US2340397A - Heat exchanger - Google Patents

Description

Feb; 1, 1944. D. R; MCNEAL HEAT EXCHANGER 2 Sheets-Sheet 1 Filed May 15, 1942 INVENTO ATTORNEYS fiF b. 1 1944;

D. R. MONEAL 2,340,397

HEAT EXCHANGER Filed May 15, 1942 2 Sheets-Sheet 2 ATTORNEYS Patented Feb. 1, 1944 HEAT EXCHANGER Daniel Raymond McNeal, Abington, Pa., assignor to Andale Company, Philadelphia, Pa., a corporation of lennsylvania application May 15, 1942, Serial No. 443,088 7 2 Claims; (crash-222) This invention relates to heat xchangers and particularly to that type .which is known as a tube and shell exchanger wherein a bundle of tubes is enclosed within a surrounding shell, there being provided suitable passages and connections for circulating one of the fluids through the interior of the tubes and the other fluid around the exterior of th'e tubes.

The'primary objects of :the invention are to provide an-exchanger of the tube and shelltype in which the tube bundle can be inserted or removed without disturbing any of the piping c'onnections for either of the fluids and in which all possibility of leakage of one fluid into the other fluid is prevented while, at the same time, providing a construction by means of which it is possible to utilize for each of the fluids whatever kind of metal or alloyis best suited for the particular installation in question. The following specific example will emphasize'the importance and value of the improvements disclosed herein by means of which I have attained these primary objectives. r

Exchangers or the tube and shell type are often used-in connection with the cooling of oil, and in many installations of this kind the oil is frequently very hot and also under considerable.

pressure, so that the structure must be made of substantial strength. Furthermore, the units may be used in situations where any damage to the cooler may result in dangerous flres and possible death. This is particularly true inmarine installations where the escape of highly heated oil would imperil the safety of, the passengers and crew. This has been emphasized during the present war emergency, during which so many naval as well as merchant vessels are being in volved in dangerous combat.

' In marine installations the cooling medium is generally sea water which, of course, has a strongly corrosive action on steel. For this reasonit has heretofore generally been customary to make the shell and its fluid connections of .bronze or of some other corrosion resistant alloy instead of steel. Alloys of this kind, however,

have a far less factor of strength and. generally meltat a far lower temperature than does steel,

sothat in the event of damage to the boat such as would be caused, for example, by a torpedo, a shell made of such resistant alloy is far more liable to. rupture of melt and permit the escape of the contained oil than is a steel'shell. This naturally greatly increases the fire hazard and the possible danger tdlife.

With the foregoing specific situation in. mind, the principal objects ofmy invention, as stated it is possible to save a large percentage of any expensive special alloy which may be required for one of the fluids while at the same time re taining all of the strength and rigidity which may be necessary for the particular installations in question; the provision of a construction in which a special, separable and readily replaceable tube-circulationconnection member is provided for completing'the circulating path of oneofthe fluids involved," generally the cooling fluid which, in my improved device, passes through the interior of the tubes; the provision of a construction in which all joints are maintained in absolutely leak-proof condition by clamping my improved connection member between the customar a movable main head of the exchanger and asuitable supporting flange on the exterior of the shell; and in general to overcome certain diflieulties incident to previous constructions while atthe same time in no way interfering with other necessary and important features.

How the foregoing objects, together with any other objects which may appear hereinafter or are incident to my invention, are attained, is

illustrated in preferred form in the accompanying drawings, wherein- Figure 1 is a vertical longitudinal section through a heat exchanger embodyingmy improvements; Figure 2 is a plan view of my improved connecting member for the fluid which through the tubes, and

Figure 3 is a side elevation of the upper poris not intended to limit the invention to this field of service.

closes a tube-bundle 5. The upper ends of the tubes are mounted in the fixed or stationary tube above, will be more fullyappreciated; I wish it Y to be understood, however, that the usefulness of the invention is not in anyway" to be limited to the speciflc instance described butis equally applicable to any situation where it is advsnta- 3 sheet 6' while the lower ends are secured in the floating tube sheet 1 against which is mounted the lower or floating head 8. The oil to be cooled passes around the exterior of the tubes and is conducted to and from the shellthrough the passages 9, l0, ll and 12, the oil in its passage through ,the shell being circulated back and forth to. I

bame plates-ll in-a manner well understood in across the tubes bymeans of the customary is passed The shell 4' of my improved heat exchanger en- Y 25 by means of the studs 3 this art. Th'e passages 9 to l2 are under the control of a valve I4 which can be turned either to the position indicated in the drawings where all of the oil is sent through the cooler or to any intermediate position where the oil can be divided so as to deliver any desired proportion of it to the cooler and by-passing the remainder, depending upon the temperature of the oil.

The tube sheet 6 fits against a seat l5 around the open upper end of the shell, and between the tube sheet and this seat is located a suitable gasket it. Over the upper face of the tube sheet 6 is placed the main head l'l which has an interior bathe or wall 88 adapted to divide the tubes into two series, one of which is the downflow series and the other of which is the upflow series. The chamber i9 is connected to the water inlet and the chamber to the water outlet, so that, as viewed in Figure l, the downflow tubes are to the left oi the baflie 18' and the upflow tubes to the right. The outer end of-the head I1 is closed by a cover 2! between which and the head is another gasket 22, the cover being secured by means of the studs 23 and nuts 24. I

Between the main head I I and a suitablesupporting flange 25 on the exterior of the shell 4 I clamp the tube-circulation connecting member 35 which rests on a carefully machined seat 21 on the flange 25. This connecting member is in the form of a ring, as shown to best advantage inrFigure 2, and is provided with a water inlet passage 28 and a water outlet passage 29, both of which are suitably flanged as at 30 and 3! for connection to the piping (not shown) through which the cooling fluid is supplied to andwithdrawn from the unit. The head, of course, is prosages 28a and 29a which are adapted to register with the passages 28 and 29, respectively. Thepassages 28 and 28a and 29 and 29a have their opposing faces carefully machined so as to ensure accurate seating and are made tight by the introduction of gaskets 32, these gaskets lying in a horizontal plane which passes approximately through the mid plane of the tube sheet 6. Between the. head l1 and the upper face of the sheet 6 there is another gasket 33 so that all fluid joints are tightly sealed.

In the event of damage to any of the gaskets any leakage of either of the fluids would pass out through the vent 4| between the gasket IS on the one hand and the gaskets 32 and 33 on the other hand. In other words, fluid from the interior-of the shell leaking past the gasket l6 could not reach the fluid which tubes and the passages 28-2811 and 23-41:; should either of the gaskets 32 and 33 be defective because it would enter the vent 4i before it could do so from whence it would be discharged to the exterior of the exchanger. In addition, such discharge would serve as a telltale so that proper repairs to the afie ted gaskets could be made.

The ring 26 is positioned circulates through the o and held on the flange 4 and the nuts 35, the studs passing through suitable apertures in the flange 25. The parts are clamped in position and all joints made studs 36 which are secured in threaded openings 31 in the flange 25, the studs extending upwardly through apertures in the flange 38 on the main head I! and nuts 40 being applied at the upper ends of the studs.

' It will now be clear that my invention makes absolutely tight by means of the that is necessary it possible to construct the exchanger in such a way as to employ whatever type of metal or alloy may bebest suited for each or thetwo fluids involved, to. prevent leakage of either fluid into the other, and, at the same time, to provide for the removal of the tube bundle without disturbing any of the piping connections for either fluid. In connection with the latter feature, all to do is to remove the ,upper head and then withdraw the tube bundle with its tube sheets through the top opening, the lower head being left in place on the lower sheet or first removed as desired. ,It is also possible to substitute in the same shell a tube assembly and tube-circulation connecting member of a different metal or alloy so that the exchanger can be adapted to some other field of service, if desired.

To revert again to the specific use of cooling oil by means of sea water it will be seen that my invention makes it possible to construct the shell l entirely'of steel and thereby secure the strength and high melting point of that metal in order to provide a flow path for the exterior of the tubes, which flow path provides a great margin of safety in the handling of this fluid in dangerous installations. The tube sheets, heads and connecting ring may all be mad so th t the entire flow path for the cooling medium (salt water immarine installations) is com- Posed of t .metal and therefore strongly resists the corrosive action of the water. The varvided with corresponding inlet and outlet pasmember, a headadapted to seat on said ious seats are accurately machined and when the gaskets are introduced and the head drawn down against the flange 25 as described, it is obvious that absolutely leak-proof joints are provided and that the structure is exceedingly strong andrigid. The arrangement effects a large saving in the quantity of, special alloy needed and at the same time provides the greatest'possible measure of strength and resistance to melting for those portions of the structure in which the oil is conveyed and which come into direct contact with the surrounding atmosphere.

I claim:

1. In a tube and shell type 'heat exchanger, an external flange near an end of the shell, a separable ring-Jike tube-circulation connection member surrounding seat on said flange, said member having an inlet passage and an outlet passage for the fluid which is to be passed through the tubes,- 9, tube sheet having a seat on the end or the shell, tubes connected to said sheet, the outer margin of the tube sheet lying to the inside of said connection .tube

sheet, said head having corresponding inlet and outletpassages, the passages in said head and those insald connection member region which lies beyond the outer margin of the tube sheet, and means for securing the head against the tube sheet withthe inlet and the outlet passages in registry, whereby to complete a fluid flow path through the interiorof said tubes. the head and the tube sheet with its tubes being removable without removing said connection member, and the head and the connection member being removable without removing the tube sheet with its tubes. I v

2. The device of claim 1 in which the securing means for the headincludes means for clamping the oil around 7 of bronze or other corrosion resistant alloy thev shell and adapted to

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