US 2152266 A
Description (OCR text may contain errors)
March 28, 1939 D. R. MCNEAL QUIPMENT HEAT EXS'JHANGE E Filed May 14, 1937 65@ ATroRNEYs Patented Mar. 28,1939
nEA'r EXCHANGE EQUIPMENT Daniel Raymond McNeal, Abington, la., assignor to Andale Company, Philadelphia, Pa., acorporation of Pennsylvania Application May 14, 1937, Serial No. 142,552
This invention relates to heat exchange equipment and is particularly concerned with a heat exchanger of the type incorporating a tubular shell and a tube bundle, the two being relatively 5 separable for the purpose of cleaning, replacement of tubes or the like. y
Generally considered, the invention is concerned with a novel arrangement of tube sheets and also with features of a flexible joint between a tube sheet and the shell to accommodate relative expansion and contraction of the tubes and shell.
More specifically, the invention provides a novel relationship between elements of the flexible joint and a tube sheet providing for ready removal of the tube bundle including said sheet.
The invention also contemplates employment of two tube sheets at each end of the tube nest. the two sheets being spaced and the space being in communication with a passage providing for testing of the tube joints in both sheets by in-l troduction of lluid under pressure into the intersheet space. In association with this feature the invention also has in view connection of the viiexi ble joint above-mentioned with the inner one of the two tube sheets. Y
Further advantages of the invention including further features of the structure mentioned above will be pointed out more fully herein following a description of the accompanying drawing which illustrates the preferred embodiment of the invention.
The gure of the drawing is a vertical sectional view through an upright heat exchanger incorporating the features of this invention, the mid portion of theshell and tubes being broken out.
The reference numeral I indicates a shell and the numeral 2 designates tubes of the nest thereof` which extends longitudinally through the shell.
46 At their lower ends the tubes are provided with an inner tube sheet 3 and an outer tube sheet 4,
the former being of diameter larger than the diameter of the shell and the latter being of smaller diameter than the i'lrst. 'I'he shell and, in
fact, the entire unit may receive support from a base 5 or the like on which the outer portion of the sheet 3 rests and to which it may be secured by means of studs 6.
The inner tube sheet 3 may be secured to the shell as by means of a ring I and studs 8, a packed joint 9 being provided `between the sheet 3 and the ring l.
The upper ends of the tubes are also provided with inner and outer tube sheets I0 and II, re-
spectively, and in both cases the two tube sheets are preferably secured to each otherin slightly spaced relation, as by a beading I2 formed on one of them, around which beading a welded joint I3 is used.
At the upper end, the inner sheet I0, although 5 of larger diameter than the outer sheet II, is small enough to fit inside of the shell and to move therein to accommodate relative expansion and contraction of the tubes and shell. This relationship in size of the tube sheet I0 also permits 10 separation of the tube bundle (including its tube sheets) from the shell. In the form illustrated this may be accomplished by disconnecting the studs 8 at the bottom of the unit and then withdrawing the shell upwardly. For this purpose ll the upper header I4, of course, would first be removed.
Header I4 is secured to the outer tube sheet II by means of a ring I5 and studs I6, .andthis header is provided with a connection I1 which 0 preferably serves as the inlet connection to the tubes.
An outlet header I8 is similarly attached to the lower tube sheet 4, this outlet header being provided with an outlet connection I9. Flow of` 2l the heat exchangev medium around the tubes and through the shell may be effected by means of the inletand outlet connections 20 and 2 I. A number of ballies such as those shown at 22, spaced by means of sleeves 23, may be employed to direct 30 the iiowof the heat exchange medium during passage thereof from the inlet connection 2|) to the outlet connection 2 I. These features form no part of the present invention, per se, and they are,
therefore, not described in detail herein although 35 it should be noted that in accordance with the .A invention it is preferable to employ a tube nest or bundle (including tube sheets, bailles, spacers, n etc.) which is removable as a unit.
Sincethe tube sheet 3 at the bottom of. the 40 unit is secured to the shell, the upper ends of the tubes and the associated tube sheets are arranged for sliding movement axially of the shell to aecommodate expansion and contraction, and with this in mind the present invention provides a 45 flexible joint member 24, preferably of the bellows type and desirably nlade of thin, annealed steel, one edge of this bellows being secured, as by welding, to the shell as indicated at 25 and the other edge being similarly secured to a ring 26. The 5o ring 26 and the tube sheet III are preferably provided with tongue and groove elements 21 adapted to cooperate with packing providing a seal for the shell space. Studs 28 serve to secure the ring 26 to the sheet I0.
A port or passage 28 is provided in each oi.' the outer tube sheetsA and Il, these ports being in communication with the inter-sheet space at each end of the unit and preferably being threaded for convenient attachment oi.' a uid pressure line for reasons mentioned herebelow.
With the foregoing description of structur features in mind, it will be apparent that during operation of the unit'. heat exchange is effected between the fluid surrounding the tubes and the uid passing therethrough. The iluid surrounding the tubes flows through the shell from its inlet 20 to its outlet 2|, and the other iluid, of course,
moves in counterilow from the inlet header I l' to the outlet header I8. During normal operation it is contemplated that the passages 28 in the outer tube sheets 4 and Il shall remain open. In view of this any leakage at the tube joints in either tube sheet is vented to atmosphere, which is in contrast with single sheet arrangements, wherein leakage results in ow of uid from one side of the unit into the other, for example, from a header into the shell space. v
The ports 28 in the outer tube sheets may also be employed (when the equipment is not in service) as a means for testing the tightness of the tube joints in both of the tube sheets. To accomplish this a fluid pressure connection (for example, an air supply) may be coupled with one of the ports 28 and iluid pressure introduced into the inter-sheet space. A loose tube joint in the inner tube sheet may then be detected` by the discharge of uid from theinter-sheet space through the inner sheet around a tube and, similarly, a loose tube joint in the outer tube sheet may be detected by the discharge of the testing duid from the inter-sheet space through the outer sheet around a tube.
Further attention is directed to the fact that the flexible joint 24 is provided between the shell I and the inner tube sheet I in a manner not to interfere with the normal functioning of the port 29 as a vent from the inter-sheet space. The arrangement of the'packed joint 21 between the ring 26 and the inner of the two tube sheets is also of importance in permitting independent testing ofthis joint. Still further the attachment of the exible joint member to the ring 26,
which, in turn, is attached to the inner sheet I0, also yfacilitates separation of the tube nest and the ,surrounding shell. Thus, as hereinbeiore mentioned, after disconnection of the studs 8 at the bottom of the unit, removal of the inlet header Il, and disconnection of studs 28 at the top of the unit, the shell may be withdrawn upwardly from the tube nest or bundle.
1. Heat exchange equipment including a generally upright tubular shell, a nest of tubes in the shell, a tube sheet at the bottom of the shell larger in diameter than the inside diameter of the shell, supporting elements for the device associated with said sheet and providing for support of the device in upright position, a tube sheet at the upper end of the shell of diameter such as to pass through the shell, a header removably secured to the upper tube sheet, the shell being removable upwardly from the tube nest over the upper tube sheet, and a flexible joint between said upper tube sheet and the upper edge portion of the shell including an annular bellows member connected with the shell at one edge and a ring removably attached to the upper tube sheet externally of the header, the other edge of the bellows being connected with said ring. whereby relative separation of the tube nest and shell may be effected by detachlng said ring and withdrawing the shell, bellows, and ring upwardly with respect to the tube nest and its associated tube sheets.
2.A head exchange unit of the tube and shell type having a nest of tubes in the shell, a floating tube sheet at one end of said nest of diameter such as to it and oat within the shell, a second tube sheet adjacent the same end of the tube nest arranged at the outer face of the rst sheet, with a space therebetween, the second tube sheet being of smaller diameter than the rst, a ring removably attached to the rst tube sheet and lying substantially in the plane of the second tube sheet, a header of smaller diameter than the ring for the adjacent ends of the tubes, means securing the header to the second tube sheet, and a ilexible joint including a bellows member connected with the ring and also with the adjacent edge portion of the shell.
DANIEL RAYMOND McNEAL.