US3037747A - Heat transfer apparatus - Google Patents

Description

June 1962 R. E. PRESTON ETAL 3,037,747

HEAT TRANSFER APPARATUS Filed Oct. 8, 1959 i INVENTORJ Rainy-T E PrcJTon 5 Ewald :r. Kimm United States Patent 3,037,747 HEAT TRANSFER APPARATUS Robert E. Preston and Ewald J. Kimm, Dayton, Ohio, assignors to United Aircraft Products, Inc., Dayton, Ohio, a corporation of Ohio Filed Oct. 8, 1959, Ser. No. 845,266 4 Claims. (Cl. 257-313) This invention relates to valve and heat exchanger assemblies, having especial reference to small and light weight integrated devices of the kind described for use in aerial craft.

An object of the invention is to adapt assemblies as described to the use of high pressure, high temperature air as a source of heat to warm fuel and for like purposes.

Another object of the invention is to construct a valve providing for accurate control over a flowing, high pressure, high temperature air through thermally responsive means in which fluid pressure effects upon the valve are substantially balanced out.

Another object of the invention is to provide a generally new valve unit in an assembly as described, characterized by a valve resiliently mounted to take up positions as indicated by a thermostat without being directly connected to such thermostat.

Still another object of the invention is to present a generally new heat exchanger and valve combination especially characterized by simplified flow therebetween of the separated confined fluids in heat transfer relation.

Other objects and structural details of the invention will appear from the following description when read in connection with the accompanying drawing, which is a view in side elevation partly broken away, of a valve and heat exchanger assembly in accordance with the illustrated embodiment of the invention.

Referring to the drawing, it its illustrated embodiment the invention is comprised in a fuel heater, flowing liquid fuel which may entrain ice crystals being warmed by high temperature air drawn from a suitable source. The assembly is a fabricated structure, being made up of a number of parts and sub-assemblies of parts joined to one another in a brazing or like operation. The assembly comprises a heat exchanger casing 10, a valve casing 11 in parallel adjacent relation to the heat exchanger casing and an interconnecting manifold 12.

Installed on one end of the heat exchanger casing is a flange 12A receiving a mounting ring 13. The latter provides a seat at its inner end for a perforate header plate 14. The opposite end of the casing 10 is closed by a dome-like cap 15. In inwardly spaced relation to the cap 15 is a similarly formed part 16 secured to a flange 17 mounted to the exterior of a second header plate 18. Tubes 19 extend between and interconnect the header plates 14 and 18, the tubes being made thin for heat transfer through their walls at a favorable rate. Stifi'eners 21 are mounted upon the tubes and lend strength to the tube assembly, it being understood that within the heat exchanger casing and extending between the plates 14 and 18 is a substantial number of closely spaced heat exchange tubes, the two here shown being merely representative of the total number.

The heat exchanger casing 10, with its contained core of heat exchange tubes, accordingly provides a place for an interchange of heat between separated fluids, one flowing through the tubes and the other flowing around and between tubes. The described other fluid enters the casing by way of an upper inlet 22, is permitted to descend transversely across the tube bundle or core and leaves the heat exchanger casing by way of an oppositely disposed opening 23. The described one fluid is in the illustrated instance directed through the assembly of tubes in a dual pass. The mounting ring 13 is bisected in its interior by a rib 24. A partition 25 extends from the rib 24 to the header plate 114 and so effectively separates the mounting ring interior into upper and lower passes each communicating with a respective group of tubes. At the opposite end of the casing the part 16 and the plate 18 define a turn around chamber 26 in which the fluid passing through the first or upper group of tubes may return in the opposite direction to the second or lower group. The described one fluid accordingly enters and leaves the heat exchanger casing at the same end thereof.

The valve casing 11 has mounted on its opposite ends flanges 27 and 28 In an intermediate portion of the valve casing are spaced apart supports 29 and 31 which provide a mounting for a valve sleeve 32. The latterhas a vertical solid portion 33 acting as a closure for one end of the casing 11, with the sleeve proper extending axially inwardly of the casing and having a portion resting on the supports 29 and 31 which act in effect as support bearings. The sleeve 32 is more particularly made up of a circumferential series of longitudinally extending spaced apart portions 34 interconnecting the solid portion 33 and an annular ring 35, and, beyond these portions, a similarly extending circumferentially spaced apart series of portions 36 interconnecting the annular ring 35 and a similar ring 37. A free flow of fluid axially through the rings 35 and 37 and laterally between the portions 34 and 36 thus is possible. At the inner ends of the rings 35 and 37 are respective valve seats 38 and 39. On opposite sides of the bearing supports 29 and 31 the casing 11 is formed with openings 41 and 42 communicating through the opening 23 with the interior of heat exchanger casing 10. Intermediate the bearing supports 29 and 31 is an outlet opening 43 in the casing 11. Flow from the heat exchanger casing, of the fluid which passes over and around the tubes 19, accordingly is directed to the valve casing by way of the openings 41 and 42 and follows two paths through the ring portions 35 and 37 and of the sleeve 32 to outlet 43.

Controlling this latter flow is a valve unit 44 comprising a tubular portion 45 on which are spaced flange or valve portions 46 and 47 adapted to seat upon or to engage respective valve seats 38 and 39. So positioned, the valve unit 44 closes off fluid flow to the outlet 43. A shaft 48 extends longitudinally through the tubular portion 45 of the valve unit and through the valve thereon and has collars 49 and 51 in sliding engagement with the valve unit. Further, on the exterior of the tubular portion of the valve unit are longitudinally spaced apart sets of guide vanes or flutes 52 and 53 having sliding bearings respectively in the rings 35 and 37. The lefthand or inner end of the shaft 48 has a bracket 54 fixed thereto providing a base for one end of a compression spring 55, the other end of which bears upon the valve 47 of the valve unit urging it rightward or in a direction to engage the valve portions with the seats 38 and 39. Engaging the opposite end of the valve unit, through a loosely mounted sleeve 56, is a compression spring 57 based upon the solid portion 33 of the sleeve 32. The shaft 48 extends through and beyond the collar 56 and is pinned to an extension 58 thereof having a stem 59 which projects through and beyond end closure 33 in order that the tip thereof may serve as an indicator to the longitudinal position of adjustment of the valve unit.

Such longitudinal adjustment of the valve unit is under control of a thermostat '61 of a known kind wherein a material having the property of forceful expansion under heat is contained in a case 62 and arranged as a result of its expansion relatively to extend a plunger 63 at its outer end. The thermostat 61 is mounted in a wall 64 stationarily mounted in the casing 11 between the opening 41 thereof and that end opposite the end closed by portion 33 of the valve sleeve. The wall 64 defines with the de shaft.

adjacent end of valve casing 11.

scribed adjacent end of the casing 11 a chamber 65 opening to the exterior of the casing through the open end of the latter and through a lateral opening 66. The thermostat 61 is arranged in alignment'with'the shaft 48 and the extensible plunger 63 engages the adjacent end of the Under applied heat, therefore, the plunger 63 extends and effects an axial motion of the shaft 48 toward the right as seen in the drawing. Under the pressure resiliently applied through spring 55, therefore, the valve unit is moved to a seated or closed position and at the same time spring 57 is compressed. In response to cooling of the thermostat the spring 57 is allowed to expand and in so doing to move the valve unit 44 leftward or to an open position and at the same time to return the plunger 63 inward within the thermostat. An overtravel of the thermostat beyond that necessary to engage the valve 46 and 47 with their respective seats is absorbed by a yielding of the spring 55. The exterior of the thermostat 61 is suitably formed to accommodate seals 67 and 68 which preclude intercomrnunication between the spaces on opposite sides of the wall 64. Between the seals 67 and 68 is an annular space '69 communicating through a passage 71 in the wall 64 with the exterior of the valve casing whereby to avoid any build up of pressure between the sealing elements 67 and 68 and to carry off any fluids which may gain access to the space 69.

On the lefthand end of the valve and heat exchanger assembly, as viewed in the drawing, there is bolted or otherwise secured a plate 72 providing a mounting for a housing structure comprising a hollow housing element 73 in generally closing relation to one end of the heat exchanger casing and a housing element 74 in generally closing relation to one end of the valve casing. An inlet duct 75 leads to the housing element 73 and supplies to the valve and heat exchanger assembly the fluid for flow through the tubes 19. Transversely disposed in the housing element 73 is a Wall 76 anchored at its one end in the rib 24 to separate the interior of the housing element 73 into upper and lower portions in accordance with the dual pass principle before described. Thus, fluid admitted from the duct 75 to the housing element 73 is restricted initially to the space above the transverse wall 76 and passes through communicating tubes 19 to the turn around chamber 26 and then returns through the lower set of tubes 19 to the space in the housing element beneath wall 76. Within the wall 76 is mounted a check valve assembly comprising a housing 77 and a valve 78, the construction and arrangement being such that in the event of a flow restriction of predetermined extent in the tubes of the heat exchanger at least some of the fluid entering housing element 73 may bypass the heat exchange tubes and flow directly to the lower portion of the housin g element.

Such lower portion of housing element 73 is formed with a circular projecting portion 79 registering with a similar portion 81 on the lower housing element 74. A ring 82 receives the respective portions 79 and 81 and interconnects the upper and lower housing elements. The fluid completing its passage through the heat exchanger core and returning to the lower part of housing element 73 accordingly is free to flow through the ring 32 to the lower housing element 74 where it may enter the open Here the fluid passes through the chamber 65 and leaves the valve casing by "way of opening 66, passing, as it does so, in contact with the thermostat 61. The latter accordingly senses the temperature of the fluid and makes corresponding and automatic adjustments in the position of the plunger 63 and thereby in the position of the valve unit 44. In the illustrated instance, the fluid entering duct 75 is a low temperature liquid fuel whereas the fluid entering inlet 22 is a high temperature, high pressure air or gas. The latter descends through the tube bundle or core and exits from the heat exchanger casing by way of the openings 41 and 42, flowing, in an open position of the valve unit 44, through the valve casing to the outlet 43. Flow of the fuel is, as described, through the upper part of housing element 73 through an upper set of the tubes 19 into turn around chamber 26 and through a lower set of tubes 19 to the lower part of housing element 73 and thence to housing element 74, chamber in the valve casing and out by way of opening 66. It will be understood that in response to changing temperatures of the fuel, as sensed in chamber 65 and indicating a greater or lesser need for the addition of heat, adjustments are made in the position of the valve unit 44 to permit a greater or lesser amount of the heated air to flow through the tube bundle. Infinite variations may in this manner be made in the rate of warming of the fuel.

The valve unit 44 presents the outer surfaces of the valve portions 46 and 47 to the high pressure high temperature air and thus tends to balance in a set position of adjustment without requiring the application of excessive force by the thermostat for this purpose.

What is claimed is:

l. A valve and heat exchanger assembly, including a valve casing and a heat exchanger casing in side by side parallel relation, inlet and outlet means for a first fluid in said heat exchanger casing, a pair of inlets in said valve casing communicating with said outlet means in said heat exchanger casing, an outlet from said valve casing intermediate said pair of inlets therein, a pair of spaced apart valve seats in said valve casing on opposite sides of said last named outlet and intermediate said pair of inlets,

valve means movable to open and close flow through said valve seats, a thermostat actuating said valve means, and means defining a flow path through said casings for a second fluid, said first and second fluids being in heat exchange relation to said heat exchanger casing, said thermostat being in said flow path and influenced by the temperature of said second fluid.

2. A valve and heat exchanger assembly, including a valve casing and a heat exchanger casing in side by side parallel relation, inlet and outlet means for a first fluid in said heat exchanger casing, said valve casing having a longitudinally spaced apart pair of inlets communicating with said outlet means to receive said first fluid, an outlet from said valve casing for said first fluid located intermediate said inlets therein, means defining longitudinally spaced apart valve seats in said valve casing on opposite sides of said outlet therein, said first fluid flowing through said valve seats to said outlet, valve means comprising unitarily connected valves engageable with respective valve seats to prevent flow therethrough, said valves being exposed to the pressure of the fluid from said inlet in said valve casing to balance said valve means, a spring to urge said valve means in a direction to unseat said valves, a thermostat to move said valve means in a direction to seat said valves, another spring interposed between said thermostat andsaid valve means absorbing overtravel of said thermostat, and a path for a second fluid through and between said casings, said thermostat responding to the temperature of said second fluid.

3. A valve and heat exchanger assembly, including a valve casing and a heat exchanger casing in side'by side parallel relation, a common mounting plate installed on corresponding ends of said casings, a housing structure on said plate providing intercommunicating chambers in further respective communication with the said corresponding ends of said casings, an inlet to the chamber communicating with said heat exchanger casing for a first fluid, division wall means in said last named chamber, means defining a turn around chamber at the opposite end of said heat exchanger casing, said first fluid entering one portion of said chamber at the said one end of said heat exchanger casing, flowing to the opposite end thereof and thence back to said chamber on the opposite side of said division wall therein and thence to the other chamber in said housing structure and into said valve casing, a thermostat in said valve casing responding to the temperature of said first fluid, and a valve in said valve casing adjusted by said thermostat controlling How of a second fluid through said casings.

4. A valve and heat exchanger assembly according to claim 3, characterized by a check valve in said division wall providing for flow of said first fluid in by-passing relation to said heat exchanger casing under conditions of predetermined pressure drop on opposite sides of said division Wall.

UNITED STATES PATENTS Shaw Apr. 26, Bolesky Aug. 16, Shaw Aug. 30, Carroll et a1. Oct. 15,

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