JP2000131204A - Device for controlling applied pressure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure a stabilized testing characteristic by avoiding a pressure impact and controlling an applied pressure with simplified construction. SOLUTION: A gas-filled buffer tank 5a is provided in a pressure application line and a pressure sensor 4b and a flow passage connection valve are provided to control a flow passage for avoiding pressure impact and controlling and applied pressure. By utilizing a relief of pressure change by an effect of gas filled in a buffer chamber, the impact at the time of pressure application is avoided. A variable pressure can be applied in this way without a high-cost pressure regulating mechanism and a control system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for avoiding shock when a liquid pressure is applied and a method for controlling the applied pressure.
Used for airtight tests. The present invention relates to an applied pressure control device that controls a flow path to a device configured by a buffer chamber filled with gas and a flow path switching mechanism.

[0002]

2. Description of the Related Art A method and an applied pressure control device for avoiding a pressure shock at the time of applying a hydraulic pressure, particularly when the volume of an object to be subjected to pressure application is small, is controlled by a conventional pump or the like to control a small amount of flow and to apply an applied pressure. Cannot be used because control is not possible. In addition, as a method of changing the pressure, there is a method using a pressure adjusting valve or a flow control valve. However, in order to automatically change the pressure, a driving mechanism and a control mechanism of the adjusting valve are required, which increases the cost and size of the device. Is a problem.

[0003]

A method and an applied pressure control device for avoiding a pressure shock at the time of applying a hydraulic pressure cannot be used because a conventional pump or the like cannot control a very small amount of flow and an applied pressure. In addition, there is a method in which a drive mechanism and a control mechanism are provided in the pressure regulating valve and the flow regulating valve to automatically vary the pressure. However, the cost and size of the apparatus become problematic.

An object of the present invention is to obtain a stable test characteristic by avoiding a pressure shock and controlling an applied pressure with a simple structure.

[0005]

In order to achieve the method and apparatus for controlling an applied pressure according to the present invention, a buffer chamber in which a gas is sealed in a pressure applying system is formed, and when a pressure is applied, the gas is compressed. The action alleviates a sudden change in pressure and achieves applied pressure control without pressure shock.

In order to achieve the applied pressure control method according to the second aspect of the present invention, a pressure sensor in the pressure applying system and a flow path control valve for sealing the pressure are provided, and the pressure in the system in which the pressure change is reduced is provided. The control of the applied pressure is achieved by detecting the completion of the control and controlling the flow path control valve.

In order to prevent a decrease in sensitivity of the pressure resistance and airtightness during the test according to the third aspect of the present invention, a flow path connecting valve capable of shutting off a buffer chamber filled with gas is provided, and the pressure in the system can be increased. At the same time as confirming, the buffer chamber is cut off from the pressure application system by the flow path connection valve,
Achieves prevention of sensitivity reduction in airtightness.

[0008]

FIG. 1 shows an embodiment of the present invention. This device is for automatic pressure control of multiple valves 8 for automatic biochemical blood analyzer.
This is an airtight test device. The apparatus includes a pressure control unit that applies the pure water pressure to the multiple valve 8 and a pressure measurement unit that measures the applied pressure. The multiple valve 8 to be tested is connected to a pressure application system. The pure water in the pure water tank 1 is pressurized by a pressurizing pump 2, and is further controlled by a pressure regulating valve 3 to a pressure equal to or higher than a pressure resistance / airtightness test pressure and displayed on a pressure gauge 4a.

When pressure is applied to the multiple valve 8, the control CPU
The control is started by controlling the on / off valve 6b to be closed and the connection switching valve 7 to be connected to the application system and the buffer tank 5a, and then to open the on / off valve 6a. The pure water 5c in the application system is pressurized so that the buffer tank 5a
Compress the air 5b inside. The pressure change in the system is reduced by this compression action, and pressure shock to the multiple valve 8 is avoided.

The control of the applied pressure to the target value is performed by controlling the output of the pressure sensor 4b based on the reduced pressure change in the system.
This is achieved by continuously measuring at 10 and controlling the on-off valve 6a to be closed when the target value is reached. Further, in order to prevent the sensitivity of the pressure resistance and airtightness from decreasing due to the compression and expansion of the air 5b in the buffer tank 5a, the connection switching valve 7 is cut off from the application system at the same time as the on-off valve 6a, so that stable pressure resistance and airtightness can be obtained. It is possible to obtain.

With the above operation, the pressure filling to the multiple valve 8 is completed. The measurement of the characteristic is obtained by automatically measuring the output of the pressure sensor 4b by the control CPU 10 in the state where the pressure is sealed. After the measurement is completed, the control CPU 10
The opening and closing valve 6b is opened, the buffer tank 5a is connected to the flow control valve 9 by the connection switching valve 7, and the pressure is adjusted to the pure water tank 1.
The test is completed by releasing. Flow control valve 9
Is the air 5 in the buffer tank 5a due to rapid pressure release.
This is to prevent b from coming off.

[0012]

The present apparatus is a method of controlling the applied pressure by utilizing the compression action of the gas in the buffer chamber filled with the gas to avoid the impact at the time of applying the pressure and to reduce the pressure change. It does not require disassembly, maintenance and cleaning, etc. Further, since an automatic control mechanism for the pressure regulating valve is not employed, a variable pressure can be applied without the need for a high-cost mechanism system and control system.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an automatic pressure resistance and airtightness test apparatus according to an embodiment of the present invention.

[Explanation of symbols]

1 ... pure water tank, 2 ... pressurizing pump, 3 ... pressure regulating valve, 4
a: pressure gauge, 4b: pressure sensor, 5a: buffer tank, 5b: air, 5c: pure water, 6a, 6b: open / close valve, 7
... Connection switching valve, 8 ... DUT (multiple valve), 9: Flow control valve, 10: CPU for control.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshio Aoki 882-mo, Oji-shi, Hitachinaka-city, Ibaraki Pref., Ltd.Measurement division of Hitachi, Ltd. 2G061 AA02 AA20 AB01 CB13 DA01 EA05

Claims (3)

[Claims] In a static pressure application control device at the time of a pressure and air tightness test of parts and devices by hydraulic pressure, a buffer chamber in which gas is sealed in a pressure application system path is formed, and a pressure chamber for applying pressure by gas compression action. An applied pressure control device characterized in that shock and pressure changes can be reduced. 2. A pressure sensor according to claim 1, wherein a pressure sensor and a flow path control valve are provided in said system, and a change in pressure alleviated by the action of the gas buffer chamber is measured and flow path switching control is performed to thereby control an applied pressure. An applied pressure control device for performing control. 3. A pressure control valve according to claim 1, further comprising a flow path control valve for shutting off the gas buffer chamber and the characteristic measuring system to prevent a decrease in sensitivity of the pressure resistance and airtightness due to the compressed gas in the gas buffer chamber during the pressure resistance and airtightness test. An applied pressure control device, characterized in that: