Filter drier

• US 4,637,881 A
• Filed: 12/03/1984
• Issued: 01/20/1987
• Est. Priority Date: 03/30/1983
• Status: Expired due to Term

• Current Assignee: Emerson Electric Company
• Original Assignee: Emerson Electric Company
• Inventors: Sciuto, George J.
• Primary Examiner(s): Fisher, Richard V.
• Assistant Examiner(s): Jones, W. Gary
• Application Number:
  US06/677,934
• Time in Patent Office: 778 Days
• Field of Search: 55/316, 55/418, 55/482, 55/509, 55/DIG. 17, 62/474, 62/475, 210/264, 210/266, 210/282, 210/283, 210/285, 210/287, 210/289, 210/290, 210/291, 210/435, 210/446, 210/451, 210/456, 210/DIG. 6, 210/689, 210/806
• US Class Current: 210/689
• CPC Class Codes: B01D 27/00 Cartridge filters of the throw-away type
• CPC Class Codes: B01D 27/02 with cartridges made from a mass of loose granular or fibrous material
• CPC Class Codes: F25B 43/003 Filters
• CPC Class Codes: Y10S 210/06 Dehydrators

Abstract

A filter drier is disclosed for installation in a liquid refrigerant line of a refrigeration system, the filter drier comprising a housing having an inlet at one end thereof and an outlet at the other end thereof. The liquid refrigerant is discharged from the inlet into the housing in a jet and a perforate plate is provided within the housing against which this jet impinges for diffusing the refrigerant jet substantially across the width of the housing. A filter filters the diffused liquid refrigerant and a bed of desiccant beads is provided with a perforate divider between the filter and the desiccant. A perforate support plate supports the desiccant bed and a second filter bears on the downstream perforate support plate with the desiccant being engageable with the second filter. A spring is interposed between the perforate divider and the housing upstream from the desiccant bed so that the spring applies a resilient, compressive force on the desiccant bearing on the second filter thereby to maintain the desiccant beads in a compacted state such that the diffuser plate and the first filter prevents the jet of liquid refrigerant from impinging directly on the desiccant beads thereby to substantially prevent movement of the beads relative to one another with attendant breakage or chipping of the desiccant beads.

Claims

1. A method of filtering liquid refrigerant in a refrigeration system, said system comprising a compressor for receiving refrigerant vapor and for compressing it to an elevated pressure, a condensor for rejecting heat from said compressed vapor, an evaporator for absorbing heat from its surroundings, and a thermostatic expansion valve between said condensor and said evaporator for expanding said refrigerant, said method comprising the steps of:

between said condensor and said evaporator, first directing a jet of said refrigerant into a filter drier, said filter drier having a housing having an inlet and an outlet;

then, diffusing said jet as it enters said filter drier;

then, passing said diffused jet of refrigerant through a primary filtering means, said primary filtering means comprising a plurality filter pads stacked in face-to-face relation;

then, passing said refrigerant through an intermediate perforate support plate;

then, passing said refrigerant through an upstream fibrous filtering pad, said upstream pad being of a fibrous filtering media extending transversely across the full cross section of said filter drier housing, said intermediate plate and said upstream pad being axially shiftable within said filter drier;

then, passing said refrigerant through a bed of desiccant media comprising a multiplicity of desiccant beads;

passing said refrigerant through a downstream fibrous filtering pad;

then, passing said refrigerant through a downstream perforate support plate for discharge from filter drier housing via said outlet; and

resiliently compacting said desiccant bed between said upstream and downstream filtering pads thereby to maintain said desiccant beads in a compacted state even when the flow of said jet of refrigerant is alternately started and terminated so as to substantially prevent movement of said beads relative to one another upon the start-up and shut down of said compressor.

2. The method of claim 1 wherein, during operation of said refrigeration system, alternately compressing and releasing the compression of said primary filtering means upon the start-up and shut down of the flow of liquid refrigerant through said filter drier so as to dislodge particulate matter entrapped on said primary filtering means and to entrap said dislodged particulate matter on another portion of said primary filtering means prior to coming into contact with said desiccant bed.

3. A filter drier for installation in a liquid line of a refrigeration system, said filter drier comprising a housing having a shell and a shell end at each end of said shell, an inlet, an outlet, and a flow path for the flow of liquid refrigerant through said housing from said inlet to said outlet, a bed of desiccant media including a multiplicity of desiccant beads within said housing adjacent said outlet, downstream filter means between said desiccant bed and said outlet, downstream perforate support means, the latter being fixed relative to said downstream shell end against axial movement toward said outlet for holding said desiccant bed and said downstream filter means in position within said housing and for permitting the flow of liquid refrigerant from said downstream filter means to said outlet, intermediate perforate support means within said housing on the upstream side of said desiccant bed, said intermediate perforate support means being movable axially within said housing and being positioned upstream from said desiccant bed, upstream filter means disposed between said desiccant bed and said intermediate perforate support means, primary filter means between said intermediate perforate support means and said inlet, said primary filter means having a primary filter body, upstream perforate support means between said primary filter means and said inlet for diffusing a jet of liquid refrigerant discharged from said inlet substantially across the width of said shell at the upstream end thereof so that said diffused stream of refrigerant flows through said primary filter means, said upstream perforate support means being fixed relative to said upstream shell end against axial movement toward and away from said inlet, said downstream and upstream filter means each comprising one or more suitable pads of fibrous filtering media extending transversely across substantially the full cross section of said housing, and a compression spring interposed between said upstream perforate support plate and said intermediate perforate support means for applying a resilient, compacting force on said desiccant bed between said upstream filter pad and said downstream filter pad thereby to maintain said desiccant bed in a compacted state even when the flow of said refrigerant is alternately started and stopped so as to substantially prevent movement of said beads relative to one another, said spring being free of said primary filter body such that said primary filter body is substantially free of axial compaction by said spring.

4. A filter drier as set forth in claim 3 wherein said primary filter means includes a plurality of filter pads stacked in face-to-face relation constituting said primary filter body and a last filter pad opposite said inlet, said last filter pad extending across substantially the entire cross section of said housing while the other pads constituting said primary filter body being of a cross sectional area somewhat less than the cross section of said housing, said filter pads constituting said primary filter body being alternately compressed and released upon startup and shutdown of the flow of liquid refrigerant whereby particulate matter entrapped on the upstream pads of said primary filter body is dislodged upon the axial compression and elongation of said primary filter body and is then entrapped by said last filter pad of said primary filter means thereby to increase the dirt retention properties of said primary filter means.