CN1083575C

CN1083575C - Helium leakage detector

Info

Publication number: CN1083575C
Application number: CN96106153A
Authority: CN
Inventors: 冈本英树
Original assignee: Shimadzu Corp
Current assignee: Shimadzu Corp
Priority date: 1995-06-26
Filing date: 1996-04-26
Publication date: 2002-04-24
Anticipated expiration: 2016-04-26
Also published as: CN1142605A; JPH0915082A; KR970002277A; JP3358394B2; KR100217434B1; TW293086B

Abstract

To resume the leak test effectively by lowering the background level at a mass spectrometric section quickly even when a large quantity of He is mixed into an oil in an oil-sealed rotary vacuum pump due to gross leak. When a measurement at a mass spectrometric section ANAL exceeds a threshold level, a microcomputer unit 14 judges that gross leak has occurred, and controls a solenoid valve GBV fixed to the gas ballast port 21 of an RP2 to open for a predetermined time. Consequently, atmospheric air is introduced through the gas ballast port 21 into the RP2 and He bubbles in the oil are stirred to be discharged quickly through the RP2. Since no He is discharged again from the RP2, the problem of increasing background level at the mass spectrometric section ANAL is solved.

Description

Helium leak detector

Used helium leak detector when the present invention relates to carry out leakage check or airtight inspection.

Check that pipeline has or not when leaking, helium leak detector is a kind of effective means.

As shown in Figure 3, this device has the ANAL of quality analysis portion that only detects helium (He), be provided on the position that all can vacuumize this ANAL of quality analysis portion and detected body EXP turbomolecular pump (TMP) 1 as main pump, play the oily rotary vacuum pump (RP) 2 of the backing pump effect of this TMP1, simultaneously, configuration detection valve TV between detected body EXP and TMP1, configuration blocked valve FV between TMP1 and RP2, and then, configuration intermediate valve BV on the direct piping of detected body EXP and RP2.Among the figure, TP is used for the detection mouth of the detected body EXP of device loading and unloading relatively.

The leak test of this device is undertaken by following order.At first keep intermediate valve BV and detection valve TV to close, blocked valve FV opens, and starts TMP1 and RP2, thus the ANAL of quality analysis portion is pumped to predetermined vacuum tightness.Thick line among Fig. 4 is represented the position of bleeding.Secondly, detected body is connected to a detection mouthful TP, changes maintenance detection valve TV and blocked valve FV into and close, intermediate valve BV opens, and shown in thick line among Fig. 5, detected body EXP is pumped to predetermined vacuum tightness by RP2.Then, close, detect valve TV and blocked valve and open, constitute the circuit of bleeding shown in Fig. 6 thick line by keeping intermediate valve BV, the He gas blowout to detected body EXP.At this moment, if detected body EXP has leakage, the part of He overflows into the ANAL of quality analysis portion, detects with this and leaks roughly proportional He, and consequently the air tightness of body EXP is test in indirect determination.

; when having a large amount of He, detected body EXP leaks under the situation of (being called serious leakage); when hunting leak thereafter; can not make the background values (zero point) of the He in the ANAL of quality analysis portion enough low, often cause also being judged to the state that can not carry out efficiency test of bad product and so on thus without any the good detected body EXP of problem.

Trace it to its cause, verified is because during serious the leakage, the air of He very high concentrations is sucked among the RP2 as the running of the backing pump of TMP1 in a large number, this moment, He dissolved in the oil of RP2, and the bubble that has dissolved in He is overflowed from air entry at any time, and flow backward to the ANAL of quality analysis portion, background values is risen.

In order to eliminate this defective, can consider with the running that stops whole device, the oil of RP2 is replaced by new oily this way handles.But do like this, whole device elongates prestarting once more stop time, and is big to the work efficiency influence of device, safeguards aspect also very big expense of necessaryization expense and labour.

The present invention is conceived to above-mentioned problem and constitutes, its purpose is to provide a kind of helium leak detector, when this sniffer is sneaked into a large amount of He in the oil of oily rotary vacuum pump, also can evacuate this oil rapidly, the background values of quality analysis portion is reduced rapidly, can restart Leak Detection effectively.

In order to achieve the above object, the present invention adopts following formation.

That is, helium leak detector of the present invention comprises: the main pump that only detects the quality analysis portion of helium, all can vacuumize this quality analysis portion and detected body, the oily rotary vacuum pump that works as the backing pump of this main pump; It is characterized in that, on described oily rotary vacuum pump, have town's gas port, the solenoid valve of switch selectively is set on described town gas port, simultaneously, be provided with when the helium measured value of measuring with quality analysis portion surpasses predetermined threshold value, control described solenoid valve and keep certain hour control of turning means.

In the above-described configuration, if the value corresponding to serious leakage is set at threshold value, then actually produce serious the leakage and after sucking a large amount of He in the oily rotary vacuum pump, even He dissolves in the oil, because the helium measured value of quality analysis portion surpasses threshold value, the control device action, control the subsidiary solenoid valve maintenance certain hour unlatching that is provided with on the oily rotary vacuum pump town gas port, in oily rotary vacuum pump, import atmosphere, the beating action of the He that dissolves in the bubble state in the oil by atmosphere stir oil in the oily rotary vacuum pump by atmosphere, so also can quicken to discharge.Thus, the He concentration in the oil descends rapidly, even restart Leak Detection thereafter, also because of the He burst size from oily rotary vacuum pump significantly reduces, He overflows into quality analysis portion and the defective of background values rising can greatly be improved.And, according to the present invention, therebetween, the oil rotary vacuum pump is from self-evident, even the running of other device part such as quality analysis portion and high vacuum pump also needn't stop, thereby can big harmful effect not arranged to the continuous behavior in service of system, leak after the short time can be restarted Leak Detection with remaining valid serious.

Fig. 1 is the loop diagram of one embodiment of the invention.

Fig. 2 is the summary section of the oily rotary vacuum pump that adopts in the foregoing description.

Fig. 3 be with shown in the loop diagram of the corresponding example in the past of Fig. 1.

Fig. 4 is the figure of Leak Detection general sequence in the key diagram 3.

Fig. 5 is the figure of Leak Detection general sequence among Fig. 3.

Fig. 6 is the figure of Leak Detection general sequence among Fig. 3.

Among the figure, ANAL is a quality analysis portion, and EXP is detected body, and GBV is a solenoid valve, and 1 is main pump (turbomolecular pump; TMP), 2 is oily rotary vacuum pump (RP), and 4 is control device (microcomputer unit), and 21 are town's gas port.

Below, with reference to the description of drawings one embodiment of the invention.

The helium leak detector that is shown in Fig. 1 is basic identical with the formation that is shown in Fig. 3.Promptly, it also has: the ANAL of quality analysis portion that only detects helium (He), be provided on the position that all can vacuumize turbomolecular pump (TMP) 1 as main pump to this ANAL of quality analysis portion and detected body EXP, the oily rotary vacuum pump (RP) 2 that works as the backing pump of this TMP1, simultaneously, configuration detection valve TV between detected body EXP and TMP1, configuration blocked valve FV between TMP1 and RP2, and then, at detected body EXP and the straight-through pipeline intermediate configurations intermediate valve BV of RP2.

Again, also the order with the prior art of Fig. 4 to Fig. 6 explanation is identical for the order of Leak Detection.At first, keep intermediate valve BV and detection valve TV to close, blocked valve FV opens, and by starting TMP1 and RP2 the ANAL of quality analysis portion is evacuated to predetermined vacuum level (referring to Fig. 4).Secondly, detected body EXP is connected to a detection mouthful TP, changes maintenance detection valve TV and blocked valve FV into and close, intermediate valve BV opens, and by RP2 detected body EXP is evacuated to predetermined vacuum level (referring to Fig. 5).Then, keep intermediate valve BV to close, detect valve TV and blocked valve FV and open, the He gas blowout to detected body EXP (with reference to Fig. 6).At this moment, if in the detected body leakage is arranged, the part of He overflows into to the ANAL of quality analysis portion, detects and the roughly proportional He of leakage, gets final product the rate of pressurization of the detected body EXP of indirect determination.

Hereinbefore, vacuum seal imprecision and even damage when the sealing of detected body EXP and the junction of envelope close state extreme difference, detected body EXP and rough turning pipeline (detecting a mouthful TP part), and when a large amount of He taking place leaking (the serious leakage), take to stop fast the measure of detection by other sequential control, at this moment as sucking the air of a large amount of He very high concentrations among the RP2 of the backing pump of TMP1 running, thereby dissolve in He in the oil of RP2.Thus, when restarting Leak Detection after serious the leakage, the He bubble that has dissolved in discharges from air entry simultaneously once more, and blows back into the ANAL of quality analysis portion, background values is risen, and become the state that in fact Leak Detection can not be proceeded.

Therefore, present embodiment has town's gas port 21 on RP2, selectively atmosphere is imported this town's gas port 21, to address the aforementioned drawbacks.

Details are as follows, the aspiration pump that this RP2 plays a part to know, that is: as shown in Figure 2, eccentric position in cylinder 22 is with the interior state configuration rotor 23 that connects, the extended indentation of radial direction be contained in all sliding contacts in the top of blade 24 of rotor 23 and the cylinder 22, filling pump oil among the pump chamber P that is separated by cylinder 22, rotor 23, blade 24 drives rotor 23 by rotation, the gas that compression on one side sucks from air entry 25 is Yi Bian be sent to exhausr port 26.Again, what suppose to extract out is that water vapour and so on is when having the gas of condensability, because pressure gas liquefaction, for the overall performance of the pump that prevents to cause thus worsens, illustrated RP2 has town's gas port 21 near exhausr port 26, before the gas compression, import atmosphere by this town's gas port 21, possess the function that does not improve dividing potential drop and bleed.

In the present embodiment, on this town's gas port 21, switchably attach solenoid valve GBV is set, simultaneously, by microcomputer unit this solenoid valve of 4 gauge tap GBV as control device of the present invention.

Solenoid valve GBV is conventional valve, can have town's gas port 21 at least by the electric signal of importing and selectively switch and state of remaining on out or off status.

Microcomputer unit 4 is the known computer that possess CPU, memory and interface etc., in memory, store preset program, after the ANAL of quality analysis portion input measured value S, the comparison of stipulating, computing, output switching signal a is to above-mentioned solenoid valve GBV according to this program for CPU.

Below, according to the order of this program description control.At ordinary times, solenoid valve GBV keeps closed condition.CPU periodically compares the measured value S from the ANAL of quality analysis portion input with the threshold value S0 that is scheduled to.This threshold value S0 is set at certain value that the He above allowance in the RP2 may import, and promptly is set at and the serious corresponding measured value of leakiness.Again, when the measured value S that is judged as input surpasses this threshold value S0, then be judged to be serious leakage, make above-mentioned solenoid valve GBV keep the certain hour opening.Thus, through town's gas port 21, a large amount of atmosphere are imported in the pump chamber P of RP2 from outside.During serious the leakage, a large amount of He are sucked into the pump chamber P of RP2, and it dissolves in the oil with bubble form.This He is stirred in inside by the atmosphere that imports through town's gas port 21, thereby the beating action of He by this atmosphere quickens to be discharged by exhausr port 26.Thus, the He concentration in the oil reduces rapidly, even after this restart Leak Detection, also because of the He burst size from RP2 significantly reduces, He overflows into the ANAL of quality analysis portion and the defective of background values rising can greatly be improved.And, according to present embodiment, during this period, RP2 is from self-evident, even other device part such as ANAL of quality analysis portion and TMP1 also needn't shut down, thereby the continuous runnability of device can not be subjected to big harmful effect, can leak after the utmost point short time is just restarted Leak Detection with remaining valid serious.In addition, above-mentioned control is all carried out automatically, thereby even the user of lack of knowledge, also operating control suitably can improve the utilization factor and the degree easy to use of device effectively.

Again, the concrete formation of each several part is not limited to the foregoing description, does not break away from essential scope of the present invention, can make all variations.

Helium leak detector of the present invention because above-mentioned formation is arranged, when serious the leakage taken place, detects this situation, within a certain period of time atmosphere is imported in the oily rotary vacuum pump, by stirring, thereby can discharge the He that dissolves in the oil fast.Thus,, also can remain on low value to the background values of quality analysis portion, can hunt leak effectively even after serious the leakage, restart Leak Detection.And, do not damage continued operation therebetween, even uncomfortable operator operates this device, also can recover automatically, thereby have and can improve the work efficiency of device and the excellent results of performance easy to use effectively from serious leakage.

Claims

1. helium leak detector comprises: only detect helium quality analysis portion, to quality analysis portion and detected body all can carry out vacuum suction main pump, play the oily rotary vacuum pump of the backing pump effect of this main pump; It is characterized in that, on described oily rotary vacuum pump, have town's gas port, on this town's gas port, the solenoid valve of switch selectively is set, simultaneously, be provided with when the helium measured value of measuring with described quality analysis portion surpasses the threshold value of being scheduled to, make described solenoid valve maintenance certain hour control of turning means.