver/drier defined in claim 1, wherein said closureheader (12), said closure plate (24), and said inner shell (20) with said desiccanttherein are assembled over said standpipe (18) and attached to said closureheader to form a sub-assembly.
4. The receiver/drier defined in claim 2, wherein said first and second filtermeans (32,30) each comprises a layer of fibrous material.
5. The receiver/drier defined in any of claims 1-4, wherein said spaced openings (26; 28) insaid inner shell (20) and said closure plate (24) are louvered.
6. The receiver/drier defined in claim 1, wherein said header (12) has a reduceddiameter portion and said inner shell (20) is thereover and secured thereto bylocalized deformation thereof.
7. The receiver/drier defined in claim 1, wherein said inner shell (20), the closureplate (24), and standpipe (18) are formed of aluminum material.
8. The receiver/drier defined in claim 1, wherein said desiccant comprisesglass bead material (22).
9. The receiver/drier defined in claim 1, wherein said spaced openings (26) insaid inner shell (20) are louvered in a manner so as to direct flow therethroughagainst the inner surface of said outer shell.
10. The receiver/drier defined in claim 1, wherein said desiccant materialcomprises beaded material.
11. The receiver/drier defined in claim 4, wherein said filter materialcomprises fibrous glass material.
12. The receiver/drier defined in claim 1, wherein said standpipe (18) is press-fittedinto said closure header (12).

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