JPH0828291B2 - Pressure holding device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a pressure holding device for a liquid helium injection device that supplies liquid helium to a superconducting magnet.

(Prior Art) FIG. 2 shows a conventional liquid helium injection device. This device comprises a pressurizing solenoid valve 3 (a valve that opens when electricity is applied), a solenoid valve 4 for recovery (a valve that closes when electricity is applied), a liquid level sensor 10, and a controller 14 that controls them.

When supplying liquid helium to the superconducting magnet 11,
When button A of the controller 14 is pressed, the pressurizing solenoid valve 3 is opened and the collecting solenoid valve 4 is closed.
The helium gas kept at a constant pressure by the pressure regulator 2 of FIG.

Due to this pressure, the liquid helium 7 is injected through the liquid helium transfer pipe 8 into the cryostat 13 in which the superconducting magnet 11 is installed. When the liquid level helium is filled up to a predetermined amount, the liquid level sensor 10 senses it, and at the same time, the pressurizing solenoid valve 3 is closed and the recovery solenoid valve 4 is opened, so that the pressure in the liquid helium container 22 is balanced with the atmospheric pressure. Exit to a gas bag (not shown). At this time, the controller 14
The button (stop lamp) lights up.

Therefore, the internal pressure of the liquid helium container 22 becomes almost the same as the atmospheric pressure, and the transfer of liquid helium to the cryostat 13 is stopped. When button A of the controller is pressed again when the liquid helium is exhausted in the cryostat 13, the pressurizing solenoid valve 3 opens and at the same time the recovery solenoid valve 4 is opened.
Is closed, and the inside of the liquid helium container 22 is pressurized with helium gas.

(Problems to be Solved by the Invention) In order to increase the internal pressure of the liquid helium container 22 which is in equilibrium with the atmospheric pressure, it takes an unexpected time for the helium gas, and therefore, the supply of liquid helium is delayed, which is an inconvenience. there were.

Therefore, it is an object of the present invention to provide a pressure maintaining device which keeps the inside of the liquid helium container at a constant pressure and can immediately take out the liquid helium when necessary.

(Means for solving the problem) A check valve and a solenoid valve (a valve that closes when energized) are used in parallel to adjust the flow of helium gas in the liquid helium container so as to maintain a constant pressure above atmospheric pressure. did.

(Function) The liquid helium container can be kept at a constant pressure so that liquid helium can be immediately taken out when needed.

(Example) An example of the present invention will be described with reference to FIG.

The feature of the present invention is that the pressure-holding solenoid valve 16 (the valve that closes when energized) and the check valve 17 (the gas flow from the collection solenoid valve to the gas bag) precedes the heavy-duty collection solenoid valve 4 (FIG. 2). Installed so that the flow) is configured by a parallel circuit.

Liquid helium is now accumulated in the cryostat 13 up to a predetermined amount, and at the same time when the liquid level sensor 10 senses it, the pressurizing solenoid valve 3 is closed, the recovery solenoid valve 4 is opened, and the pressure holding solenoid valve 16 is closed. In this state, liquid helium container 22
The flow of helium gas from is shown by arrow 20 in the figure.
Here, since the check valve 17 is configured to be closed at a certain pressure or less and opened at a certain pressure or more, the internal pressure of the liquid helium container 22 is maintained at a certain pressure.

For example, if it is desired to keep the internal pressure of the liquid helium container at 0.5 PSi or less, the internal pressure of the liquid helium container 22 can be maintained at 0.5 PSi by installing a check valve whose opening and closing is adjusted to 0.5 PSi.

When liquid helium is needed in the cryostat 13, if the valve 21 of the liquid helium transfer pipe is opened, the inside of the liquid helium container 22 has already been raised and the liquid helium is immediately supplied into the cryostat 13. There is no loss of time and helium gas until the internal pressure of the liquid helium container 22 is increased as in the conventional case.

When it is no longer necessary to supply liquid helium into the cryostat 13, the stop button D is pressed to open the pressure-holding solenoid valve 16, so that the liquid helium container is kept under pressure.
The helium gas in 22 flows as shown by arrow 19 in the figure and is collected in the gas bag. The internal pressure of the liquid helium container 22 is in equilibrium with the atmospheric pressure.

〔The invention's effect〕

By using the present invention, the consumption of helium gas required to pressurize the inside of the liquid helium container can be reduced. The effect of shortening the time for injecting liquid helium into the superconducting magnet is achieved.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of the present invention, and FIG. 2 is a schematic view showing a conventional device. 3 ... pressurizing solenoid valve, 4 ... recovery solenoid valve, 6 ... liquid helium container, 13 ... cryostat, 16 ... pressure-holding solenoid valve, 17 ... check valve.

Claims (1)

[Claims] 1. A pressure maintaining device comprising a solenoid valve (closed when energized) and a check valve capable of holding a constant pressure as a parallel circuit provided in a helium gas flow path of a liquid helium container.