US 3797565 A
A refrigerated air or like dryer in which apparatus to perform the several functions of such a dryer are combined in a unit of small, compact size. A heat exchange device is uniquely constructed to perform both the principal cooling and the precool-reheat functions. A housing in an enclosing relation to the heat exchange device induces separation and drainage of liquid from the cooled gas, eliminating the need for external separator means and attendant connections.
Description (OCR text may contain errors)
United States Patent [191 Fernandes REFRIGERATED GAS DRYER  Inventor: Joseph F. Fernandes, Centerville,
 Assignee: United Aircraft Products, Inc.,
Dayton, Ohio 22 Filed: Nov. 22, 1971 21 Appl. No.: 200,947
l/1966 Alderson etal. 62/93 -X [1 1] 3,797,565 1 Mar. 19, 1974 3,541,807 11/1970 Henderson 62/93 X 2,237,332 4/1941 Bretzlaff et al. 62/93 X 3,453,809 7/1969 Henderson 165/66 X Primary Examiner-Albert W. Davis, Jr.
Assistant ExaminerS. J. Richter Attorney, Agent, or FirmJ. E. Beringer 5 7 ABSTRACT A refrigerated air or like dryer in which apparatus to perform the several functions of such a dryer are combined in a unit of small, compact size. A heat exchange device is uniquely constructed to perform both the principal cooling and the precool-reheat functions. A housing in an enclosing relation to the heat exchange device induces separation and drainage of liquid from the cooled gas, eliminating the need for external separator means and attendant connections.
7 12 Claims, 4 Drawing Figures REFRIGERATED GAS DRYER SUMMARY OF THE INVENTION This invention relates to a refrigerated gas or like dryer, particularly as used in compressor systems to cool and to dry inherently warm and moist air or gas. Refrigerant cooled in an air or water cooled condensing unit is frequently used in compressor systems to reduce the temperature of a compressed air or gas in order that it may be supplied for use at a proper temperature level. Apparatus for the purpose has heretofore been comprised of a plurality of parts, including separate relatively bulky heat exchangers to perform the principal cooling and the precoolreheat functions and further including an individual unit for separating and draining off of liquid entrained in the cooled air or gas.
The present invention brings into a single unit the several elements ofa refrigerated air or like dryer. Heat transfer requirements are met in a small, light weight, high performance device embodying in itself the means to refrigerate the air or gas and the means to ,carry out a precool-reheat function in connection therewith. In addition, the requirement for an independent demister and liquid separator is eliminated, this function being inherently performed in a heat exchanger housing uniquely cooperating with the heat exchanger device for the intended purpose.
To provide a refrigerated air or like dryer characterized as in the foregoing is an object of the invention.
Other objects and structural details of the invention will appear from the following description, when read in connection with the accompanying drawings,
FIG. 1 is a view in longitudinal section, and partly diagrammatic, of a refrigerated air or like dryer in accordance with the illustrated embodiment of the invention;
FIG. 2 is a view in perspective of the heat exchanger device of the dryer of FIG. 1;
FIG. 3 is a view in cross section taken substantially along the line 3-3 of FIG. 1; and
FIG. 4 is a view in cross section taken substantially along the line 44 of FIG. 1.
DESCRIPTION OF ILLUSTRATED EMBODIMENT Referring to the drawings, the invention is disclosed as embodied in a refrigerated air dryer. It contemplates a unitary, one-piece structure comprising a heat transfer device and a housing 11. The latter includes a center cylindrical section 12 to the opposite ends of which are fixed internally recessed closure bells 13 and 14. End closures l3 and 14 are secured, as by welding, to respective ends of the cylindrical section 12. End 13 has a relatively wide diameter opening 15 centrally thereof. End 14 has a similarly positioned but smaller opening 16. Near what may be considered its upper end cylindrical section 11 provides an opening 17 of lateral extent. Positioned within the cylindrical section 12, respectively above and below lateral opening 17, are partitions l8 and 19. In the partitions 18 and 19 are respective aligned, centrally positioned openings 21 and 22. At their peripheries, the partitions 18 and 19 sealingly engage cylindrical section 12 and may be fixed thereto, as by welding. End closure 13 and partition 18 define therebetween a chamber 23 which, as will hereinafter more clearly appear, may be identified as an inlet chamber for warm moist compressed air supplied from a source external to the dryer. Partitions l8 and 19 define intermediately thereof a chamber 24 which together with opening 17 may be identified as the outlet means for cooled, dry air. Partition 19 and end closure 14 provide intermediately thereof a chamber 25 which may be variously identified as a liquid outlet chamber and as a separation and reentrant chamber.
The heat exchange device 10 is of multi-piece construction, with, however, the multiple pieces unitarily joined to one another by means forming a seal and a bond at interfacial, contacting locations. In its lateral dimensions it agrees with the configuration of partition openings 21 and 22. The heat exchanger device is adapted to be positioned within such openings with what may be considered its upper end disposing substantially flush with the upper surface of partition 18 and with what may be considered its lower end projecting through and beyond partition 19 a substantial distance into chamber 25. By a welding or like process, marginal edges of the partitions 18 and 19 may be closed around the heat exchanger device thus fixing the device in position within the housing and at the same time sealing chamber 23 from chamber 24 and sealing chamber 24 from chamber 25.
In construction, the heat exchanger 10 is a plate and fin device utilizing both cross flow and counterflow principles of operation.
In its construction details, the heat exchanger comprises a plurality of spaced apart plates 26 of rectangular configuration. The plates are thin and made of a metal selected for its good heat conductivity and strength to weight ratio. The plates 26 may be considered as occurring in adjacent pairs. Alternate pairs of plates have channel shaped members 27 installed between the side edges thereof in a manner to define spaced apart through flow passages 28. The pair of plates 26 between each defined flow passage 28 has installed at the upper end thereof a channel shaped member 29 and at the lower end thereof a channel shaped member 31. In addition, a channel shaped member 32 is installed to lie in an opposing spaced relation to channel member 31. Still further, opposed channel members 33 shorter in length than channel members 27 and longitudinally spaced from channel members 29 and 32 are installed between longitudinal edges of the plates 26 intermediate flow passages 28. Between the flow passages 28, therefore, the heat exchanger may be considered to provide a short length flow path 34 above and below which are respective chambers 35 and 36 which open through sides of the heat exchange device. Further, channel members 31 and 32 together with adjacent plates 26 define a flow passage 37. The flow passages 34 and 37 are in an alternating relation to flow passages 28. Passages 34 dispose parallel to the flow passages 28 and terminate in respective chambers 35 and 35. Passages 37 extend transversely of flow passages 28 and extend through the heat exchange device to terminate exteriorly thereof. The flow passages 28 are occupied by corrugated strip fin material 38. Passages 34 have installed therein similar corrugated strip fin material 39 and there is installed in flow passages 37 a like fin material 41. The strip fin material 38, 39 and 41 is sized to be in contact with adjacent plates 26 and provides secondary heat transfer surface. The various plates, channel members and fin material, are united with one another, in a brazing or like operation, and form an integratd unit. The fin material, in having its peaks and valleys brazed to the plates 26, tend to impart additional strength and rigidity to the unit, as well as performing a heat transfer function.
Manifold members 42 and 43 are secured as by welding to opposite sides of the heat exchanger in position to be in closing relation to opposite ends of the flow passages 37. Tubes 44 and 45 communicate at their one ends with the interiors of respective manifolds 42 and 43. At their other ends the tubes 44 project through and beyond housing 11 and are adapted at their ends to be connected in a separate fluid circulating system. Where the tubes 42 and 45 project through the housing weld material or the like is deposited to seal against the escape of pressure fluid from the chamber 25.
In the operation'of the refrigerated air dryer, inlet opening 15 is suitably connected to a source of warm moist compressed air. Liquid outlet 16 is connected to a trap or the like defining a place of disposal of released liquid. Outlet 17 is connected to a place of use of cooled, dry air. The tubes 44 and 45 are connected in a vapor cycle refrigeration system or the like. From an air cooled or water cooled condenser, refrigerant is directed to one of the tubes 44 or 45, as the tube 44, and is returned to the condenser by way of the other tube and a refrigeration compressor intermediately disposed between such other tube and the condenser.
The warm moist compressed air entering inlet 15 fills chamber 23. There it has access to the upper ends of flow passages 28 and flows downwardly through such passages to discharge therefrom into chamber 25. In chamber 25 the air has access to heat exchanger chamber 36 and flows into such chamber and upwardly through passages 34 to chamber 35. From chamber 35 the air discharges to outlet chamber 24 and exits therefrom by way of outlet opening 17. At the same time the refrigeration system is in operation. Refrigerant which has been cooled in the condenser is admitted by way of tube 44 to manifold 42. There it has access to and flows longitudinally through the passages 37 to the opposite manifold 43, returning finally by way of tube 45 and communicating components to the condenser. Within passages 37, the refrigerant undergoes a controlled expansion, cooling the directly contacted fin material 41 and adjacent portions of plates 26. In a convectionconduction process of heat transfer, heat from the flowing air in passages 28 is rejected to and absorbed in the flowing refrigerant. The air emerging from flow passages 28 into chamber 25 accordingly is appreciably cooled or refrigerated. The discharge ends of flow passages 28 are in a position to discharge perpendicularly toward the continuously curving surface 46 on the interior of end bell 14. This surface acts as a deflector, redirecting the flowing air laterally and upwardly toward chamber 36, as indicated by the arrows 47. The refrigerated air issuing from the flow passages 28 has suffered a substantial decrease in its liquid holding capacity. This coupled with the abrupt reversal in the direction of flow tends to free liquid droplets which are thrown or dropped by gravity upon the surface 46 and collect in a condensate pool 48. The pool 48 is drained by opening 16.
The air reaching chamber 36 accordingly is a dry, refrigerated air. As such dry, refrigerated air passes upwardly in passages 34 it is placed in heat transfer relation to the warm moist compressed air in flow passages 28 through the fin material 39 and other adjacent portions of the plates 26. The result is a precool-reheat function in which the refrigerated air in passages 34 absorbs some of the heat from the air in passages 28. The air in flow passages 28 accordingly is somewhat reduced in temperature before it reaches the refrigerated portion of the heat exchanger unit whereby to reduce the cooling requirements of the refrigeration system. Also, the refrigerated air issuing into outlet chamber 24 is somewhat increased in temperature and its transmission from the dryer unit to a place of use is less likely to be accompanied by condensation on transmitting I pipes and tubes.
The invention has been disclosed with reference to a particular embodiment. Structural modifications obviously are possible to a person skilled in the art to which the invention relates and are considered to be within the intent and scope of the invention.
What is claimed is:
11. A refrigerated gas dryer, including means defining flow passages for a warm moist compressed gas, means for flowing a refrigerant in heat transfer relation to said gas in a first portion of said flow passages, means for flowing cooled gas issuing from said first portion of said flow passages in counterflowing heat transfer relation to uncooled gas in a second portion of said flow passages in advance of and longitudinally spaced from said first portion for a precool-reheat function, said last named means including an inlet chamber intermediate said portions, and means for guiding cooled gas from said first portion to said second portion in a manner to encourage release of moisture therefrom, said flow passages and said flowing means being comprised in a unitary heat exchange device, said guiding means including a housing positioning said heat exchange device therein and enforcing divided flow and a change of direction of issuing cooled gas as it moves from said first portion of said flow passages toward said second portion, said inlet chamber being open at opposite ends to receive the cooled gas.
2. A refrigerated gas dryer according to claim 1, wherein said heat exchange device is positioned in spaced relation to a wall of said housing, issuing cooled gas from said first portion of said flow passages discharging toward said wall, said wall being curved effectively to divide and reverse the direction of flow of the issuing gas, said wall having an opening for drainage of released moisture.
3. A refrigerated gas dryer, including means defining flow passages for a warm moist compressed gas, means for flowing a refrigerant in heat transfer relation to said gas in a first portion of said flow passages, means for flowing cooled gas issuing from said first portion of said flow passages in heat transfer relation to uncooled gas in a second portion of said flow passages in advance of said first portion for a precool-reheat function, said flow passages and said flowing means being comprised in-a heat exchange device, said flow passages being in a parallel separated relation in said device and defining other intermediate passages, different portions of said other intermediate passages being used to flow a refrigerant and to flow cooled gas in the precool-reheat function, said different portions being longitudinally spaced apart to form between them an'inlet for the cooled gas, and means for guiding cooled gas from one different portion of said other intermediate passages to another in a manner to encourage. a release of moisture therefrom.
4. A refrigerated gas dryer according to claim 3, wherein said heat exchange device is a plate and fin heat exchanger, parallel spaced apart plates defining said flow passages and said other intermediate flow passages and insert means in said other intermediate flow passages defining a refrigerant flow path in cross flow relation to the gas flowing in said flow passages and defining a cooled gas flow path counter to the gas flowing in said flow passages, fin material for secondary heat transfer purposes being installed in said flow passages and in said refrigerant and cooled'gas flow paths.
5. A refrigerated gas dryer, including a housing providing at one end an inlet for a warm moist compressed gas and at the other end an outlet for liquid separated from said gas, partition means in said housing defining at said one' end an inlet chamber and at said other end a liquid outlet chamber and intermediate the two an outlet chamber for cooled dry air, said housing providing an opening communicating with said dry air outlet chamber, a heat exchanger device positioned in said housing providing first flow passages extending from said inlet chamber to said liquid outlet chamber and providing second flow passages in adjacent relation to portions of said first flow passages extending from said liquid outlet chamber to said dry air outlet chamber, said heat exchanger device further providing third flow passages in adjacent relation to other portions of said first flow passages, and means for achieving a segregated flow of a refrigerant through said third flow passages, said heat exchanger device being comprised of a plurality of spaced apart plates, certain adjacent plates defining said first flow passages and certain other adjacent plates defining spaces occupied in part by said second flow passages and in other part by said third flow passages, said second and third flow passages being longitudinally spaced apart and said heat exchange device intermediately thereof defining an inlet from said liquid outlet chamber to said second flow passages.
6. A refrigerated gas dryer according to claim 5, wherein said liquid outlet chamber is constructed to serve as a separation and reentrant chamber, a change of direction of flow of cooled gas issuing from said first flow passages inducing a release of liquid which moves to said liquid outlet while the cooled dry gas is directed to reenter the heat exchanger device by way of said second flow passages.
7. A refrigerated gas dryer according to claim 6, wherein said second and third flow passages are positioned to place the fluid therein in heat transfer relation to the gas in said first flow passages, the gas in said first flow passages first encountering the cooled gas in said second flow passages and second encountering the refrigerant in said third flow passages.
8. A refrigerated gas dryer according to claim 7, wherein the means for achieving a segregated flow of a refrigerant through said third flow passages includes manifold means mounted to said heat exchange device and inlet and outlet flow connections extending to and from said manifold means through said housing.
9. A heat exchanger for use in a refrigerated gas dryer or the like, including evaporator and reheatprecool sectins in end to end relation, said sections providing common through passages for flow of a moist warm gas first through said reheat-precool section and then through said evaporator section, said through passages having inlet and outlet ends with respect to the direction of gas flow, and other separated passages in said reheat-precool section and in said evaporator section for flow of respective fluids in heat transfer relation with said moist warm gas, the said other passages in said reheat-precool section terminating at their one ends in an inlet chamber intermediate said sections and terminating at their other ends in an outlet chamber longitudinally spaced from said inlet chamber toward the said inlet end of said through passages, and manifold means providing for segregated flow of a refrigerant fluid through the said other passages in said evaporator section.
10. A heat exchanger according to claim 9, wherein said heat exchanger has a unitized plate construction in which a plurality of spaced apart plates and separator members define said common through passages and said other passages, separator members at the sides of said other passages being interrupted to define said inlet and outlet chambers.
11. A heat exchanger according to claim 10, wherein separator members in a transverse relation to the separator members at the sides of said other passages seal off upper ends of the said other passages and define upper and lower closed walls respectively of said outlet chamber and said inlet chamber.
12. A refrigerated air dryer including a heat exchanger unit comprising a portion through which a moist compressed gas is passed in heat transfer relation to a refrigerant and another portion in advance of the first portion through which cooled gas counterflows introduced moist compressed gas for a precool-reheat function, said heat exchanger unit providing at sides thereof oppositely disposing inlet means for entrance of cooled gas to said other portion, a housing presenting a curved wall upon which cooled gas exiting from the said first portion discharges, said curved wall redirecting issuing cooled gas in divided form to said inlet means at opposite sides of said unit, and a liquid drain in said curved wall substantially in line with the path of flow taken by the gas through the heat exchange unit. =l=