Vacuum gauge on-line calibration device and calibration method

Abstract

The present application belongs to the technical field of vacuum measurement, and discloses a vacuum gauge online calibration device and a calibration method. A trace adjustment valve is arranged at the top end of a calibration chamber. A fourth vacuum valve, a fifth vacuum valve and a sixth vacuum valve are arranged on the calibration chamber. A first vacuum gauge interface is arranged on the fifth vacuum valve, and a second vacuum gauge interface is arranged on the sixth vacuum valve. A standard vacuum gauge is connected to the calibration chamber through the fourth vacuum valve. One end of a first vacuum valve is connected to a mechanical pump, and the other end is connected to the fifth vacuum valve and the sixth vacuum valve. The bottom end of the calibration chamber is connected to the air outlet of the mechanical pump through a second vacuum valve and is connected to a vacuum device through a third vacuum valve. One end of a vacuum display instrument is connected to an upper computer. A temperature and humidity meter is arranged on one side of the calibration chamber and is used for detecting the temperature and humidity on site. The calibration of a full-range vacuum gauge is realized, and the online calibration of the vacuum gauge on site and the regular pressure rise rate and leakage rate test in combination with the vacuum device are facilitated.

Description

Technical Field

[0001] This invention belongs to the field of vacuum measurement technology and relates to an online calibration device and calibration method for a vacuum gauge. Background Technology

[0002] To improve the heat treatment quality of metal parts, heat treatment manufacturers widely use vacuum heat treatment equipment. All such equipment requires the measurement and control of the vacuum level within its internal space. This control method involves using a tested or calibrated vacuum gauge connected to a matching display instrument to monitor the vacuum level inside the equipment. This control method places high demands on the accuracy of the vacuum gauge; inaccurate control will negatively impact product quality.

[0003] However, since most companies lack vacuum calibration equipment, they outsource the calibration of their vacuum gauges to metrology departments. This requires sending the vacuum gauge and its associated display instruments to the metrology department, resulting in a lengthy testing cycle and impacting the use of vacuum heat treatment equipment. Furthermore, calibrated vacuum gauges often become contaminated during use, causing measurement distortions and affecting product quality. Simultaneously, the lack of necessary on-site verification devices makes it impossible to determine the accuracy of the vacuum gauges. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide an online calibration device and calibration method for a vacuum gauge.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] In a first aspect, the present invention provides an online vacuum gauge calibration device, comprising a first vacuum valve, a second vacuum valve, a third vacuum valve, a calibration chamber, a standard vacuum gauge, a mechanical pump, vacuum equipment, a vacuum display instrument, a host computer, and a temperature and humidity meter; a micro-adjustment valve is provided at the top of the calibration chamber; a fourth vacuum valve, a fifth vacuum valve, and a sixth vacuum valve are provided on the equatorial plane of the calibration chamber, the fifth vacuum valve having a first vacuum gauge interface for connecting to the first vacuum gauge, and the sixth vacuum valve having a second vacuum gauge interface for connecting to the second vacuum gauge; the standard vacuum gauge is connected to the calibration chamber via the fourth vacuum valve. Connections: One end of the first vacuum valve is connected to the mechanical pump, and the other end is connected to the ends of the fifth and sixth vacuum valves furthest from the calibration chamber; a vacuum interface is provided at the bottom of the calibration chamber, which is connected to the pump's suction port through the second vacuum valve and to the vacuum equipment through the third vacuum valve; one end of the vacuum display instrument is connected to the host computer, and the other end is equipped with a first vacuum gauge display interface for connecting the first vacuum gauge and a second vacuum gauge display interface for connecting the second vacuum gauge; a temperature and humidity meter and a standard vacuum gauge are connected to the host computer; the temperature and humidity meter is located on one side of the calibration chamber for detecting the on-site temperature and humidity.

[0007] Optionally, a vacuum filter device may be provided between the third vacuum valve and the vacuum equipment.

[0008] Optionally, a gas storage rubber ball is provided on the end of the micro-adjustment valve away from the calibration chamber, and the gas storage rubber ball contains nitrogen gas with a purity of 99.999% or higher.

[0009] Optionally, the measurement range of the standard vacuum gauge is 1×10⁻⁶. -4 ~1×10 5 Pa, the combined standard uncertainty of the measurement is less than 5%, and the combined measurement range of the first and second vacuum gauges covers 1×10 -3 ~1×10 5 Pa, the combined standard uncertainty of the measurement is less than 15%.

[0010] Optionally, the first vacuum gauge is an ionization vacuum gauge, a resistance temperature detector (RTD) vacuum gauge, or a thermocouple vacuum gauge; the second vacuum gauge is an ionization vacuum gauge, an RTD vacuum gauge, or a thermocouple vacuum gauge.

[0011] Optionally, the calibration chamber is a spherical container, and the sphere radius R of the calibration chamber satisfies: 80≤R≤150mm.

[0012] Optionally, the standard vacuum gauge interface, the first vacuum gauge interface, and the second vacuum gauge interface are all flange interfaces, and the angle between the adjacent flange interfaces on the equatorial plane and the line connecting the center of the calibration chamber is 120°.

[0013] Optionally, the combined pumping speed of the mechanical pump and vacuum equipment is greater than 50 L / s.

[0014] In a second aspect, the present invention provides a vacuum gauge online calibration method based on the above-described vacuum gauge online calibration device, comprising:

[0015] S1, Connect the first and second vacuum gauges to be calibrated;

[0016] S2. Open the second vacuum gauge. If the reading of the second vacuum gauge is less than the first preset value, adjust the second vacuum gauge to full capacity after a preset stabilization time, and then evacuate the calibration chamber.

[0017] S3. Turn on the standard vacuum gauge and the first vacuum gauge. When the standard vacuum gauge shows that the vacuum level in the calibration chamber is less than the second preset value and stabilizes for a preset time, perform a zeroing operation on the second vacuum gauge.

[0018] S4. Read the temperature and humidity data collected by the temperature and humidity meter and the data from the standard vacuum gauge and the first vacuum gauge via the host computer at 10. -3 ~10 -1After the indicated values of each pressure calibration point within the Pa range are obtained, calibrate the range of 10 -3 ~10 -1 Pa for the first vacuum gauge;

[0019] S5. Read the temperature and humidity collected by the temperature and humidity meter through the host computer, as well as the indicated values of each pressure calibration point of the standard vacuum gauge and the second vacuum gauge within the range of 10 -1 -10 2 Pa. Then, calibrate the range of 10 -1 -10 2 Pa for the second vacuum gauge;

[0020] S6. Read the temperature and humidity collected by the temperature and humidity meter through the host computer, as well as the indicated values of each pressure calibration point of the standard vacuum gauge and the second vacuum gauge within the range of 10 2 -10 5 Pa. Then, calibrate the range of 10 2 -10 5 Pa for the second vacuum gauge;

[0021] Among them, during calibration, when the vacuum gauge to be calibrated is a hot cathode vacuum gauge, a thermal resistance vacuum gauge or a thermocouple vacuum gauge, it is qualified when the error ≤ 50%; otherwise, it is unqualified; when the vacuum gauge to be calibrated is a cold cathode vacuum gauge, it is qualified when -60% ≤ error ≤ 100%; otherwise, it is unqualified; among them, error = (P G -P G1 ) / P G1 ; among them, P G1 is the indicated value of the standard vacuum gauge, and P G is the indicated value of the vacuum gauge to be calibrated.

[0022] Optionally, S4 includes:

[0023] Vacuum the calibration chamber until the indicated value of the first vacuum gauge is less than the third preset value. Close the first vacuum valve and the sixth vacuum valve. Introduce gas into the calibration chamber through the micro regulating valve, so that the air pressure in the calibration chamber gradually increases from 10 -3 Pa to 10 -1 Pa. Select multiple pressure calibration points between 10 -3 Pa and 10 -1 Pa, and read the indicated values of the standard vacuum gauge and the first vacuum gauge at each pressure calibration point and record them as P G1 and P G2 respectively. Then, calculate the calibration curve of the first vacuum gauge within the range of 10 G1 / P G2 to obtain the calibration curve of the first vacuum gauge within the range of 10 -3 ~10 -1 Pa;

[0024] S5 includes:

[0025] Close the first, second, and third vacuum valves, and introduce gas into the calibration chamber through the micro-adjustment valve to reduce the gas pressure in the calibration chamber from 10... -1 Pa gradually increases to 10 2 Pa, at 10 -1 Pa to 10 2 Select multiple pressure calibration points between Pa, and read the readings of the standard vacuum gauge and the second vacuum gauge at each pressure calibration point, recording them as P respectively. G1 and P G3 Then, according to C2 = P G1 / P G3 The calculation yielded the second vacuum gauge at 10 -1 ~10 2 Calibration curve within the Pa range;

[0026] S6 includes:

[0027] Close the first, second, and third vacuum valves, and introduce gas into the calibration chamber through the micro-adjustment valve to reduce the gas pressure in the calibration chamber from 10... 2 Pa gradually increases to 10 5 Pa, at 10 2 Pa to 10 5 Select multiple pressure calibration points between Pa, and read the readings of the standard vacuum gauge and the second vacuum gauge at each pressure calibration point, recording them as P respectively. G1 and P G3 Then, according to C3=P G1 / P G3 The calculation yielded the second vacuum gauge at 10 2 ~10 5 Calibration curve within the Pa range.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] This invention relates to an online vacuum gauge calibration device. It achieves vacuuming of the calibration chamber using a mechanical pump and vacuum equipment. The vacuum value inside the calibration chamber is adjusted via a micro-adjustment valve, accurately adjusting the vacuum value to the calibration point and maintaining stability. This enables calibration of vacuum gauges across the entire range. A standard vacuum gauge interface, a first vacuum gauge interface for connecting a first vacuum gauge, and a second vacuum gauge interface are set on the equatorial plane of the calibration chamber. During use, the first and second vacuum gauges to be calibrated are installed on the first and second vacuum gauge interfaces for calibration. This facilitates online calibration of vacuum gauges on-site and allows for periodic pressure rise and leakage rate testing in conjunction with vacuum equipment, reducing downtime for the vacuum equipment. Simultaneously, a fourth, fifth, and sixth vacuum valve, along with the first vacuum valve, are provided. All valves can be closed at any time, allowing for the installation and removal of vacuum gauges and vacuum display instruments without affecting the normal operation of the equipment. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of the online calibration device for a vacuum gauge according to an embodiment of the present invention.

[0031] Figure 2 The first vacuum gauge in the online calibration method of the vacuum gauge according to an embodiment of the present invention is 10 -3 ~10 -1 Calibration curve within the Pa Pa range.

[0032] Figure 3 The second vacuum gauge in the online calibration method of the vacuum gauge according to an embodiment of the present invention is in 10 -1 ~10 5 Calibration curve within the Pa range.

[0033] Figure 4 This is a schematic diagram illustrating the principle of the online calibration method for a vacuum gauge according to an embodiment of the present invention.

[0034] Wherein: 1-Calibration chamber; 2-Standard vacuum gauge; 3-First vacuum gauge; 4-Second vacuum gauge; 5-Mechanical pump; 6-Vacuum filter device; 7-Vacuum equipment; 8-Vacuum display instrument; 9-Host computer; 10-Temperature and humidity meter; 11-Fourth vacuum valve; 12-Fifth vacuum valve; 13-Sixth vacuum valve; 14-First vacuum valve; 15-Second vacuum valve; 16-Third vacuum valve; 17-Micro-adjustment valve. Detailed Implementation

[0035] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0036] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0037] The present invention will now be described in further detail with reference to the accompanying drawings:

[0038] See Figure 1 The present invention provides an online vacuum gauge calibration device, comprising a first vacuum valve 14, a second vacuum valve 15, a third vacuum valve 16, a calibration chamber 1, a standard vacuum gauge 2, a mechanical pump 5, a vacuum device 7, a vacuum display instrument 8, a host computer 9, and a temperature and humidity meter 10.

[0039] A micro-adjustment valve 17 is connected to the top of the calibration chamber 1; a fourth vacuum valve 11, a fifth vacuum valve 12, and a sixth vacuum valve 13 are installed on the equatorial plane of the calibration chamber 1. The fifth vacuum valve 12 has a first vacuum gauge interface for connecting to the first vacuum gauge 3, and the sixth vacuum valve 13 has a second vacuum gauge interface for connecting to the second vacuum gauge 4; the standard vacuum gauge 2 is connected to the calibration chamber 1 through the fourth vacuum valve 11; one end of the first vacuum valve 14 is connected to the mechanical pump 5, and the other end is connected to the ends of the fifth vacuum valve 12 and the sixth vacuum valve 13 away from the calibration chamber 1; a vacuum interface is opened at the bottom of the calibration chamber 1, which is connected to the suction port of the mechanical pump 5 through the second vacuum valve 15, and to the vacuum equipment 7 through the third vacuum valve 16; one end of the vacuum display instrument 8 is connected to the host computer 9, and the other end has a first vacuum gauge display interface for connecting to the first vacuum gauge 3 and a second vacuum gauge display interface for connecting to the second vacuum gauge 4; a temperature and humidity meter 10 and the standard vacuum gauge 2 are connected to the host computer 9; the temperature and humidity meter 10 is located on one side of the calibration chamber 1 and is used to detect the temperature and humidity at the site.

[0040] The host computer 9 can be a computer, and the temperature and humidity meter 10 can be a Bluetooth temperature and humidity meter 10, which is connected to the host computer 9 via Bluetooth.

[0041] Meanwhile, to ensure the accuracy of the calibration results, the standard vacuum gauge 2 needs to be calibrated before use. The standard vacuum gauge 2 should be a high-precision composite vacuum gauge, within the range of 1×10⁻⁶. -5 ~1×10 5 The Pa measurement range has an error better than ±5% and a measurement uncertainty better than 7%, and the combined measurement range of the first vacuum gauge 3 and the second vacuum gauge 4 covers 1×10 -3 ~1×10 5 Pa, the combined standard uncertainty of the measurement is less than 15%. On the other hand, calibration chamber 1 is set as a spherical container, and the radius R of the sphere of calibration chamber 1 satisfies: 80≤R≤150mm.

[0042] In this embodiment, the first vacuum gauge 3 and the second vacuum gauge 4 can be one or a combination of an ionization vacuum gauge, a resistance temperature detector (RTD) vacuum gauge, or a thermocouple vacuum gauge. The vacuum equipment, mechanical pump, vacuum valves, connecting pipes, and interfaces constitute the pumping system, and the leakage rate of each selected vacuum valve is less than 10%. -7 Pa·L / s; the selected mechanical pump 5 and vacuum equipment 7 form a pumping unit with a no-load pumping capacity of 5×10 Pa·L / s. -4 The pumping speed is above Pa and the combined pumping speed is greater than 50 L / s.

[0043] Before using the online vacuum gauge calibration device of this invention, all interfaces and valves must be checked for airtightness using a leak detector. In this embodiment, the main technical specifications of the online vacuum gauge calibration device are as follows: ultimate vacuum degree better than 1×10⁻⁶. -3 Pa; the dynamic pressure stability of calibration chamber 1 within 1 minute is no greater than 1%; the static pressure of calibration chamber 1 within 1 minute remains <2×10 Pa. -2 Pa; calibration range is 1×10 -3 ~1×10 5 Pa; measurement uncertainty is within 1 × 10⁻⁶. -3 ~1×10 5 The Pa measurement range is better than 15%.

[0044] In one possible implementation, a vacuum filter 6 is provided between the third vacuum valve 16 and the vacuum device 7. The vacuum filter 6 filters various gases generated by the vacuum device 7 below to prevent contamination of the standard vacuum gauge 2.

[0045] In one possible implementation, a gas-storing rubber bulb is disposed at the end of the micro-adjustment valve 17 furthest from the calibration chamber 1, the gas-storing rubber bulb containing nitrogen gas with a purity of 99.999% or higher. (For use only in 1×10⁻⁶ applications) -3 ~1×10 +3 Pa, the rest of the gas-filled rubber balls were removed and released directly into the surrounding air.

[0046] In one possible implementation, the standard vacuum gauge interface, the first vacuum gauge interface, and the second vacuum gauge interface are all flange interfaces, and the angle between the adjacent flange interfaces on the equatorial plane and the line connecting the center of the calibration chamber 1 is 120°. This ensures that gas molecules collide with the tube wall at least once before entering the working area of ​​the vacuum gauge, resulting in more accurate measurement values.

[0047] In this embodiment, to further ensure the accuracy of the results, the following requirements are met between the components:

[0048] 1. The volume of calibration chamber 1 should be at least 20 times the total volume of all vacuum gauges connected to the system;

[0049] 2. The shape of calibration chamber 1 should minimize the ratio of its surface area to its volume. Therefore, a spherical container is ideal. If a cylindrical container is used, the ratio of its length to its diameter should not exceed 4.

[0050] 3. The shape of the vacuum gauge connecting tube must ensure that gas molecules collide with the tube wall at least once before entering the working area of ​​the vacuum gauge;

[0051] 4. The pressure and temperature differences between all vacuum gauges installed in calibration chamber 1 should not cause significant measurement errors;

[0052] 5. The conductivity of the vacuum gauge connecting tube should be at least 100 times the adsorption or desorption rate of the vacuum gauge; 6. The ultimate pressure of the system should be less than 2% of the minimum calibration pressure.

[0053] In addition, when connecting each component to calibration chamber 1, it can be done by means of flange connection, generally KF flange.

[0054] When using the online vacuum gauge calibration device of this invention, after the vacuum is drawn to the ultimate vacuum by the mechanical pump 5 and the vacuum equipment 7, the calibration gas is slowly released by adjusting the micro-adjustment valve 17 connected to the upper end of the calibration chamber 1. Then, calibration is performed point by point according to the magnitude, and the readings are recorded. The reading of the standard vacuum gauge 2 is the actual value; the readings of the first vacuum gauge 3 and the second vacuum gauge 4 are the measured values. The 1×10⁻¹⁰ value is calculated point by point using both dynamic comparison method and static comparison method. -3 ~1×10 5Within the Pa range, the actual and measured values ​​of the standard vacuum gauge 2, the first vacuum gauge 3, and the second vacuum gauge 4 are read respectively, and then connected to the display instrument and the host computer 9 through the signal line. The host computer 9 reads the temperature and humidity of the site in real time through the connected temperature and humidity meter 10. At the same time, it collects the signal indication values ​​of the standard vacuum gauge 2, the first vacuum gauge 3, and the second vacuum gauge 4 in real time through the preset internal correction program and calculates the corrected indication error. After correction, the error value / uncertainty of the measurement system composed of the first vacuum gauge 3 and the second vacuum gauge 4 and the display instrument can be obtained to determine whether it meets or does not meet the requirements. Then, the vacuum gauge is corrected in real time through the signal line, or manually corrected or updated. Then, the calibration procedure is repeated to recalibrate.

[0055] In summary, the vacuum gauge online calibration device of the present invention achieves vacuuming of the calibration chamber 1 through a mechanical pump 5 and vacuum equipment 7, and adjusts the vacuum value inside the calibration chamber 1 through a micro-adjustment valve 17, accurately adjusting the vacuum value to the calibration point and maintaining stability, thus enabling full-range vacuum gauge calibration. A standard vacuum gauge interface, a first vacuum gauge interface for connecting a first vacuum gauge 3, and a second vacuum gauge interface for connecting a second vacuum gauge 4 are set on the equatorial plane of the calibration chamber. During use, the first vacuum gauge 3 and the second vacuum gauge 4 to be calibrated are installed on the first and second vacuum gauge interfaces for calibration, facilitating online calibration of vacuum gauges on-site and periodically testing pressure rise rate and leakage rate in conjunction with vacuum equipment, reducing downtime of vacuum equipment. Simultaneously, a fourth vacuum valve 11, a fifth vacuum valve 12, a sixth vacuum valve 13, and a first vacuum valve 14 are provided, each of which can be closed at any time. After closure, the vacuum gauges and vacuum display instruments can be installed and removed without affecting the normal operation of the equipment. Furthermore, the detachable structure facilitates on-site calibration.

[0056] See Figures 2 to 4 In another embodiment of the present invention, a vacuum gauge online calibration method is provided, which can be performed based on the above-mentioned vacuum gauge online calibration device. Specifically, the vacuum gauge online calibration method includes the following steps:

[0057] S1, connect the first vacuum gauge 3 and the second vacuum gauge 4 to be calibrated.

[0058] S2. Open the second vacuum gauge 4. If the reading of the second vacuum gauge 4 is less than the first preset value, after the preset time is stabilized, the second vacuum gauge 4 is adjusted to full capacity, and then the calibration chamber 1 is evacuated.

[0059] S3. Turn on the standard vacuum gauge 2 and the first vacuum gauge 3. When the standard vacuum gauge 2 shows that the vacuum level in the calibration chamber 1 is less than the second preset value, and after a preset time of stabilization, perform a zeroing operation on the second vacuum gauge 4.

[0060] S4. After the host computer 9 reads the temperature and humidity collected by the thermometer - hygrometer 10, as well as the indicated values of each pressure calibration point within the range of 10 -3 ~10 -1 Pa of the standard vacuum gauge 2 and the first vacuum gauge 3, calibrate the range of 10 -3 ~10 -1 Pa of the first vacuum gauge 3.

[0061] S5. After the host computer 9 reads the temperature and humidity collected by the thermometer - hygrometer 10, as well as the indicated values of each pressure calibration point within the range of 10 -1 -10 2 Pa of the standard vacuum gauge 2 and the second vacuum gauge 4, then calibrate the range of 10 -1 -10 2 Pa of the second vacuum gauge 4.

[0062] S6. After the host computer 9 reads the temperature and humidity collected by the thermometer - hygrometer 10, as well as the indicated values of each pressure calibration point within the range of 10 2 -10 5 Pa of the standard vacuum gauge 2 and the second vacuum gauge 4, then calibrate the range of 10 2 -10 5 Pa of the second vacuum gauge 4.

[0063] Among them, during calibration, when the vacuum gauge to be calibrated is a hot - cathode vacuum gauge, a thermal - resistance vacuum gauge or a thermocouple vacuum gauge, it is qualified when the error ≤ 50%; otherwise, it is unqualified; when the vacuum gauge to be calibrated is a cold - cathode vacuum gauge, it is qualified when - 60% ≤ error ≤ 100%; otherwise, it is unqualified; where, error = (P G -P G1 ) / P G1 ; where, P G1 is the indicated value of the standard vacuum gauge 2, and P G is the indicated value of the vacuum gauge to be calibrated.

[0064] Among them, the sensitive element of the hot - cathode vacuum gauge is a metal filament. When it is powered on and heated during operation, when the gas conducts electricity, the gas molecules collide with the high - speed flying electrons and are ionized. The frequency of the collision is related to the density of the gas molecules. The greater the density, the higher the collision frequency and the more ions are generated; and the density of the gas molecules has a direct relationship with the gas pressure. Therefore, if the magnitude of the ion current ionized in the gas can be measured, the gas pressure can be determined. The hot - cathode ionization vacuum gauge is made according to the above principle.

[0065] Like hot cathode vacuum gauges, cold cathode vacuum gauges utilize the characteristic that the ionization current of gas molecules under low pressure is related to pressure. They use the discharge current as the measurement of vacuum level, and an ammeter is used as the vacuum level indicator. The typical range is 0–100 μA. The difference between cold cathode and hot cathode vacuum gauges lies in the ionization source.

[0066] Specifically, step S4 includes: evacuating the calibration chamber 1 until the indicated value of the first vacuum gauge 3 is less than a third preset value; closing the sixth vacuum valve 13 and the first vacuum valve 14; and introducing gas into the calibration chamber 1 through the micro-adjustment valve 17 to reduce the gas pressure in the calibration chamber 1 from 10... -3 Pa gradually increases to 10 -1 Pa, at 10 -3 Pa to 10 -1 Multiple pressure calibration points are selected between Pa, and the readings of the standard vacuum gauge 2 and the first vacuum gauge 3 at each pressure calibration point are recorded as P. G1 and P G2 Then, according to C1 = P G1 / P G2 The calculation yielded the first vacuum gauge 3 at 10 -3 ~10 -1 Calibration curve within the Pa range.

[0067] Step S5 includes: closing the first vacuum valve 14, the second vacuum valve 15, and the third vacuum valve 16; and introducing gas into the calibration chamber 1 through the micro-adjustment valve 17, so that the gas pressure in the calibration chamber 1 is reduced from 10... -1 Pa gradually increases to 10 2 Pa, at 10 -1 Pa to 10 2 Select multiple pressure calibration points between Pa, and read the indication values ​​of the standard vacuum gauge 2 and the second vacuum gauge 4 at each pressure calibration point, and record them as P respectively. G1 and P G3 Then, according to C2 = P G1 / P G3 The calculation yielded the second vacuum gauge 4 at 10 -1 ~10 2 Calibration curve within the Pa range.

[0068] Step S6 includes: closing the first vacuum valve 14, the second vacuum valve 15, and the third vacuum valve 16; and introducing gas into the calibration chamber 1 through the micro-adjustment valve 17, so that the gas pressure in the calibration chamber 1 is reduced from 10... 2 Pa gradually increases to 10 5 Pa, at 10 2 Pa to 10 5Select multiple pressure calibration points between Pa, and read the indication values ​​of the standard vacuum gauge G1 and the second vacuum gauge 4 at each pressure calibration point, and record them as P respectively. G1 and P G3 Then, according to C3=P G1 / P G3 The calculation yielded the second vacuum gauge 4 at 10 2 ~10 5 Calibration curve within the Pa range.

[0069] Specifically, when calibrating the first vacuum gauge 3, closing the sixth vacuum valve 13 reduces the impact of the gas intake and exhaust effect generated by the second vacuum gauge 4 during high vacuum measurements on the stability of the reading of the first vacuum gauge 3. When calibrating the second vacuum gauge 4, closing the fifth vacuum valve 12 reduces the impact of gas contamination on the stability of the reading of the first vacuum gauge 3 during use.

[0070] The first preset value is set to 4 full scale of the second vacuum gauge, which generally refers to atmospheric pressure corresponding to 1×10⁻⁶. 5 Pa, the second preset value is set to the zero point of the second vacuum gauge 4, generally referring to a vacuum corresponding to 1×10 -1 The Pa preset value and the third preset value are set to the first vacuum gauge zero point 3, generally referring to a vacuum corresponding to 1×10. -3 Pa preset value.

[0071] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A vacuum gauge online calibration method based on a vacuum gauge online calibration device, characterized in that, The vacuum gauge online calibration device includes a first vacuum valve, a second vacuum valve, a third vacuum valve, a calibration chamber, a standard vacuum gauge, a mechanical pump, vacuum equipment, a vacuum display instrument, a host computer, and a temperature and humidity meter; A micro-adjustment valve is connected to the top of the calibration chamber; a fourth, fifth, and sixth vacuum valve are installed on the equatorial plane of the calibration chamber. The fifth vacuum valve has a first vacuum gauge interface for connecting to the first vacuum gauge, and the sixth vacuum valve has a second vacuum gauge interface for connecting to the second vacuum gauge; the standard vacuum gauge is connected to the calibration chamber through the fourth vacuum valve; one end of the first vacuum valve is connected to the mechanical pump, and the other end is connected to the ends of the fifth and sixth vacuum valves furthest from the calibration chamber; a vacuum interface is opened at the bottom of the calibration chamber, which is connected to the pump port of the mechanical pump through the second vacuum valve and to the vacuum equipment through the third vacuum valve; One end of the vacuum display instrument is connected to the host computer, and the other end is equipped with a first vacuum gauge display interface for connecting the first vacuum gauge and a second vacuum gauge display interface for connecting the second vacuum gauge; the temperature and humidity meter and the standard vacuum gauge are connected to the host computer; The temperature and humidity meter is located on one side of the calibration room and is used to detect the temperature and humidity on site. The online calibration method for the vacuum gauge includes: S1, Connect the first and second vacuum gauges to be calibrated; S2. Open the second vacuum gauge. If the reading of the second vacuum gauge is less than the first preset value, adjust the second vacuum gauge to full capacity after a preset stabilization time, and then evacuate the calibration chamber. S3. Turn on the standard vacuum gauge and the first vacuum gauge. When the standard vacuum gauge shows that the vacuum level in the calibration chamber is less than the second preset value and stabilizes for a preset time, perform a zeroing operation on the second vacuum gauge. S4, 10 for the first vacuum gauge -3 ~10 -1 Calibrate the Pa range: Evacuate the calibration chamber until the reading of the first vacuum gauge is less than the third preset value. Close the first and sixth vacuum valves. Introduce gas into the calibration chamber through the micro-adjustment valve, reducing the pressure in the calibration chamber from 10... -3 Pa gradually increases to 10 -1 Pa, at 10 -3 Pa to 10 -1 Select multiple pressure calibration points between Pa, and read the readings of the standard vacuum gauge and the first vacuum gauge at each pressure calibration point, recording them as P. G1 and P G2 Then, according to C1 = P G1 / P G2 The calculations obtained the first vacuum gauge at 10 -3 ~10 -1 Calibration curve within the Pa range; S5, 10 for the second vacuum gauge -1 ~10 2 Calibrate the Pa range: Close the first, second, and third vacuum valves, and introduce gas into the calibration chamber through the micro-adjustment valve to reduce the gas pressure in the calibration chamber from 10 Pa. -1 Pa gradually increases to 10 2 Pa, at 10 -1 Pa to 10 2 Select multiple pressure calibration points between Pa, and read the readings of the standard vacuum gauge and the second vacuum gauge at each pressure calibration point, recording them as P respectively. G1 and P G3 Then, according to C2 = P G1 / P G3 The calculation yielded the second vacuum gauge at 10 -1 ~10 2 Calibration curve within the Pa range; S6, 10 for the second vacuum gauge 2 ~10 5 Calibrate the Pa range: Close the first, second, and third vacuum valves, and introduce gas into the calibration chamber through the micro-adjustment valve to reduce the gas pressure in the calibration chamber from 10 Pa. 2 Pa gradually increases to 10 5 Pa, at 10 2 Pa to 10 5 Select multiple pressure calibration points between Pa, and read the readings of the standard vacuum gauge and the second vacuum gauge at each pressure calibration point, recording them as P respectively. G1 and P G3 Then, according to C3=P G1 / P G3 The calculation yielded the second vacuum gauge at 10 2 ~10 5 Calibration curve within the Pa range; Among them, during calibration, when the vacuum gauge to be calibrated is a hot cathode vacuum gauge, a thermal resistance vacuum gauge or a thermocouple vacuum gauge, it is qualified when the error ≤ 50%; otherwise it is unqualified; when the vacuum gauge to be calibrated is a cold cathode vacuum gauge, it is qualified when -60% ≤ error ≤ 100%; otherwise it is unqualified; among them, the error = (P G -P G1 ) / P G1 ; where P G1 is the indicated value of the standard vacuum gauge, and P G is the indicated value of the vacuum gauge to be calibrated.

2. The online calibration method for a vacuum gauge according to claim 1, characterized in that, A vacuum filter is installed between the third vacuum valve and the vacuum equipment.

3. The online calibration method for a vacuum gauge according to claim 1, characterized in that, The micro-adjustment valve is equipped with a gas storage rubber ball at the end furthest from the calibration chamber, and the gas storage rubber ball contains nitrogen gas with a purity of 99.999% or higher.

4. The online calibration method for a vacuum gauge according to claim 1, characterized in that, The standard vacuum gauge has a measurement range of 1×10⁻⁶. -4 ~1×10 5 Pa, the combined standard uncertainty of the measurement is less than 5%, and the combined measurement range of the first and second vacuum gauges covers 1×10 -3 ~1×10 5 Pa, the combined standard uncertainty of the measurement is less than 15%.

5. The online calibration method for a vacuum gauge according to claim 1, characterized in that, The calibration chamber is a spherical container, and the spherical radius R of the calibration chamber satisfies: 80mm≤R≤150mm.

6. The online calibration method for a vacuum gauge according to claim 5, characterized in that, The standard vacuum gauge interface, the first vacuum gauge interface, and the second vacuum gauge interface are all flange interfaces, and the angle between the adjacent flange interfaces on the equatorial plane and the line connecting the center of the calibration chamber is 120°.

7. The online calibration method for a vacuum gauge according to claim 1, characterized in that, The combined pumping speed of the mechanical pump and vacuum equipment is greater than 50 L / s.

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