US 2492409 A
Description (OCR text may contain errors)
Dec. 27,, 1949 "G. A. WORN ETAL HEAT EXCHANGER Filed July 31, 1946 1 z 7 a; a Z 3 a my g w M li||.. OLA w w m 1 z 1 4/ 4/ 9 1 q 4 J H M M 2 a m I 660 36 Mir/22.5 Jr
Patented Dec. 27, 1949 HEAT EXCHANGEB George A. Worn, Greenwich, Com, and George W. Evans, Teaneck, N. J., 'assignors to The Lummus Company, New York, N. Y., a corporation of Delaware Application July 31, 1946, Serial No. 687,330
This invention relates to improvements in heat exchangers of the shell-and-tube type and more particularly to improvementsin a leakage interception feature to prevent intermingling of the shell-side fluid and the tube-side fluid.
An important object of the invention is to provide an advantageous combination of a leakage interception feature with means for holding a tube sheet against displacement under an unbalanced pressure.
A further object of the invention is to provide a satisfactory embodiment of such a combination in a heat exchanger of a removable bundle type wherein the tube sheet at one end of a tube bundle is removably seated within a channel or header at one end of the shell and the leakage interception feature is employed to prevent leakage from either the shell or the channel past the edge or margin of the tube sheet.
These and other objects and advantages of the invention will appear from the following description taken in connection with the accompanying drawing.
In the drawing:
Fig. 1 is a vertical sectional view of a heat exchanger unit embodying the invention, the section being taken approximately on the line l-I of 'Fig. '2;
Fig. 2 is a horizontal section on the line 2-2 of Fig. 1; and,
Fig. 3 is an enlarged detail vertical section approximately on the line 3--3 of Fig. 2.
According to the invention, in the embodiment shown, a vertical heat exchanger unit is provided with an enlarged channel or header at the upper end of its shell. Within said channel a tube sheet has its margin seated upon an annular shoulder or ledge at the bottom of the channel, and a tube bundle depends from the tube sheet into the shell. A leakage interception means is located at the periphery of the tube sheet and, in cooperation with said means, there is an abutment structure for retaining the tube sheet upon its seat when there is an unbalanced pressure within the shell, at the under side of the tube sheet. The said abutment structure is releasable and removable from the channel to afford access to the leakage interception means and also to permit upward withdrawal of the tube sheet and its pendent bundle as a unit through the channel. While the invention is illustrated as embodied in a vertical heat exchanger unit, it may be employed satisfactorily in a unit otherwise disposed.
The structure of the unit includes a cylindrical 3 Claims. (01. 257-221) shell I closed at its lower end by a welded-on plate 2 and having at its upper end an outwardly extending welded-on flange 3. Adjacent its upper and lower ends respectively, the shell has an inlet nozzle 4 and an outlet nozzle 5. Beneath the nozzle 5 the shell has a cleanout nozzle 5a which is normally plugged. An L-shaped vent 6 leads from the interior of the shell outwardly through the flange 3 and downwardly to the under side of the flange.
At the upper end of the shell there is a channel or header structure. In the present instance said structure is detachably secured to the shell, but it may be welded on or otherwise secured. This structure includes an annular body I, of materially greater diameter than the shell and formed with outwardly extending flanges 8 and 9 at its upper and lower ends, respectively. A removable cover plate I0 is bolted, as at II, to the flange 8, and the flange 9 is bolted, as at l2, to the shell flange 3, gaskets being interposed in said two joints. The channel body has inlet and outlet nozzles 13 and I4 respectively at points suitably spaced therearound. At the lower end thereof the channel body is also formed with an inwardly extending annular flange l5 forming a shoulder or ledge for supporting the tube bundle.
The tube bundle includes a tube sheet l6 and a bundle of U-tubes ll depending from the tube sheet into the shell. In lieu of U-tubes, however, straight tubes may be employed together with a floating head structure at the lower end of the bundle. The bundle of U-tubes bears a series of staggered transverse baiiles l8 arranged along the bundle between the shell nozzles 4 and 5. In Fig.
1 only a few of the tubes are shown, in order to simplify the illustration.
A countersunk seat I9 is formed in the ledgeforming flange l5 to receive the tube sheet. The internal diameter of the flange I5 and that of the shell flange 3 corresponds to the internal diameter of the shell, the diameter of the tube sheet exceeds the internal diameter of the flange l5, and
the margin of the sheet rests upon the bottom of ception'feature. The packing assembly includes a rigid spacing element in the form of a lantern ring 2| having annular grooves 22 in its circumferential i'aces, anda series of radial passages 23 spaced around the ring and connecting said grooves. Suitable packing is disposed above and below the lantern ring. In the present instance the packing at each side of said ring comprises a gasket ring 24 of rubber or other suitable compressible material. A vent passage or weep hole 2! leads from the packing space through the flanges I5 and 9 and is threaded at its outer end for attachment of piping to conduct on leakage intercepted by the packing assembly.
Within the channel or header an abutment ring 28 is bolted, as at 21, to the upper surface of the bottom flange I5, outwardly of the countersink. The abutment ring overlaps the margin of the tube sheet and serves to retain the latter upon its seat. At its under side said ring has a groove or channel 28 accommodating the upper portion of a gland ring 29 whose lower edge bears againstradially inward in cross section and the surfaces of said ring and the countersunk seat which engage the packing rings converge radially outward, to obtain effective compression of the packing rings against said surfaces and against the tube sheet and the lantern ring for a good sealing eflect. The abutment ring and the gland ring are made in sections and the sections accommodate between them a pass partition 32 located between the header nozzles 13 and I4 and dividing the header into two compartments. The lantern ring and the compressible packing rings are each continuous. Each of the U-tubes of the bundle opens at one end into the compartment in communication with the inlet nozzle i3 and at its opthe partition abuts the cover Ill.
7 While its utility is by no means limited to that purpose, the unit was designed more particularly for cooling lubricating oil conducted from a turbine or other mechanism. In such service the unit will be mounted upon the top of a tank, inu dicated at T, with the shell depending into the tank. Water or other cooling fluid will be passed through the header nozzle I3 and the tubes of the bundle and discharged through the nozzle I 4. Oil
to be cooled will be passed through the upper shell nozzle 4 and thence downwardly over the cooling tubes and out through the nozzle 5 which discharges into the tank surrounding the shell. If desired, the flow of cooling fluid may be re versed so that the fluid will enter the shell through the nozzle 5 and leave through the nozzle. 4. Cooled oil will be passed from the tank to the turbine or other mechanism to be lubricated. The" Leakage from eitherthe shell or the header to the edge of the tube sheet is there intercepted by the packing assembly and passed out through the vent 25 so that intermlngling of the shellside fluid and the tube-side fluid is prevented. The abutment ring 26 serves to retain the tube sheet against upward displacement when the shell is subjected to high internal testing pressure for the purpose of detecting leakage at the joints between the tubes and the tube sheets. In addition to that, the abutmen ring forms a mounting for the screws 30 for compressing the packing and serves to take the reaction of the compressing force applied by the screws.
The exchanger is designed for insertion and removal of the tube bundle through the header without the necessity of breaking any piping connections to the exchanger unit. For removal of the bundle the cover I and the pass partition 32 are removed and the abutment ring 26 is unbolted and removed through the upper end of the header. Thereby the gland ring is uncovered for withdrawal and the tube sheet is freed for upward withdrawal of the sheet and the bundle as a unit through the header. Removal of the abutment ring also renders the packing accessible for removal and servicing without the necessity of removing the tube sheet and bundle. When the parts are assembled the leakage interception means is entirely enclosed and protected from tampering so that the packing adjustment can be maintained.
It will be seen from the foregoing that our invention provides a very advantageous combination of a leakage interception feature and a tube sheet retaining feature. While we have disclosed a very satisfactory structural embodiment of the invention, it will be understood that the disclosure is merely illustrative and in nowise limiting and that the invention comprehends such modifications as will come within the scope of the following claims.
1. Tube sheet mounting and sealing means for a heat exchanger of a type including a shell, a channel at one end of the shell and detachably connected thereto and a tube bundle with a tube sheet at the end thereof adjacent said shell end, and in which the shell and bundle are separable by relative movement therebetween longitudinally of the bundle and the bundle and said tube sheet are together removable through the outer end of the channel, said means comprising an annular inwardly extending flange borne by said channel at the end thereof adjacent the shell and having at its inner margin within the channel an annular inwardly facing countersunk seat for the margin of said tube sheet and an annular wall around the edge of the tube sheet and spaced therefrom and from the inner side wall of the channel, a packing assembly between the edge of the tube sheet and said wall including a lantern ring and packing at opposite sides of said ring, a vent in said wall and leading from the space occupied by said ring, a gland ring bearing against the packing at the outer side of said lantern ring, the packing at the inner side of the lantern ring bearing against said seat, an abutment ring within the channel overlapping the margin of the tube sheet and said flange and releasably secured to the portion of the flange between said flange wall and the inner wall of the channel to retain the tube sheet upon said seat, and screws in threaded connection with said abutment ring at points spaced therearound and engageable with the gland ring to force the lat-;,
' tube sheet being shiftable for removal past the packing assembly.
2. Tube sheet mounting and sealing means as claimed in claim 1 wherein the said abutment ring and the said gland ring are formed in sections to accommodate a pass partition of the channel between their sections.
3. Tube sheet mounting and sealing means for a heat exchanger of a type including a shell, a channel at one end of the shell and detachably connected thereto and a tube bundle with a tube sheet at the end thereof adjacent said shell end, and in which the shell and bundle are separable by relative movement therebetween longitudinally of the bundle and the bundle and said tube sheet are together removable through the outer end of the channel, said means comprising an annular inwardly extending flange borne by said channel at the end thereof adjacent the shell and having at its inner margin within the channel an annular countersunk seat for the margin of said tube sheet and an annular wall around the edge of the tube sheet and spaced therefrom and from the inner side wall of the channel, a packing assembly between the edge of the tube sheet and said wall including a lantern ring and packing at opposite sides of said ring, a vent in said wall and leading from the space occupied by said ring, a gland ring bearing against the packing at the outer side of r 1 said lantern ring the packing at the inner side of the lantern ring bearing against said seat, abutment means within the channel overlapping the margin of the tube sheet and said flange and releasably secured to the portion of the flange between said flange wall and the inner side wall of the channel to retain the tube sheet upon said seat and screws in threaded connection with said abutment means and engageable with the gland ring to force the latter against the packing said abutment means, after release thereof from the flange, being removable through the outer end of the channel and the tube sheet being shiftable for removal past the packing assembly.
- GEORGE A. WORN.
GEORGE W. EVANS.
REFERENCES CITED The following references are of record in the file of this patent:
' UNITED STATES PATEN'I'S Number Name Date 1,810,286 MacPhee June 16, 1931 1,811,402 McNeal June 23, 1931 2,127,129 McNeal Aug. 16, 1938 2,226,495 Jacocks Dec. 24, 1940 2,363,526 Hobbs Nov. 28, 1944 FOREIGN PATENTS Number Country Date Great Britain 10, 1943