JPH0440074Y2 - - Google Patents

Description

[Detailed description of the invention] <Field of industrial application> The present invention is a piping expansion joint used in a fluid transport device, more specifically a bellows type piping expansion joint, which is heated or cooled from the outside to control the temperature of the fluid inside the expansion joint. This invention relates to the improvement of a so-called double-pipe expansion joint for controlling.

<Prior art> Conventionally, bent piping or bellows-type piping expansion joints have been used to counter thermal expansion and contraction of fluid transport piping, but due to space and strength issues, stress can be easily alleviated even in narrow spaces. Bellow type piping expansion joints are often used. Particularly in pipes that require temperature control of the fluid in the pipe, for example, in pipes where the fluid has the property of solidifying, a jacket is installed around the outer periphery of the bellows 21 of the bellows type piping joint as shown in Fig. 3 in order to maintain the fluidity of the fluid. A so-called double-pipe expansion joint is used in which a chamber 23 is provided and a heat medium is passed through the jacket chamber so that the temperature of the bellows 21 is higher than the melting point of the fluid in the bellows pipe (hereinafter referred to as pipe fluid).

In this double pipe expansion joint, bellows 21,
22 has a highly flexible structure to absorb piping displacement, and is usually formed from a thin plate of 0.3 to 2.0 mm, so the heat transfer medium contacts the fluid in the pipe only through the thin plate, resulting in large heat transfer. You can get it.

However, the bellows 21 and 22 are subject to displacement in the direction perpendicular to the axis in addition to expansion and contraction in the direction of the tube axis, and are also subject to severe conditions such as repeated stress from expansion and contraction, making them susceptible to cracking. In this case, there is a major drawback that the fluid in the pipe and the heat medium are mixed with each other.

In particular, if the cracks in the bellows 21 are minute and a very small amount of the heating medium gets mixed into the fluid inside the pipe, detection may be delayed.Furthermore, cracks in the bellows 22 may cause the heating medium to leak to the outside, resulting in a serious accident. There is a risk that it may lead to

Furthermore, it is difficult to detect minute cracks, and since the jacket chamber 23 in the former double pipe expansion joint is usually formed of a welded structure, it is not possible to visually check the structural damage such as cracks from the outside of the bellows 22. However, the inspection was difficult.

<Purpose of the invention> The present invention was made to solve this problem, and it not only efficiently transfers the heat in the jacket chamber located on the outer periphery of the bellows to the fluid inside the pipe, but also allows easy visual confirmation of damage to the bellows. It is an object of the present invention to provide a bellows-type piping joint that can be used in a piping joint, and furthermore, even if a crack or the like occurs, the heat medium and the fluid in the pipe will not mix with each other.

<Structure of the invention> In order to achieve this purpose, the invention has the following structure. That is, the present invention is characterized in that a heating jacket chamber is disposed around the outer periphery of the bellows type expansion joint so as to surround the expansion joint, and the jacket chamber has a separate structure that allows it to be separated. This is a piping expansion joint.

<Example> The present invention will be explained below based on the drawings. Fig. 1 is a vertical sectional view showing an embodiment of the present invention, and Fig. 2 is a longitudinal sectional view showing an embodiment of the present invention.
It is a view taken along the line X-X' in the figure.

In the figure, 1 is the bellows main body, which is connected to piping (not shown) via flanges 2 and 3 at both ends, and absorbs piping displacement caused by thermal strain in the piping system or installation dimensional error by its expansion and contraction. This is to relieve the severe stress that occurs within the body. A jacket chamber 4 is provided on the outer periphery of the bellows body 1 so as to surround the bellows body 1 while maintaining a constant value S for a predetermined period.

The jacket chamber 4 has a two-part structure that can be vertically divided, and is connected by flanges 7, 7', 8, 8'. Output nozzles 9, 9', 10, 10' are provided. The jacket chamber 4 is fixed at one end to the flange 3 by bolts or the like to prevent movement.

When temperature control is required for the fluid in the pipe flowing through the bellows body 1, for example, when the fluid has the property of solidifying, there is a A heat medium is passed through a jacket chamber 4 provided in the pipe, and heat transfer from the heat medium causes the temperature of the bellows body 1 to be higher than the melting point of the fluid in the pipe. In this case, since the heat medium passes through the jacket chamber 4, which is strong and hardly expands or contracts, there is no risk of leakage.

On the other hand, the bellow body 1 is subjected to lateral displacement in the direction perpendicular to the axis in addition to expansion and contraction in the tube axis direction, and is also subject to severe conditions such as repeated expansion and contraction stress, so there is a risk of cracking. There is a gap S between the bellow body 1 and the bellow body 1, which is open and easy to inspect. Particularly in this case, if the jacket chamber 4 can be separated from the bellows body 1, for example, by dividing it into two parts as shown in the figure and fixing each part with flanges 7, 7', 8, and 8', then the jacket chamber 4 can be removed. Not only can damage conditions such as cracks be easily checked visually,
Even if a leak occurs due to a crack, the fluid inside the pipe simply leaks out to the outside, and an abnormal situation such as a heating medium getting mixed into the fluid inside the pipe does not occur.

However, since the jacket chamber 4 is provided independently from the bellow body 1, there is an air layer (S) between the two, and the heat transfer performance is inferior to that of the conventional double pipe expansion joint. Therefore, there are cases where the temperature of the heat medium must be made higher than in the conventional method. In particular, when the bellows body 1 is subjected to lateral displacement in the direction perpendicular to the axis, the jacket chamber 4 cannot be placed in close contact with the bellows body 1, so the air layer must be larger than the lateral displacement, and the heat transfer performance is further reduced. It will be low.

To solve this problem, it is possible to raise the temperature of the heat medium, but since the energy loss becomes large, another method is to insert a metal filler 11 into the air layer to improve heat transfer performance. . The metal filler 11 is generally a linear body, but any elastic body that can absorb expansion and contraction acting in the axial direction of the bellows body 1 and lateral displacement in the direction perpendicular to the axis may be used, depending on the size of the wire diameter and the material. Regardless of the packing density, etc., it may be selected as appropriate depending on the structure and temperature conditions of the piping expansion joint. Also, here is the bellow body 1
Assuming that there is a lateral displacement in the direction perpendicular to the axis, it is preferable that the metal filling 11 is a linear body having elastic force, but if there is no lateral displacement in the direction perpendicular to the axis, it is not necessary to be limited to a linear body. Any metal filling may be used.

Further, the structure of the jacket chamber 4 may be circular or rectangular, and as long as it is located on the outer periphery of the bellows body 1, it is of course not necessary to cover the entire periphery.

<Effects of the invention> As explained above, according to the invention, troubles such as liquid leakage can be detected early, and the state of damage to the bellow body can be easily confirmed visually, making it extremely effective in terms of maintenance such as preventive measures. It is true.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a view taken along the line X-X' in FIG.
The figure is a sectional view showing a conventional embodiment. 1... bellow body, 4... jacket chamber, 5,
6... Half jacket room.

Claims (1)

[Scope of utility model registration request] A piping expansion joint characterized in that a heating jacket chamber is provided around the outer periphery of the bellows type expansion joint so as to surround the expansion joint, and the jacket chamber has a divided structure in which the jacket chamber can be separated.