JPH0733866Y2 - Gas leak measuring device - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to an apparatus for measuring gas leakage amount, and particularly used for a gas permeation performance test apparatus for semipermeable membranes, etc. The present invention relates to a device for measuring gas leakage amount.

[Prior Art and its Problems] In this type of gas leakage measuring device, the leaked gas is introduced into a water-sealed bottle filled with water, and the water in the bottle is transferred to another container by the pressure of this gas. It was adapted to measure the weight or volume of this water.

Therefore, it cannot be applied when the leaked gas is a water-soluble gas.

In other gas leakage amount measuring devices, the differential pressure between the reference gas and the sample gas is detected by the differential pressure sensor, the flow rate is calculated by calculation, and this is displayed.

However, since the pressure on the leaking side of the semipermeable membrane differs depending on the flow rate of the leaked gas from the semipermeable membrane, the measurement conditions cannot be made constant and the measurement error increases.

In view of the above problems, an object of the present invention is to provide a gas leakage amount measuring device which can be applied to all gases and can accurately measure the gas leakage amount.

[Means for Solving Problems] In the gas leakage amount measuring device according to the present invention, a cylinder into which leaked gas from the outside is introduced into the inside through a flow path, and a cylinder inside which moves inside the cylinder to reduce the internal volume. The variable piston, the driving means for driving the piston, and the flow passage to one of the compartments partitioned by a partition wall, and the reference gas to the other compartment partitioned by the partition wall. A differential pressure detector for detecting a differential pressure between the two, a control means for controlling the driving means so that the differential pressure becomes zero, and a means for obtaining a gas leakage amount by using the moving amount of the piston. It is characterized by that.

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

An inflow pipe 12 that guides leaked gas into the cylinder 10 is connected to the tip end surface of the cylinder 10. The leaked gas is, for example, a gas leaked from the semipermeable membrane of the semipermeable membrane permeation performance testing device, and may be water-soluble or not.

The inflow pipe 12 and the reservoir 14 are connected to the respective compartments of the differential pressure detector 16, and the differential pressure between the pressure of the leaked gas and the pressure of the reference gas is detected. The detection signal is supplied to the controller 18, and as described later, the piston 20 fitted in the cylinder 10 is driven backward so that the differential pressure becomes zero. The differential pressure detector 16 has high sensitivity and can detect a slight differential pressure of, for example, 1 mmH ₂ O, so that the gas leak amount can be measured with high accuracy.

In this embodiment, since the pressure of the reference gas is used instead of the atmospheric pressure, even if the atmospheric pressure fluctuates during the measurement, it is not affected. Moreover, even if the ambient temperature changes, the temperature inside the cylinder 10 and the temperature inside the reservoir 14 change approximately the same, so the temperature is automatically corrected, and the movement amount of the piston 20 is determined by the amount of gas (substance amount) in the cylinder 10. ).

An O-ring 21 seals between the cylinder 10 and the piston 20. Bracket 22 at the base of piston 20
Is fixed and the screw rod 24 is screwed through the bracket 22. When the screw rod 24 is rotated, the piston 20 is driven in the axial direction. A base end of the screw rod 24 is fixed to the center of a spur gear 26, and a spur gear 28 is meshed with the spur gear 26.

Therefore, when the spur gear 28 is rotated by the pulse motor 30, the piston 20 is driven in its axial direction. The rotation of the pulse motor 30 is controlled by the controller 18.

The rotation amount of the spur gear 28 is detected by the pulse generator 32. Each time the spur gear 28 rotates by a predetermined angle, a pulse is supplied from the pulse generator 32 to the counter 34, and the number of pulses is counted.

In this embodiment, the spur gears 26, 28, the bracket 22, and the screw rod
Since the deceleration mechanism consisting of 24 and the pulse generator 32 are used, the piston 20 can be finely adjusted, and the gas leakage amount can be measured with high accuracy.

The front end position of the piston 20 is detected by the position sensor 36,
The count value of the counter 34 is reset by this detection signal. This count value is supplied to the data processing device 38, and the data processing device 38 converts this into a gas leakage amount (volume) and supplies the gas leakage amount and the elapsed time from the measurement start time to the display 40 and the recorder 42. To do.

An exhaust pipe 44 for exhausting gas is connected to the front end side surface of the cylinder 10. The flow path of the discharge pipe 44 is opened and closed by a solenoid valve 46. If the position sensor 36 does not detect the end position of the piston 20 before the start of measurement, the controller 18 opens the solenoid valve 46, rotates the pulse motor 30, and outputs a pulse when the end position is detected. The rotation of the motor 30 is stopped and the solenoid valve 46 is closed.

When the measurement start signal is supplied to the controller 18, the controller 18 reads the differential pressure from the differential pressure detector 16, rotates the pulse motor 30 so that the differential pressure becomes zero, and retracts the piston 20.

As a result, the gas pressure in the cylinder 10 becomes equal to the gas pressure in the reservoir 14. Therefore, the pressure on the gas leakage side of the semipermeable membrane becomes constant regardless of the gas flow rate, and the gas leakage amount can be measured under constant measurement conditions. If the gas pressure in the reservoir 14 is reduced, the measurement sensitivity of the gas amount is improved.

The rotation of the pulse motor 30 increases the count value of the counter 34, the amount of leaked gas and the elapsed time from the start of measurement are displayed on the display 40, and the recorder 42 creates the graph.

In this way, the gas leakage amount is accurately measured, and the gas permeation performance of the semipermeable membrane can be known.

In the present invention, one compartment of the differential pressure detector 16 may be connected to the atmosphere without using the reservoir 14. In this case, the reference gas is the atmosphere itself. Further, the reservoir 14 may be kept at a constant temperature.

Further, the pressure or temperature in the cylinder 10 may be detected, and the detected value may be supplied to the data processing device 38 to obtain the leaked gas amount in the standard state.

[Advantage of the Invention] In the gas leakage measuring device according to the present invention, the leaked gas is introduced into the cylinder, and the difference between the gas pressure of the leaked gas introduced and the gas pressure of the reference gas is detected by the differential pressure detector. , The piston is driven so that this pressure difference becomes zero, and the amount of gas leakage is calculated using the amount of movement of the piston, so any gas leakage amount can be measured regardless of whether it is water-soluble or not. In addition, since the pressure on the gas leak side such as the semipermeable membrane can be made constant regardless of the gas leak flow rate, it is possible to accurately measure the gas leak amount under a constant measurement condition. effective.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a gas leakage amount measuring device according to an embodiment of the present invention. 10: Cylinder, 14: Reservoir 16: Differential pressure detector, 20: Piston 30: Pulse motor, 32: Pulse generator

Claims (1)

[Scope of utility model registration request] 1. A cylinder in which leaked gas from the outside is introduced into the inside through a flow path, a piston that moves in the cylinder to change the internal volume, drive means for driving the piston, and a partition wall. The flow path is connected to one of the partitioned chambers, the reference gas is connected to the other of the partitioned chambers, and a differential pressure detector for detecting a differential pressure between the separated chambers and the differential pressure detector. A gas leakage amount measuring device, comprising: a control unit that controls the driving unit so that the value becomes zero; and a unit that obtains a gas leakage amount using the movement amount of the piston.