JPS5947838B2 - Heat exchanger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat exchanger, in particular a heat exchanger with double-walled heat exchanger tubes.

It is desirable to ensure separation of the heating fluid and the heated lfi, bodies within the heat exchanger, and the effort and expense required to ensure their separation depends on the compatibility of the fluids used. It changes depending on.

Double-walled heat transfer tubes, with one wall grooved at its interface, have been proposed as a very reliable method of maintaining fluid separation.

However, the joint between the two tubesheets is prone to leakage.

By providing double tubesheets at both ends of the tube, leaks at the tube-to-tubesheet junction can be detected, thereby reducing the possibility of undetected leaks and mixing of the two aflFs.

However, such a configuration is very expensive.

Therefore, an object of the present invention is to provide a highly reliable double-walled heat exchanger tube heat exchanger that has the same function as a heat exchanger equipped with a double-walled tube plate and is also very inexpensive. be.

To this end, the present invention provides a heat exchanger comprising a shell and a plurality of double-walled heat exchanger tubes having an inner wall and an outer wall and mounted on tube sheets supported at both ends in the shell. In the device, the double-walled heat exchanger tube is attached at one end to a single tubesheet and at the other end to a pair of spaced apart tubesheets, and the double-walled heat exchanger tube The inner wall portion of the double-walled heat exchanger tube has a distal end proximate to and sealed to one of the pair of tube sheets, and the outer wall portion of the double-walled heat exchanger tube has a distal end adjacent to the other of the pair of tube sheets. adjacent and sealed thereto, the outer wall of the double-walled heat transfer tube being sealed at inner and outer junctions with the single tubesheet, the outer wall being sealed to the single tubesheet; at least one opening in the tubesheet through the outer wall, and the inner and outer walls are sealed at the ends of the double-walled heat exchanger tubes outside the single tubesheet. This is a heat exchanger characterized by the following.

The invention will become more readily apparent from the following description of preferred embodiments of the invention, shown by way of example only in the accompanying drawings.

The accompanying drawings, in particular FIG. 1, show a heat exchanger 1 having an outer shell 3 and a plurality of double-walled heat exchanger tubes 5. FIG.

A single tube plate 7 is arranged at one end of the shell 3, shown at the lower end;
A pair of tube sheets 9 and 11 are arranged at the other end of the shell 3, at the upper end in the figure.

The tube sheets 9 and 11 are spaced apart and together with the shell 3 form a closed space 13 therebetween.

Semispherical heads 15 and 17 are attached to tube sheets 7 and 11 respectively and together form a header for guiding fluid flow through double walled heat exchanger tubes 5.

The shell 3 flares outward near each end to form a sterile flow path for incoming or outgoing shell side fluid.

The double-walled heat exchanger tube 5 is a double-walled heat exchanger tube that has a gap between both walls or has one or more grooves 6 at the interface between the two walls.

One end of each double-walled heat transfer tube terminates near a single tubesheet 7, as shown in detail in FIG.

This one end of the double-walled heat exchanger tube 5 is sealed by a circumferential weld 19 at the interface between the inner wall 21 and the outer wall 23.

Tubesheet 7 has a plurality of holes 25 for receiving double-walled heat exchanger tubes 5 (only one shown).

Each hole is provided with a boss 27 at both ends to facilitate forming a sealing weld 28 between the outer wall 23 and the boss 27 on both sides of the tubesheet 7.

The portion of the outer wall 23 between the welds 28 that lies within the bore 25 of the tubesheet 7 is provided with one or more openings 29 that communicate with the groove 6 and that are free from any of the restraining welds 28. Since all leaked fluid enters the groove 6, it can be detected.

As shown in FIG. 3, the tube sheets 9 and 11 are spaced apart, and the inner tube sheet 9 has holes 31 for receiving the double-walled heat exchanger tubes 5.
is provided.

The boss 27 surrounds each hole, and a sealing weld 28 is provided between the boss 27 and the outer wall 23 of the double-walled heat exchanger tube passing through it.
It makes it easy to form.

The distal end of the outer wall 23 is adjacent to the inner tubesheet 9 and the inner wall 21 extends through the space 13 between the tubesheets 9 and 11 and through the hole 35 in the outer tubesheet 11.

A boss 27 is formed around the hole 35 in the outer tubesheet 11 to facilitate forming a sealing weld 28 between it and the end of the inner wall 21 extending through the tubesheet 11.

The groove 6 provided at the interface between the inner wall part 21 and the outer wall part 23 is
It communicates with the space 13 between the tube sheet 9 and the tube sheet 11.

This space 13 is the inner wall portion 21 or outer wall portion 23 of the heat exchanger tube.
Sealing welding from or between double-walled heat exchanger tubes and tube sheets 2
It acts as a header to collect leakage of heating fluid or fluid to be heated.

Such a leak indicates the occurrence of a leak before one piece of driftwood is contaminated by the other's fluid.

Although the heat exchanger described above only requires three tube sheets, there is no leakage from either the weld between the double-walled heat exchanger tube and the tubesheet or the tube wall of the double-walled heat exchanger tube. This also indicates the occurrence of such occurrence, thereby ensuring separation of the heating fluid and the fluid to be heated.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional side view of a heat exchanger according to the present invention, FIG.
Figure 3 is an enlarged partial cross-sectional view showing the joint between a double-walled heat exchanger tube and a single tubesheet, and Figure 3 is an enlarged section showing the joint between a double-walled heat exchanger tube and a pair of tubesheets. This is a cross-sectional view. 1: heat exchanger, 3: shell, 5: double wall heat exchanger tube, 6: groove,
7: Single tube sheet, pair of tube sheets 9 and 11, 21: Inner wall portion, 23: Outer wall portion, 27: Boss, 28: Sealing weld, 29:
Opening.

Claims (1)

[Claims] 1. A heat exchanger comprising a shell and a plurality of double-walled heat exchanger tubes having an inner wall and an outer wall and mounted on tube sheets supported at both ends within the shell. The double-walled heat exchanger tube is attached at one end to a single tubesheet and at the other end to a pair of spaced apart tubesheets, and the double-walled heat exchanger tube The inner wall has an end proximate to and sealed to one of the pair of tube sheets, and the outer wall of the double-walled heat exchanger tube has an end proximate to the other of the pair of tube sheets. and sealed thereto, the outer wall of the double-walled heat transfer tube being sealed at inner and outer junctions with the single tubesheet, the outer wall being sealed to the single tubesheet. at least one opening in the tubesheet through the outer wall, and the inner and outer walls are sealed at the ends of the double-walled heat exchanger tubes outside the single tubesheet. Features of heat exchanger. 2. Claims in which either the inner wall portion or the outer wall portion of the double-walled heat exchanger tube is provided with at least one groove extending over the entire length of the double-walled heat exchanger tube at the interface therebetween. The heat exchanger according to paragraph 1. 3. The heat exchanger according to claim 1 or 2, wherein the seal is formed by welding. 4. The single tubesheet comprises a boss on each side surrounding each double-walled heat exchanger tube to facilitate sealing welding of the double-walled heat exchanger tube to both sides of the tubesheet. The heat exchanger according to item 3.