SU688842A1 - Device for measuring gas leakage through piston seal - Google Patents

Description

I

The invention relates to the field of mechanical engineering and can be used to measure gas flow through a piston seal and to monitor the tightness of various devices, in particular for compressors.

Devices for measuring control gas neretrans through a piston seal are known; they contain a double-acting pneumatic cylinder with a working gas supply system, check valves, a reducer, a gas meter with a valve, in which there is an excess gas through the valve and a gas to maintain a constant pressure in the piston-cylinder cavity. the counter is released to the atmosphere.

The disadvantages of these devices are the presence of measurement error of leakages due to the gas pressure pulsation in the cylinder piston cavity, since its volume is limited, and the inertia of the check valve.

The closest to the technical essence of the invention is a device for measuring the flow of working gas through a piston seal containing a double-acting non-cylinder, compensating capacity, communicating with the over-piston cylinder cavity, the control gas supply system and gas

counter with throttle valve, connected to the cylinder piston cavity. The gas loss arising in the piston cavity of the cylinder is compensated by the capacity in which a pressure equal to the pressure in the substep cavity is maintained by means of the control gas supply system.

A disadvantage of the known device is a significant error in measuring the gas flow, as there is a reverse flow of gas from the bristle cavity to the super-piston due to pressure fluctuations in the bristle cavity.

The aim of the invention is to improve the accuracy of measuring gas flow through a nonshne seal.

This goal is achieved by the fact that the device is equipped with a spool regulating the gas supply from the tank, installed in the cylinder's annular cavity and pivotally connected to the piston of adjustable length, and an elastic diaphragm installed in the compensating tank and dividing it into two volumes, one of which is connected to nadoporschnevoy, and the other with a subshrup cavity.

FIG. 1 is shown schematically

the proposed device; in fig. 2 is a pressure chart before measuring leakages;

in fig. 3 is a pressure chart for leakage measurements.

The device comprises a pneumatic cylinder 1 of double-acting, divided by piston 2 with the sealing element 3 under investigation into the over piston cavity 4 and sub piston cavity 5. The spool 6 is connected pivotally to the piston 2 by means of a rod 7 of adjustable length.

The container 8 is divided by an elastic diaphragm 9 (for example, a bellows) into a volume 10 connected by a pipe 11 to a piston cavity through windows 12 in the form of rectangular w, spruces, and a volume 13 connected by a pipe 14 to a piston chamber 5.

The control gas supply system 15 is connected to the volume 10 by the pipeline 16.

The gas meter 17 is connected to the cavity 5 via the throttle valve 18. The pressure transmitter 19 is connected to the pneumatic cylinder 1.

The device is driven from the electric motor 20 through the V-belt drive with interchangeable pulleys 21, which provides control of the speed of the stirring, of the piston 2.

The gas pressure in the cavity 5 is monitored by a pressure gauge 22. The measurement of the water flow is carried out by the flow indicator 23.

The device works as follows.

The pneumatic cylinder 1 is filled with the test gas to the required pressure using the gas supply system 15.

With the reciprocating movement of the spool G, the windows 12 open at the moment when, in the process of lowering the pressure PI in cavity 4 along line ab (see Fig. 2), it becomes equal to the pressure in cavity 5 (point in Fig. 3).

As a result of the gas entering at a volume of 10 through windows 12, pressure I; remains unchanged and equal to the pressure P2 (line be in Fig. 3).

Windows 12 are closed by a spool 6 when the pressure of the cavity 4 in the pneumatic cylinder rises. This achieves unidirectional flow of gas from cavity 4 through the sealing element 3 of the piston 2 into the cavity 5. The gas that flows through the seal from cavity 4 into cavity 5 is then directed through valve 18, a gas meter 17 to the atmosphere. The valve 18 is opened so that the pressure in the cavity 5 remains unchanged. The gas portion 17 discharged through the counter is compensated from the gas supply system 15 which is constantly open in the process of measuring the overflows.

Exact match the moment of discovery

15 windows 12 the moment of equal pressure in the cavities 4 and 5 of the pneumatic cylinder 1 is provided by changing the distance between the piston 2 and the spool 6 by adjusting the length of the rod 7. The pressure in the cavity 5 fluctuates when the working gas volume changes as the piston 2 moves. the connection of the cavity 5 with the volume 13 of the container 8 through the elastic diaphragm 9.

Claims (1)

Invention Formula A device for measuring gas overflows through a norshne seal, containing a double-acting pneumatic cylinder, a compensating tank communicating with a piston cylinder, a control gas supply system and a gas meter with a throttle valve, 5 connected to a cylinder piston cavity, characterized in that, in order to improve measurement accuracy, it is equipped with a spool regulating the gas flow from the container, installed in the cylinder piston cavity above and pivotally connected to the piston by a rod of adjustable length, and an elastic diaphragm installed in the compensating container and dividing it into two volumes, one of which is connected to the overhead piston and the other to the sub piston cavity. Zf 22 20 W 8 16 0 40 80 no 1SO 200 2tO 280 320 (pU3.J