US1947109A - Heat exchange apparatus - Google Patents

Description

Feb. 13, 1934. A, P R 1,947,109

HEAT EXCHANGE APPARATUS Filedsept. 20, 1932 INVENTOR JOHN A. POTTER.

A TTORNE Y Patented Feb; 13, 1934 PATENT OFFICE- nEA'r EXCHANGE APPARATUS John A. Potter, Prospect Park, in, assignor to 'Westlnghouse Electric & Manufacturing Company, East Pittsburgh, Pa.,

Pennsylvania a corporation of Application September 20,1932 Serial No. 634,041-

3 Claims.

My invention relates to heat exchange apparatus, and more particularly to the type comprismg a shell structure defining a. heat transfer chamber, a plurality of'fluid-circulating tubes rigidly secured to the tube sheets by rolling their ends within the openings. In securing the tubes in this manner, an effective and inexpensive fluid-tight joint is provided. Theheader structures are disposed at the side of the tube sheet opposite the entrance of the tube ends and are rigidly secured to both the tube sheets and to the adjacent ends of the shell.

An example of the abovev apparatus is found in the conventional type of surface air cooler wherein water flowing through the tubes serves to cool relatively warm air flowing through the heat-transfer chamber.

In the, above described apparatus, it is to be noted that, as both'the shell and tubes are rigid- 1y secured to the headers, no provision is made for differential expansion of the shell and tubes. Although this structure is. considered satisfactory for the smaller sizes, the amount of difierential expansion increases with the size of the apparatus and in the larger sizes undesirable strains may be imposed on the various parts by following this practice.

In the normal operation of this particular class of apparatus, the shell expands more than the tubes. However, the reverse may be true where some abnormal condition results in the overheating of the tubes.

It is therefore an object of the present invention to provide, in heat exchange apparatus of this type, an improved form of connection between the header and shell which permits the shell to expand relative to the header, the .tube

sheet and the tubes.

According to this invention, I attain the above object by providing a shell, tube sheets at opposite sides of the shell, tubes extending between the tube sheets and fixed thereto at their ends by rolling, header structures fixed to the tube sheets,

and an elastic gasket means interposed between at least one of the header structures and the shell so as to permit the shell to expand relative to the header and tubes and at the same time maintain the necessary fluid-tight joint.

These and other objects are effected by my invention, as will be apparent from the following description and claims taken in connection with the accompanying drawing, forming a part of this application, in which: I

- Fig. 1 is a fragmentary longitudinal sectional view through a heat exchanger constructed in accordance with the present invention;

Fig. 2 is a fragmentary end view of the structure shown in Fig. 1, certain parts being broken away for the sake of cleamess; and,

Fig. 3 is an enlarged fragmentary, sectional view illustrating more clearly certain details of construction of my invention.

Referring now in detail to the construction illustrated, the reference numeral 10 indicates,

in its entirety, a surface air cooler constructed in accordance with the present invention. The cooler 10 comprises a shell 11 having sides 12 defining a heat transfer chamber 13. The sides of the shell" are rigidly held in their proper spaced relation by angles 14 extending between the sides at the upper and lower corners thereof. The shell is' open at the bottom and top and the air to be cooled passes therethrough. As the air passes through the shell, it comes" into contact with a plurality of cooling tubes 15, through which the cooling medium, for example, water is circulat'ed.

' Tube sheets 16 and 1'7 are disposed at opposite sides of the shell and are provided with openings 18 through which the ends of the tubes ex tend. The ends of the tubes are rigidly secured to the tube sheets by rolling as indicated at 19.

The tube sheet 16 may be rigidly secured to the adjacent angles 14 and to-the sides 12'by any suitable means. Rigidly secured to the outer side of the tube sheet 16 is a header structure 20 having inlet and outlet connections 21 and 22 respectively, for the cooling water.

I have chosen to show a cooler of the two-pass or double-flow type. The header 20 is divided transversely by a partition 23 so that the water entering through the connection 21 flows into andthrough the upper portion of the nest of tubes and into a header structure 24 rigidly secured to the other tube sheet 17, and is returned through the lower portion of the nest of tubes to the header 20, from which it is carried away through The tube sheet 1'! is composed of a plurality oi sections 25 in order to facilitate the removal of tubes, and each of the sections 25 is rigidly secured by suitable bolts 26 to a dummy or false tube sheet 2'? forming a part of the header structure 24. The dummy sheet 27 is provided with openings 28 which are in alignment with the openings 18 in the tube sheet 1'7 so as to permit the flow of cooling water to and from the ends of the tubes. A gasket member 29 is disposed between the dummy sheet 27 and the tube sheet 17 to prevent leakage, and the gasket 29 extends outward and between the shell structure 11 and a flange 30 formed on the header structure 24.

As has already been pointed out, I provide an improved form of connection between the shell 11 and the header 24 which permits the shell to expand relative to the header and at the same time prevents leakage of media therethrough. This connection may be'modifled in a number of ways without ,departing from the spirit of my invention.

In the drawing, I have shown this connection as comprising a plurality of bolts 31 fixed at one end to the angles 14 and sides 12 of the shell structure and extending loosely through openings 32 provided in the flange 30 of the header 24. A soft rubber gasket 33 is disposed between the gasket 29 and the flange 30 and serves to keep the gasket 29 firmly pressed against the angles 14 and sides 12. Nuts 34 are secured to the ends of the bolts 31 and serve to limit movement of the shell and header away from one another and thereby maintain a fluid-tight joint between the shell and header. The soft rubber gasket 33 permits movement of the shell relative to the header within the limits set by the nuts 34.

A lock washer 35 is placed on the bolt 31 between the nut 34 and the flange 30 so as to give resiliency to the structure should the tubes become overheated due to an abnormal condition and expand more than the shell.

As previously stated, a connection of this kind has a distinct advantage in relatively large heat exchangers wherein the medium to be cooled heats the shell and causes the latter to expand, and the cooling medium tends to keep the tubes and header cool and thereby prevents their expansion. According to my invention, the shell may freely expand without damage to the joint between the tubes and tube sheet.

While I have shownmy invention in but one form, it will be obvious to those skilled in the art that it is not so limited but is susceptible of various changes and modifications without departing from the spirit thereof and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set forthin the appended claims.

What I claim is: I

1. In heat exchange apparatus, the combination of a shell structure defining a heat transfer chamber; tube sheets disposed atopposite sides of the chamber and having openings therethro'u'gh; tubes extending through the chamber and having their ends extending within the openings in the tube sheets; the ends of the tubes being rigidly secured to their respective tube sheets; a header structure memos rigidly secured to one of the tube sheets and defining a chamber for supplying fluid to or receiving fluid from the tubes; and means for securing the header structure to the shell structure comprising an elastic gasket member. interposed between the structures and disposed in a plane normal to the longitudinal dimension of the tubes, a stud member passing through the gasket member and connected to the shell and header in such a manner as to permit relative movement therebetween; and means on the stud member for limiting the movement of the header and shell away from each other so as to prevent breaking of the fluid-tight seal provided by the gasket member.

2. In heat exchange apparatus, the combination of a shell structure defining a heat transfer chamber; tube sheets disposed at opposite sides of the shell and having aligned openings therein, at least one of the tube sheets being composed of a plurality of sections; tubes extending across the heat transfer chamber and having their ends extending within the openings and fixed to the tube sheets; header structures rigidly secured to the tube sheets at the side opposite the entrance of the tubes to define chambers for supplying fluid to and receiving fluid from the tubes; the header structure adjacent the sectional tube sheet including a dummy tube sheet lying parallel and immediately adjacent the sectional tube sheet and having openings therein aligned'with the openings in the sectional tube sheet, and the dummy tube sheet being secured to the sectional tube sheet by bolts rigidly connecting each section of the latter with the dummy tube sheet; gasket means interposed between the sectional tube sheet and dummy tube sheet to effect a seal and extending outwardly and between the header and shell structures; a second gasket means interposed between the header structure at the side adjacent the sectional tube sheet and the shell structure and com prising a relatively thick elastic member; and means for securing the header at the side adjacent the sectional tube sheet to the shell structure, and providing for relative movement of the header and shell in directions parallel to the longitudinal dimension of the tubes but at the same time preventing relative movement away from one another beyond a point required to maintain the fluid-tight seal efiected by the gasket means.

3. In heat exchange apparatus, a structural member comprising a nest of tubes and headers rigidly connected to opposite ends of the tubes, a shell member providing for passage of media about and past the tubes, said shell member being rigidly connected at one end to one of the headers,

and means for connecting the other end of the shell member to the other header and providing for relative expansion and contraction of said members, said means comprising studs connected to one of the members and slidably engaging openings formed in the other of said members, elastic spacing means encompassing the studs and arranged between the members, and means cooperating with the studs to hold th members and the spacing means together under initial compression,

JOHN A. POTTER.

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