JPH02266176A - Relief valve for low temperature - Google Patents

Abstract

PURPOSE:To maintain relief pressure, where a cutoff member separates from a seat even there is a temperature change by having spring force and gas pressure sealed in a gas charged chamber affected on the cutoff member interrupting a fluid as adjoined to the seat. CONSTITUTION:When fluid pressure in an inlet 10 and a passage 11 is small, a cup 6 is pushed to the right by dint of a spring 2 and pressure of filled gas in a chamber 4, and a seat 7 comes into contact with a seat 14 of a casing 13, interrupting a connection between the inlet 10 and an outlet 12. Next, when the fluid pressure in the passage 11 goes up to a specified value, the spring 2 and a bellows 1 are compressed by the fluid pressure against the spring 2 and the filled gas pressure in the chamber 4, whereby the cup 6 is moved in the pressure direction, the seat 7 separates from the seat 14 and the inlet 10 and the outlet 12 are interconnected to each other, thus the fluid flows into the outlet 12 and is relieved. Accordingly, if a difference of force by a gas pressure differential in the filled gas due to a temperature difference is set so as to be equal to that of spring force, a difference in force between them is offset, thus relief pressure is maintained to a constant value even if there is a temperature change.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a low-temperature relief valve designed to offset changes in relief pressure due to temperature changes.

[Conventional technology]

In the conventional relief valve, as shown in FIG. 2, a seal o5 of a bobeso hO6 is pressed against a seat 03 by a spring o2.

In FIG. 2, as the pressure on the left side of the poppet 06 increases, the spring 02 is compressed and the poppet seal 05 and the seat 0 are compressed.
3 separates, poppet seal 03 and seat 03
Relieve fluid through the gap.

[Problem to be solved by the invention]

In the above-mentioned conventional relief valve, when used at low temperatures, the spring force is increased compared to when used at room temperature, so that the relief pressure that separates the poppet from the seat is higher. for example,
Using a relief valve at low temperatures from 20 to 90
The IJ pressure increases by about 10% compared to the case at room temperature. Therefore, when installing an IJ-F valve in the escape system of a storage tank for low-temperature liquids such as liquid oxygen and liquid hydrogen, the relief pressure changes depending on the temperature at the point where it is installed, so there is little margin in the safety factor. In the case of storage tanks for special purposes such as rockets, this relief pressure change becomes a problem.

The present invention aims to improve the above-mentioned conventional problems and provide a low-temperature relief valve equipped with a mechanism that offsets the increase in spring force due to temperature changes.

[Means to solve the problem]

The low-temperature relief valve of the present invention is a low-temperature relief valve equipped with a spring attached to a fluid cutoff member toward a seat against fluid pressure, and in which gas pressure is applied to the cutoff member toward the seat. A gas-filled chamber was provided for the action.

[Effect]

In the present invention, the fluid blocking member is pressed against the seat by the spring force and the gas pressure of the gas-filled chamber to block the fluid. Although the spring force increases as the temperature decreases, the gas pressure in the gas chamber decreases, and the sum of the spring force acting on the blocking member and the force due to the gas pressure in the gas chamber remains constant. Therefore, the relief pressure of the fluid that separates the blocking member from the seat against the force of the above-mentioned spring force and the gas pressure of the gas-filled chamber remains constant even if the temperature changes.

〔Example〕

An embodiment of the present invention will be described with reference to FIG.

In this embodiment, the present invention is applied to a pilot type relief valve for operating a large relief knob.

Reference numeral 13 denotes a casing provided with an inlet 10 and an outlet 12 for fluid in the system, and a passage 11 between the inlet 10 and the outlet 12. Inside the casing 13, there is a seat 1 of the casing 13.
A cup 6 having a seat 7 at one end thereof which opens and closes communication leading to the outlet 12 of the passage 11 in contact with and separating from the cup 6 is arranged, and the opening force/knob 6 is controlled by the connection between the flange 3 on its outer periphery and the spring receiver 5 of the casing 13. The seat 7 is biased towards the seat 14 of the casing 13 by a spring 2 mounted therebetween. Further, one end of the bellows 5 is airtightly attached to the end of the cup 6 opposite to the seat 7, and the other end of the bellows 5 is airtightly attached to the cup 8 attached to the casing 13. Pressure gas such as helium is sealed in the sealed chamber 4 formed by the cup 6.8, and the seat 7 of the cup 6 is pushed toward the seat 14 of the casing 13 by the pressure of the sealed gas. It looks like this.

In this embodiment, when the pressure of the fluid in the inlet 10 and the passage 11 is low, the pressure of the spring 2 and the gas sealed in the chamber 4 pushes the cup 6 to the right in FIG.
contacts the seat 14 of the casing 13 and interrupts the communication between the population 10 and the outlet 12. When the pressure of the fluid in the passage 11 rises to a certain value, the fluid pressure compresses the spring 2 and the bellows 1 against the pressure of the sealed gas in the spring 2 and the chamber 4, and the cup 6 moves to the left in FIG. When the seat 7 moves away from the seat 14, the inlet 10 and the outlet 12 communicate with each other, and the fluid flows to the outlet 12 and is relieved.

As described above, in this embodiment, when the force due to the fluid pressure acting on the cup 6 through the inlet 10 increases with respect to the sum of the force due to the force of the spring 2 and the force due to the sealed gas pressure in the chamber 4, the fluid in the system increases. is relieved from the inlet 10 to the outlet 12.

The spring force of the spring 2 increases as the temperature becomes lower, as described above. -The pressure of the gas enclosed in Mechanics 4 decreases at low temperatures. Therefore, in this embodiment, by setting the difference in force due to the gas pressure difference of the sealed gas due to the temperature difference to be equal to the difference in spring force, the difference in both forces is canceled out.
Even if there are temperature changes, the relief pressure that relieves the fluid in the system is maintained at a constant value.

〔Effect of the invention〕

The present invention maintains the relief pressure at which the blocking member leaves the seat at a constant level even when there is a temperature change by applying a spring force and gas pressure sealed in a gas-filled chamber to the blocking member that comes into contact with the seat to cut off fluid. can be held.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of one embodiment of the present invention, and FIG. 2 is a sectional view of a typical conventional relief valve. 1...Heroes, 2...Spring, 3...Flange, 4...Gas filling chamber, 5...Spring holder, 6...Cup, 7.14...Seat, 8・・・
- Cup, ]0...Fluid inlet, 11...Fluid passage, 12...Fluid outlet, 13...Casing.

Claims (1)

[Claims] A low-temperature relief valve equipped with a spring that urges a fluid blocking member toward a seat against fluid pressure, including a gas-filled chamber that applies gas pressure to the blocking member toward the seat. A low temperature relief valve featuring: