US2502675A

US2502675A - Cleanable type heat exchanger

Info

Publication number: US2502675A
Application number: US717987A
Authority: US
Inventors: Clyde S Simpelaar
Original assignee: Modine Manufacturing Co
Current assignee: Modine Manufacturing Co
Priority date: 1946-12-23
Filing date: 1946-12-23
Publication date: 1950-04-04
Anticipated expiration: 1967-04-04

Description

April 4, 1950 c. s. SlMPELAAR CLEANABLE TYPE HEAT EXCHANGER 2 Sheets-Sheet 1 m CZ @532 Filed Dec. 23, 1946 April 4, 1950 cps. SIMPELAAR CLEANABLE TYPE HEAT EXCHANGER 2 Sheets-Sheet 2 Filed Dec. 25, 1946 1/ ehar Patented Apr. 4, 1950 2,502,675 GLEANABLE TYPE HEAT EXCHANGER Clyde S. Simpelaar, Racine, Wis., assignor to Modine Manufacturing Company, Racine, Wls., a corporation of Wisconsin Application December 23, 1946, Serial No. 717,987

2 Claims.

The invention relates generally to heat exchangers, and more particularly to a cleanable type of heat exchanger.

The utilization of heat exchangers in certain applications, particularly for use in chemical and food industries, requires that such equipment be so constructed that the same may be readily cleaned.

In the past, heat exchangers utilizing a plurality of heat exchange tubes or a tube bundle, while providing easy accessibility for cleaning the tubes, have been so constructed that adequate cleaning of the Outside tube surfaces could not be obtained. This condition resulted from the necessity of closely spacing tubes to secure adequate heat transfer in reasonable bulk, maintaining a gasketed seal at the free end of the tube bundle, as well as the necessity of havin access to both ends of the exchanger.

It will be apparent that as the conventional tube bundle type of exchanger with a floating end requires considerable precision machining of the shell and piston-dike head to secure a satisfactory seal, the cost of construction is necessarily greater, and the overall size is increased, as such construction requires a shell having an internal diameter substantially larger than the overall diameter of the tube bundle.

The present invention has, among its objects, the production of a heat exchanger which does not require accessibility at both ends for cleaning, but at the same time provides ready accessibility of both ends of the tubes in which both passes or sides of the exchanger are mechanically cleanable.

Another object of the invention is the production of such a heat exchanger having a minimum number of joints between the fluids passed through the same in heat exchange relation, and embodying a simple casing and tube bundle structure which does not require any machine fits at the floating end, whereby the present invention may be utilized for heat exchange of fluids under high pressure.

A further invention is the production of such an exchanger having a finned tube bundle structure which may be easily removed from its casing, and in which the internaldiameter of the latter is relatively little greater than the diameter of the tube bundle.

A further object of the invention is the production of a heat exchanger having high efficiency in which the bailles incorporated therein are also utilized as heat transfer surfaces, and the space normally occupied by a floating piston tube memher in the conventional exchangers utilized for additional heat transfer.

Many other objects and advantages of the construction herein'shown and described will be obvious to those skilled in the art from the disclosure herein given.

To this end my invention consists in the novel construction, arrangement and combination of parts herein shown and described, and more particularly pointed out in the appended claims.

In the drawings, wherein like reference characters indicate like or corresponding parts:

Fig. 1 is a longitudinal sectional view of a heat exchanger embodying the present invention, taken approximately on the line of Fig. 2;

Fig. 2 is a sectional view taken approximately on the line 22 of Fig. 1, and

Fig. 3 is a sectional view taken approximately on the line 3-3 of Fig. 2.

The present invention contemplates the use of tubes bent or otherwise formed into a more or less U-shape, whereby both ends of each tube may be secured to a single tube sheet, the main portions of the tubes being positioned substantially at one side of the tube sheet with the tubes opening on the other side of the sheet. Provision is made for circulating a fluid through the tubes and circulating another fluid across the exterior surfaces of the tubes, to which may be secured a plurality of heat transfer fins, the tubes being so constructed that the only joints existing between the two fluids being circulated are the connections of the tube ends with the single tube sheet, and as such tubes are soldered, brazed or otherwise bonded to the tube sheet, all gasketed joints between the circulating fluids are eliminated.

Referring to the drawings, 1 indicates generally a casing, illustrated in the present instance as being cylindrical in cross-section, having an end wall 2, permanently secured thereto by welding or the like or, if desired, made integrally with the sides of the casing. Theopposite end of the casing I is provided with an outwardly extending a peripheral flange 3, seated upon a tube sheet 4,

a suitable gasket 5 being interposed therebetween. Positioned at the opposite side of the tube sheet 4 is a tubular cover member, indicated generally by the numeral 6, closed at its outer end by an end wall 1, permanently secured thereto or integrally formed therewith, the opposite or inner end of the cover 6 being provided with an outwardly extending peripheral flange 8 corresponding to the flange 3 of the casing, a gasket member 5' being interposed between the flange 8 and-the adjoining portion of the tube sheet 3. The casin: I, cover 3 and tube sheet [are secured together by any suitable means, such as the bolts 9 passing through the flange 3, tube sheet I and flange I and the cooperating nuts II. Positioned within the casing I are a plurality of tubes I2 and I3, which are provided with reverse bends I4 and I5 respectively, whereby the ends of the tubes are-brought back and secured to the tube sheet 4, the latterbeing provided with apertures it of a size to receive the tubes which are secured to the sheet by soldering, brazing or other suitable means, all of the tubes opening on the side of the tube sheet adjacent the cover 3.

-It will be noted that the tubes are arranged in two horizontal rows, with the bends of the respective tubes lying in parallel planes, and the curved portions I4 of the tubes I2 extending beyond the curved portions I5 of the tubes I3, the latter tubes being positioned between the two legs of the respective tubes I2.

Secured to the tubes I2 and I3 are a plurality of heat transfer fins I1, the side edges I8 of which are shaped to closely fit the adjacent surface of the casing I, while the edges I9 and 2| thereof are spaced from the adjacent surface of the casing I to provide fluid passages above and below the tubes. Also secured to the tubes I2 and I3, at spaced intervals, are a plurality of baffle members 22, which in the present instance are shown as constructed from a. slightly heavier material than the fins I1, and are extended to closely fit the casing I, and block the passage above or the passage below the tubes; the baille members 22 being positioned in the present instance to alter-.

nately block such passageways, thereby providing a circuitous fluid path across the tubes I2 and I3 and fins l1. It will be apparent that the number of baffle members 22 may be varied to provide any desired number of fluid passes across the tube bundle.

The casing I is provided with suitable pipe flanges 23 and 24 for making connections with

fluid supply pipes

25 and 26, either of the

pipes

25 and 26 forming the fluid inlet or outlet. For the purpose of illustration, the fluid flow through the casing I is indicated in Fig. 1 by arrows with the pipe 25 being the inlet and the pipe 26 the outlet, fluid in such case entering the casing from the pipe 25, passing across the looped ends I4 and V I5 of the tubes around the baflie 22, adjacent the closed end of the casing, but across the tubes and around the top of the second balile 22, and so on until it passes from the casing through the pipe 26.

It will be noted that fluid entering the casing from the pipe 25 passes over the looped ends I4 and. I5, thereby providing heat transfer in this space, which would normally be occupied in the conventional exchanger by a floating piston type head, providing substantially no heat transfer.

Each of the tubes I2 and I3 are provided with one long leg 21 and one short leg 28, the latter in the present instance terminating substantially flush with the face of the tube sheet 4 adjacent the cover 6, as clearly illustrated in Figs. 1 and 3, while the legs 21 project outwardly into the cover 8. Positioned in the cover 6 is a baffle member 29, having apertures 3i therein, through which the ends of the legs 21 extend. The baflie member 29 may be held in position by any suitable means, as, for example, an internally extending flange 32, carried by the cover 5, and a, plurality of sleeves 33 encircling the legs 21 and seated at their respective ends on the tube sheet I and battle member 29. The latter is preferably held 4 a in position by such interlocking between the respective parts, rather than by any bonding means. to facilitate dis-assembly and cleaning oi the tubes, as will hereinafter be described.

It will be noted that the bailie member 23 divides the interior of the cover 3 into two chambers 34 and 35 .respectively, the chamber 34 communicating with the open ends of the relatively long legs 21 of the tubes, while the chamber 35' communicates with the open ends of the relatively short legs 23 of the tubes. The cover 3 is provided with two pipe flanges I6 and 31 for connection with suitable pipes 33 and 39, forming an inlet and outlet for the second fluid being circulated through the exchanger. Either of the pipes may be utilized as the inlet or outlet. For example, assuming the pipe 33 to be the inlet, fluid will flow through the tubes in the directions indicated by arrows in Fig. l, fluid entering into the chamber 34, passing into the legs 21 of the tubes and through the same, being exhausted into the chamber and out through the pipe 39.

It will be apparent that as the same fluid flows on both sides of the bailie 29, it is not necessary to provide a sealed or gasketed Joint between the same and the cover 8 or tube legs 21, a close fit within production tolerances being satisfactory, as any fluid by-passed around the baii'ie from one chamber to another will be negligible in amount. The same is also true of the baflies 22.

Extending parallel with the legs of the tubes I2 and I3 in the construction illustrated, are a II are utilized merely to preserve a substantially geometrical tube pattern and resultant flow pattern across the tubes and flu surfaces, and also provide to some extent additional heat transfer surface.

To clean the exchanger it is necessary merely to remove, the bolts 9 and the cover I, disconnecting the pipes 38 and 39, if necessary, after which the tube sheet 4 and associated tubes and fins may be withdrawn from the casing. The baiile member 29 is removed from the legs 21, thereby exposing the open ends of the shorter legs 23 of the tubes, whereby suitable cleaning apparatus may be run through the tubes, the radius or curvature of the looped ends I4 and I1 being of suflicient size to permit the passage of ordinary tube cleaning apparatus. Likewise, as indicated in Fig. 2 of the drawing, a brush B or other device may be readily passed between the various outer tube and fin surfaces to clean the latter, and, if desired, the entire tube structure may be'readily dipped or soaked in cleaning or solvent solutions, or

further cleaned by the use of steam. Obviously, cleaning of the casing I and cover 6, as well as the bafile member 29 and sleeves 33, may be readily .accomplished by the usual methods. After cleaning, the tube bundle is reinserted in the casing I and sleeves 33 applied to the legs 21 of the tubes, baflle 29 installed, and the cover 6 and bolts replaced.

It will be noted from the above description that I have provided a heat exchanger which is readily cleanable, and in which the number of joints between the two fluids being circulated, as a result of the U-shape construction, is reduced approximately to one-third those. in past devices.

It will also be noted that the present construction provides a very eflicient device which may