CN2087337U

CN2087337U - Micro-leakage measuring instrument

Info

Publication number: CN2087337U
Application number: CN 91200945
Authority: CN
Inventors: 王启浩; 俞惠琴; 张琳; 王洁高; 伍先达; 张维琦
Original assignee: High Tech Development Co Of Hefei Institute Of Intelligent Machinery Chinese Academy Of Sciences
Current assignee: High Tech Development Co Of Hefei Institute Of Intelligent Machinery Chinese Academy Of Sciences
Priority date: 1991-01-17
Filing date: 1991-01-17
Publication date: 1991-10-23

Abstract

The utility model discloses a micro-leakage measuring instrument which particularly is an instrument used for measuring the micro-leakage of a sealing device. The utility model is formed by a gas source 1, a pressure reduction valve 2, a three-way magnetic valve 3 and a three-way magnetic valve 4 which are connected in series and then divided into ways one of which is connected with a three-way magnetic valve 6 and an absolute pressure sensor 5 and connected with the measured object 11, the other way is connected with a three-way magnetic valve 7 and connected with a standard component 12. A differential pressure transducer 9 and a two-way magnetic valve 8 are connected between the measured component 11 and the standard component 12. The utility model solves the problems that the micro-leakage measuring lack of effective means, overcomes the defects of the existing micro-leakage measuring instrument, and is an ideal micro-leakage measuring instrument.

Description

Micro-leakage measuring instrument

The utility model is a kind of instrument of special test air locking sealing property, can be used for pipeline, the valve member of gas heater, the closed conduit of conditioning device for refrigerator, the test of sealing properties such as oil pump nozzle, ICL GOIM3/26.

About the detection of leaking, traditional method is: with U type pipe, the lifting of water column is judged and is had or not leakage in the U type pipe; Or the container after will pressurizeing immerses in the water, observes to have or not bubble to produce, and judges leakage with this.The advantage of these two kinds of methods is simple, and shortcoming is that low precision, work efficiency are low, and can not satisfy need of industrial production.

In order to measure micro-leakage more exactly, in the last few years, adopted mostly both at home and abroad " relative method ".Its basic structure as shown in Figure 1,1 among Fig. 1 is source of the gas, the 2nd, reduction valve, 3,4,5 all is three-way solenoid valve, the 6th, differential pressure pick-up, the 7th, anchor clamps, the 8th, measured piece, the 9th, be used for the comparative standard part, detection method is after pressurizeing, and is detected 8 leakage by differential pressure pick-up 6.Survey in this way and leak, though good than classic method, there is following shortcoming and defect:

1, because the pressure that detects decides by inflationtime, be subjected to the influence of factor such as source of the gas fluctuation in addition, make test pressure inconsistent, this has influenced the accuracy of testing.Though some leak detector has added absolute pressure sensor, control because of detect pressing to be still, thereby still fail to overcome this shortcoming by inflationtime.

2, bigger small opening is arranged when measured piece 8, or anchor clamps 7 do not clip measured piece 8, close at

valve

4,5 like this, begin before the test, the body of inflating has almost all leaked, and the test of this moment is to carry out under the situation of not having the pressure of detecting, and its testing result is worthless.

3, be connected on the test macro owing to being used for comparative standard part 9, and the body of inflating after each test, can not discharge fully, when instrument needed constantly test, residual gas was just compressed repeatedly, gas temperature raises in the instrument to making, thus the accuracy of influence test.

4, because the differential pressure pick-up 6 that is used for leaking hunting is worked under the unprotect condition, this makes differential pressure pick-up very easily damage.

In order to overcome the existing existing shortcoming of leak hunting instrument with not enough; In order to measure micro-leakage more accurately, the spy makes the utility model.

Basic skills of the present utility model is: will fill the gas of same pressure in a measured piece and the standard component with, at first measure and have or not gross leak, again measured piece and standard component are divided into two independent sectors, compare both pressure differentials, and determine the leakage rate of measured piece with this.

Below in conjunction with accompanying drawing, the utility model is illustrated it.

Accompanying drawing 2 is structural drawing of the present utility model, among the figure 1 is source of the gas, the 2nd, reduction valve, 3,4,6,7 all is three-way solenoid valves, the 8th, two-way electromagnetic valve, the 5th, absolute pressure sensor, the 9th, little differential pressure sensor, the 10th, anchor clamps, the 11st, measured piece, the 12nd, directly be connected in the standard component on the tester, the 13rd, single-chip microcomputer.

Source of the gas 1 of the present utility model is and reduction valve 2, and three-

way solenoid valve

3,4 is cascaded, and is divided into two-way then, and one the tunnel connects three-

way solenoid valve

6,6 and absolute pressure sensor 5 links, and three-way solenoid valve 6 connects measured piece 11 by anchor clamps 10 again; Another road connects three-

way solenoid valve

7,7 and connects standard component 12 again.Connecting differential pressure pick-up 9,2 three-way electromagnetic valves 8 in 12 in measured piece 11 and standard component is in parallel with differential pressure pick-up 9.Absolute pressure sensor 5 and differential pressure pick-up 9 link with single-chip microcomputer 13 respectively, and accompanying drawing 3 is connection layout.

During test, at first

open solenoid valve

3,4,6,7, source of the gas is by reduction valve 2, respectively to measured piece 11 and standard component 12 inflations, after absolute pressure sensor 5 gaging pressures reach predetermined value, variation of gas pressure in shut-off

valve

3,4, the whole pipeline of supervision if pressure has bigger variation, can conclude that then measured piece has than gross leak, at this moment, open valve 4, discharge gas, stop test.If pressure does not have bigger variation, then the no gross leak of explanation then needs shut-off

valve

6,7,8 at this moment, and measured piece 11 and standard component 12 are divided into two independent sectors, and the variation of differential pressure pick-up 9 shows the sealing property of measured piece, and can show intuitively by single-chip microcomputer 13.After the end of test (EOT),

open valve

4,6,7,8, the gas in the instrument is discharged by valve 4; Unclamp anchor clamps then, take out measured piece, end of test (EOT).

Because the utility model adopts absolute pressure sensor 5 and three-way solenoid valve 6 to link, make the absolute pressure in the pipeline be in monitored condition all the time, detect to press and controlled by the output of absolute pressure sensor 5, this has been avoided controlling this shortcoming of pressure measurement by inflationtime;

Because absolute pressure sensor 5 is connected in the pipeline, can know pressure and variation thereof in the preceding pipeline of test, this has been avoided not having the blindness test that detects under the pressure situation;

Owing to adopted three-way solenoid valve 4, make before each test, to drain gas in the standard component 12, avoided arranging to go out not compressed repeatedly because of gas, influence the shortcoming of measuring accuracy to elevating the temperature;

Because two-way electromagnetic valve 8 is protection differential pressure pick-ups 9, this makes differential pressure pick-up 9 be in " short circuit " always, have only when the leak hunting instrument operate as normal, and measured piece 9 is just started working when not having than gross leak.This has fundamentally protected differential pressure pick-up.Two-way electromagnetic valve 8 can also quicken the discharge of gas in the standard component 12 in addition.

In a word, the utility model has solved micro-leakage and has detected this difficult problem of shortage effective means.Not only safety has overcome the defective that existing leak hunting instrument exists, also owing to selected homemade little differential pressure sensor for use, and solved dosimetric sensors flimsy difficult problem under big static pressure effectively, reduced micro-leak detector cost, prolonged serviceable life of instrument, be a kind of desirable micro-leakage tester.

Claims

1, a kind of micro-leakage tester of forming by source of the gas, reduction valve, three-way solenoid valve, differential pressure pick-up, anchor clamps etc., it is characterized in that, two three-way solenoid valves of series connection on source of the gas and the reduction valve, be divided into two-way then, one the tunnel connects a three-way solenoid valve that links with absolute pressure sensor, and links by anchor clamps and measured piece; Another road connects a three-way solenoid valve, links differential pressure pick-up that links to each other with two-way electromagnetic valve in parallel between measured piece and standard component with standard component.