Supporting device for heat exchanger tubes

Abstract

 The affected technical field is that of heat exchangers, and the invention relates to a tube supporting device therefor.
The technical problem is that of providing a supporting device which can ensure substantial cancellation of the longitudinal forces transferred from the tubes to the header.
The solution resides in a device which comprises a sleeve (2,17) associated to each tube, connected with the end of a connecting rod (5,20) hinged at the other end (6,21) to a carrier element constituted, for at least one connecting rod (5, 20), by the exchanger frame (9).

Description

[0001] The invention relates to a supporting device for heat exchanger tubes.

[0002] It is known that with a great majority of heat exchangers the support for the tube nest tubes is provided by resting the same, with the possible interposition of a sleeve, onto the lateral surfaces of holes made through plates which are rigid with the exchanger structure. With this arrangement, the weight of the tubes is entirely taken up by said rest surfaces, thereby as a sliding movement is originated by the thermal expansion differential between said tubes and said rest surfaces, a strong frictional force is generated in the longitudinal directions of the tubes.

[0003] This frictional force directly stresses the header to which the tubes are conducted, and,in view of the tubes being usually provided in a large number, the header is to accept a high stress which causes no concern where said header is constructed with a large thickness dimension and has a circular cross-section of considerable rigidity, but cannot be readily taken up by headers which, for some thermal reasons, must be constructed with thin thickness dimensions and exhibit poor rigidity, as is the case,for example, with very slim headers with quadrangular cross-section such as are used in sodium-air exchangers for nuclear plants.

[0004] This invention is directed to provide a supporting device for heat exchanger tubes which can ensure substantial cancellation of the longitudinal forces transferred from the tubes to the header.

[0005] Within the proposed aim, it is an object of the invention to provide a supporting device of great simplicity, thereby bringing about decreased costs and the utmost reliability in operation.

[0006] According to one aspect of the invention, the proposed aim and cited object are achieved by a supporting device for heat exchanger tubes, as defined in Claim 1.

[0007] According to a preferred embodiment the device is characterized in that it comprises a sleeve associated with the external surfaces of each of the tubes, connected with the end of a connecting rod substantially hinged at the other end to a carrier element, said carrier element being constituted, for at least one connecting rod, by the exchanger frame.

[0008] Advantageously, the carrier element, whereto a connecting rod connected to a sleeve associated with one tube is hinged, is formed by the sleeve associated with an adjacent tube.

[0009] With this expedient, each tube becomes supported by a connecting rod which, in its movements caused by the tube expansions, generates no forces along the axes of the tubes themselves, which accordingly, will impose no longitudinal forces on the header to which they are connected.

[0010] Further features and advantages will be more clearly apparent from the description of a preferred but not exclusive, embodiment of the invention, as illustrated by way of example and not of limitation in the accompanying drawings, where:

Figure 1 is a front view of an embodiment of the invention, in which a modification has been indicated by dotted lines; and

Figure 2 is a sectional view in the plane II-II of Figure 1.

[0011] With reference to the aforesaid views, indicated at 1 is a finned tube of a heat exchanger, with the external surface whereof, as suitably stripped of fins at the selected area, there is associated the sleeve 2 formed by the half-shells 2a and 2b clamped around the tube by the action of the bolts 3 and 4.

[0012] The stem of the bolt 3 forms the pivot pin for the connecting rod 5, which, with its other end, is hinged at 6 to the carrier element comprising the small ears. 7 and 8 made rigid with the structure 9 of the exchanger frame.

[0013] The sleeve 2 is passed freely through the hole 10 formed in the plate 11, rigid with the structure of the exchanger frame, to which there are attached, opposedly in a substantially perpendicular direction to the plane containing the connecting rod 5, the small plates 12 and 13 by means of screws such as 12a; said small plates serve the function of restricting the transverse movements of the tube 1, as caused by seismic events or vibration induced by the fluid sweeping past it, to contact respectively the ridges 14 and 15 provided on the half-shells 2a and 2b. Said ridges and the sides of the small plates adjoining them are coated with a wear-preventing material such as stellite, in view of the likelihood of relative movements, however small these may be, caused by thermal expansion differentials between the exchanger frame and header.

[0014] The tube 16 is supported similarly to the tube 1: associated with the external surface thereof is in fact the sleeve 17, formed by the two half-shells 17a and 17b clamped together by the bolts 18 and 19, connected to one end of the connecting rod 20 pivoted with the other end at 21 to the carrier element formed by the ears 22 and 23 rigid with the plate 11. The constraint to the lateral movements of the tube 16 is provided by the plates 24 and 25 being secured to the edges of the hole 26 wherethrough there is inserted the sleeve 17, by contact with the ridges 27 and 28 provided on the half-shells 17a and 17b.

[0015] The tubes 2 and 17 shown in the drawing may extend not only in a horizontal or a vertical plane, but in any inclined plane, obtaining the same effect by the above described supporting structure. Moreover, the entire structure shown in Fig. 1 may be rotated through 90° about a horizontal axis parallel to that of the tubes 2 and 17. The same effect would be obtained also in such case by the supporting system. In addition the sliding engagement between the ridges 14,15; 27,28 and the plates 12,13; 24,25, respectively, would become in part effective depending on the gravity action on the tubes.

[0016] It may be appreciated from the foregoing that the invention provides a support for heat exchanger tubes which is almost free of forces along the axes of the tubes, which accordingly, can be connected without problems even to headers exhibiting poor inherent rigidity.

[0017] The invention just described is susceptible to many modifications and variations, all of which fall within the scope of the inventive concept: thus, the connecting rod connected with one end to a sleeve could be hinged at the other end, rather than to the structure of the exchanger frame, to the adjacent sleeve, which may be in turn carried on a connecting rod pivoted at the other end to another sleeve or to the stationary structure, and so on.

[0018] In fact, according to this modification, the connecting rod 20 may be omitted and in its place a connecting rod 205, shown in dotted lines, may be hinged with one end thereof to the sleeve 17 and with the opposite end thereof to the sleeve 2 at the bolts 18 and 4, respectively. It may be advantageous to select this type of connection between tubes which are at a substantial lateral distance from one another in order to have the connecting rod 205 with a sufficient length.

[0019] From the foregoing it will be understood that, when the dilatation of the tubes occurs the sleeves 2 and 17 move axially together with the tube portion they clamp while the connecting rods 5 and 20 or 205 follow such axial movement by an angular displacements thereof. When the structure is at room temperature, the inclination of the rods 5 and 20 is chosen so that at half the thermal dilatation the rods 5 and 20 are perpendicular to the axes of the tubes 2,17 and with the full thermic dilatation the inclination of such rods is opposite to the one shown in Fig. 2.

[0020] In practicing the invention, all of the details may be replaced with other, technically equivalent elements; furthermore, the materials used, as well as the shapes and dimensions, may be any ones contingent on individual requirements.

Claims

1. A supporting device for heat exchanger tubes, characterized by an articulated linkage system (5,20, 205) connected with one end thereof to at least one heat exchanger tube (1,16) and with the other end thereof to at least one carrier member (7,22,4,18) at a distance from said tube (1,16), said linkage system allowing free limited displacement of said at least one tube at least in the axial direction thereof and supporting said tube in at least one direction transverse to the tube axis.

2. A device according to Claim 1, Wherein said articulated linkage is a connecting rod (5,20,205).

3. A device according to Claims 1,2, wherein said carrier element is a heat exchanger tube (1,16) supported by said articulated linkage system (5,20).

4. A supporting device for heat exchanger tubes, characterized in that it comprises a sleeve (2,17) associated with the external surfaces of each of the tubes, connected with the end of a connecting rod (5, 20) substantially hinged at the other end (6,21) to a carrier element (7,8,9) said carrier element being constituted, for at least one connecting rod (5,20), by the exchanger frame (9).

5. A supporting device according to Claim 4, characterized in that the carrier element whereto one connecting rod (5) connected to a sleeve (2) associated with one tube is hinged comprises the sleeve (17) associated with an adjacent tube.

6. A supporting device according to one or more of the preceding claims, characterized in that each sleeve (2,17) comprises two half-shells (2a,2b,17a,17b) clamped around the tube by bolts (3,4,18,19) adapted to form the pivot pin for the connecting rods (5,20).

7. A supporting device according to one or more of the preceding claims, characterized in that the sleeves (2,17) associated with the tubes are passed through holes (10,26) formed in a plate (11) included with the exchanger frame, there being provided for each hole (10,26) two small plates (12,13,24,25) attached to the plate (11) opposedly in a substantially perpendicular direction to the plane of the connecting rods (5,20), adapted to contact ridges (14,15,27,28) provided on the half-shells (2a,2b,17a,17b) of the sleeves (2,17) so as to restrict the transverse movements of the tubes.

8. A supporting device according to one or more of the preceding claims, characterized in that the ridges (14,15,27,28) provided on the half-shells (2a,2b,17a,17b) of the sleeves (2,17) and the sides of the small plates (12,13,24,25) adjoining them are coated with a wear-preventing material.

9. A supporting device for heat exchanger tubes, according to the preceding claims and substantially as herein described and illustrated;

Drawing