CN102944369A - Positive pressure leak hole calibration method - Google Patents

Abstract

The invention discloses a positive pressure leak hole calibration method, which belongs to the technical field of vacuum measurement. The method comprises the following steps that (1) a helium mass spectrum leak detector is preheated, and local air is respectively led into two gas collectors; (2) background signals IO of helium gas as leak indication gas in the gas collectors are read by the helium mass spectrum leak detector; (3) a standard positive pressure leak hole and a positive pressure leak hole to be calibrated are respectively put into the two gas collectors; (4) the leak indication gas flowing from the two positive pressure leak holes is accumulated in the gas collectors, and the start time tS1 and tL1 is respectively recorded; (5) after the leak indication gas flowing from the two positive pressure leak holes is accumulated in the gas collectors for a period of time, accumulating signals IS and IL of the leak indication gas in the two gas collectors are respectively read by the helium mass spectrum leak detector, and the end time tS2 and tL2 is recorded; and (6) the leak rate of the calibrated positive pressure leak hole is calculated. The method has the advantages of simplicity, easiness in implementation and low cost and can be applied to calibrated positive pressure leak holes with different orders of magnitude, the calibration range is extended, and the calibration efficiency and the calibration practicability on site are increased.

Description

A kind of method of calibrating positive pressure leak hole

Technical field

The present invention relates to a kind of method of calibrating positive pressure leak hole, belong to the vacuumatic measuring technical field.

Background technology

In document " design of constant pressure type positive pressure leak hole calibration device; " vacuum science and technology journal "; the 5th phase in 2007; the 442nd page～446 pages ", introduced a kind of method that adopts constant-voltage method calibration positive pressure leak hole, the method is directly introduced in the transfiguration chamber of constant-voltage method Pressure Leak Calibration Apparatus for the probe gas that positive pressure leak hole is flowed out, and changes the displacement of piston so that the volume of transfiguration chamber increases and the constant principle of assurance transfiguration room pressure, obtains the calibration of positive pressure leak hole.

When the weak point of this method was to calibrate, calibrating installation was complicated, and calibrating installation needs extract system, calibration system, TT﹠C system, and calibrating installation is with high content of technology, expensive, and researchist and operating personnel are had relatively high expectations.Secondly, only adopted constant-voltage method directly to calibrate positive pressure leak hole, the constant-voltage method calibration range is narrow.Again, can not be used for the scene and carry out large batch of calibration, only can use in the laboratory.

Summary of the invention

The object of the present invention is to provide a kind of method of calibrating positive pressure leak hole, described method calibration process is simple, and cost is low; What can be used in different magnitudes is corrected the pressure small opening, has extended calibration range; Can accumulate simultaneously many and be corrected the pressure small opening, save accumulated time, improve calibration efficiency; Improved the feasibility of calibrating under the site environment.

Purpose of the present invention is realized by following technical scheme:

A kind of method of calibrating positive pressure leak hole, described method step is as follows:

Step 1, helium mass spectrometer leak detector preheating are introduced local air in two gas collectors respectively, then seal two gas collectors;

Step 2, the helium mass spectrometer leak detector suction gun is inserted in any gas collector, read under the local atmospheric pressure background signal I of probe gas helium in the gas collector by helium mass spectrometer leak detector ₀

Step 3, with the standard positive pressure leak hole and be corrected and press small opening to put into respectively two gas collectors; Wherein, described standard positive pressure leak hole is same type with being corrected the pressure small opening, and the leak rate of standard positive pressure leak hole is known, and it is unknown to be corrected the leak rate of pressing small opening;

The probe gas of step 4, two positive pressure leak hole outflows begins accumulation in gas collector, respectively start-of-record moment t _S1And t _L1Wherein, t _S1Be the zero hour of standard positive pressure leak hole, t _L1For being corrected the zero hour of pressing small opening;

The probe gas of step 5, two positive pressure leak hole outflows is accumulated a period of time in gas collector after, read respectively probe gas accumulating signal I in two gas collectors with helium mass spectrometer leak detector _SAnd I _L, end of record (EOR) is t constantly _S2And t _L2I wherein _SBe the probe gas accumulating signal of standard positive pressure leak hole, I _LFor being corrected the probe gas accumulating signal of pressing small opening, t _S2Be the finish time of standard positive pressure leak hole, t _L2For being corrected the finish time of pressing small opening;

Step 6, calculating are calibrated the leak rate of positive pressure leak hole; The leak rate value is directly proportional with the probe gas signal magnitude with the product of accumulated time, has according to relative method:

$\frac{Q_L(t_{L2}-t_{L1})}{Q_S(t_{S2}-t_{S1})}=\frac{(I_L-I_0)}{(I_S-I_0)}$

Wherein, the leak rate of standard positive pressure leak hole is Q _S, being corrected and pressing the leak rate of small opening is Q _LThen

$Q_L=\frac{Q_S(I_L-I_0)}{(I_S-I_0)}\×\frac{(t_{S2}-t_{S1})}{(t_{L2}-t_{L1})}$

So far, finish the calibration of positive pressure leak hole.

Beneficial effect

(1) the method for the invention calibration process is simple, by field calibration, has avoided the different leak rate deviations that cause from calibration environment of site environment, be conducive to the correct use of positive pressure leak hole under the site environment, and cost is low.

(2) the method for the invention adopts the method for accumulation comparison to calibrate, and under the environment, by accumulating rear comparison standard positive pressure leak hole and being corrected the accumulating signal of pressing small opening, obtains being corrected the leak rate of pressing small opening at the scene, has improved the feasibility of calibration.

(3) the method for the invention can be selected the standard positive pressure leak hole of different magnitudes, and what be used for different magnitudes is corrected the pressure small opening, has extended calibration range.

(4) cycle the method for the invention alignment time weak point, the method that adopts accumulation to compare can be accumulated simultaneously many and is corrected the pressure small opening, can save accumulated time, improves calibration efficiency.

Description of drawings

Fig. 1 is the process flow diagram of the method for the invention.

Embodiment

Below in conjunction with the drawings and specific embodiments in detail the present invention is described in detail, but is not limited to this.

Embodiment 1

As shown in Figure 1, a kind of method of calibrating positive pressure leak hole, described method step is as follows:

Step 1, helium mass spectrometer leak detector preheating 3h introduce local air in two gas collectors respectively, then seal two gas collectors;

Step 2, the helium mass spectrometer leak detector suction gun is inserted in any gas collector, read under the local atmospheric pressure background signal I of probe gas helium in the gas collector by helium mass spectrometer leak detector ₀=1.05 * 10 ^-7Pa.m ³/ s;

Step 3, with the standard positive pressure leak hole and be corrected and press small opening to put into respectively two gas collectors; Wherein, described standard positive pressure leak hole is same type with being corrected the pressure small opening, and the leak rate of standard positive pressure leak hole is known, and it is unknown to be corrected the leak rate of pressing small opening;

The probe gas of step 4, two positive pressure leak hole outflows begins accumulation in gas collector, respectively the t zero hour of record standard positive pressure leak hole _S1Be 11: 15: 30 for 11:15:30(represents the time, implication is identical therewith for following time representation mode), be corrected the t zero hour that presses small opening _L1Be 11:20:30;

The probe gas of step 5, two positive pressure leak hole outflows is accumulated a period of time in gas collector after, read the probe gas accumulating signal I of standard positive pressure leak hole with helium mass spectrometer leak detector _S=2.32 * 10 ^-6Pa.m ³/ s, the t finish time of record standard positive pressure leak hole _S2Be 15:15:30, read and be corrected the probe gas accumulating signal I that presses small opening _L=3.35 * 10 ^-6Pa.m ³/ s, record is corrected the t finish time that presses small opening _L2Be 15:20:30;

Step 6, calculating are calibrated the leak rate of positive pressure leak hole; The leak rate value is directly proportional with the probe gas signal magnitude with the product of accumulated time, has according to relative method:

$\frac{Q_L(t_{L2}-t_{L1})}{Q_S(t_{S2}-t_{S1})}=\frac{(I_L-I_0)}{(I_S-I_0)}$

Wherein, the leak rate Q of standard positive pressure leak hole _S=4.72 * 10 ^-6Pa.m ³/ s, being corrected and pressing the leak rate of small opening is Q _LThen

$Q_L=\frac{Q_S(I_L-I_0)}{(I_S-I_0)}\•\frac{(t_{S2}-t_{S1})}{(t_{L2}-t_{L1})}=6.85{\×10}^{-6}\mathrm{Pa}.m^3/s$

So far, finish the calibration of positive pressure leak hole.

The present invention includes but be not limited to above embodiment, every any being equal to of carrying out under the principle of spirit of the present invention, replace or local improvement, all will be considered as within protection scope of the present invention.

Claims (1)

1. method of calibrating positive pressure leak hole, its feature exists: described method step is as follows:

Step 1, helium mass spectrometer leak detector preheating are introduced local air in two gas collectors respectively, then seal two gas collectors;

Step 2, the helium mass spectrometer leak detector suction gun is inserted in any gas collector, read under the local atmospheric pressure background signal I of probe gas helium in the gas collector by helium mass spectrometer leak detector ₀

Step 3, with the standard positive pressure leak hole and be corrected and press small opening to put into respectively two gas collectors; Wherein, described standard positive pressure leak hole is same type with being corrected the pressure small opening, and the leak rate of standard positive pressure leak hole is known, and it is unknown to be corrected the leak rate of pressing small opening;

The probe gas of step 4, two positive pressure leak hole outflows begins accumulation in gas collector, respectively start-of-record moment t _S1And t _L1Wherein, t _S1Be the zero hour of standard positive pressure leak hole, t _L1For being corrected the zero hour of pressing small opening;

The probe gas of step 5, two positive pressure leak hole outflows is accumulated a period of time in gas collector after, read respectively probe gas accumulating signal I in two gas collectors with helium mass spectrometer leak detector _SAnd I _L, end of record (EOR) is t constantly _S2And t _L2I wherein _SBe the probe gas accumulating signal of standard positive pressure leak hole, I _LFor being corrected the probe gas accumulating signal of pressing small opening, t _S2Be the finish time of standard positive pressure leak hole, t _L2For being corrected the finish time of pressing small opening;

Step 6, calculating are calibrated the leak rate of positive pressure leak hole; The leak rate value is directly proportional with the probe gas signal magnitude with the product of accumulated time, has according to relative method:

$\frac{Q_L(t_{L2}-t_{L1})}{Q_S(t_{S2}-t_{S1})}=\frac{(I_L-I_0)}{(I_S-I_0)}$

Wherein, the leak rate of standard positive pressure leak hole is Q _S, being corrected and pressing the leak rate of small opening is Q _LThen

$Q_L=\frac{Q_S(I_L-I_0)}{(I_S-I_0)}\×\frac{(t_{S2}-t_{S1})}{(t_{L2}-t_{L1})}.$

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