CN114636517A - Constant-pressure positive-pressure leak hole calibration device and test method thereof - Google Patents
Constant-pressure positive-pressure leak hole calibration device and test method thereof Download PDFInfo
- Publication number
- CN114636517A CN114636517A CN202110366382.XA CN202110366382A CN114636517A CN 114636517 A CN114636517 A CN 114636517A CN 202110366382 A CN202110366382 A CN 202110366382A CN 114636517 A CN114636517 A CN 114636517A
- Authority
- CN
- China
- Prior art keywords
- piston
- motor
- pressure
- mounting plate
- leak hole
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000010998 test method Methods 0.000 title claims description 8
- 238000005259 measurement Methods 0.000 claims abstract description 32
- 238000012360 testing method Methods 0.000 claims abstract description 20
- 238000006073 displacement reaction Methods 0.000 claims description 14
- 238000000034 method Methods 0.000 claims description 4
- 238000001514 detection method Methods 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 239000001307 helium Substances 0.000 description 2
- 229910052734 helium Inorganic materials 0.000 description 2
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 1
- 229910052736 halogen Inorganic materials 0.000 description 1
- 150000002367 halogens Chemical class 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005057 refrigeration Methods 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M3/00—Investigating fluid-tightness of structures
- G01M3/007—Leak detector calibration, standard leaks
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M3/00—Investigating fluid-tightness of structures
- G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
- G01M3/26—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measuring Fluid Pressure (AREA)
Abstract
The application discloses a constant-pressure positive-pressure leak hole calibration device which comprises a reference end, a measurement end and a first equivalent component, wherein a capacitance film gauge for measuring the pressure difference between the reference end and the measurement end is arranged between the reference end and the measurement end, and the first equivalent component is communicated with the measurement end; the measuring device is characterized in that the reference end is provided with a deflation valve, the measuring end is provided with a test valve, and an isolating valve is arranged between the reference end and the measuring end. This application has the effect that improves measuring precision.
Description
Technical Field
The application relates to the technical field of leak hole calibration measurement, in particular to a constant-pressure positive-pressure leak hole calibration device and a test method thereof.
Background
Standard orifices have two forms: one is a vacuum standard leak hole, one end of which is vacuum and the other end is leakage indicating gas in a pressurized state; in another type, the leak hole has one end at atmospheric pressure and the other end higher than one atmospheric pressure, and is often called a positive pressure standard leak hole. The former leak orifice is mostly used for calibrating a helium mass spectrometer leak detector; the latter is often used in calibrating halogen leak detectors and helium mass spectrometers.
At present, positive pressure leak detection is widely adopted in the industries of refrigeration, machinery, automobile manufacturing and the like due to the advantages of convenient operation, portability, low leak detection cost and the like. The positive pressure leak hole is used for calibrating the sensitivity of the positive pressure leak detector, and the uncertainty of leak rate calibration directly relates to the sensitivity of the leak detector and the effectiveness of leak detection. The calibration standard of the leak of many national standards at home and abroad at present comprises a calibration method and a corresponding device for the positive pressure leak. But there is a need to improve the measurement accuracy.
Disclosure of Invention
In order to improve the measuring precision, the application provides a constant pressure positive pressure leak hole calibrating device, still provides a constant pressure positive pressure leak hole calibrating device's test method.
The technical scheme of one purpose is as follows: a constant-pressure positive-pressure leak hole calibration device comprises a reference end, a measurement end and a first equivalent component, wherein a capacitance film gauge for measuring the pressure difference between the reference end and the measurement end is arranged between the reference end and the measurement end, and the first equivalent component is communicated with the measurement end;
the measuring device is characterized in that the reference end is provided with a deflation valve, the measuring end is provided with a test valve, and an isolating valve is arranged between the reference end and the measuring end.
As a preferred technical solution, the first equivalent assembly includes a first piston, a first displacement sensor, a first motor and a first mounting plate, a piston rod of the first piston is fixed on the first mounting plate, the first motor is fixed on the first mounting plate, and the first displacement sensor is fixed on the first mounting plate; a first screw rod is fixed on a motor shaft of the first motor, and the first piston is connected to the first screw rod in a sliding mode.
As a preferred technical solution, the first equivalent assembly further includes two first limiting plates for limiting a movement range of the first piston, and the two first limiting plates are respectively fixed on two sides of the first mounting plate.
As a preferred technical solution, the measuring device further includes a capacity expansion assembly for expanding the measurement range, the capacity expansion assembly includes two capacity expansion chambers, one of the capacity expansion chambers is communicated with the reference end, and the other capacity expansion chamber is communicated with the measurement end.
As a preferred technical solution, the expansion assembly further includes two expansion valves, one of the expansion valves is installed between the expansion chamber and the reference end, and the other of the expansion valves is installed between the expansion chamber and the measurement end.
As a preferable technical scheme, the measuring end is also communicated with a second equivalent component for expanding the measuring range.
As a preferred technical solution, the second equivalent assembly includes a second piston, a second displacement sensor, a second motor and a second mounting plate, a piston rod of the second piston is fixed on the second mounting plate, the second motor is fixed on the second mounting plate, and the second displacement sensor is fixed on the second mounting plate;
and a second screw rod is fixed on a motor shaft of the second motor, and the second piston is connected to the second screw rod in a sliding manner.
As a preferred technical solution, the second equivalent assembly further includes two second limiting plates for limiting a moving range of the second piston, and the two second limiting plates are respectively fixed on two sides of the second mounting plate.
The second technical proposal is that: s1, opening a deflation valve, a test valve and an isolation valve, wherein the number displayed on the capacitance film gauge is zero;
s2, closing the air release valve and the isolating valve, opening the test valve, and displaying the number on the capacitance film gauge as a positive value;
s3, starting a first motor, wherein the first motor drives a first screw rod to rotate, and the rotation of the first screw rod drives a first piston to move;
s4, opening two expansion valves when the measurement is in a larger range;
and S5, starting a second motor, driving a second screw rod to rotate by the second motor, and driving a second piston to move by the rotation of the second screw rod.
As a preferred embodiment, Q ═ P0 · X · a · T τ/T · Δ T (1)
In the formula: q-the leakage rate of the standard leak hole, unit Pa.m 3/s;
p0 — calibrate the absolute pressure in the chamber at t1, (which can be replaced by the local atmospheric pressure at t1), in Pa;
a- -piston rod cross-sectional area, unit m 2;
x- -piston travel distance (L2-L1), in m;
t tau- -reference temperature of standard leak, in K;
t- -ambient temperature, in K;
Δ t- -the time interval (t2-t1) at which calibration begins and ends, in units of 1.
Has the advantages that:
(1) the invention provides a constant-pressure positive-pressure leak hole calibration device and a test method thereof.A first equivalent component is adopted to replace the pressure change in a measurement end, so that the measurement result is more accurate, and the measurement accuracy is realized; by arranging the capacity expansion assembly, the measurement range of the equipment is improved, and the adaptability of the equipment is improved; by arranging the second equivalent component, the measuring range of the device is enlarged.
(1) The invention provides a constant-pressure positive-pressure leak hole calibration device and a test method thereof.A reference end is creatively arranged, and the traditional absolute pressure test is changed into a relative pressure difference test between the test end and the reference end, so that the test error is greatly reduced, the uncertainty of the test result is reduced, and the uncertainty of the test value of the device can reach 3-4%.
(2) The volume constant is introduced into the testing method, the working principle of the capacitance film gauge is fully utilized, namely the quantity of gas leaked into the device and the pressure indication value of the capacitance film gauge accord with a linear relation, the linear error of the capacitance film gauge is not more than 0.3 percent of the indication value, the requirement of positive pressure leak hole leak rate calibration can be met, the determined volume of a gas pipeline in the measuring device is not needed after the volume constant is introduced, the volume change value is used for replacing the volume change value, the error of volume measurement is prevented from being introduced into the calculation result, and the testing error of the leak rate is greatly reduced.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic structural diagram of an embodiment of the present application.
Reference numerals: 1. a reference terminal; 11. a deflation valve; 2. a measuring end; 21. a test valve; 3. a capacitance film gauge; 4. a first equivalent assembly; 41. a first piston; 42. a first displacement sensor; 43. a first motor; 431. a first lead screw; 44. a first mounting plate; 45. a first limit plate; 5. a second equivalent element; 51. a second piston; 52. a second displacement sensor; 53. a second motor; 531. a second lead screw; 54. a second mounting plate; 55. a second limiting plate; 6. a capacity expansion component; 61. a flash chamber; 62. a capacity expansion valve; 7. a block valve.
Detailed Description
The disclosure of the present application may be understood more readily by reference to the following detailed description of preferred embodiments of the application and the examples included therein. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. In case of conflict, the present specification, including definitions, will control.
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
Referring to fig. 1, the constant-pressure positive-pressure leak hole calibration device comprises a reference end 1, a measurement end 2 and a first equivalent component 4, wherein a capacitance film gauge 3 for measuring the pressure difference between the reference end 1 and the measurement end 2 is arranged between the reference end 1 and the measurement end 2, and the first equivalent component 4 is communicated with the measurement end 2; the reference end 1 is provided with a deflation valve 11, the measurement end 2 is provided with a test valve 21, and an isolating valve 7 is arranged between the reference end 1 and the measurement end 2.
The first equivalent assembly 4 comprises a first piston 41, a first displacement sensor 42, a first motor 43 and a first mounting plate 44, the piston rod of the first piston 41 is fixed on the first mounting plate 44, the first motor 43 is fixed on the first mounting plate 44, and the first displacement sensor 42 is fixed on the first mounting plate 44; a first lead screw 431 is fixed on a motor shaft of the first motor 43, and the first piston 41 is slidably connected to the first lead screw 431.
The first equivalent assembly 4 further includes two first limiting plates 45 for limiting the moving range of the first piston 41, and the two first limiting plates 45 are respectively fixed on both sides of the first mounting plate 44.
The device further comprises a capacity expansion assembly 6 for expanding the measurement range, wherein the capacity expansion assembly 6 comprises two capacity expansion chambers 61, one capacity expansion chamber 61 is communicated with the reference end 1, and the other capacity expansion chamber 61 is communicated with the measurement end 2.
The flash module 6 further includes two flash valves 62, one flash valve 62 is installed between the flash chamber 61 and the reference end 1, and the other flash valve 62 is installed between the flash chamber 61 and the measurement end 2.
The measuring end 2 is also communicated with a second equivalent component 5 for expanding the measuring range.
The second equivalent assembly 5 comprises a second piston 51, a second displacement sensor 52, a second motor 53 and a second mounting plate 54, wherein the piston rod of the second piston 51 is fixed on the second mounting plate 54, the second motor 53 is fixed on the second mounting plate 54, and the second displacement sensor 52 is fixed on the second piston 51; a second screw 531 is fixed on a motor shaft of the second motor 53, and the second piston 51 is slidably connected to the second screw 531.
The second equivalent 5 further includes two second limit plates 55 for limiting the moving range of the second piston 51, and the two second limit plates 55 are fixed to both sides of the second mounting plate 54, respectively.
A test method of a constant-pressure positive-pressure leak hole calibration device is completed by adopting the constant-pressure positive-pressure leak hole calibration device and comprises the following steps:
s1, opening the atmosphere valve 11, the test valve 21 and the isolating valve 7, wherein the number displayed on the capacitance film gauge 3 is zero;
s2, closing the atmospheric valve 11 and the isolating valve 7, opening the test valve 21, and displaying the number on the capacitance film gauge 3 as a positive value;
s3, starting the first motor 43, wherein the first motor 43 drives the first lead screw 431 to rotate, and the rotation of the first lead screw 431 drives the first piston 41 to move;
s4, when the measurement is in a larger range, opening the two expansion valves 62;
s5, the second motor 53 is started, the second motor 53 drives the second lead screw 531 to rotate, and the rotation of the second lead screw 531 drives the second piston 51 to move.
Q＝P0·X·A·Tτ/T·Δt(1)
In the formula: q-the leakage rate of the standard leak hole, unit Pa.m 3/s;
p0 — calibrate the absolute pressure in the chamber at t1, (which can be replaced by the local atmospheric pressure at t1, in Pa;
a- -piston rod cross-sectional area, unit m 2;
x- -piston travel distance (L2-L1), in m;
t tau- -reference temperature of standard leak, in K;
t- -ambient temperature, in K;
Δ t- -the time interval t2-t1 at which calibration begins and ends, in 1.
The foregoing examples are merely illustrative and serve to explain some of the features of the methods described herein. The appended claims are intended to claim as broad a scope as is contemplated, and the examples presented herein are merely illustrative of selected implementations in accordance with all possible combinations of examples. Accordingly, it is applicants' intention that the appended claims are not to be limited by the choice of examples illustrating features of the present application. Also, where numerical ranges are used in the claims, subranges therein are included, and variations in these ranges are also to be construed as possible being covered by the appended claims.
Claims (10)
1. The utility model provides a constant pressure malleation small opening calibrating device which characterized in that: the device comprises a reference end (1), a measuring end (2) and a first equivalent component (4), wherein a capacitance film gauge (3) for measuring the pressure difference between the reference end (1) and the measuring end (2) is arranged between the reference end and the measuring end, and the first equivalent component (4) is communicated with the measuring end (2);
the device is characterized in that a deflation valve (11) is arranged on the reference end (1), a test valve (21) is arranged on the measurement end (2), and an isolating valve (7) is arranged between the reference end (1) and the measurement end (2).
2. The apparatus according to claim 1, wherein the constant pressure positive pressure leak hole calibration device comprises: the first equivalent assembly (4) comprises a first piston (41), a first displacement sensor (42), a first motor (43) and a first mounting plate (44), a piston rod of the first piston (41) is fixed on the first mounting plate (44), the first motor (43) is fixed on the first mounting plate (44), and the first displacement sensor (42) is fixed on the first mounting plate (44);
a first screw rod (431) is fixed on a motor shaft of the first motor (43), and the first piston (41) is connected to the first screw rod (431) in a sliding mode.
3. The apparatus according to claim 2, wherein: the first equivalent assembly (4) further comprises two first limiting plates (45) used for limiting the moving range of the first piston (41), and the two first limiting plates (45) are respectively fixed on two sides of the first mounting plate (44).
4. The apparatus according to claim 1, wherein the constant pressure positive pressure leak hole calibration device comprises: still including dilatation subassembly (6) that enlarge measuring range, dilatation subassembly (6) include two dilatation rooms (61), one dilatation room (61) intercommunication is in reference end (1), another dilatation room (61) intercommunication is in measuring end (2).
5. The apparatus according to claim 4, wherein: the dilatation subassembly (6) still includes two dilatation valves (62), one dilatation valve (62) are installed between dilatation room (61) and reference end (1), another dilatation valve (62) are installed between dilatation room (61) and measuring end (2).
6. The apparatus according to claim 5, wherein the constant pressure positive pressure leak hole calibration device comprises: and the measuring end (2) is also communicated with a second equivalent component (5) for expanding the measuring range.
7. The apparatus according to claim 6, wherein the constant pressure positive pressure leak hole calibration device comprises: the second equivalent assembly (5) comprises a second piston (51), a second displacement sensor (52), a second motor (53) and a second mounting plate (54), a piston rod of the second piston (51) is fixed on the second mounting plate (54), the second motor (53) is fixed on the second mounting plate (54), and the second displacement sensor (52) is fixed on the second mounting plate (54);
a second screw rod (531) is fixed on a motor shaft of the second motor (53), and the second piston (51) is connected to the second screw rod (531) in a sliding mode.
8. The apparatus according to claim 7, wherein the constant pressure positive pressure leak hole calibration device comprises: the second equivalent assembly (5) further comprises two second limiting plates (55) used for limiting the moving range of the second piston (51), and the two second limiting plates (55) are respectively fixed on two sides of the second mounting plate (54).
9. A test method of a constant-pressure positive-pressure leak hole calibration device is characterized by comprising the following steps: the method is completed by using a constant pressure and positive pressure leak hole calibration device according to any one of claims 1 to 8, and comprises the following steps:
s1, opening the air release valve (11), the test valve (21) and the isolating valve (7), and displaying the number on the capacitance film gauge (3) as zero;
s2, closing the air release valve (11) and the isolating valve (7), opening the test valve (21), and displaying the number on the capacitance film gauge (3) as a positive value;
s3, starting a first motor (43), wherein the first motor (43) drives a first screw rod (431) to rotate, and the rotation of the first screw rod (431) drives a first piston (41) to move;
s4, when the measurement range is large, opening two expansion valves (62);
s5, starting a second motor (53), driving a second screw rod (531) to rotate by the second motor (53), and driving a second piston (51) to move by the rotation of the second screw rod (531).
10. The method for testing the constant-pressure positive-pressure leak hole calibration device according to claim 9, wherein:
Q＝P0·X·A·Tτ/T·Δt (1)
in the formula: q-the leakage rate of the standard leak hole, unit Pa.m 3/s;
p0 — absolute pressure in the calibration chamber at t1, (which can be replaced by local atmospheric pressure at t1), in Pa;
a- -piston rod cross-sectional area, unit m 2;
x- -piston travel distance (L2-L1), in m;
t tau- -reference temperature of standard leak, in K;
t- -ambient temperature, in K;
Δ t- -the time interval (t2-t1) at which calibration begins and ends, in units of 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110366382.XA CN114636517A (en) | 2021-04-06 | 2021-04-06 | Constant-pressure positive-pressure leak hole calibration device and test method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110366382.XA CN114636517A (en) | 2021-04-06 | 2021-04-06 | Constant-pressure positive-pressure leak hole calibration device and test method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114636517A true CN114636517A (en) | 2022-06-17 |
Family
ID=81945617
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110366382.XA Pending CN114636517A (en) | 2021-04-06 | 2021-04-06 | Constant-pressure positive-pressure leak hole calibration device and test method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114636517A (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101470042A (en) * | 2007-12-28 | 2009-07-01 | 中国航天科技集团公司第五研究院第五一〇研究所 | Variable-volume chamber of constant pressure type positive pressure leak hole calibration device |
| KR101075074B1 (en) * | 2011-06-09 | 2011-10-19 | 최경택 | Pneumatic control-module for the leak tester |
| CN105043489A (en) * | 2015-07-13 | 2015-11-11 | 兰州空间技术物理研究所 | High-precision volume measurement method used for multi-magnitude positive-pressure leak calibration |
| JP2016156627A (en) * | 2015-02-23 | 2016-09-01 | ダイハツ工業株式会社 | Leakage measurement device |
| CN114623979A (en) * | 2021-04-06 | 2022-06-14 | 上海东贝真空设备有限公司 | Constant-volume positive-pressure leak hole calibration device and test method thereof |
-
2021
- 2021-04-06 CN CN202110366382.XA patent/CN114636517A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101470042A (en) * | 2007-12-28 | 2009-07-01 | 中国航天科技集团公司第五研究院第五一〇研究所 | Variable-volume chamber of constant pressure type positive pressure leak hole calibration device |
| KR101075074B1 (en) * | 2011-06-09 | 2011-10-19 | 최경택 | Pneumatic control-module for the leak tester |
| JP2016156627A (en) * | 2015-02-23 | 2016-09-01 | ダイハツ工業株式会社 | Leakage measurement device |
| CN105043489A (en) * | 2015-07-13 | 2015-11-11 | 兰州空间技术物理研究所 | High-precision volume measurement method used for multi-magnitude positive-pressure leak calibration |
| CN114623979A (en) * | 2021-04-06 | 2022-06-14 | 上海东贝真空设备有限公司 | Constant-volume positive-pressure leak hole calibration device and test method thereof |
Non-Patent Citations (3)
| Title |
|---|
| CALCATELI G等: "The IMGC-CNR flowmeter for automatic measurements of low-range gas flows", MEASUREMENT, vol. 34, no. 2, 31 December 2003 (2003-12-31), pages 121 - 132, XP004438895, DOI: 10.1016/S0263-2241(03)00029-0 * |
| 冯焱等: "正压漏孔校准技术的发展概况", 真空, vol. 50, no. 01, 31 January 2013 (2013-01-31), pages 41 - 47 * |
| 王金锁, 许红, 胡央丽, 唐景远: "正压漏孔校准装置的研制", 真空科学与技术, no. 06, 30 November 2004 (2004-11-30), pages 439 - 441 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102944358B (en) | High and low temperature vacuum calibrating device and method | |
| US7620522B2 (en) | Diagnostic device for at least one pneumatic valve actuator arrangement | |
| CN103808457B (en) | Vacuum correction device and method under low temperature | |
| JPS63277948A (en) | Temperature compensating method and device of detection of leakage | |
| CN112113707A (en) | Small leak rate positive pressure leak hole calibration method and device | |
| CN116398421B (en) | High vacuum pump pumping speed testing device and using method thereof | |
| CN112484916B (en) | Temperature response characteristic calibration method for patch type pressure sensor | |
| CN107843391A (en) | A kind of small leak rate Pressure Leak Calibration Apparatus and method | |
| CN106679897A (en) | Leakage hole's leakage rate measuring apparatus | |
| CN106289666B (en) | Calibration device and method for vacuum leak at ambient temperature | |
| CN114636517A (en) | Constant-pressure positive-pressure leak hole calibration device and test method thereof | |
| US20240141931A1 (en) | Constant value method for detecting and evaluating internal leakage of hydraulic cylinder and detection device thereof | |
| CN213120977U (en) | Small-leak-rate positive-pressure leak hole calibration device | |
| CN105043489A (en) | High-precision volume measurement method used for multi-magnitude positive-pressure leak calibration | |
| CN104198115A (en) | Calibration device for detecting vacuum gauges with relative errors of indicating values no less than 30% | |
| CN114623979A (en) | Constant-volume positive-pressure leak hole calibration device and test method thereof | |
| CN109991271B (en) | Magnetocaloric effect measuring instrument with reference temperature and measuring method | |
| CN106500910B (en) | Dynamic contrast calibration device for vacuum gauge | |
| CN115060414B (en) | Device and method for providing high-precision pressure standard | |
| CN215115053U (en) | Positive pressure leak hole calibrating device | |
| Wälchli et al. | Fundamental leak calibration system for gas leaks with a defined pressure difference over the leak element | |
| CN116067565A (en) | Capacitive film vacuum gauge detection device and method | |
| CN215339931U (en) | Accelerometer low-pressure performance testing device | |
| CN106768436A (en) | Method for detecting electromotor winding temperature | |
| CN113324711A (en) | Leakage amount detection method and system with temperature compensation function |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |