US1876401A

US1876401A - chatfield

Info

Publication number: US1876401A
Authority: US
Publication date: 1932-09-06
Anticipated expiration: 1949-09-06

Description

Spt. 6, 1932. v. M. CHATFIELD HEAT EXCHANGER Filed July 28, 1951 INVENTOR. vmToR M. CHATHELD fim W ATTQRNEYJ 2 Sheets-Shae VIII/Ar P 6, 1932- v. M. CHATFIELD 1,876,401

HEAT EXCHANGER Filed July 28, 1931 2 Sheets-Sheet 2 INVENTOR. VICTOR M.CHATF\E\ D BY muu ATTORNEYS Patented Sept. 6, 1932 1 usual) STATES PATENT OFFICE,

"VICTOR M. CHA'IFIEIJ), F PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO SUN OIL COMPANY, OF PHILADELPHIA, PENNSYLVANIA, A. CORPORATION OF NEW JERSEY HEAT nxcnnnonn Application filed July 28, 1931. Serial No. 553,538.

' The present invention relates to heat exchangers and particularly to that type of exchanger in which one of the heat exchanging fluids is passed thru along tube/of fairly alarge diameter in which a smaller tube or a nest of smaller tubes is .disposed, to provide "passage for the other fluid, which may be either the heat container or the fluid to which 7 heat is to-be transmitted. v

described, no provision is made for readily ,dissemblin and cleaning the various parts of accumuIated rust,lscale and deposits left by the fluids passingtherethru. In fact, --heat' exchangers of welded'so as to compose almost a unitary structure, which necessitates scrapping certain portions of the structure every time it is dissembled for cleaning, as such dissemtore It is needless tosay that this procedureis both wasteful and expensive. i

v Another objection to structures of the ex isting type is that no provision is made for the stresses caused by. the unequal expansion of the outside tube and the smaller tube or tubes therein. It is readily appreciablethat such stresses must be set up, as the outer tube 'is approximately at thetemperature of the heat containing fluid, while the inner tubes are at the lower temperature of the fluid to which heat is being transferred, or the tube temperatures are just the reverse, depending on whether the heat containing fluid is passed,

base of the invention can'be dealt with to etter advantage after a detailed'description ofthe drawings.

Alf object of the present invention is to construct va heat exchanger which may readily betaken apart for cleaning or renewing". corroded part s. Another object isto provide a'structure with readily interchange able parts so that lspare clean parts may be kept on hand and substituted for clogged or corroded parts with a minimum of time involved in the shutdown.

Another object is to; overcome the stresses setup by unequal expansion of the fluid ar- In existingjheat exchangers of the type V the present type are i blih must be done by means of a cutting thru the inner or outer'tubes. However, this rying tubes, and thereby prevent disrupting of anyof the tubes due to such stresses and the loss caused by the necessary shut-down for repairs.

A better understanding of the invention may be had by reference to the accompanying drawings.

Figure 1 is a longitudinal-sectional View of one section of my heat exchanger.

Figure 2 is adiagrammatic view of four sections of my heat exchanger connectedin series.

Figure 3 is a view of the movable tube sheet.

Figure 4 is a view of an end connection for/ the outer tube.

0 Figure 5 is a view of the gasket retaining ring. 1

Figure 6 is a View of the flexible gasket.

In the drawings, l'designates the external tube of the heat exchan er having inlet and outlet ports 6, 6, respect vely. To each end of this external tube is welded a flange designated 4:, 4, respectively, each flange having bolt holes therein. W1thin the external tube is a nest of smaller tubes, 3, which are longitudinally disposed with respect to the external tube. The ends of the smaller tubes are rolled into tube sheets 2 and 12 respectively. The tube sheet 12 is of the same diameter as the flanges on the external tube, and is provided withbolt holes coinciding with the bolt holes in the flanges of the external tube. The tube sheet 2 (Fig. 3) is slightly smaller indiameter than the inside of the external tube. There is provided" a flexible gasket 10, (Fig. 6) which is detachably secured to the tube sheet 2iby means of a retaining ring 5, (Fig. 5) and bolts 7. At each endof each exchanger a pipe fitting 13 is provided. These pipe fittings have flanges of the same diameter as the flanges of the externaltube, and are also provided with bolt holes'coin-' ciding with the bolt holes in the flanges of the external tube.

In. assembling the exchanger, the 'smaller tubes, 3, are rolled into the tube sheets. The end of the nest having the smaller tube sheet therein is introduced into the external tube and pushed through until the flange on the serted and drawn home.

larger tube sheet abuts the flange on the external tube.

The bolt holes in these two flanges are then aligned. One of the pipe fittings is then lined up-with the two previously mentioned flanges, the bolts are 'lIl-f A tight joint is made betwen the elements 4, 12, and 13 by means of the gaskets 11 The other end of the heat exchanger is then tightened 11p in the following manner. The flexible gasket 10 is secured between the flange of the external tube and the flange of the pipe fitting and the bolts drawn home. In order that the flexible gasket 10 will not have to carry the weight of one end of the tube nest, I weld a shim 16 to the inside of the external tube. This shim positions the tube sheet 2 concentricallywith the external tube, the tube sheet 2 being free to slide back and forth upon the shim.

In practice several of the sections above described are connected in series as shown in Fig. 2 of the drawings. The fittings 13 are welded to return bends 14 as shown at 15 in Figs. 1 and 2. The inlets and outlets 6 are also welded as shown in Fig. 2.

In the operation of the described heat exchanger, if the external tube carries the'heat containing fluid, this tube will be at a higher temperature than the tubes'3, which are carrying the fluid to which heat is being transferred. As a natural consequence, the tube l'will expand to agreater extent than thetubes 3. This expansion is taken up by the corrugation in the gasket 10. If the process is reversed, and the small tubes 3 carry the heat containing the fluid, and the tube 1 the fluid to which heat is to be transferred, the tubes 3 will expand more than the tube 1. Again this expansion will be taken up by the gasket 10. In case there is a greater relative expansion between the

elements

1 and 3 than the elastic limit of the gasket 10 will permit, I have provided abutments 13a which limit the expansion of tubes 3 or the contraction of tube 1-.

If the gasket 10 were not provided, and this .end of the exchanger were constructed as the other end, it is readily seen that any relative contraction or expansion between the

elements

1 and 3 would cause stresses to be set up within theheat exchanger. In this case the 'tubefs3 would bow or the welded 'joints betweenf the flanges of the external tube and the tube would give way, either of which is likely to'cause damage to the structure. I

As already pointed out, the describedheat exchanger permits easy removal of the tube nest for cleaning. 'In'practice, spare tube nests are kept on hand, and when it is necessary to dismantle the exchanger for cleaning, a spare nest is immediately inserted into the externaltube, which procedure greatly reduces the time lost by shutting down.

It isto be understood that both' 'ends of the heat exchangermaybeprovided with elasticity in relative expansion and contraction between the elements.

I claim: V

1,. A heat exchanger comprising a flanged tube of fairly large diameter having inlet and outlet ports inthe walls thereof, a plurality of smaller tubes longitudinally disposed within said tubes, tube sheets into which the ends of the smaller tubes are rolled, a flexible. gasket detachably secured to, and of larger diameter than, one of the tube sheets, flanged pipe fittings, means for securingthe periphery of said gasket between the flange of one of the fittings and one of the flanges of the larger tube to seal the end of the larger tube, .said gasket permitting relative expansion and contraction between the largerjtube and the smaller tubes, said last named pipe fitting having abutments therein to limit the movement ofthe smaller tubes.

2. A heat exchanger'comprising a flangedposed within said tube, a tube sheet of the same diameter as the flanges of the larger (tube, into which one endof each of the smaller tubes is rolled, a pipe fitting having a flange of the same diameter as the flanges of the larger tube, means for clamping the tube sheet between the flange of the fittings. and a flange of the large tube,'another tube sheet of smaller diameter than the inside of the larger tube, into which the other end of each of the smaller tubes is rolled, a flexible gasket oflarger diameter than said last mentioned tube sheet and detachably secured thereto, a pipe fitting having a flange of the same diameter as the flanges of the larger tube, means for clamping the periphery of the j iio gasket between the flange of the last mentioned pipe fitting and the other end of the larger tube to seal that end of the larger tube and" permit relative expansion and contraction between the larger tube and the smaller tubes, said last mentioned pipe'fitting hav ing abutments therein to limit the movement of the smaller tubes.

In testimony of which invention, I have hereunto set my hand, at Philadelphia, Pennsylvania; on this 17th day of J uly, 1931; VICTOR M..CHA'IFIEILDr ise