US3313123A

US3313123A - Condensate removal apparatus

Info

Publication number: US3313123A
Application number: US490451A
Authority: US
Inventors: Chester D Ware
Original assignee: Trane Co
Current assignee: Trane US Inc
Priority date: 1965-09-27
Filing date: 1965-09-27
Publication date: 1967-04-11
Anticipated expiration: 1984-04-11

Description

p L 67 I C.D.WARE 3,313,123

CONDENSATE REMOVAL APPARATUS Filed Sept. 2'7, 1965 INVENTOR.

CHESTER D. WARE Jig. 2 BY 2 M 4AM ATTORNEYS United States Patent Office 3,313,123 Patented Apr. 11, 1967 3,313,123 CONDENSATE REMOVAL APPARATUS Chester D. Ware, La Crosse, Wis., assignor to The Trane Company, La Crosse, Wis., a corporation of Wisconsin Filed Sept. 27, 1965, Ser. No. 490,451 11 Claims. (Cl. 62-272) This invention relates to refrigeration and cooling apparatus and more particularly to means for effectively re moving condensate from a fin-and-tube type heat ex-' a heat exchanger coil with a staggered fin edge on the leaving side of the coil. Specifically my invention comprises in combination a heat exchanger coil having an entering face and a leaving face; means for passing a stream of vapor containing gas from said entering face through said coil to said leaving face; said coil including a plurality of first and second fins arranged in face-toface relationship; each of said fins having a leaving edge disposed adjacent and substantially parallel to said leaving face; means for cooling said fins below the dewpoint of said vapor; over at least a substantial area of said leaving face, the leaving edges of said second fins being disposed downstream of the leaving edges of said first fins whereby condensate collected at the leaving edges of said first fins is transferred to the portions of said second fins disposed downstream of the leaving edges of said first fins where said condensate imposes little resistance to the passage of said gas through said coil.

It is a prime object of my invention to provide in a cooling fin-and-tube type heat exchanger means to reduce condensate carryover when operated under dehumidifying conditions.

It is a further object to provide means of reducing the pressure drop across a fin type heat exchanger caused by excessive accumulation of condensate. These and other objects will become more apparent as this specification proceeds to describe this invention with reference to the drawings in which:

FIGURE 1 is a schematic view of a refrigeration system incorporating my invention; and

FIGURE 2 is an enlarged section taken at line 22 of FIGURE 1 showing a portion of the heat exchanger coil thereof.

Referring to the drawing, a refrigeration circuit is shown as having a refrigerant compressor 10, a refrigerant condenser 12 connected to the discharge of compressor 10, a refrigerant expansion valve 14 connected to the outlet of condenser 12, and a refrigerant evaporator 16 connected to receive liquid refrigerant from valve 14 and to discharge vaporized refrigerant to the inlet of compressor 10.

Evaporator 16 includes a fin-and-tube heat exchange coil 18 having an entering face 20 and a leaving face 22. A fan 24 is arranged to pass moisture containing air through coil 18 from face 20 to face 22. A shroud 26 may be provided to direct the air from fan 24 to coil 18. A condensate drain pan 28 may be provided to collect condensate drained from the leaving face of coil 18.

Coil 18 is comprised of a plurality of generally planar metallic fins 30 of rectangular configuration disposed in spaced face-to-face relationship.

A plurality of tubes 32 extend perpendicularly through fins 30. Fins 30 may be connected to tubes 32 in any well known manner to provide a thermal conducting joint for transmission of heat from the fins to the tubes. The tubes 30 are appropriately connected at their ends as by U-bends 34 for providing a continuous refrigerant circuit from valve 14 to compressor 10. It should be understood that cooling media other than a refrigerant may be circulated through tubes 32 such as for example chilled water. Furthermore, other arrangements of the tubes may be employed without departing from the spirit of my invention.

Certain fins 36 of fins 30 have leaving edges 38 which are disposed downstream of the leaving edges 40 of other adjacent fins 42 of fins 30. The leaving edges 38 and 46 are vertically disposed. Fins 30 are spaced sufficiently close to enable condensate droplets to bridge between pairs of fins and permit condensate to be transferred from the surface of one fin to the surface of another fin.

During operation of the refrigerant system, compressor 10 compresses refrigerant and delivers it in a hot gaseous state to condenser 12 whereupon it is cooled and condensed to a liquid. The liquid refrigerant from condenser 12 is throttled to a lower pressure by valve 14 into coil 18. Evaporation of the liquid refrigerant within the tubes 32 of coil 18 cools fins 30 below the dewpoint of air passing thereover via fan 24. The evaporated refrigerant then flows to the suction side of compressor 10 for recirculation.

Since the fins 30 are cooled below the dewpoint of the air, moisture is condensed from the air along surfaces between the fins. The flow of air moves condensate droplets to the leaving face 22 of the coil. Droplets which reach the leaving edges 40 of fins 42 transfer to the portions 44 of fins 36 downstream of the leaving edges 40 thereof. Since portions 44 are free of notches, holes and attachments, they provide ideal paths for the condensate to flow freely downward into drain pan 28 without entraining condensate in the air passing over the fins. Furthermore, tests show that the pressure drop across the fins is materially reduced when a staggered leaving fin edge in accordance with this invention is employed.

While it is not clearly understood why my invention improves the condensate drainage and pressure drop characteristics of a fin-and-tube cooling coil, several reasons have been postulated. Condensate which bridges between fins may tend to hang up within the coil because of the adhesion forces presented by the fin surfaces on each side of the condensate droplets. In my invention the condensate droplets are permitted to move on to the extended portion of certain fins where the force of adhesion acts on only one side of the droplets.

Since this single force is insuflicient to uphold the droplets, the condensate runs freely downward along the extended fin portions. It is also thought that the maximum air velocity at the leaving face of a coil incorporating my invention is lower than that in a coil of conventional design which may also attribute to the desirable drainage characteristics.

Although I have described in detail the preferred embodiment of my invention, I contemplate that many changes may be made without departing from the scope or spirit of my invention, and I desire to be limited only by the claims.

I claim:

1. In combination a heat exchanger coil having an entering face and a leaving face; means for passing a stream of vapor containing gas from said entering face through said coil to said leaving face; said coil including a plurality of first and second fins arranged in face-to-face relationship; each of said fins having a leaving edge disposed adjacent and substantially parallel to said leaving face; means for cooling said fins below the dewpoint of said vapor; over at least a substantial area of said leaving face, the leaving edges of said second fins being disposed downstream of the leaving edges of said first fins whereby condensate collected at the leaving edges of said first fins is transferred to the portions of said second fins disposed downstream of the leaving edges of said first fins where said condensate imposes little resistance to the passage of said gas through said coil.

2. The apparatus as defined by claim 1 wherein said leaving edge of each of said second fins encompassed by said area extends vertically, whereby condensate accumulated at the leaving edges of said second fins flows downwardly therealong with reduced carryover into the stream of said gas.

3. The apparatus as defined by claim 2 wherein said leaving edge of each of said second fins encompassed by said area is substantially vertical.

4. The apparatus as defined by claim 1 wherein alternate adjacent fins of said coil are of said first and second fin construction respectively.

5. The apparatus as defined by claim 1 wherein the entering edges of said first and second fins are disposed in a common plane.

6. In combination a heat exchanger coil having an entering face and a leaving face; means for passing a stream of vapor containing gas from said entering face through said coil to said leaving face; said coil including a plurality of fins arranged in face-to-face relationship; each of said fins having a leaving edge disposed adjacent and substantially parallel to said leaving face; means for cooling said fins below the dewpoint of said vapor; over at least a substantial 'area of said leaving face, the leaving edge of each of certain of said fins being disposed upstream of the leaving edge of other of said fins next adjacent thereto whereby condensate collected at the leaving edges of said other of said fins is transferred to the portions of said certain fins disposed downstream of the leaving edges of said other fins where said condensate imposes little resistance to the passage of said gas through said coil.

7. The apparatus defined by claim 6 wherein said leaving edge of each of said other fins encompassed by said area extends vertically, whereby condensate accumulated at the leaving edges of said other fins flows downwardly therealon'g with reduced carryover into the stream of said gas.

8. The apparatus as defined by claim 7 wherein the leaving edge of each of said other fins encompassed by said area is substantially vertical.

9. The apparatus as defined by claim 6 wherein the entering edges of said certain and other fins are disposed in a common plane.

10. Incombination a heat exchanger coil having an entering face and a vertically extending leaving face; means for passing a stream of vapor containing gas from said entering face through said coil to said leaving face; said coil including a plurality of first and second vertically extending fins arranged in fact-to-face relationship; said fins being spaced sufficiently close at the leaving face of said coil to permit condensate to transfer from one fin to the next adjacent fins, each of said second fins being provided with a condensate drain path disposed downstream of the leaving edge of said first fins; each of said drain paths comprising a portion of one of said second fins extended downstream of the leaving edges of said first fins; said downstream extended portion being continuous throughout its length to permit free uninterrupted fiow of condensate from the leaving face of said coil.

11. Heat exchange apparatus comprising a fin-and-tube type heat exchanger coil having a plurality of generally planar first fins interleaved with a plurality of generally planar second fins in face-to-face relationship and arranged in such proximity as to permit liquid condensate to bridge between said first and second fin; means for passing a stream of vapor containing gas from the front face of said coil through said coil between the fins thereof, to the rear face of said coil; each of said first and second fins having a vertically extending rear edge disposed rearwardly of the rearmost tube of said coil and extending generally parallel to the rear face of said coil; means for passing a cooling fluid through the tubes of said coil of sufficiently low temperature to cool said fins below the dewpoint of said vapor; said rear edges of said second fins being disposed rearwardly of said rear edges of said first fins whereby condensate collected at the reared-ge of said first fins is transferred to the portions of said second fins disposed rearwardly of the rear edges References Cited by the Examiner UNITED STATES PATENTS 1,975,066 9/1934 Sanderson 62-285 2,613,065 10/1952 Didier 16 5146 WILLIAM J. WYE, Primary Examiner.