JPH0343515Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a joint structure for a plastic tube heat exchanger that can reduce the outer diameter of the joint, increase the pull-out strength, and reduce costs.

[Conventional technology]

Generally, a plastic tube heat exchanger has a construction as shown in FIGS. 2 to 4, for example. In the figure, 1 is a tube bundle, and the tube bundle 1 is, for example, formed by bundling a large number of tubes made of fluororesin (particularly tetrafluoroethylene perfluoroalkyl vinyl ether copolymer) in the present applicant. This tube bundle 1
The plastic sleeve 2 fitted over this end and the tube walls of each tube end are fused to each other by means such as heating, and are integrated into a honeycomb-shaped end 3 as shown in FIG. is formed. The fluid is passed through each tube from one end 3 to the other end 3 to exchange heat with the fluid outside the tube.

When using such a plastic tube heat exchanger, pipes for supplying the fluid to be passed therethrough are connected to the exchanger at the sleeve 2 part. As shown in FIGS. 2 and 3, for example, an end cap 6 that is screwed together with a socket 4 that is a pipe side connector via a nipple 5 is fitted onto the sleeve 2 of the heat exchanger. Alternatively, as shown in FIG. 5, the pipe 7 is directly heated and softened and fitted onto the sleeve 2, and the contact surfaces of the two are heat-sealed. , there is a method using an end connector 8 as shown in FIG.

This end connector 8 consists of an inner socket 9 that is a pipe side connector and an outer socket 10 that is externally fitted and screwed into the inner socket 9. The sleeve 2 has a semicircular spacer 11 that is fitted into the outer socket 10.
The heat exchanger is connected by being latched by. Reference numeral 12 denotes an O-ring, which is interposed to maintain watertightness or airtightness with the outside of the heat exchanger.

In addition, if a plastic tube heat exchanger is installed in a pickling tank or the like, corrosion resistance is also required at the connection part with the piping (for example, pipe 7), so the plastic tube heat exchanger is made of fluorocarbon resin as mentioned above. end connectors 8 have also been used.

[Problem that the invention attempts to solve]

However, the end connector 8 made of fluorine resin is expensive, and if the number of plastic tubes is large or the total length is considerably long, the weight becomes large, and furthermore, when passing liquid inside, the end connector 8 becomes expensive. Because of the weight involved, there was a problem in that the screw threads that screwed together the inner socket 9 and the outer socket 10 were made of plastic, so they formed under the load and could become unthreaded.

In addition, a method of directly fitting the pipe 7 onto the plastic sleeve 2 shown in FIG.
Tube 1, sleeve 2, and pipe 7 are all FEP ( (Tetrafluoroethylene-hexafluoropropylene copolymer) is used, and therefore there are problems such as not being able to reduce the cost much and not having sufficient bonding strength.

This invention was devised in view of these conventional problems, and aims to solve the above problems by, for example, providing a hook at the end of the pipe or end connector.

[Means for solving problems]

This idea consists of a tube bundle made by bundling a large number of plastic tubes, and a plastic sleeve is fitted over the end of the tube bundle, and these are integrated by fusion to form a honeycomb-shaped terminal part. In a joint structure between an exchanger and an end portion of a plastic pipe that is externally fitted and fixed to a plastic sleeve of the heat exchanger, a hook portion is provided at the end of the plastic pipe and projects inwardly, and this hook is provided at the end of the plastic pipe. This is a joint structure for a plastic tube heat exchanger in which the plastic sleeve is press-fitted into the stop part and the plastic pipe or end connector is fused to the plastic sleeve in a state where it is latched.

[Function] At the end of the plastic pipe or end connector fitted onto the outside of the plastic sleeve, a hook part is formed that protrudes inward, so that the plastic tube heat exchanger is fixed in the direction of removal from the plastic pipe. Therefore, against a load in the pulling direction, it has a resistance force equal to the strength of the fusion bond between the plastic pipe and the plastic sleeve plus the deformation or breaking strength of the hanging portion. In addition, since the strength to deform or destroy the hook is extremely high, the strength of the fusion bond does not need to be so high, and therefore there is no need to choose a particularly expensive plastic material for the joint, as was the case in the past. .

〔Example〕

This invention will be explained below with reference to the drawings. FIG. 1 is a diagram showing an embodiment of this invention.

In the figure, reference numeral 17 is a plastic pipe made of PTFE (polytetrafluoroethylene), which is a relatively inexpensive fluororesin.
7a is formed into a circular flange shape.

In order to connect the plastic tube heat exchanger 1 to this plastic pipe 17, first
The area around the hooking portion 17a of the heat exchanger 1 is heated to soften it, and the plastic sleeve 2 of the heat exchanger 1 is press-fitted into the pipe 17 to form the state shown in FIG. 1a. Thereafter, the contact surfaces between the inner surfaces of the pipe 17 and the hooking portion 17a and the outer periphery of the sleeve 2 are heat-sealed.

In this way, the end of the plastic pipe 17 is used as a joint part, and the inner surface of the hook part 17a is also fused to the sleeve 2, so the airtightness is higher than before, and the pull-out strength of this joint part is equal to that of the pipe. The fusion strength with the sleeve plus the deformation or breaking strength of the hooking portion 17a is extremely large. Further, in this case, since the joint strength does not depend only on the fusion strength as in the conventional case, the plastic pipe 17 and the plastic sleeve 2 can be made of a fluororesin material which is cheaper than the conventional one.

[Effect of idea]

As explained above, according to this invention, there is no need to use an expensive end joint made of fluororesin as in the past, and the structure is extremely simple and a high pull-out strength can be maintained.

[Brief explanation of drawings]

Figure 1a is a cross-sectional view of the joint structure according to the present invention, Figure b is a cross-sectional view taken along line A-A in Figure a, Figure 2 is a side view of a heat exchanger having a conventional joint structure, and Figure 3 is a cross-sectional view of the joint structure according to the present invention. BB sectional view in Fig. 3, Fig. 4 is a perspective view of the honeycomb-shaped end portion, Fig. 5 is a sectional view of the conventional example,
FIG. 6 is a half-sectional view of another conventional example. DESCRIPTION OF SYMBOLS 1... Tube bundle, 2... Plastic sleeve, 5... Honeycomb-shaped terminal part, 7, 17... Plastic pipe, 8... End connector, 17a
...Latching part.

Claims (1)

[Scope of utility model registration request] A plastic tube heat exchanger in which a plurality of plastic tubes are bundled to form a tube bundle, a plastic sleeve is externally fitted to the end of the tube bundle, and these are integrated by fusion to form a honeycomb-shaped end portion; In this joint structure with the end portion of the plastic pipe that is fitted onto and fixed to the plastic sleeve of the heat exchanger, the end portion of the plastic pipe is provided with a hook portion that protrudes inwardly, and this hook portion is provided with the above-mentioned hook portion. A joint structure for a plastic tube heat exchanger, characterized in that a plastic sleeve is press-fitted and latched, and the sleeve and the plastic pipe are fused together.