JPS6347340Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a low-temperature valve, and particularly to a low-temperature valve used in a superconducting magnetically levitated railway cryostat, an on-vehicle helium refrigerator, and the like.

Conventionally, there has been a low temperature valve of this type as shown in FIG. In the figure, a valve barrel 4 having a cryogenic fluid inlet 1, a cryogenic fluid outlet 2, and a valve seat 3 in contact with the valve stem.
A movable valve stem 5 is inserted into the interior, and the rear end of the valve stem 5 has a threaded portion 5 that holds the valve stem 5 and opens and closes the valve.
a, a normal temperature manual section 5b is formed. The valve cylinder 4 is provided with a valve cylinder-side thermal anchor 6 for reducing heat entering the low temperature side through the valve cylinder 4, and the thermal anchor 6 is connected to a heat shield plate 8 by a fastener 7.
is combined with A mounting flange 9 is formed at the rear end of the valve cylinder 4, into which a threaded portion 5a of the valve stem 5 is screwed. Reference numeral 10 denotes a valve stem-side thermal anchor that is structured to be brought into contact with the valve cylinder 4 attached to the valve stem 5.

Here, although there are various factors for heat intrusion, it is mainly due to heat conduction. Therefore, the amount of heat penetration Q is generally expressed by the following formula.

Q=kA/(T _H −T _C ) [W] K: Average thermal conductivity of a substance [W/cm・K] A: [Cross-sectional area [cm ² ] : [Length [cm]] T _H : [ High-temperature side temperature [K] T _C :〃 Low-temperature side temperature [K] From the above formula, if k and A are constant, the amount of heat input Q is the term (T _H − T _C ), that is, the temperature difference is small. It turns out that there are fewer. The thermal anchor is provided to reduce the above temperature difference, and sets an intermediate temperature between a certain high temperature side and a certain low temperature side to reduce the amount of heat intrusion into the low temperature side.

The conventional low-temperature valve has a valve stem 5 and a valve cylinder 4 as described above.
Since the structure is such that the valve stem thermal anchor 10 provided between the valve stem and the valve stem 4 is simply brought into contact with each of the valve stem 5 and the valve cylinder 4, when used for a magnetically levitated railway, it may become non-contact due to the effects of vibration, etc. In some cases, reliable heat conduction was not achieved. Furthermore, when the valve stem 5 is operated repeatedly, the contact portion with the valve cylinder 4 is worn out and a gap is created, resulting in a disadvantage that reliable heat conduction cannot be carried out.

This idea was made to eliminate the drawbacks of the conventional ones as described above, and it uses a pair of thermal anchor members that are fixed to or in contact with the valve stem and valve cylinder, respectively, and a flexible joint that connects them. By providing a valve stem side thermal anchor consisting of
It is an object of the present invention to provide a low temperature valve that allows reliable and reliable heat conduction, allows setting of an intermediate temperature, and reduces the amount of heat intrusion into the low temperature side.

An embodiment of this invention will be described below with reference to the drawings. In Figure 2, the valve stem side thermal anchor 1
01 is a first thermal anchor member 101a on the valve stem 51 side, a second thermal anchor member 101b on the valve cylinder 41 side, and a thermal anchor member 101a and 1
Thermal anchor members 101a and 101b are formed by grooves 51a and 41a formed in the valve stem 51 and valve cylinder 41, respectively.
is fixed. As the flexible joint 101c,
A spring made of a good thermal conductor is used to mechanically connect the thermal anchor members 101a and 101b and to improve heat conduction between them.

With the above configuration, the valve stem side thermal anchor 10
1 is a thermal anchor member 101a on the valve stem 51 side.
and a thermal anchor member 101b on the valve cylinder 41 side, and these are connected by a flexible joint 101c made of a good thermal conductor, so that it is possible to prevent contact failure due to vibration or long-term use.

In addition, in the above embodiment, in order to reliably thermally connect the valve cylinder 41 and the valve stem 51, the flexible joint 101 that connects the thermal anchor members 101a and 101b is used.
The one using a spring of good thermal conductor is shown in c.
The flexible joint may be made of a material other than a spring such as a bellows as long as it is flexible enough to match the movable stroke of the valve stem 51 and is a good thermal conductor. 41 and the valve stem 51, but may have a structure in which they are brought into reliable contact with each other without being fixed.

As described above, this invention has the effect of ensuring appropriate heat conduction between the valve stem and the valve cylinder with a simple structure.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view showing a conventional low temperature valve, and FIG. 2 is a vertical sectional view of an embodiment of this invention. 1...Cryogenic fluid inlet, 2...Cryogenic fluid outlet, 3
... Valve seat, 41 ... Valve cylinder, 51 ... Valve stem, 41
a, 51a... Concave groove, 6... Valve cylinder side thermal anchor, 7... Fastener, 8... Heat shield plate, 9...
Mounting flange, 101...valve stem side thermal anchor, 101a, 101b...first and second thermal anchor members, 101c...flexible joint. In each figure, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A valve cylinder, a valve rod that is inserted into the valve cylinder and opens and closes a flow path for a low-temperature fluid by operating a normal-temperature manual part;
A low-temperature valve including a valve cylinder side thermal anchor provided outside the valve cylinder and a valve stem side thermal anchor interposed between the valve cylinder and the valve stem, the first thermal anchor being coupled to the valve stem. an anchor member, a second thermal anchor member coupled to the valve barrel, and the valve stem-side thermal anchor comprising a flexible joint made of a good thermal conductor that couples the first and second thermal anchor members. A low temperature valve characterized by comprising: (2) The low temperature valve according to claim 1, wherein the flexible joint is a spring. (3) The low temperature valve according to claim 1, wherein the flexible joint is a bellows.