CN219038269U - Online calibrating device of vacuum gauge - Google Patents
Online calibrating device of vacuum gauge Download PDFInfo
- Publication number
- CN219038269U CN219038269U CN202223408370.8U CN202223408370U CN219038269U CN 219038269 U CN219038269 U CN 219038269U CN 202223408370 U CN202223408370 U CN 202223408370U CN 219038269 U CN219038269 U CN 219038269U
- Authority
- CN
- China
- Prior art keywords
- vacuum
- vacuum gauge
- gauge
- calibration
- line
- 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.)
- Active
Links
Images
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
Landscapes
- Measuring Fluid Pressure (AREA)
Abstract
The utility model discloses an on-line vacuum gauge calibrating device which comprises a vacuum calibrating chamber, wherein the bottom of the vacuum calibrating chamber is vertically communicated with a guide pipe, the other end of the guide pipe is connected with a vacuum furnace, the two ends of the vacuum calibrating chamber are symmetrical relative to the guide pipe, and the top of the vacuum calibrating chamber is vertically communicated with a first connector for installing a vacuum gauge to be detected and a second connector for installing a standard vacuum gauge. The utility model can ensure that the vacuum gauge can have a large enough vacuum environment during detection, and all the vacuum gauges can be vertically installed, so that the on-line installation state of the vacuum gauge to be detected is restored to the greatest extent, the measurement error is reduced, and the reliability of the measurement result is ensured.
Description
Technical Field
The utility model relates to the technical field of measurement of vacuum gauges, in particular to an on-line calibration device of a vacuum gauge.
Background
The vacuum heat treatment is a novel heat treatment technology combining a vacuum technology and a heat treatment technology, and when the vacuum heat treatment device works, the environment of a processed product in a furnace is an atmosphere environment lower than one atmosphere, including low vacuum, medium vacuum, high vacuum and ultrahigh vacuum, and the vacuum heat treatment device actually belongs to atmosphere control heat treatment. The vacuum heat treatment refers to the heat treatment process which is carried out in a vacuum state in all or part of the heat treatment process, and the vacuum heat treatment can realize almost all the heat treatment processes related to the conventional heat treatment, so that the heat treatment quality is greatly improved. Compared with the conventional heat treatment, the vacuum heat treatment can realize no oxidation, no decarburization and no carburization, can remove phosphorus scraps on the surface of a workpiece, has the functions of degreasing, degassing and the like, and further achieves the effect of surface brightening and purifying. Therefore, the vacuum heat treatment equipment is usually provided with a vacuum gauge, and the vacuum gauge is mainly used for monitoring the vacuum pressure in the heat treatment furnace and ensuring that the products subjected to heat treatment in the furnace are in a vacuum state, so that the products are prevented from oxidative discoloration.
With further maturation of vacuum technology in the key parts of aircraft blades, engines, landing gear and the like, the requirements of the American society of metal heat treatment, the American institute of metal treatment and the industry technical hall of the United states department of energy on the quality control of heat treatment are further strict, and the special process quality control file for vacuum heat treatment, SAE AMS2769D-2020, is updated in 2020, and provides special metering requirements for a monitoring vacuum gauge, and according to the file requirements, the vacuum gauge and a connecting cable which are resident in a heat treatment furnace are required to be compared and metered on site as a whole to be inspected with a set of standard vacuum gauge which can trace to the national standard and has known correction factors, wherein the interval is not more than three months.
The vacuum gauge on-line calibration device is mainly applied to the combined calibration of various vacuum gauges such as resistance vacuum gauges, heat conduction vacuum gauges and the like and vacuum gauges matched with the vacuum gauges for use. The traditional vacuum gauge online test is common in the comparison and confirmation of the measurement effect of the resident vacuum gauge in the production field in the production enterprises, and the comparison method is generally to connect a standard vacuum gauge with a tested vacuum gauge by adopting a vacuum tee joint, and read the display value of each vacuum gauge for comparison after continuous air extraction and stabilization of equipment. However, as the vacuum three passes through the small cavity and the vacuum gauge to be detected and the standard vacuum gauge cannot be guaranteed to be vertically installed, the operation and measurement easily cause large errors, the measurement result is unreliable, and the calibration requirement of the vacuum gauge cannot be met.
Disclosure of Invention
The utility model provides an on-line calibration device for a vacuum gauge, which can ensure that the vacuum gauge can have a large enough vacuum environment during detection, and all the vacuum gauges can be vertically installed, so that the on-line installation state of the vacuum gauge to be detected is restored to the greatest extent, the measurement error is reduced, and the reliability of the measurement result is ensured.
The technical scheme of the utility model is as follows:
the utility model provides an on-line calibration device of vacuum gauge, includes vacuum calibration room, vacuum calibration room's bottom communicates perpendicularly has the pipe, the other end and the vacuum furnace of pipe are connected, vacuum calibration room's both ends are with the pipe symmetry, vacuum calibration room's top communicates perpendicularly has the first joint that is used for installing the vacuum gauge of examining, and is used for installing the second joint of standard vacuum gauge.
According to the utility model, the vacuum calibration chamber is adopted to replace a traditional vacuum tee joint, so that the vacuum volume during detection is effectively enlarged, the two vacuum gauges can have a large enough vacuum environment for detection during detection, and two connectors are vertically connected to the same side of the vacuum calibration chamber, so that the standard vacuum gauge and the vacuum gauge to be detected are vertically installed, the on-line installation state of the vacuum gauge to be detected is reduced to the greatest extent, the measurement error can be effectively reduced, and the reliability of the measurement result is ensured. Meanwhile, the guide pipe for vacuumizing the vacuum standard chamber is arranged in the middle of the bottom of the vacuum standard chamber, so that the gas distribution space in the vacuum measurement area can be ensured to be sufficiently uniform, and the measurement error can be further reduced.
In a preferred embodiment, the first and second connectors are symmetrical about the conduit.
Two vacuum gauges are installed at two ends of a vacuum standard chamber through two symmetrical connectors, so that the uniformity of the vacuum degree detected during measurement can be ensured, and the measurement error is reduced.
In a preferred embodiment, the first connector is a phi 15.5mm socket, and the vacuum gauge to be inspected is inserted into the first connector through a vacuum sealing ring.
In a preferred embodiment, the second connector is a KF25 quick release flange connector, and the standard vacuum gauge is connected to the second connector by a KF25 dedicated clip.
In a more preferred embodiment, the top of the vacuum furnace is provided with a furnace body gauge seat, and one end of the guide pipe is connected with the furnace body gauge seat through a phi 15.5mm interface or a KF flange interface.
In a preferred embodiment, the volume of the vacuum calibration chamber is 1-3 times of the total volume of the vacuum gauge to be detected and the connecting pipeline thereof.
In order to ensure that the vacuum calibration chamber can have a sufficiently large vacuum environment, the volume of the vacuum calibration chamber is set to be 1-3 times of the total volume of a vacuum gauge to be detected and a connecting pipeline thereof. It should be noted that the volume of the vacuum calibration chamber may be set according to the actual detecting apparatus and the industry thereof, and is not limited only herein.
In a more preferred embodiment, the temperature difference between any point within the vacuum calibration chamber is less than 1 ℃. The temperature difference in the vacuum calibration chamber is ensured to be stable, the indoor gas vacuum degree can be stabilized, and uneven indoor gas distribution caused by temperature difference change is avoided, so that the metering accuracy is influenced.
In a preferred embodiment, the standard vacuum gauge is 1×10 in traceability -4 Pa～1×10 4 Pa, calibration spread uncertainty is not more than 10%.
In a more preferred embodiment, the vacuum calibration chamber is a cylinder. According to industry detection standards, the calibration room adopts cylinders, which can be beneficial to ensuring that the gas distribution space in the calibration room is fully uniform.
In a preferred embodiment, the conduit is an alloy conduit, which maintains sufficient hardness to avoid deformation, and allows the vacuum furnace to rapidly pump air into the vacuum calibration chamber, thereby reducing metering errors.
Compared with the prior art, the utility model has the following beneficial effects:
according to the utility model, the vacuum calibration chamber is added in the field detection process, so that the vacuum gauge can have a large enough vacuum environment during detection, all the vacuum gauges are vertically installed, the on-line installation state of the vacuum gauge to be detected is restored to the greatest extent, and the reliability of the measurement result is ensured. The on-line calibrating device of the vacuum gauge can be based on the specification of American standard SAE AMS2769D-2020, and the measuring range is 1 multiplied by 10 -4 Pa～1×10 4 Pa, suitable for film vacuum gauge, thermocouple vacuum gauge, pirani vacuum gauge, ionization vacuum gauge, etc.
Drawings
FIG. 1 is a schematic diagram of the on-line vacuum gauge calibration apparatus of the present utility model;
FIG. 2 is a calibration flow chart of the vacuum gauge online calibration apparatus of the present utility model;
fig. 3 is a graph of the detection result in example 2.
In the figure: a vacuum calibration chamber 1, a conduit 2, a first connector 3, a second connector 4 and a furnace body gauge seat 5.
Detailed Description
The drawings are for illustrative purposes only and are not to be construed as limiting the present patent; for the purpose of better illustrating the embodiments, certain elements of the drawings may be omitted, enlarged or reduced and do not represent the actual product dimensions; it will be appreciated by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted. The positional relationship depicted in the drawings is for illustrative purposes only and is not to be construed as limiting the present patent.
Example 1:
the traditional vacuum gauge online test is common in comparison and confirmation of the measurement effect of the production site resident vacuum gauge in the production enterprise, and the comparison method generally adopts a vacuum tee joint to connect a standard vacuum gauge and a detected vacuum gauge, so that the operation measurement error is large (even the vertical installation of the vacuum gauge cannot be ensured), and the measurement result is judged to be ineligible. According to the American standard specification, the measurement result is judged and derived from the specification, the measurement result can be traced to the national standard, and the measurement range covers 1X 10 < -4 > Pa to 1X 104Pa.
As shown in fig. 1, the present embodiment provides an on-line vacuum gauge calibrating device, which includes a vacuum calibrating chamber 1, wherein a conduit 2 is vertically connected to the bottom of the vacuum calibrating chamber 1, the other end of the conduit 2 is connected to a vacuum furnace (not shown in the figure), two ends of the vacuum calibrating chamber 1 are symmetrical with respect to the conduit 2, and a first joint 3 for installing a vacuum gauge (not shown in the figure) to be inspected and a second joint 4 for installing a standard vacuum gauge (not shown in the figure) are vertically connected to the top of the vacuum calibrating chamber 1.
According to the utility model, the vacuum calibration chamber 1 is adopted to replace a traditional vacuum tee joint, so that the vacuum volume during detection is effectively enlarged, the two vacuum gauges can have a sufficiently large vacuum environment for detection during detection, and two connectors are vertically connected to the same side of the vacuum calibration chamber 1, so that the standard vacuum gauge and the vacuum gauge to be detected are vertically installed, the on-line installation state of the vacuum gauge to be detected is reduced to the greatest extent, the measurement error can be effectively reduced, and the reliability of the measurement result is ensured. Meanwhile, the conduit 2 for vacuumizing the vacuum standard chamber 1 is arranged in the middle of the bottom of the vacuum standard chamber 1, so that the gas distribution space in the vacuum measurement area can be ensured to be sufficiently uniform, and the measurement error can be further reduced.
In a preferred embodiment, the first and second connectors 3, 4 are symmetrical about the conduit 2. In the embodiment, the two vacuum gauges are arranged at the two ends of the vacuum standard chamber 1 through the two symmetrical connectors, so that the uniformity of the vacuum degree detected during measurement can be ensured, and the measurement error can be reduced.
In a preferred embodiment, the first connector 3 adopts a socket with the diameter of 15.5mm, and the vacuum gauge to be tested is inserted into the first connector 3 through a vacuum sealing ring.
In a preferred embodiment, the second connector 4 is a KF25 quick release flange connector, and the standard vacuum gauge is connected to the second connector 4 by a KF25 dedicated clip.
In a preferred embodiment, the top of the vacuum furnace is provided with a furnace body gauge seat 5, and one end of the guide pipe 2 is connected with the furnace body gauge seat 5 through a phi 15.5mm interface or a KF flange interface.
In a preferred embodiment, in order to ensure that the vacuum calibration chamber 1 has a sufficiently large vacuum environment, the volume of the vacuum calibration chamber 1 is set to be 1-3 times the total volume of the vacuum gauge to be tested and the connecting pipeline thereof. The volume of the vacuum calibration chamber 1 may be set according to the actual detecting apparatus and the industry thereof, and is not limited only herein.
In a preferred embodiment, in order to ensure that the temperature difference in the vacuum calibration chamber 1 is stable, the temperature difference between any points in the vacuum calibration chamber 1 is less than 1 ℃. The design can stabilize the indoor gas vacuum degree, and avoid uneven indoor gas distribution caused by temperature difference change, thereby affecting the metering accuracy.
In a preferred embodiment, the standard vacuum gauge is 1×10 in traceability -4 Pa～1×10 4 Pa, calibration spread uncertainty is not more than 10%.
In a preferred embodiment, the vacuum calibration chamber 1 is a cylinder. According to industry detection standards, the calibration room adopts cylinders, which can be beneficial to ensuring that the gas distribution space in the calibration room is fully uniform.
In a preferred embodiment, the conduit 2 is an alloy conduit, which maintains sufficient hardness to avoid deformation, so that the vacuum furnace can rapidly pump and inflate the vacuum calibration chamber 1, and the metering error is reduced.
As shown in fig. 2, the detection steps and calibration principle of the vacuum gauge online calibration device of the utility model are as follows:
1) Before on-site detection, connecting a standard vacuum gauge to a second connector 4 on a vacuum calibration chamber 1 by using a KF25 special clamp, inserting the vacuum gauge to be detected into a first connector 3 on the vacuum calibration chamber 1 through a vacuum sealing ring, and connecting a conduit 2 at the bottom of the vacuum calibration chamber 1 with a furnace body gauge seat 5 of a vacuum furnace through a phi 15.5mm interface or a KF flange interface (according to an instrument self interface), so as to finish installation;
2) Starting the vacuum furnace during detection, and continuously exhausting the vacuum calibration chamber 1 through the guide pipe 2 until reaching the designed limit vacuum value of the vacuum furnace, and baking the vacuum calibration chamber 1 if necessary;
3) The vacuum value in the current vacuum calibration chamber 1 is measured and read by the detected vacuum gauge and the standard vacuum gauge at the same time, the values of the two vacuum gauges at the moment are recorded to be A1 and B1 respectively, A1 is the background pressure of the detected vacuum gauge, and B1 is the background pressure of the standard vacuum gauge;
4) Switching the vacuum furnace into an inflation mode, closing an air extraction valve of the vacuum furnace, opening the air extraction valve, and filling common gas (usually 99.999% pure argon) of the equipment into the vacuum calibration chamber 1 through a conduit 2 so as to enable the vacuum calibration chamber 1 to reach a required calibration pressure point;
5) The vacuum value in the current vacuum calibration chamber 1 is measured and read by the vacuum gauge to be detected and the standard vacuum gauge at the same time, the values of the two vacuum gauges at the moment are recorded to be A2 and B2 respectively, A2 is the detection value of the vacuum gauge to be detected on the calibration pressure point, and B2 is the detection value of the standard vacuum gauge on the calibration pressure point;
6) Taking the difference between B1 and B2 and multiplying by 10 ±0.5 Taking the difference as the upper and lower limits of the standard tolerance, and comparing the difference between A1 and A2 with the upper and lower limits of the standard tolerance to finish the online calibration.
According to the process requirements, if the common vacuum process of the vacuum gauge to be detected is greater than 0.133Pa, the calibration point of the low vacuum above 0.133Pa (the standard is a thermocouple vacuum gauge at the moment) is mainly detected, and if the common vacuum process of the vacuum gauge to be detected is less than 0.133Pa, the high vacuum calibration point below 0.133Pa (the standard is an ionization vacuum gauge at the moment) is mainly detected.
In order to improve the accuracy of measurement, the steps 2-5 can be repeated, the measurement difference values are compared for a plurality of times, and the average value of the measurement is taken for a plurality of times so as to reduce the measurement error.
In this embodiment, in order to further and rapidly improve the reduction efficiency, the reading values of the two vacuum gauges may be output to the control center of the background for recording, then the result comparison is performed in the display screen of the background control center, and the calibration result is directly announced on site through the alarm, so that the operator on site can rapidly know the calibration result, and the measurement efficiency is improved. The background control center can send the result to the mobile terminal of the metering personnel for display, and the metering calibration work of the personnel can be further facilitated.
According to the utility model, the vacuum calibration chamber 1 is added in the field detection process, so that the vacuum gauge can have a large enough vacuum environment during detection, all the vacuum gauges are vertically installed, the on-line installation state of the vacuum gauge to be detected is restored to the greatest extent, and the reliability of the measurement result is ensured. The on-line calibrating device of the vacuum gauge can be based on the specification of American standard SAE AMS2769D-2020, and the measuring range is 1 multiplied by 10 -4 Pa～1×10 4 Pa, suitable for film vacuum gauge, thermocouple vacuum gauge, pirani vacuum gauge, ionization vacuum gauge, etc.
Example 2:
in order to verify the measurement reliability and stability of the on-line calibration device of the vacuum gauge, the device is used for carrying out on-line detection on an FRG series ionization vacuum gauge produced by Agilent manufacturers at intervals of 15 days, 8 times of detection are carried out, a graph is completed according to the upper and lower limits of tolerance required in the SAE AMS2769D-2020 and the actual measurement correction coefficient of the vacuum gauge to be detected, and the detection result is shown in figure 3.
And the fluctuation of the actual measurement correction coefficient range of the vacuum gauge to be detected is 27% -45% of the upper limit range and the lower limit range of the qualified interval, and the variation range is less than 30% by analyzing the data of the multiple measurement results, so that the measurement result of the vacuum gauge on-line calibration device is proved to be reliable.
Example 3:
the present embodiment is similar to embodiment 1, except that in the present embodiment, three threaded holes are formed at the top two ends and the bottom middle of the vacuum calibration chamber 1, and the first connector 3, the second connector 4 and the conduit 2 are all mounted on the vacuum calibration chamber in a threaded connection manner.
In this embodiment, the first connector 3, the second connector 4 and the conduit 2 are installed in a threaded connection manner, so that the whole device can be conveniently detached and installed. Meanwhile, the confidentiality of the connection part is required to be paid attention to, and the air tightness detection can be carried out after the installation is finished so as to ensure that the air tightness of the whole device is good.
The three components of the embodiment can be installed in other fixing connection modes, such as integral molding casting or interference fit plugging, and the like, which meet the air tightness requirement.
It is to be understood that the above examples of the present utility model are provided by way of illustration only and are not intended to limit the scope of the utility model. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. Any modification, equivalent replacement, improvement, etc. which come within the spirit and principles of the utility model are desired to be protected by the following claims.
Claims (10)
1. The utility model provides a vacuum gauge online calibration device, its characterized in that includes vacuum calibration room (1), the bottom vertical intercommunication of vacuum calibration room (1) has pipe (2), the other end and the vacuum furnace of pipe (2) are connected, the both ends of vacuum calibration room (1) are with regard to pipe (2) symmetry, the top vertical intercommunication of vacuum calibration room (1) has first joint (3) that are used for installing the vacuum gauge of examining, and is used for installing second joint (4) of standard vacuum gauge.
2. An on-line vacuum gauge calibrating device according to claim 1, characterized in that the first joint (3), the second joint (4) are symmetrical with respect to the conduit (2).
3. The on-line calibrating device for vacuum gauge according to claim 1, wherein the first connector (3) is a phi 15.5mm socket, and the vacuum gauge to be inspected is inserted into the first connector (3) through a vacuum sealing ring.
4. The on-line calibration device of a vacuum gauge according to claim 1, wherein the second joint (4) is a KF25 quick release flange joint, and the standard vacuum gauge is connected to the second joint (4) by a KF25 dedicated clamp.
5. The vacuum gauge on-line calibrating device according to claim 1, wherein a furnace body gauge seat (5) is arranged at the top of the vacuum furnace, and one end of the guide pipe (2) is connected with the furnace body gauge seat (5) through a phi 15.5mm interface or a KF flange interface.
6. The on-line vacuum gauge calibrating device according to claim 1, characterized in that the volume of the vacuum calibrating chamber (1) is 1-3 times of the total volume of the connecting pipeline of the vacuum gauge to be detected.
7. An on-line vacuum gauge calibration device according to claim 1, characterized in that the temperature difference between any points within the vacuum calibration chamber (1) is less than 1 ℃.
8. The vacuum gauge online calibration device according to claim 1, wherein the traceability range of the standard vacuum gauge is 1 x 10 -4 Pa～1×10 4 Pa, calibration spread uncertainty is not more than 10%.
9. An on-line vacuum gauge calibrating device according to claim 1, characterized in that the vacuum gauge chamber (1) is a cylinder.
10. An on-line vacuum gauge calibrating device according to claim 1, characterized in that the conduit (2) is an alloy conduit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202223408370.8U CN219038269U (en) | 2022-12-14 | 2022-12-14 | Online calibrating device of vacuum gauge |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202223408370.8U CN219038269U (en) | 2022-12-14 | 2022-12-14 | Online calibrating device of vacuum gauge |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN219038269U true CN219038269U (en) | 2023-05-16 |
Family
ID=86277710
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202223408370.8U Active CN219038269U (en) | 2022-12-14 | 2022-12-14 | Online calibrating device of vacuum gauge |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN219038269U (en) |
-
2022
- 2022-12-14 CN CN202223408370.8U patent/CN219038269U/en active Active
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108700485B (en) | Leak inspection device and method | |
| CN110376272B (en) | On-line measuring device and method for gas partial pressure | |
| US10948378B2 (en) | Device, system, and method for detecting equipment leaks | |
| CN112556774B (en) | Gradient inflatable SF based on weighing method 6 Method for measuring volume of gas chamber | |
| CN110836699B (en) | Internet of things temperature and pressure compensation diaphragm meter suitable for high-altitude area and compensation method | |
| CN219038269U (en) | Online calibrating device of vacuum gauge | |
| CN207991747U (en) | A kind of full-automatic pressure sensor batch detection calibration console | |
| CN110763403A (en) | System and method for rapidly detecting air tightness of automobile part | |
| US20210148783A1 (en) | Device, system, and method for detecting leaks from pressurized equipment | |
| CN117538217A (en) | Device and method for analyzing permeation and migration characteristics of helium-rich natural gas in rock | |
| CN220322645U (en) | Tightness test system | |
| CN109026804B (en) | Molecular pump pumping speed test system and method based on CF400 interface | |
| CN107741452B (en) | method for testing volume fraction of martensite in austenitic stainless steel | |
| CN219015429U (en) | Mass flowmeter calibrating device | |
| CN105529281A (en) | Semiconductor equipment leakage detection method | |
| CN112255138B (en) | Inspection and maintenance method for special fire extinguishing agent concentration measurement system | |
| CN112710440B (en) | Air detection machine leakage detection method with temperature compensation | |
| CN114354061A (en) | Online calibration method for vacuum furnace pressure gauge | |
| CN111896191B (en) | On-site calibration method and auxiliary calibration equipment for integral oil tank leakage detection equipment | |
| CN103558000A (en) | Rapid-detection control method used for differential leak detector | |
| CN110243444B (en) | Negative pressure source device, gas meter verification gas circuit system and verification method | |
| CN211318673U (en) | Pressure switch complete detection table | |
| JP5749377B1 (en) | Flow rate measuring method and flow rate measuring device | |
| CN208818441U (en) | A kind of calibration detection apparatus of referance leak | |
| CN113310626B (en) | Vacuum gauge calibration device and calibration method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |