SU1312425A1 - Device for checking gas flow - Google Patents

Abstract

The invention relates to a device for monitoring leaktightness and improves the reliability of monitoring by eliminating the effect of residual bubbles. Transparent sealed vessel 1 is partially filled with liquid. The inlet tube 2 is connected to the vessel 1 below the liquid level, and the inlet pipe 3 is above the liquid level. The source 4 of the light and the photodetector 5 are located on the same level and installed above the cut-off of the tube 2 of the input. at a distance d selected from the condition d y 12 rff / gn, where 6 is the coefficient of surface tension of the liquid, p is the density of the liquid, t is the radius of the lead-in tube 2, and g is the acceleration of free fall, which ensures reliable recording of the separated bubble at any the slope of the vessel 1. The tube 3 of the output is connected with the product under test, the tube 2 of the input is connected to the reference capacitance. In the process of monitoring, the number of bubbles during the monitoring time is recorded by the photodetector 5. 1 il. (L C II. O N0 J SD CL 6YHO5

Description

one

The invention relates to a testing technique and can be used to monitor the tightness of hollow articles, as well as to control the roughness.

The purpose of the invention is to increase the reliability of control by eliminating the influence of residual gas bubbles and reliable recognition of large flows.

The drawing shows a diagram of the device.

The device for controlling the gas flow rate contains a transparent hermetic vessel 1, partially filled with liquid, an input tube 2 and an output tube 3, a light source 4, for example, an AL107B LED, and a photodetector 5, for example, a FDZ photodiode.

The light source 4 and the photodetector are located on the same level and are installed above the tube cutoff 2 of the input at a distance d chosen from the condition

d, gp

where 0 is the surface coefficient

fluid tension, P is the density of the fluid, g is the radius of the inlet tube 2, g is the acceleration of free fall. The inlet tube 2 is connected to the vessel 1 below the liquid level, and the inlet pipe 3 is above the liquid level.

V. The moment of detachment from the cut-off of the tube 2, the insertion of an Archimedes force acting on the air bubble is balanced by the force of the surface tension of the liquid. The puffed air of a spherical shape formed when it is detached has a volume

V

H

 where d is the diameter of the bubble.

So the power of Archimedes

 ,

where p is the density of the liquid;

g - free fall acceleration; Surface tension force

F 2 5T gb-,

where g is the radius of the tube 2 input;

b - surface coefficient

tensioning the fluid. Thus, the ratio

2 5T g (5

 1. a p

g

and distance

on which the light beam is located relative to the cut-off of the input tube 2

  gp

The location of the light beam above the cut-off of the insertion tube 2 at the indicated distance leads to the fact that the light beam remains for the monitoring time completely blocked only when the controlled air flow has a magnitude, moreover, the deviation of the bubble rise trajectory to the surface of the liquid the possible inclination of the transparent vessel does not affect the reliability of the registration of bubbles by the photodetector 5.

In the case of leak testing, the test article is connected to the lead tube 3, the lead tube 2 is connected to a sealed reference container.

The device DP control gas flow when testing for tightness works as follows.

In preparation for testing, the reference tank and the test product are pressurized with air, and the pressure in the reference tank must slightly exceed the pressure in the test product to compensate for capillary effects in tube 2 of the inlet.

Then the compressed air supply to the izelie and reference tank is stopped. The reference container remains connected through the inlet tube 2, the vessel 1, the outlet tube 3 with controlled isielia.

 If the product is leaking, the air pressure in it is reduced due to leaks. Air begins to flow from the reference tank through the inlet tube 2, vessel 1, outlet pipe 3 into the product, which leads to the appearance of air bubbles in vessel 1.

Since the surface of the air bubble has the ability to reflect light, the light beam from the light source 4 to the photodetector 5 is blocked by the appearance of air bubbles. The tightness of the product is judged by the number of electrical pulses at the output of the photodetector 5, counted, for example, by using an electric pulse counter.

31312425

If the photoreceiver 5 detects the overlap of the light beam for a time longer than necessary for a single bubble rising to the surface of the liquid at a known speed, this situation is classified 5 as having an air jet

ha

d gi not ti not

in vessel 1, i.e. large leakage from a controlled product.

In the case of control of the roughness, the lead-in tube 2 is connected to a source of compressed air, and the tube 3 of the bore is connected to the measuring nozzle, which must be pressed without clearance to the test surface. Due to the fact that the surface of the product has microroughness, air flows through the tube 2 of the inlet, the vessel 1, the tube 3 of the probe and the measuring nozzle into the atmosphere, the roughness of the test surface is judged by the number of air bubbles in the vessel 1,

The invention makes it possible to eliminate the effect of residual bubbles on the measurement results, as well as to detect large leaks.

Editor A. Sabo Order 1964/40

Compiled by L.Vihl ev

Tehred L. Oliynyk Proofreader S. Cherni

Circulation 777 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., d, 4/5

Production and printing company, Uzhgorod, Projecto st., 4.

Claims (1)

Invention Formula A device for controlling gas flow, containing a transparent sealed vessel, partially filled with liquid, a gas inlet tube connected to the vessel below the liquid level, a tube out of the vessel connected to the vessel above the liquid level, a light source and a photodetector located on the outside of the vessel at the same level from its diametrically opposite sides, I differ. w; e with the fact that, in order to increase authenticity, light source and photo. the transceiver is installed above the end of the input tube at a distance d chosen from the conditions d 12GG where b is the surface coefficient fluid tension; P is the density of the liquid; g is the radius of the input tube; g - free fall acceleration.