JPH0361785A - Pipe joint for low-temperature liquefied gas - Google Patents

Abstract

PURPOSE:To prevent fluid leakage in a pipe and rotate a pipe joint itself by inserting the first motion seal between both pipes, coupling, sealing and relatively rotatably connecting both pipes, and sealing the boundary section on the outside air side of the upper side with the second motion seal. CONSTITUTION:The first motion seal 4 is fitted to the coupling section of both pipes 1 and 2 to seal them as a slidable seal means while the leakage of some low-temperature liquefied gas is allowed, and both pipes 1 and 2 are sealed and relatively rotatably connected via the seal 4. A gap is formed and opened between the end face of the base end section of the pipe 2 and the outer periphery of the pipe 1, and a ring 10 is integrally fixed with a cylinder 9. A void is formed at the portion surrounded by the pipe 2, cylinder 9 and ring 10 as a sealed space 3 where low-temperature gas is leaked from the seal 4 and gasified and filled. The boundary section on the outside air side of the space 3 is formed with the second motion seal 5, i.e., O-ring 5, where the outer diameter side is kept in contact with a circular groove 11a.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a pipe joint used to connect pipes through which low-temperature liquefied gas flows while suppressing leakage of low-temperature liquefied gas, such as liquid oxygen, liquid nitrogen, A pipe suitable for use in the connection part when a pipe connected to a flexible hose, etc. is connected in series to a pipe installed at the low-temperature liquefied gas outlet of a tank truck that delivers low-temperature liquefied gas such as liquid argon. Regarding fittings.

[Conventional technology]

When low-temperature liquefied gas flows back through pipes connected using pipe joints, the low-temperature liquefied gas will leak from the pipe joints if the sealing properties thereof are poor.

Therefore, joints have been developed to prevent leakage of low-temperature liquefied gas. For example, as shown in FIG. 4, both pipes (51) are arranged in series to allow low-temperature liquefied gas to flow.
, (52) are connected so that they overlap while allowing the formation of a gap <S> at the connection part.
1) is connected to the other pipe (52) in a loosely fitted state, and the boundary portions on both the inner and outer sides of the gap (S) partially allow leakage of the low-temperature liquefied gas (stationary seal).
A bayonet joint has been developed which is sealed with an O-ring (53) and an O-ring (54) which provides a sufficient sealing effect when squeezed. In this example, the outer peripheries of both the tubes (51) and (52) are provided with vacuum layers (Vl) and (V2) for obtaining a heat insulating effect.
Each of them has a double structure to form a. Also, the O
The ring (54) is firmly tightened with a V-shaped band (56) and is in a squeezed state so as to obtain a sufficient sealing effect.

In such a bayonet joint, both the pipes (
51), the low temperature liquefied gas flowing through (52) leaks into the gap (S) via the gas scaler (53) and vaporizes there, forming a gas chamber (55); The gas in the gas chamber (55) is balanced with the liquid leaking into the gap (S), preventing further inflow of the liquid into the gap (S), thereby maintaining the seal (54) at room temperature. A complete seal is possible.

[Problem to be solved by the invention]

However, when connecting a flexible hose for distributing low-temperature liquefied gas to a pipe installed at the low-temperature liquefied gas outlet of a tank truck using a conventional pipe joint as described above, the structure of the pipe joint is essential. Since the flexible hose is not configured to be freely rotatable, the connection direction of the flexible hose is limited by the direction of the joint. and after distributing the low temperature liquefied gas using the flexible hose,
It is not possible to rotate the pipe joint and store it on the side of the tank lorry with the flexible hose connected, and depending on the parking position of the tank lorry, it is impossible to connect the tank lorry to the supply destination using the flexible hose. It can be. Therefore, in the past, unlike the bayonet joint, a pipe joint that did not have good sealing performance but was easy to remove was attached to the pipe installed at the low-temperature liquefied gas extraction part of the tank truck. The flexible hose was connected through the flexible hose, and after the low-temperature liquefied gas was distributed, the pipe joint was removed together with the flexible hose and stored in the side of the tank lorry, which was a cumbersome task.

The present invention has been made in view of the above circumstances, and has a structure that is rotatable while maintaining good sealing performance, and is suitable for use as a low-temperature pipe joint used when connecting the flexible hose to a tank lorry, for example. The purpose is to provide pipe fittings for liquefied gas.

[Means to solve the problem]

A pipe joint for low-temperature liquefied gas according to the present invention is a pipe joint for vertically connecting two pipes arranged in series to allow fluid to flow, and in which a first dynamic seal is interposed between the two pipes. By fitting the two tubes together while sealing, the two tubes are connected so as to be relatively rotatable while being sealed, and the fluid leaks from the inside of the two tubes to the outside air side of the first dynamic seal. A sealed space filled with gas is formed by sealing the upper boundary part on the outside air side with a second dynamic seal, and a fastening means for preventing the connection state of the two pipes from being disconnected is provided on the outer peripheral part. It is characterized by the following points.

It is more preferable that a third dynamic seal whose sealing state can be strengthened by the fastening force of the fastening means is provided on the outside air side of the second dynamic seal.

[For production]

In the pipe joint of the present invention, the presence of gas filling the sealed space prevents internal fluid from leaking as in the case of conventional bayonet joints. Further, since all of the plurality of seals are dynamic seals, the pipe joint can rotate while remaining in the connected state. Furthermore, the fastening means prevents the two pipes from being unintentionally disconnected.

Note that when the third dynamic seal is provided on the outside air side of the second dynamic seal, the sealing state of the third dynamic seal can be strengthened by the fastening force of the fastening means. Depending on the fluid leakage situation, the sealing state can be strengthened while maintaining a freely rotatable state, and when rotation is not required, the fastening means can be particularly strongly fastened to maintain a particularly high sealing performance. You will also be able to do

〔Effect of the invention〕

As described above, according to the pipe joint of the present invention, leakage of fluid within the pipe can be prevented, and the pipe joint itself can also rotate. Therefore, for example, when the flexible hose is connected to a tank lorry using the pipe joint of the present invention, after the distribution of low-temperature liquefied gas through the hose is completed, the pipe joint is rotated together with the hose. In addition to being able to store it connected to the side of a tank lorry, it also helps prevent foreign matter from entering the pipe joint and inside the hose when redistributing low-temperature liquefied gas, keeping the inside of the hose clean. Furthermore, the pipe joint of the present invention is easy to operate, and is therefore extremely suitable for connecting, for example, a tank truck and the hose. In addition, when the third dynamic seal is provided on the outside air side of the second dynamic seal, adjustment by the fastening means is added when rotating the pipe joint to improve sealing performance and rotational operability. Further improvements may be made.

In addition, the pipe joint of the present invention can of course be used to connect a hose to a non-mobile low-temperature liquefied gas tank, even if it is not a tank lorry, and in this case, it is extremely effective in improving sealing performance and workability when storing the hose. It is valid.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

Figure 2 shows a tank lorry for storing low-temperature liquefied gas and distributing it as appropriate.The tank lorry has a pipe (2 ) is provided. In the figure, (1) is connected to the upper part of the pipe (2) with its proximal end fitted inside the pipe (its distal end side (1) is connected to the flexible hose.

(2) is connected via a pipe joint which is an example of the pipe joint of the present invention.

Specifically, the pipe joint is configured as follows.

That is, first, the first dynamic seal (4) (specifically, the Teflon nose seal (4)) is installed at the fitting portion of the two pipes (1) and (2) to prevent some leakage of low-temperature liquefied gas. The pipes (1) and (2) are connected to each other so as to be relatively rotatable while being sealed by the interposition of the first moving seal (4). has been done. A gap is formed between the end surface of the proximal end of the tube (2) and the outer circumferential surface of the tube (1) and is open, and a cylinder (9) is provided at an appropriate position on the circumferential surface of the proximal end. ) is fixed to the ring (10), which is formed into an outer cylindrical body with a bottom. A gap is formed in a portion surrounded by the tube (2), the cylinder (9), and the ring (10), and the gap allows the low-temperature liquefied gas to pass through the tubes (1), ( 2) leaks from the inside via the first dynamic seal (4) and vaporizes;
The vaporized gas forms a sealed space (3) in the upper part.

The outside air side boundary portion of the sealed space (3) has an inner diameter side that fits into a circumferential groove (9a) recessed in the outer circumferential surface of the end portion of the cylinder (9) opposite to the fixed side of the ring (10). and whose outer diameter side abuts an annular groove (lla) recessed in the loosely fitting end surface of the outer fitting body (11) which is externally fitted and fixed at an appropriate position on the outer circumferential surface of the pipe (1). It is formed by two dynamic seals (5) or O-rings (5).

Note that the O-ring (5) also allows sliding movement between itself and the surrounding abutting objects. Further, a cap nut (8) as a fastening means (A) for preventing disconnection of the two pipes (1) and (2) is attached to the outer circumference of the outer fitting body (1).
It is provided by being screwed and fastened to the outer circumferential surface threaded portion (llb) of 1). Further, on the outside air side of the second dynamic seal (5), that is, the O-ring (5), there is a third dynamic seal (6) whose sealing state can be strengthened by the fastening force generated by the fastening means (A). , (7) (
Specifically, Teflon seal pankin (6), (7)”
) is provided. Thus, the athletic sticker (4)
, (5), (6).

(7), a sealed space (3), a cap nut (8) as a fastening means (A), etc., constitute the pipe joint of the present invention.

Note that the fastened state of the cap nut (8) is fixed when the end surfaces of the cap nut (8) are in contact with each other and the outer fitting body (
The cap nut (8) is attached to the outer peripheral surface threaded portion (llc) of 11).
This is done by means of a lock nut (12) that is screwed together independently of the lock nut (12). Moreover, between the bag nand (8) and the outer fitting body (11), there is a stationary seal (11) that is squeezed when the former (8) is screwed and externally fitted to the latter (11) and produces a sufficient sealing effect. 13) Specifically, an O-ring (13) is installed, and the sealing effect is supplemented by the seal (13), that is, the O-ring (13).

Thus, using the pipe joint of the present invention, both the pipes (1)
, (2), in the case of connecting both pipes (1).

(2) The presence of the sealed space (3) prevents the low-temperature liquefied gas inside from leaking to the outside air. Further, seals (4), (5), (6), (7) arranged at the inner and outer boundaries of the sealed space (3) and adjacent parts thereof
) are all dynamic seals, so the pipe joint of the present invention can rotate while in the connected state. and the second
As shown in the figure, the posture of the tube (2) on the flexible hose side can be freely changed from the usage state shown by the imaginary line to the stored state shown by the solid line. Further, the fastening means (A
) prevents the two tubes (1) and (2) from coming off unintentionally. Moreover, since the sealing state of the third dynamic seals (6) and (7) can be strengthened by the fastening force of the fastening means (A), the third dynamic seals (6) and (7) can maintain a freely rotatable state depending on the leakage situation of the low-temperature liquefied gas. Not only can the sealing state be strengthened, but also the sealing performance of the pipe joint of the present invention can be particularly enhanced by particularly strongly fastening with the fastening means (A) when rotation is not required.

Incidentally, if only one second dynamic seal (5) is arranged as shown in the figure and the sealing effect is insufficient by itself, it is preferable to arrange a plurality of the seals (5) side by side.

[Another example]

As shown in Fig. 3, the pipe joint of the present invention is such that the device position of the first dynamic seal (4) is set so that the pipe (1) on the flexible hose side is fitted onto the pipe (2) on the tank lorry side. It is also possible to consider an embodiment in which the position is the same.

Furthermore, the low-temperature liquefied gas pipe joint of the present invention can also be used when connecting a hose to a non-mobile low-temperature liquefied gas tank other than a tank truck.

Note that the "motion stickers" used extensively in the above explanation include both reciprocating motion stickers and rotational motion stickers (for example, "Product Dictionary JP" published by Toyo Keizai Shimbun).
, 176).

Incidentally, although reference numerals are written in the claims section for convenience of comparison with the drawings, the present invention is not limited to the structure of the attached drawings by such entry.

[Brief explanation of drawings]

FIG. 1 is a longitudinal side view showing an embodiment of the pipe joint for low-temperature liquefied gas according to the present invention, and FIG.
FIG. 3 is a vertical sectional side view showing another embodiment of the low-temperature liquefied gas pipe joint of the present invention, and FIG. 4 is a conventional low-temperature liquefied gas pipe joint ( FIG. (1), (2)...tube, (3)...
- Closed space, (4)...First movement seal,
(5)...Second dynamic seal, (6),
(7)...Third exercise sticker, (^)...
... fastening means.

Claims (1)

[Claims] 1. Both pipes (1) arranged in series to allow fluid to flow;
(2) is a pipe joint for connecting the pipes (1) and (2) vertically, and a first dynamic seal (4) is provided between the pipes (1) and (2).
By fitting both the pipes (1) and (2) with the interposed, the pipes (1) and (2) are connected relatively rotatably while being sealed, and the first dynamic seal On the outside air side of (4), there is a closed space (3) in which the fluid leaks from inside the pipes (1) and (2) and the upper part is filled with gas, and the upper boundary part on the outside air side is connected to a second closed space (3). A low-temperature liquefied gas formed by sealing with a dynamic seal (5), and provided with a fastening means (A) on the outer periphery to prevent the connection state of the two pipes (1) and (2) from becoming disconnected. Pipe fittings for use. 2. Third dynamic seals (6) and (7) whose sealing state can be strengthened by the fastening force of the fastening means (A) are provided on the outside air side of the second dynamic seal (5). The pipe joint for low temperature liquefied gas according to claim 1.