RU1805309C - Method of determination of non-tight zone - Google Patents

Abstract

The invention relates to remote sensing methods for determining a leak zone by a mass spectrometric method and provides testing of products with limited access to the cavity. The product is placed in a vacuum chamber and filled with control gas. Process gas, as heavier, is fed into the product from below, directing its flow perpendicular to the direction of movement of the gas separation front. Since the product is closed at the top, the control gas in the product is compressed and the leak detector recording the concentration of the control gas in the vacuum chamber increases. When the gas front reaches the leak zone, the leak detector readings fall sharply. At this moment, the gas pressure in the product is measured, and the volume of the supplied process gas and the level at which the flow is located are calculated from it. 1 C.p. f-ls, 2 ill.

Description

ate

with

The invention relates to remote methods for determining the leakage zone by mass spectrometric method and can be used in mechanical engineering, chemical, and aviation industries.

The purpose of the invention is to expand technological capabilities by providing testing products with limited access to the cavity and reducing the complexity of determining the leakage zone.

Significant differences of the proposed method are that the pressure in the product is measured at the time of a sudden change in the rate of change of the leak detector signal and the leakage zone is determined from the measured value; the control gas recorded by the leak detector is used as the first gas, and the process gas is used as the second.

In FIG. 1 shows a diagram of an installation that implements the method; in FIG. 2 - recording the readings of a helium mass spectrometric leak detector.

The installation contains an untight article 1; vacuum chamber 2; leakage 3; control leak 4; helium mass spectrometric leak detector 5, a device for changing the direction of gas supply 6.

The method is carried out as follows.

Graduate the product in units of volume in height. The product is exposed in a vacuum chamber so that the graduated direction is vertical. Close the vacuum chamber 2 and vacuum it to a predetermined value, for example, up to 1 mm Hg. Using test leak 4, test the sensitivity of system 5 to

oo

o e o o o

test gas. Let it be helium in our example. Helium is fed into article 1 and the total leakage is determined. If its value is less than the established tolerance, the tests are considered complete. If the leakage exceeds the tolerance, a leak zone is established by the proposed technology.

The gels from the article, for example, to atmospheric, are depressurized. Supply air is supplied to the lower part of the product, directing its flow perpendicular to the direction of movement of the gas interface. The test gas in the product is compressed, the leak detector readings increase. When the air front reaches the zone where leak 3 is located, the signal of the leak detector drops sharply. The pressure in the product is recorded at the moment the leak detector signal begins to fall, let, for example, 0.75 ati, and the volume of air supplied is calculated. So, in our example, this volume will be equal to

Ri

Ri + 1

VC6;

0.75

1.75

VC6 0.43 VC6.,

where Pu is 0.75 kg / cm - the amount of overpressure in the product;

Usb build volume.

Knowing the volume of air supplied and the results of calibration, are determined by s, in which the flow is located. The air supply to the product is continued until the test pressure, for example, to Pu 10 kgf / cm2. With a constant leak detector signal, we can conclude that leakage 3 was the only one (this case is shown in

FIG. 2). Signal Increase

0

5

0

5

0

5

0

indicates that the installed leak is not unique. If the test pressure is reached, but no signal decrease is observed, then the leak is in the remaining part of the product that is empty.

In the installed area, the leak location is verified using the traditional probe technique, which is very labor intensive and can hardly be automated, therefore reducing the scope of work with the probe can significantly reduce the labor and cost of testing.

The proposed method extends technological capabilities and allows to reduce the cost of testing.

Claims (2)

1. A method for determining the leakage zone of a product by filling it with a first gas, placing the product in a vacuum chamber connected by a leak detector, supplying a second gas to the product - heavy from below, and light from above perpendicular to the displacement direction, and recording a leak detector signal detecting one of the gases characterized in that, in order to expand technological capabilities by providing testing of products with limited access to the cavity, the gas pressure in the product is measured at the moment of an abrupt change in leak detector signal rate of change and the measured value determined leakage zone. 2. The method according to claim 1, characterized in that, in order to reduce the complexity in determining the leakage zone, the control gas recorded by the leak detector is used as the first gas, and the process gas is used as the second gas.