JP2000320984A - Double tube heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a fluid sealed in an air gap from leaking to the outside by making an endless groove in the inner circumferential surface of a jacket end and filling the gap with a sealant. SOLUTION: An endless groove 6 is made along the inner circumferential surface of a jacket end 11 and an injection hole 7 is made from the outer circumferential surface of the jacket end 11 to the groove 6. The groove 6 is filled with a sealant C through the injection hole 7 such that the sealant C surrounds the outer circumference of the inner tube 2. The cylindrical end jacket 11 is shrink-fitted over the inner tube 2 and welded to an outer tube 3 and then a fluid B, e.g. water or steam, is sealed in the outer tube 3. According to the structure, the fluid B sealed in the air gap can be prevented from leaking to the outside.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a double-pipe heat exchanger, and more particularly to a double-pipe heat exchanger of a high-pressure polyethylene manufacturing facility, in which a heat pipe is sealed between an outer pipe and an inner pipe. The present invention relates to a double-pipe heat exchanger suitable for preventing leakage of a fluid to the outside.

[0002]

2. Description of the Related Art Conventionally, in the structure of a double-pipe heat exchanger, the inner pipe to which high pressure is applied is made of a high carbon steel material for the purpose of maintaining strength. Therefore, a structure in which the jacket end is shrink-fitted to the inner tube and fixed is generally used. That is, as shown in FIG. 4, the inner pipe 2 through which the ethylene gas A flows and the fluid B such as water or steam for adjusting the temperature of the inner pipe 2 flow between the inner pipe 2 and the inner pipe 2. An outer tube 3 having a space, and a jacket end 1, and a cylindrical jacket end 1 is shrink-fitted to the outer diameter of the inner tube 2;
The outer tube 3 and the jacket end 1 are welded (welded portion 4),
It is configured to seal the fluid B inside the outer tube 3.

Accordingly, in a structure in which the jacket end is used without using the gasket, the shrink-fitting of the jacket end 1 is caused by direct contact between the metal of the inner tube 2 and the jacket end 1 so that the contact portion is damaged. The fluid B sealed between the outer tube 3 and the inner tube 2
It was necessary to take measures to prevent leakage from the shrink-fit portion between the sleeve and the jacket end 1.

[0004]

SUMMARY OF THE INVENTION As described above,
If fluid leaks from the shrink-fit portion during operation of the equipment, corrosion of the outer circumference of the inner pipe may progress or an accident may occur due to the leaked high-temperature fluid. The present invention has been made to solve these problems, and an object of the present invention is to provide a double-pipe heat exchanger suitable for improving the safety of equipment.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide an outer tube, an inner tube, and a cylindrical jacket end, wherein the inner tube is fixed within the outer tube, as described in the claims. A double-pipe heat exchange in which the inner diameter of the jacket end is shrink-fitted to the outer diameter of the inner pipe to form a gap between the inner diameter of the outer pipe, the outer diameter of the inner pipe, and one end face of the jacket end. In the container, a groove formed endlessly on the inner peripheral surface of the jacket end, and a sealant injection portion provided so as to communicate with the groove from the outer peripheral surface of the jacket end, through the sealant injection portion By filling the groove with the sealant, the fluid sealed in the gap is prevented from leaking to the outside.

[0006] Since the outer tube is generally made of structural steel, it is possible to seal the fluid by welding the jacket end to the boundary surface, so that the fluid from the joint between the outer tube and the jacket end can be sealed. Leakage can be prevented. Therefore, by shrink-fitting the inner diameter of the jacket end to the outer diameter of the inner pipe using a high carbon steel material, the gap between the inner diameter of the inner pipe and the inner diameter of the jacket end is smaller than the "tight fit" according to the JIS standard. A much stronger fitting connection is obtained. Thus, leakage of the fluid to the outside from between the connecting portions between the inner tube and the jacket end can be primarily prevented. Furthermore, even if the inner tube and the jacket end are in direct contact with each other, even if the contact portion is damaged by burrs or the like, the inner end surface of the jacket end is provided in the groove provided endlessly through the sealant injection portion. By evenly filling the sealant, a "seal ring" is formed between the outer tube and the inner tube by the sealant, so that secondary leakage prevention means can be formed.

[0007] for use in the present invention is a suitable sealant low viscosity variation with less fluidity by temperature conditions, for example, those of MoS ₂ system is used.

[0008]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a view showing a structure of an embodiment of a jacket end of a double-pipe heat exchanger according to the present invention, FIG. 2 is a cross-sectional view taken along a line II of FIG. 1, and FIG. It is a part enlarged view. The double-pipe heat exchanger of the present embodiment is an example applied to a double-pipe heat exchanger of a high-pressure polyethylene production facility, and a cylindrical jacket end 11 is shrink-fitted to the outer diameter of the inner pipe 2. The outer tube 3 and the jacket end 11 are welded to each other, and the fluid B such as water or steam is sealed inside the outer tube 3 according to the conventional technique shown in FIG. The feature of the present embodiment lies in the structure of the jacket end 11, in which the groove 6 is formed endlessly along the inner circumference of the jacket end 11, and as shown in FIG. Inject hole 7 to reach groove 6
And filling the groove 6 with the sealant C through the injection hole 7 so that the sealant C surrounds the outer periphery of the inner tube 2. Further, the injection hole 7 is provided with a pipe screw 7a into which the sealing agent cap 5 can be screwed. By rotating the sealing agent cap 5, the sealing agent C is injected without leakage. It is pumped from the hole 7 and is evenly filled in the groove 6. The shape of the track of the groove 6 is not limited as long as it is endless.

The sectional shape of the groove 6 may be rectangular or trapezoidal in addition to the circular arc shape as shown in FIG. 3, and is not particularly limited. Processing is preferred to prevent damage.

In the above-described embodiment, ethylene gas is used as the fluid A flowing in the inner pipe 2, but the type of fluid applied by the double-pipe heat exchanger used in the manufacturing equipment is naturally. different.

[0011]

According to the present invention, a simple double-pipe heat exchanger suitable for preventing water or steam as a fluid flowing in the outer pipe from leaking to the outside of the heat exchanger is provided. Therefore, it is possible to provide a simple structure and improve the facility operation rate and the safety.

[Brief description of the drawings]

FIG. 1 is a diagram showing a structure of an embodiment of a jacket end of a double-pipe heat exchanger according to the present invention.

FIG. 2 is a sectional view taken along line II of FIG.

FIG. 3 is an enlarged view of a portion A in FIG. 1;

FIG. 4 is a view showing a structure of a jacket end of a conventional double tube heat exchanger.

[Explanation of symbols]

1, 11 ... jacket end 2 ... inner pipe 3 ... outer pipe 4 ... welded part 5 ... cap 6 ... groove 7 ... injection hole 7a ... pipe screw A ... (fluid A) ethylene gas B ... (fluid B) water or steam C ... Sealant

Claims (1)

[Claims] 1. An outer tube, an inner tube, and a cylindrical jacket end, wherein the inner tube is fixed in the outer tube, and an inner diameter of the jacket end is shrink-fitted to an outer diameter of the inner tube. In a double-pipe heat exchanger in which a gap is formed between the inner diameter of the outer pipe, the outer diameter of the inner pipe, and one end face of the jacket end, a groove endlessly formed in an inner peripheral face of the jacket end. And a sealant injecting portion provided so as to communicate with the groove from the outer peripheral surface of the jacket end. By filling the groove with the sealant through the sealant injecting portion, A double-pipe heat exchanger, wherein a sealed fluid is prevented from leaking to the outside.