JPH05272669A - Double ball valve - Google Patents

Abstract

PURPOSE:To prevent the breakage of a connection pipe by installing a collar on which an O-ring is installed, on the inner periphery at the edge part of the connection pike into which a pipe is inserted, and making the collar from the material different from that of the connection pipe, as for a double ball valve used for the coolant pouring port of a magnetic floating-up type railroad. CONSTITUTION:A stepped part 2b having a slightly large diameter is formed on the inner periphery at the right edge of a ground side connection pipe 2, and a groove 2c is formed on the inner periphery at the opened port edge of the stepped part 2b, and a stop ring 7 is formed in fitting-enabled form. At the stepped part 2b, a tubular collar 3A made of fluorinated resin is installed, and an O-ring 3a is formed on the left side on the inner periphery of the collar 3A, and an O-ring 3b is formed at the right edge on the outer periphery of the collar 3A, and O-rings 4A and 4B are installed. On the outside of the right side of the ground side connecting pipe 2, a slender screw 2a is formed, and a box nut 5 is screwed with this screw 2a. The box nut 5 is tightened, and the top edge at the pipe 1 is pressed on the ball of a ball valve through a stopper 6 on the outer periphery of the pipe 1, and the pouring and recovery of coolant are carried out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double ball valve used for a refrigerant inlet of a magnetic levitation railway.

[0002]

As is well known, liquid helium for cooling a superconducting magnet mounted on a magnetic levitation railway vehicle, and
The vehicle is the base of the vehicle for the injection and recovery of liquid nitrogen that cools the heat shield plate of the tank that stores liquid helium, and the recovery of the helium gas that is recovered from inside the superconducting magnet when the superconducting magnet is demagnetized. It is carried out when the goods are stored in. This injection / recovery operation is performed by connecting the above-ground piping connected to the above-ground tank to each injection / recovery port attached to the superconducting magnet of the vehicle.

FIG. 4 is a view showing a conventional double ball valve, and FIG. 5 is an enlarged sectional view taken along the line AA of FIG. As shown in FIGS. 4 and 5, the double ball valve is a female double ball valve on the vehicle side that laterally protrudes from the side surface of the vehicle 30.
31A and this female double ball valve 31 when injecting and collecting
Ground side male double ball valve 31B connected to A
And a handle 34 provided on the upper part thereof.

Of these, a ball 33A is inserted inside the female double ball valve 31A, and a ball 33B which is the same as the ball 33A is inserted inside the male double ball valve 31B.
Has been inserted. On the male side double ball valve 31B,
A ground side connecting pipe 32 made of stainless steel pipe is connected, a fine male screw 32a is formed on the outer periphery of the end of the ground side connecting pipe 32, and an O ring groove is formed on the inner periphery of the O ring 4A.
Has been inserted.

The cap nut 5 is inserted from the outside into the male screw 32a of the ground side connecting pipe 32, and inside the ground side connecting pipe 32 and the cap nut 5, the tip portion of the ground pipe 1 made of stainless steel pipe. Is inserted in advance, and an annular stopper 6 is previously welded to the ground pipe 1 as shown in FIG.

In the double ball valve thus constructed, by tightening the cap nut 5, the tip of the ground pipe 1 is pressed against the ball 33B via the stopper 6,
Injection and recovery of the refrigerant are performed. The O-ring 4A prevents a slight amount of refrigerant leaking from the tip of the ground pipe 1 from flowing out.

When the vehicle travels, the nut 5
Tighten and pull out the ground pipe 1, and then turn the handle 34 to turn the female double ball valve 31A and the male double ball valve.
Close 31B and disconnect the male side double ball valve 31B,
A valve (not shown) provided on the female side double ball valve 31A is closed.

[0008]

However, in the double ball valve thus constructed, the ground pipe 1
When the male side double ball valve 31B is inserted / removed, the inner periphery of the ground side connecting pipe 32 and the outer periphery of the ground pipe 1 are slid, and the outer peripheral surface of the ground pipe 1 is scratched. When friction increases. In particular, these ground pipes 1
Since the ground side connecting pipe 32 is made of stainless steel pipe that has a low thermal conductivity and adiabatic property at low temperature, if the sliding surface is scratched, the friction will be extremely increased, and the increased friction will cause scratches. If it is forcibly inserted / removed in a vicious circle that increases, the O-ring 4A may be damaged, and the ground pipe 32 may be bent or seized.

Therefore, a method may be considered in which the inner diameter of the O-ring mounting portion on the inner circumference of the ground side connecting pipe 32 is increased to increase the gap with the ground pipe 1, but the refrigerant leaked from the tip of the ground pipe 1 is then considered. Since the gas directly contacts the O-ring 4A,
The O-ring 4A freezes and is further damaged by the insertion and removal of the ground pipe 1, the sealing property is impaired, the refrigerant gas leaks to the outside, the cap nut 5 freezes, and the threaded portion with the ground side connection pipe 32 comes off. It may disappear.

Therefore, an object of the present invention is to obtain a double ball valve capable of maintaining the sealing property of the end of the ground connecting pipe by repeatedly inserting and removing the ground pipe for a long period of time.

[0011]

A first invention is a double ball valve in which a pipe for injecting / recovering a cryogenic fluid is inserted into a connecting pipe through an O-ring, and an end portion of the connecting pipe into which the pipe is inserted. It is characterized in that a collar with an O-ring is attached to the inner circumference of the.

A second aspect of the present invention is a double ball valve in which a pipe for injecting / recovering a low temperature fluid is inserted into a connecting pipe via an O-ring, and the pipe is inserted into an inner periphery of an end portion of the connecting pipe. , O-rings are attached, and a collar having a hardness lower than the outer circumference of the pipe is attached.

[0013]

In any of the inventions, the material of the collar is made of a material different from that of the pipe to reduce the friction with the pipe inserted into and removed from the double ball valve, thereby damaging the surface of the pipe and the damage caused by the damage. O-ring damage is eliminated.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the double ball valve of the first and second inventions will be described below with reference to the drawings. FIG. 1 is a sectional view showing an essential part of the double ball valve of the first and second inventions, and is a view corresponding to FIG.

In FIG. 1, a stepped portion 2b having a slightly larger diameter is formed on the inner periphery of the right end of the ground side connecting pipe 2, and a groove 2c is formed on the inner periphery of the open end of the stepped portion 2b. ing. An annular collar 3A made of fluororesin is inserted into the stepped portion 2b, an O-ring groove 3a is formed on the left side of the inner circumference of the collar 3A, and an O-ring is also formed on the right side of the outer circumference of the collar 3A. The groove 3b is formed. Of these, O
An O-ring 4A is inserted in the ring groove 3a, and an O-ring 4B is inserted in the O-ring groove 3b. Further, a hole retaining ring 7 is inserted into the groove 2c.

On the other hand, on the outer circumference at the right end of the ground side connecting pipe 2,
The fine screw 2a is formed in the same manner as the conventional one, and the fine screw 2a
The same cap nut 5 as the conventional one is screwed into a, and the ground pipe 1 is inserted into the ground side connecting pipe 2 as in the conventional case.
A stopper 6 which is pressed by the cap nut 5 is welded to the outer circumference of the ground pipe 1 in advance as in the conventional case.

In the double ball valve thus constructed, the hardness is lower, the friction coefficient is smaller, and the wear resistance is lower on the inner circumference of the end of the ground side connecting pipe 2 than the ground pipe 1 made of stainless steel pipe. By inserting the collar 3A made of fluororesin, which is excellent and has low thermal conductivity, it is possible to prevent the generation of scratches on the outer circumference when the ground pipe 1 is inserted into or removed from the male side double ball valve, and the O ring. Not only can damage of 4A and 4B be prevented, but also heat transfer from the outer periphery of the ground pipe 1 to the end of the ground connection pipe 2 can be reduced.

FIG. 2 is a half sectional view showing a main part of another embodiment of the double ball valve of the first and second inventions. Figure 2
In the inner periphery of the right end of the ground side connecting pipe 12,
Subsequent to 12b, a fine thread 12c having a diameter larger than that of the stepped portion 12b is formed. Of these, the stepped portion 12b includes
The O-ring groove is formed and the O-ring 4C is inserted.

On the other hand, inside the stepped portion 12b and the fine screw 12c, a collar 3B made of fluororesin and having a substantially convex section is formed.
Has been inserted. At the right end of the outer periphery of this collar 3B,
A fine male screw 3b to be screwed with the fine screw 12c is formed, an O-ring groove is formed on the inner circumference, and an O-ring 4A is inserted. In addition, a plurality of holes 3 are provided on the right side surface of the collar 3B.
c is formed. In this case as well, similar to the double ball valve shown in FIG. 1, generation of scratches on the outer circumference of the ground pipe 1 inserted into and removed from the double ball valve and O-rings 4A, 4C.
Can prevent damage.

FIG. 3 is a half sectional view showing a main part of another embodiment of the double ball valve of the first and second inventions which is different from the above. In FIG. 3, on the inner periphery at the right end of the ground side connecting pipe 22, a stepped portion 22b having the same diameter as the inner periphery at the right end of the ground side connecting pipe 2 of FIG. Are formed.

Of these, the stepped portion 22b is fitted with an annular collar 3C having a substantially convex cross section. This color 3C
An O-ring groove is formed on the inner circumference of the O-ring 4A, and an O-ring 4A is inserted and the O-ring groove is formed on the outer circumference of the collar 3C. An annular nut 8 is inserted between the outer periphery at the right end of the collar 3C and the fine female screw 22c. Also in this case, similarly to the double ball valve shown in FIGS. 1 and 2, it is possible to prevent the occurrence of scratches on the outer periphery of the ground pipe 1 inserted into and removed from the double ball valve and the O-ring.

In the above embodiment, the color 3
Although A, 3B, and 3C have been described as being made of fluororesin, other resins having excellent wear resistance and a small friction coefficient may be used. Further, not made of resin, but copper alloy or sintered alloy. May be used. Also, it was explained when it is used for liquid helium or liquid nitrogen that is injected into the superconducting magnet of a magnetic levitation railway vehicle, but if it is a low temperature fluid injection / recovery part, for example, other low temperature fluid such as liquid oxygen But it's okay.

[0023]

As described above, according to the first aspect of the invention, in the double ball valve in which the pipe for injecting and recovering the low temperature fluid is inserted into the connecting pipe through the O-ring, the end portion of the connecting pipe into which the pipe is inserted is By installing a collar with an O-ring installed on the inner circumference, the material of the collar is made different from the connecting pipe, and the friction with the connecting pipe that is inserted into and removed from the double ball valve is reduced. Damage to the tube surface,
It is possible to obtain a double ball valve capable of eliminating damage to the O-ring due to this damage.

According to the second invention, in the double ball valve in which the pipe for injecting / recovering the low temperature fluid is inserted into the connecting pipe through the O-ring, the inside of the end portion of the connecting pipe into which the pipe is inserted. An O-ring is attached to the circumference, and a collar with a hardness lower than the outer circumference of the pipe is attached to reduce friction with the pipe inserted into and removed from the double ball valve. It is possible to obtain a double ball valve capable of eliminating damage to the O-ring due to this damage.

[Brief description of drawings]

FIG. 1 is a sectional view showing an essential part of an embodiment of a double ball valve of the first and second inventions.

FIG. 2 is a cross-sectional view showing the main parts of another embodiment of the double ball valve of the first and second inventions.

FIG. 3 is a cross-sectional view showing a main part of another embodiment of the double ball valve of the first and second inventions.

FIG. 4 is a view showing an example of a conventional double ball valve.

5 is an enlarged cross-sectional view taken along the line AA of FIG.

[Explanation of symbols]

1 ... ground piping, 2 ... ground side connecting tubes, 3A, 3B, 3C ...
Collar, 4A, 4B, 4C ... O-ring, 5 ... Cap nut,
6 ... Stopper, 7 ... Hole ring, 30 ... Vehicle, 31A ... Female double ball valve, 31B ... Male double ball valve.

Claims (2)

[Claims] 1. A double ball valve in which a pipe for injecting / recovering a cryogenic fluid is inserted into a connecting pipe via an O-ring, wherein the O-ring is provided on an inner circumference of an end portion of the connecting pipe into which the pipe is inserted. A double ball valve that is equipped with a collar that has been installed. 2. The double ball valve according to claim 1, wherein the collar is a member having a hardness lower than that of the outer circumference of the pipe.