RU1837189C - Tightness test method - Google Patents

Description

The invention relates to a test technique and can be used to measure the leakage rate of detachable pipe connections operating under internal overpressure of a neutral liquid, for example, to control the detachable connections of space temperature controllers (SC) of spacecraft (SC).

In the process of preparing and operating A, it often becomes necessary to check the tightness of the joint of detachable joints (hydraulic sockets) of the PTP pipelines, the counterparts of which are located before assembling the connection under pressure of the control fluid. ; The aim of the invention is to provide control of the tightness of the detachable connection of pipelines located

under internal pressure of a chemically neutral working fluid, for example, PMS-1.5r coolant.

The method is carried out using the device shown in the drawing.

Pipelines 1 and 2 are joined in a detachable tight connection using a union nut 3 and an existing seal barrier, which consists of one or more annular gaskets 4. A second seal barrier, consisting of one or more annular gaskets 5, which remains in connection all the time of its operation, the cavity 6 thus formed with additional tightness by means of a fitting 7, an adapter 8, a pipe 9 through a liquid nitrogen filled

With

with

00

from VI

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a trap 10 and a valve 11 are connected to a vacuum pump 12. To measure the pressure in the cavity 6, a pressure sensor 13 is used with a secondary device 14. A leak detector 16 is connected to the pipe 9 through the valve 15. The valve 17 serves to let gas into the test system. .

Having opened the valve 11, the cavity is evacuated to the set pressure, and the trap 10 is filled with liquid nitrogen. Open valve 15 and use a helium leak detector to check the tightness of the test system, including installing an adapter 8, connecting the pipe 9, trap 10, valve 11, blowing them with helium. If leaks are found in the test system, repair them.

By eliminating the leakage of the test lines in this way, the valves 15, 11 are closed, and for a fixed period of time At, the pressure increase of AP in the cavity b is measured using instrument 14.

The leakage of compound Q is determined by the ratio

Q V

AR At

where V is the free volume of the cavity 6 and the test system to the valve 11.

In this way, the tested sealed second seal barrier ensures the seal is tight even if the main available seal seal barrier is leaky. In this case, the total leakage of the compound does not exceed the measured value of Q. Vapors of the working fluid from the cavity and the test system are removed by evaporating the working fluid that has penetrated through the leakage of the main seal barrier in the cavity b by vacuum pump 12, freezing on the trap 10. In the time for measuring the pressure increase of the working fluid pair is frozen out by the trap 10, without creating the entire proportion of the pressure increase in the cavity 6 and the test system. For this, the trap has

corresponding amount of surface area. The liquid which has not evaporated remains in the cavity 6 without causing any increase in pressure in it.

Thus, the value of A P represents

is the pressure increase due to external leakage of the cavity 6 (leakage of the test system, as noted above, is previously excluded).

At the end of the measurements, turn off the pump 12, open the valve 11, through the valve 17, let in a helium-air mixture into the test system and cavity 6. The adapter 8 with the pipeline is disconnected from the fitting 7. A standard sealed plug is installed on the nozzle 7, which is similar in design to the adapter 8, but does not have an internal channel. Then

check the tightness of the plug installation with a helium leak detector using a suction cup (or RVC) method by installing a sealed suction cup (or RVC) on the surface 18 of the nozzle 7. Helium is used as a control gas in the cavity 6 after filling it at the end and testing the sealing barriers of the pipe joint. This ensures complete sealing of the process

fitting 7.

Claims (2)

1. A method of monitoring the tightness of a detachable pipe connection, which measure the pressure in the cavity between barriers of the double-barrier seal of the joint and pressure changes indicate the leak of the joint, which is also distinguished by the fact that, in order to expand technological capabilities by providing control of pipelines under the internal pressure of a chemically neutral working fluid, the inter-barrier cavity is vacuumized before measuring the pressure and remove the pairs from it working fluid. 2. The method according to claim 1, with the exception that the vapor removal of the working fluid is carried out by condensing them on a cooled trap. 12