SU1597649A1 - Method of testing articles for hermetic sealing - Google Patents

Abstract

The invention relates to the monitoring of the tightness of hydraulic units and allows to increase the reliability by taking into account the dissolution of gas in a liquid. Pre-fill distributor nozzle 16 with liquid up to overflow. The distributor is a sealed vessel 14 with a nozzle 16, the upper end of which is located above the bottom of the vessel 14. Raise the fluid pressure in the nozzle 16 and the gas in the vessel 14 to the test. After a time equal to the holding time, the product 12 is filled with a liquid under test pressure, the upper end of the pipe 16 is sealed, the product 12 is reported with the pipe 16 and the measuring capacity 18. The amount of liquid drained is determined. Then, the product 12 and the pipeline section between it and the upper end of the nozzle 16 are filled with liquid under test pressure, the distributor is connected to the gas source with the test pressure. The product 12 is disconnected from the source after a holding time, the product 12 is connected to the measuring tank 18, and the amount of the drained liquid is measured. Product leakage is determined by the amount of liquid drained in both cases. 1 il.

Description

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The invention relates to a testing technique and can be used to monitor the tightness of hydraulic units and hydraulic systems.

The purpose of the invention is to increase the reliability by taking into account the dissolution of gas in the liquid.

The drawing shows a diagram of an apparatus for implementing a method for testing products for tightness.

The device contains a reservoir 1 for storing a control fluid, a discharge line with a pump 2, a filter 3, taps, a drain line with a tap 7c. A pneumatic-hydraulic accumulator 8 is connected to the discharge line, the pressure in which is monitored by a pressure gauge 9. Gas cavity the accumulator 8 through a pipeline with a valve 10 and a valve distributor 11 is connected to the injection line and through it to the test item 2, the accumulator 8 is charged from a source of compressed gas (not shown) through valve 13 The distributor 11 is a Poland sealed vessel 14, in which an IS valve is placed, which overlaps the end-pat- / cabin 16, connects the distributor cavity to the delivery line, the Pipe 16 is made with a constant internal diameter, is installed vertically, and its end is installed above two vessels. 14 Such an implementation ensures the formation of a liquid-pelvis border at the end of vessel 16 and an invariance of the contact area with a change in the level of the liquid. The liquids from the vessel 14 are slid through the pipeline with the valve 17. The cavity of the product 12 is connected to the measuring tank 18 by the pipeline with the valve 19

The method is as follows.

way

Conducting a leak test of product 12 - hydraulic unit Time Control - 2 min.

Connect the test article 12, open the taps 4-7, turn on the pump 2 and pump the liquid through the product until the air is completely removed. At the same time, open the valve 15 to the valve 17. As soon as the liquid 15 starts to drain the valve 15, close the valve. Open the valve 13 and squeezing the mouth out of the vessel 14 with compressed gas, residual liquid Pere

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close valve 17, then valve 13 When the pump is running, turn off valves 6 and 7, open valve 10. Raise the pressure in the accumulator 8 to the test one. Shut off the cranes 4. and 5, press the pump 2 Open the valve 15 and hold for 2 min.

During the holding period, the liquid-gas boundary is unchanged and is at the level of the cut-off of the nozzle 16. At this boundary gas dissolves and partially diffuses into the liquid volume. Shut off valve 5 and open valve 19. Liquid enters measuring vessel 18 due to elastic expansion of the test medium and is displaced by gas, which changes from free state to dilute and expands due to pressure drop. Determine the portion of liquid displaced

Next, overlap the taps 6, 10 and 19, open the valve 5. Priotkrish valve 17, relieve pressure in the vessel 14, which further - when opening the valve 15 - ensures that the gas enters the chamber through the nipple. Overlap After draining from the vessel 14 all the liquid overlap and the valve 17. Open the taps 6 and 10,

by creating a vessel 14 and an article 12 pressure test. Shut off valve 5 and open valve 15. Hold for 2 minutes. To compensate for the flow of liquid from the products into the pipeline 16, the flow of gas is equal to the leakage. At the same time, a part of the gas dissolves at the interface with the liquid. At the end of the holding time, the valve 15 closes and opens the valve 19. The measured capacity is replaced by a portion of the liquid V. The leakage is determined by the dependence

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Rati-. 1 / n

V (V, -V,) - (-)

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where v

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the volume of fluid displaced into the measuring tank 18 after the actual control operation, due to the expansion of the dissolved and undissolved gas;

the volume of the tongue, displaced into the measuring capacitance 18 on the

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in the primary stage, due to the expansion of the gas dissolved in the liquid;

absolute pressure in measuring tank 18 (atmospheric); absolute test pressure of article 12; p is an indicator of polytropic. The resulting value is compared with the permissible. And give a conclusion about the validity of the product 12 o

Elimination of the measurement error associated with the solubility of gas in a liquid increases the reliability of the tightness control, the associated cases of detecting a false marriage are avoided.

Claims (1)

Invention Formula The method of testing products for tightness by filling the product with a liquid under test pressure, connecting the product and through a pipeline with a distributor - with a source of gas with test pressure, disconnecting the product from the source through the soak time, the joints of the product with the measuring capacity, and the leakage of the product are determined by the amount of liquid drained, approximately 4, in order to increase the reliability by taking into account the dissolution of gas in the liquid a sealed container with a nozzle, the upper end of which is located above the bottom of the vessel, pre-filled the nozzle until the liquid overflows under test pressure, and the vessel with gas under test pressure, fill the product with liquid under test pressure m time equal to the time of expiration and seal the end of the nozzle, inform the product with the nozzle and with the measuring capacity and determine the amount of drained liquid, before connecting the product to the gas source, fill the pipeline section between the product and the upper end of the nozzle with liquid under test pressure, and not - the hermeticity of the product is determined by taking into account the amount of the preliminarily mixed fluid Editor Compiled by L.Vihl ev Tehred L. Oliynyk Proofreader S. Cherni Order 3045 Circulation 446 VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow, Zh-35, Raushsk nab. 4/5 Subscription