US2859016A - Heat exchanger - Google Patents

Description

Nm- 4, 1958 M. EPHRAIM, JR., ETAL` 2,859,016

HEAT EXCHNGERA Filed Nov. 4, 195'? 2 Sheets-Sheet l O @mi m1,@

fw' ya www@ Nov. 4, 1958 M. EPHRAIM, JR., ETAL HEAT EXCHANGER y Filed NOV. 4, 195'? 2 Sheets-Sheet 2 IIN VEN T0 Rs A TTOR/VEV United States Patent O HEAT EXCHANGER Max Ephraim, Jr., Chicago, and John F. Novacek, Riverside, Ill., assignors to General Motors Corporation, Detroit, Mich., a Vcorporation of Delaware Application November 4, 1957, Serial No. 694,064

2 Claims. (Cl. 257-227) This invention relates generally to heat exchangers and 'particularly to improvements in engine lubricating oil coolers wherein the lubricating oil to be cooled flows in the `cooler at relatively low velocities under light pressures. In heat exchangers with which the present invention is concerned there is provided a finned heatV exchanging core past which the oil to be cooled must How. Such heat exchangers have certain advantages over high pressure types inasmuch as they do not require pressure vessels, external relief valves, or high pressure connections. Because of the low velocities and pressures, however, there isa tendency for the core to clog, either becausetheoil is cold or because of sludge which collects on the core.

The present invention retains the advantages of lube oil coolerswherein the oil ows at relatively low velocities under relatively light pressures and at the same time allows the oil to flow so asA to provide cooling when there are substantial sludge deposits on the core tending to prevent ow therethrough. This has been accomplished by providing in such a cooler unique baiing means in combinationwith relatively low pressure operated pressure relief valves which provide an alternative easier path for the oil past a part of the heat exchanging media used to cool the oil. Other objectives and advantages are attained |by the invention which will be better understood by reference to the accompanying detailed description and drawings in which:

Fig. 1 is a view in elevation with portions broken away and in section of the heat exchanger showing in detail certain of the features which uniquely enhance the electiveness thereof.

Fig. 2 is a view in plan taken substantially on the line 2-2 of Fig. l illustrating particularly the unique pressure relief means utilized to allow continuous ow of lubricating oil through the heat exchanger regardless of the condition of the oil or the radiator core of the heat exchanger.

Fig.3 is a side view in elevation taken substantially on the line 3 3 of Fig. 1 further illustrating the details of construction including the unusual baiile means for directing the oil through the heat exchanger.

Fig. 4 is a fragmentary view in section taken substantially on the line 4 4 of Fig. l greatly enlarged to illustrate one of the unique pressure relief valves for allowing the oil to -by-pass the core of the radiator of the heat exchanger when the oil is either too viscous to ow therethrough or the core is clogged by reason of sludge which is picked up and carried thereto by the lubricating oil.

Referring now to the drawings, it will be observed that the heat exchanger which is indicated generally by a numeral 2 comprises an outer casing or container 4 which is closed at its lower end by a lower header 6. The lower header 6 is provided with horizontally disposed inlet and outlet chambers 8 and 10, respectively (see particularly Fig. 3). Lubricating oil which leaves an internal combustion engine is adapted to be supplied from the engine through the oil inlet pipe 12 '(see Fig. 1) which leads into chamber 8. Oil leaves the heat exchanger via the outlet chamber 10 and the pipe 14 which returns the now-cooled oil to the engine. Located within the container 4 is a radiator generally identied by the numeral 16 which comprises -an upper header 18, a radiator core 20 and a lower header 22. The lower header 22 is securely fastened to the lower header 6 and cooperates therewith to vform the `area 24. The upper header 18 of the radiator 16 defines an area 26 to which Water or other cooling media may Ibe supplied via the inlets 28 (see Fig. 1). The -upper and lower headers 18 and 22 of the radiator are placed in direct communication with each othervby the core 20 which comprises nned tubes such as 30, so that water or other cooling media may enter the inlets 28, the area 26 of upper header 18, thence flow downwardly through the finned tubes '30, to the area 24 of the lower header 22, and then out of the heat exchanger through the cooling media outlets 32. The radiator assembly 16, which is made up as a unit as previously mentioned,V is lsecurely fastened in place to the lower header 6 -by means of the studs 34. This assembly as will best appear from Figures 1, 2, and 3 divides the volume in the container 4 into an inlet area 36 and an outlet area 38 which are in communication with each other only through the core 16 and over the top of the upper header 18 as at 40. Located within the area 36 is an inlet baiile 42 which along its lower edge is clamped to the lower header 6 by a flange 44 xedto the lower edge of the container 4. The upper edge of baille 42 is sealingly connected to the upper header 18 so that the inlet area 36 is actually divided into two portions 46 and 48. The area 38 on the outlet side of the core 20 also has provided therein a baille 50 which has its lower edge sealingly fixed to the lower header 22 of radiator 16 and a portion of' its upper edge fixed to the upper header 18. The baille 50, however, is provided with a dam, the top of which is indicated by a numeral 52. Dam 52 allows oil to spill over the top of baille 50 from a portion 54 of the area 38 which is adjacent the outlet side of the core 20 into a second portion 56. It will thus be appreciated that the bafes 42 and 50 together with the upper and lower headers of the radiator 16 form a chamber 58 which contains the core 20. The inlet chamber 8 of the lower header 6 of the heat exchanger is in communication with the chamber S8 via passageway or port 60 which is -best seen in the lower lefthand corner of Fig. 3 in viewing the drawing. The area 56 which is located remote from the core on its outlet side is in communication with the outlet chamber 10 of the lower header 6 via passageway or port 62.

Referring again for a moment to the inlet ybaille 42, it Will be observed that this bailie is provided with a pair of horizontally spaced openings 64 which are maintained normally closed by pressure relief valves 66 held on their seats 68 by a leaf spring 70 which is anchored at the center thereof to the inlet balile 42 by means of the studs 72 and has its ends 74 each connected to one of the valves 66 by the stud 76.

The operation of the heat exchanger is as follows: The lubricating oil to be cooled is introduced from the engine into the pipe 12 and the oil inlet chamber 8. From chamber 8, the oil flows as indicated by the arrows into the chamber 48 which includes the core 20. The oil then ows through the core 20 where it gives up part of its heat to the cooling media flowing through the core. The oil is maintained built-up in the chamber 58 until it spills over the dam 52 into the area 56 whence it may pass downwardly through port 62, through the oil outlet chamber 10 and the piping 14 to return to the engine. Because of the very large finned area of the tubes 20, the velocity of the oil flowing past the core may be relatively low and still have adequate heat exchange. This means that relatively low pressures will maintain this low oil flow as `long as the oil can flow rather freely through the core. However, if the oil is viscous, for example, due to the starting of a cold engine, there will be some resistance to flow which, if sufficient, will unseat the pressure relief valves 66 thereby allowing the oil to flow upwardly, as indicated by the arrows in Figure 3, lover the topl of the upper header 18` Sin-ce any type of uid heat exchanging medium cany vbe used in the radiator 16 such medium can be provided to first heat the oil thereby making it less. viscous, thus a certain amount of heat exchanging may still occur although the core of the radiator is at least partially by-passed'. All this` has been accomplished without materially increasing the pressures present inthe heat exchanger or the flow of oil therethrough. The same by-passed path will-be followed inthe event the core is clogged sufficiently `to cause the pressure relief valves 66 to unseat. It willbe noted that the area of the openings 64 is relatively large and that the path over the upper header ,18 isrelatively free from obstructions so as to allow quite a free flowwof oil along such path in the event the oil cannot freely fiow through the core 20. It will be appreciated, however, that even though a part or all of the oil takes the alternative flow path, i. e., through the pressure relief valves and up over the top of the upper header 18, there still will be some heatl exchanging occurring as a result of the lubricating' oilv coming in contact with the upper header 18 in which heat exchanging medium is flowing.

From the foregoing it will be appreciated that a very effective low velocity, low pressure oil cooler has been provided which can handle both hot and cold oil as well as oil containing substantial amounts of sludge without the usual pressure problems encountered with more conventional types of oil coolers.

We claim:

l. A heat exchanger comprising an outer container, a radiator including a core and upper and lower headers dividing said container into an inlet area and an outlet area connected together through said core and over said upper header, an inlet baffle in said inlet area and an outlet baffle in said outlet area forming a chamber with said headers which contains said core, pressure relief means in said inlet bafe adapted to connect that portion of the chamber which includes a portion of the inlet area with the rest of said inlet area and with said outlet area over said upper header, said outlet baffle forming a darn in said outlet area adjacent said core over which fluid may flow into the rest of said outlet area, means for passing heat exchanging medium through said radiator, means to-introduce heat exchanging medium to said portion, and means to remove saidlast-mentioned heat exchanging medium from the said rest of said outlet area.

2. A lube oil cooler comprising an outer container having a lower header forming the bottom thereof, said header having horizontally disposed inlet and outlet chambers for the introduction and egress of lubricating oil, a radiator in said outer container including anupper header, a core, and a lower header which together with saidiirst.- mentioned lower header and the walls of said container form an inlet area and an outlet area in communication with said inlet and outlet chambers, respectively, said radiator preventing communication between said areas except through said core and over said upper header, an inlet baie in said inlet area directing ow of oil through said core and including pressure relief means to allow oil to flow over said upper header to saidl outlet area', a second baffle in said outlet area forming a dam adjacent said core over which oil after passing through said core may iiow to thereby pass into said egress chamber, and' means for passing a heat exchanging medium through said radiator.

References Cited in the file of this patent UNITED STATES PATENTS 2,373,157 Worth Apr. 10; 1945 :FOREIGNy PATENTS 45,360 France May 6, 1935

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