JPH01196527A - Leak tester - Google Patents

Abstract

PURPOSE:To obtain a leak tester which enables quick and accurate measurement with a simple handling, by connecting a container to be tested and a reference container with a bypass shut-off valve provided on the downstream from a thermal type mass flowmeter used as flowmeter. CONSTITUTION:A container 1 to be tested and a reference container 2 formed in the same shape are connected to pipelines 4 and 5 linked in parallel to each other to supply a gas for testing from a gas supply source 3. A thermal type mass flowmeter 9 is provided as flowmeter so as to connect the container 1 being tested and the reference container 2, namely connecting points B and C of the pipelines 4 and 5. Moreover, a bypass passage 10 is connected between points D and E near the container 1 being tested and the reference container 2 on the downstream from the points B and C and a bypass shut-off valve 11 is provided on the passage to move a gas until a pressure balance is reached after a pressure filling. This enables quick and accurate measurement with a simple handling.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a leak test device for testing the airtightness of structures such as containers or pipes.

[Conventional technology]

As shown in FIG. 4, the conventional leak test device connects a test container 41 and a reference container 42, which are formed in the same shape (structure) to each other, using a test container 41 and a reference container 42, as shown in Japanese Patent Publication No. 53-2351, for example. A gas supply source 44 is connected by a flow rate detector 43 consisting of a laminar flow element 43A and a differential pressure transmitter 43B.
The test gas from the container 41 and 42 is filled under pressure, and in response to the leak in the test container 41, the reference container 4
The airtightness of the test container 41 is measured by detecting the flow rate of the test gas moving from the test container 2 to the test container 41 side using the flow rate detector 43.

In addition, in the same figure, 45.45 is piping, 46 is an on-off valve,
47 is a three-way valve, 48 is a valve connecting between the pipes 45 and 45 on the upstream side of the flow rate detector 43, and 49 is a pressure gauge.

In addition, in place of the above flow rate detector 43, a
There is also one using a float type flow rate detector as shown in Publication No. 30.

[Problem that the invention seeks to solve]

However, in the leak test device having the above configuration, in response to a leak in the test container 41, the reference container 41
2 to the test container 41 side (
Since the flow rate detector 43 detects the amount of gas (leakage amount), it is greatly affected by changes in gas volume due to temperature, and therefore cannot accurately measure the gas flow rate. It is not possible to directly obtain the flow rate, and it is necessary to convert the leak amount/differential pressure/time from the differential pressure caused by the leak, which is troublesome. 41. Until the pressure of 42 reaches equilibrium, the test gas moves through the flow rate detector 43 and piping 45... The flow rate detector 43 has a large fluid resistance and requires a considerable amount of time to reach pressure equilibrium after being pressurized and filled with the test gas, and therefore has drawbacks such as the inability to quickly measure airtightness.

The present invention has been made with the above-mentioned considerations in mind, and its purpose is to provide a leak test device that eliminates the above-mentioned drawbacks, can perform measurements quickly and accurately, and is easy to handle. It is in.

[Means for solving problems]

In order to achieve the above object, in the present invention, a test container and a reference container connected via a flowmeter are each filled with gas under pressure, and gas is removed from the reference container in response to a leak in the test container. In a leak test device that tests the airtightness of a test container by measuring the flow rate of gas moving toward the test container, a thermal mass flowmeter is used as the flowmeter, and the test container and a reference are connected to each other. It is connected to the container by a bypass on-off valve provided downstream of the thermal mass flowmeter.

[Effect]

According to the above configuration, the leakage amount can be directly obtained as a mass flow rate value using a thermal mass flowmeter, eliminating the need for correction based on the pressure and temperature of the pressurized test gas, which simplifies its handling. , Thermal mass flowmeters have low fluid resistance and can perform measurements quickly and accurately. In addition, until the pressure equilibrium is reached after pressurized filling of the test gas, the gas can move through the bypass on-off valve installed downstream of the thermal mass flowmeter, so the gas cannot be pressurized. The time from filling to reaching pressure equilibrium is significantly shortened, the time required for the measurement is shortened, and the above objectives are fully achieved.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of a leak test device according to a first embodiment of the present invention, and in the same figure, 1.2 is used to compensate for the influence of changes in sealed gas pressure due to temperature changes during a leak test. Is gas supplied through a test container and a reference container that have the same shape (structure)? It is connected to conduits 4 and 5 that are connected in parallel to each other so that test gas (for example, nitrogen gas) from fJX3 is supplied. Point A is a branch point of the pipe line 4.5, 6.7 is an on-off valve for gas introduction provided in each of the pipe lines 4 and 5, and 8 is a pressure gauge.

9 is between the test container 1 and the standard container 2, more specifically,
A thermal mass flowmeter serving as a flowmeter provided to connect points B and C on the downstream side of the on-off valves 6.7 of the pipes 4 and 5, and this thermal mass flowmeter 9 includes: For example, the one described in Japanese Unexamined Patent Publication No. 62-278411 filed by the applicant of the present invention is suitable.

10 is located between the pipes 4.5 and downstream of the points B and C, and between the points E, more specifically, downstream of the thermal mass flowmeter 9 and located between the test vessels. 1 and reference container 2
Bypass flow path connecting between the points nearer and E, 1
Reference numeral 1 denotes a bypass on-off valve provided in this bypass flow path 10. As the bypass opening/closing valve 11, it is preferable to use a rotary valve that does not cause pressure shock or volume change due to its opening/closing operation, and a solenoid valve may also be used if care is taken to prevent small fluctuations.

Reference numeral 12 denotes a discharge pipe connected to the bypass passage 10 at a point, and reference numeral 13 denotes a discharge opening/closing valve provided in the discharge pipe 12.

To conduct a leak test using the leak test device having the above configuration, first, open the on-off valves 6.7 and the bypass on-off valve 11, close the on-off valve 13, and open the pipes 4 and 5. Nitrogen gas, which is a test gas, is pressurized and filled into the test container 1 and the reference container 2 at a predetermined pressure. During this pressurized filling with nitrogen gas, the test container 1 and the reference container 2 are connected in a short-circuit manner via the bypass on-off valve 11, so that the pressure equilibrium in the cocoon container 1.2 is maintained within a short period of time. It will be held in Note that the above-mentioned pressure equilibrium can be confirmed by the fact that the gas flow rate in the thermal mass flow meter 9 becomes zero.

Then, after the pressures in the test container 1 and the reference container 2 reach equilibrium, when the on-off valve 6.7 and the bypass on-off valve 11 are closed, the reference container 2
Nitrogen gas flows through the thermal mass flowmeter 9 to the test container 1 side, and this gas flow rate can be directly measured by the thermal mass flowmeter 9 to test the airtightness of the test container 1. can do.

In addition, in the above, bypass on-off valve 1 was removed during the leak test.
1, the gas flow rate in the thermal mass flowmeter 9 can be made zero at any time. FIG. 2 shows the configuration of a leak test device according to a second embodiment of the present invention.
In this embodiment, a flow path 14 that also serves as a discharge flow path is provided independently of the flow path 5, and this flow path 14 is connected to the container under test.
The channels 4 and 12 shown in FIG. 1 above are omitted.

The operation of the leak test device constructed in this manner is the same as that shown in FIG. 1 above, and therefore the explanation thereof will be omitted.

FIG. 3 shows the configuration of a leak test device according to a third embodiment of the present invention.The main difference from the embodiment shown in FIGS. 1 and 2 above is that the reference container 2 is replaced with a reference container 2. This is because a reference pressure conduit 20 for maintaining the pressure is provided. That is, for example, the reference pressure conduit 20 is constituted by a diaphragm type secondary pressure regulator 21, a pressure gauge 22, a flow path 23, and a capillary 24 through which test gas is leaked in order to finely adjust the reference pressure. , a flow path 3 connecting the test container 1
0, a thermal mass flowmeter 9 is provided between a point F on the downstream side of the pressure gauge 22 in the flow path 23 and the three-way valve 31, and a three-way valve 31 is provided in the flow path 3D. Point G on the downstream side of point F and point H on the downstream side of point F (this point H is
4 on the upper fiL side) are connected by a bypass flow path IO provided with a bypass on-off valve 11.

The leak test device configured in this way has a container under test 1.
Even if the airtightness is poor and the amount of gas leaks is large, the initial test conditions can be maintained, and when compensating for changes in flow rate, it can be adjusted with the secondary pressure regulator 21, and the result will be good. A leak test can be performed.

〔Effect of the invention〕

As explained above, the leak test device according to the present invention uses a thermal mass flowmeter as a flowmeter provided between the test container and the reference container, and uses a bypass on-off valve to connect the cocoon container. Since the short circuit is used, the leakage amount can be directly obtained as a mass flow rate value using a thermal mass flowmeter during a leak test, eliminating the need for correction based on the pressure and temperature of the pressurized gas. In addition to being easier to handle, thermal mass flowmeters have low fluid resistance and can perform measurements quickly and accurately, for example, with an accuracy of 1% and a full scale of 1 lI.
Using a thermal mass flowmeter with l/+in and a minimum detection flow rate of 0.01 m1/min, the test and reference containers were pressurized and filled with nitrogen gas at 6 atmospheres.
-'~I
A 3X1 by washing appropriately between q and 6 atm.
It has now become possible to measure the leakage amount over a wide range of 0-' to lX10at+m-(c/s).

In addition, after the test gas is pressurized and until the pressure equilibrium is reached, the gas can move through the bypass on-off valve, so the time from the pressurization filling of the test gas until the pressure equilibrium is reached is shortened. This has significantly shortened the time required for measurement, making it possible to perform leak tests more efficiently.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a leak test device according to a first embodiment of the present invention. FIG. 2 is a diagram showing the configuration of a leak test device according to a second embodiment of the present invention. FIG. 3 is a diagram showing the configuration of a leak test device according to a third embodiment of the present invention. FIG. 4 is a diagram showing the configuration of a leak test device for explaining the prior art. 1...Test container, 2...Reference container, 9...Flowmeter, 11...Bypass opening/closing valve. Applicant: Rihito Aesthetics Co., Ltd.
Patent Attorney Hideo Fujimoto Figure 1 1...Test container 2...Reference vessel 9...Flow meter 11...Bypass on/off valve Figure 2

Claims (1)

[Claims] Filling the test container and reference container connected via a flowmeter with gas under pressure, and measuring the flow rate of gas moving from the reference container to the test container in response to leaks in the test container. In the leak test device, a thermal mass flowmeter is used as the flowmeter, and the test container and the reference container are connected downstream of the thermal mass flowmeter. A leak test device characterized by being connected by a bypass on-off valve provided on the side.