Verification Regulation of Standard Dual piston pressure Vacuum Gauge
Some standard content:
National Metrology Verification Regulation of the People's Republic of China JJG159-2008
Dual Piston Pressure Vacuum Gaug
Issued on 2008-03-25
PistonPressureVacuum Gaug
Implementation on 2008-.09-25
Issued by the General Administration of Quality Supervision, Inspection and Quarantine JJG159—2008
Verification Regulation of Standard DualPistonPressureVacuumGauge JJG159—-2008
Replaces JJG159—1994
This regulation was approved by the General Administration of Quality Supervision, Inspection and Quarantine on March 25, 2008, and came into effect on September 25, 2008.
Responsible unit: National Technical Committee for Pressure Metrology Drafting unit: Shanghai Institute of Metrology and Testing Technology This regulation entrusts the National Technical Committee for Pressure Metrology to be responsible for the interpretation of this regulation Drafters of this regulation:
JJG159—2008
Hu Anlun (Shanghai Institute of Metrology and Testing Technology) Tu Limeng (Shanghai Institute of Metrology and Testing Technology) 1
Scope·
References·
Metrological performance requirementswww.bzxz.net
Accuracy level
Effective area of differential piston.
Proportional constant K value
Special code Quality
Verticality.
Duration of piston rotation
Descending speed
Discrimination…
Sealing
General technical requirements…
5.1 Appearance
5.2 Piston system
Special code and load-bearing plate
Control of measuring instruments
6.1 Verification items·
Verification conditions
Verification methods
Processing of verification results,
Verification period·
JJG159—2008
Verification record format of double piston pressure vacuum gauge Appendix A
Appendix B
Appendix C
Verification certificate and notification of verification results Internal page format Gravitational acceleration of major cities in China
(3)
(4)
(4)
(12)
1 Scope
JJG1592008
Verification procedures for double piston pressure vacuum gauges
This procedure is applicable to the initial verification, subsequent verification and in-use inspection of double piston pressure vacuum gauges with a measuring range of (-0.1～1)MPa.
References
This procedure cites the following documents:
JJF1001-1998 General metrological terms and definitions JJG99-2006 Code verification procedures
When using this procedure, attention should be paid to the use of the current valid versions of the above-mentioned referenced documents. 3 Overview
Double piston pressure vacuum gauge generally consists of a simple piston system, a differential piston system, a special base weight, and a checker. Its principle is to use the mass of the simple piston to balance the mass of the differential piston, so as to achieve a measurement standard that can measure positive and negative pressures from zero (atmospheric pressure). When measuring positive pressure, the differential piston rises, and the base weight is loaded on the differential piston to balance the differential piston and the simple piston; when measuring negative pressure, the simple piston rises, and the weight is loaded on the simple piston to balance the simple piston and the differential piston. The lower limit of the double piston pressure vacuum gauge is: -0.1MPa; the upper limit of the measurement can be: 0.25MPa, 0.6MPa, 1MPa. If the range of the double piston pressure vacuum gauge to be tested is inconsistent with the above range, the value closest to the above range can be selected.
4 Measurement performance requirements
4.1 Accuracy level
The accuracy level and maximum allowable error of the double piston pressure vacuum gauge shall comply with the provisions of Table 1. Table 1 Accuracy grade and maximum allowable error
Accuracy
Positive pressure part
Pressure value is between 0.01MPa and
Maximum allowable error
Negative pressure part
Pressure value is between (0 and 0.01)
When the upper limit of measurement is 0.02, it is the actual measured pressure value of 0.01MPa. ±0.02%
Pressure value is between 0.01MPa and
±0.02%
Pressure value is between (0 and 0.01)
When the upper limit of measurement is 0.05, it is the actual measured pressure value of 0.01MPa. ±0.05%
Pressure value is between (-0 .1~
When the pressure value is between (—0.01
0.01)MPa, it is ±0.02% of the actual
measured pressure value
When the pressure value is between (—0.1~
-0.01)MPa, it is ±0.05% of the actual
measured pressure value
±0.02% of 0.01MPa
When the pressure value is (—0.01
0)MPa, it is ±0.05% of
-0.01MPa
Effective area of differential piston
JJG159—2008
The maximum allowable error of the effective area of differential piston shall comply with the provisions of Table 2. Table 2 Maximum allowable error of effective area of differential piston Accuracy grade
Proportional constant K value
Maximum allowable error of effective area of differential piston ±0.01%
The maximum allowable error of proportional constant K value shall comply with the provisions of Table 3. Table 3 Maximum allowable error of proportional constant K value
Accuracy grade
Special base code quality
Maximum allowable error of K value
The maximum allowable error of special code quality shall comply with the provisions of Table 4. Table 4 Maximum allowable error of special code quality
Accuracy grade
Verticality
Maximum allowable error of special magnetic code quality
The deviation of the verticality of the plane of the differential piston and simple piston bearing plate of the double-acting cold pressure vacuum gauge to the piston axis shall comply with the provisions of Table 5.
Table 5 Verticality
Accuracy Grade
4.6 Piston Rotation Duration
Simple Piston
Verticality is not greater than
Differential Piston
The differential piston rotation duration should be no less than 10s, and the simple piston rotation duration should be no less than 20s. 4.7 Drop Speed
The drop speed of the simple piston and differential piston should comply with the provisions of Table 6. 2
Accuracy grade
Discrimination
Monitoring of double-piston pressure vacuum gauge
Accuracy grade
Sealing
Double-piston
On the measuring range
JJG159—2008
Descending speed
Descending speed is not more than/mm·min-1
Simple piston
Discrimination
Greater than/mg
Should comply with the provisions of Table 8
Vacuum gauge calibrator
Precision pressure gauge
General technical requirements
Geming ETR
Double-piston pressure vacuum gauge calibration
Accuracy grade, manufacturer's name and date of manufacture and other markings. The force drop of the differential piston after 5ni is no more than the model, instrument number, measuring range, 5.1.2 The instrument number, nominal pressure value or mass value shall be marked on the load plate and special code. 5.1.3 The motor shall rotate normally and smoothly without any vibration that may affect the metering performance. 5.2 Piston system The piston of the double piston pressure vacuum gauge shall rotate flexibly and move freely in the piston cylinder without any jamming. The working surface of the piston and piston cylinder shall be smooth and flawless, without any rust or scratches that may affect the metering performance. 5.3 Special base weights and bearing plates
5.3.1 The surface of the special weights and bearing plates of the double piston pressure vacuum gauges that are calibrated for the first time should be intact, with wear-resistant and anti-rust layer (such as bluing, blackening or chrome plating) The weights shall not have rust spots, and should be smooth without sand holes and other damage. 5.3.2 The concave and convex surfaces of each magnetic weight of the double piston pressure vacuum gauge must be correctly matched, not too loose or too tight, and can maintain concentricity.
5.3.3 The magnetic weights of the same nominal value should have the same shape and size. 5.3.4
If there is an adjustment cavity on the weight or bearing plate, the upper surface of the adjustment plug shall not be higher than the surface of the weight or bearing plate. 5.3.50.The special base weight of the 02-level double piston pressure vacuum gauge should be made of non-magnetic metal material. 6 Measuring instrument control
Measuring instrument control includes initial calibration, subsequent calibration and in-use inspection. 6.1
Verification items
The calibration items of the double piston pressure vacuum gauge are shown in Table 9. Table 9 Verification items
Verification items
Piston system
Special base weight and bearing plate
Effective area of differential piston
Proportional constant K value
4.4, special weight quality
Verticality
Continuous time of piston rotation
Descending speed
Discrimination
Sealing
Initial calibration
Note: "Ten" in the table indicates items that should be inspected, and "one" indicates items that may not be inspected. 6.2 Verification conditions
6.2.1 Verification equipment
6.2.1.1 Primary standard for verification
Subsequent verification
In-use inspection
A piston pressure gauge, piston pressure vacuum gauge or double piston pressure vacuum gauge with an effective area maximum allowable error absolute value less than half of the effective area maximum allowable error absolute value of the differential piston to be tested can be selected as the standard instrument. Generally, piston pressure gauges with the same upper limit of measurement are selected. 6.2.1.2 Ancillary equipment for verification
See Table 10 for the ancillary equipment for verification.
Instrument name
Standard balance or mass comparator
Standard magnetic code
Level·
Digital indicator or micrometer"
Stopwatch·
Precision pressure gauge·
Piston position indicating device
Oil-gas isolator
Note: * indicates necessary equipment.
6.2.1.3 Working medium||t t||JJG159—2008
Testing equipment
Technical requirements
Comply with the requirements of the corresponding level
Comply with the requirements of the corresponding level
Gram group, milligram group
Graduation value is 1~2
Range is 5mm or 10mm
Graduation value is Ji. or 1
Select the appropriate level and test according to the situation Upper limit position indication, resolution better than 0.1mm
Inner diameter not less than 80mm
The working medium to be used for the double piston pressure vacuum gauge is shown in Table 11. Table 11
Working medium
Transformer oil or a mixture of transformer oil and kerosene 6.2.2 Environmental conditions
Working medium and performance index
Working medium kinematic viscosity
(at 20℃)/mm·s-1
Special code mass weighing
Special code mass weighing
Verification of proportional constant K value, differential
Piston effective area, discrimination, etc.
Verification of verticality
Descending speed verification
Piston rotation duration and descending
Speed verification
Sealing degree verification
Observe piston balance| |tt||Isolate the liquid piston pressure gauge from
Different working media to be tested
Acid value is not greater than
/KOHmg·g-1
The calibration of the double piston pressure vacuum gauge is carried out in a constant temperature room at room temperature (meeting the requirements of Table 12) and relative humidity below 80%. Before calibration, the double piston pressure vacuum gauge must be placed at the calibration temperature for more than 2 hours before calibration. Table 12 Ambient temperature
Ambient temperature
Accuracy level
Piston effective area calibration
Other items calibration
(20±1)℃
(20±2)℃
(20±2)℃
6.2.3 Other conditions
JJG159—2008
Calibration should be There is no mechanical vibration that affects the measurement performance. 6.3 Verification method
6.3.1 Appearance inspection
Inspect by hand feeling, visual inspection and power on according to 5.1. 6.3.2 Piston system inspection
Take out the differential piston and simple piston of the double piston pressure vacuum gauge from the piston cylinder, clean them with aviation gasoline or solvent gasoline, and leave them for 10 minutes. When the surface solvent opens, turn the single ON pressure vacuum gauge on the double piston pressure vacuum gauge upside down, pour out the working medium of the oil system, and repeatedly rinse the two cylinders, oil system and gas system with aviation gasoline and sealant gasoline. After the solvent evaporates, inject new medium into the oil system, and then put the differential float and simple piston into their respective openings according to 5.2
In the piston cylinder filled with working medium
6.3.3 Special code and bearing inspection
Inspect by hand feeling and food test according to 5.3.
6.3.4·Seal of the tester
In the case of double piston pressure gauge with multiple outputs, the gas source valve can be closed at the test pressure specified in the
8 and the output of the pressure gauge of the pressure gauge of the specified range can be controlled. If there is
, the outlet is connected with a bolt seal without a hole. Close the valve to the atmosphere, pressurize the gas to the gauge with a pressurized gas, keep it for 5 minutes, and then re-pressurize it to the test pressure, and then close the gas source for
min, and calculate the drop value of the double piston pressure vacuum gauge during this
6.3.5 Adjust the verticality of the axis of the horizontal piston of the bearing plate
Remove the screw
The bubble on the level gauge presses one of the pistons to open the working position, and the bubble on the bearing plate should remain in the middle position. Then use a magnetic rod to move the level gauge 00° (the bearing plate does not move), and the bubble in the water should still be in the middle position. Then rotate the plate 90° to the value of the position. Use the same method to check the verticality of the other group. The bubble in any piece is the same as the bubble in any piece. 6.3.6 Piston rotation duration test. Exhaust the air in the oil circuit of the double piston pressure vacuum tester, use the power of the brick to deviate the middle piston upward, so that the other piston rises to the working position. The piston rotates clockwise at the maximum initial speed under no load, and the stopwatch is used for timing at the same time. The interval from the beginning of the piston rotation to the complete rotation is the duration of the activity. Use the same method to measure the rotation duration of the other piston. Average value.
6.3.7 Piston descending speed verification
4 plug MER
The previous interval must be measured 23 times, and the average
Open the valve of the double piston pressure vacuum gauge tester to the atmosphere, press the differential piston with a magnetic code, and add a 1kg special magnetic code on the simple piston to make it rise to about 2mm higher than the working position, close the valve of the oil pressure device leading to the piston system, and place a dial indicator (micrometer) on the simple piston to raise the contact of the meter by about 5mm. The pressure is 2min. At this time, start the motor to drive the piston to rotate, observe the moving distance of the dial indicator (micrometer) pointer, and use a stopwatch to measure the time. Each measurement time is not less than 1min, and the piston descending speed of 1min is recorded. Use the same method to verify the descending speed of the differential piston. At this time, press the simple piston with a code, and add a basic code mass equivalent to the upper limit pressure of the measurement range of 6
on the differential piston. JJG159-2008
The descending speed of the simple piston and the differential piston must be measured three times, and the maximum value of each shall be taken. 6.3.8 Verification of the proportional constant K value
Open the double piston pressure vacuum gauge tester to the atmosphere, use the oil pressure device to create pressure, make the two pistons rise to the working position, start the motor to drive the two pistons to rotate, and use the method of adding small weights to make the two pistons reach the initial balance. To determine whether the two pistons are balanced, it should be observed whether they remain stable in the working position or descend at the same insignificant speed.
After determining that the two pistons are balanced, perform the pressure increase and pressure reduction verification point by point according to the number of inspection points specified in Table 13 and the weight of the basic weight added at each inspection point. At each point, NHS is used to balance the weights added to the simple piston and the differential piston. When the balance point is returned, the initial balance shall be re-measured. The difference between the initial balance quality before and after the calibration shall not exceed the accuracy of the calibration point in Table 14, otherwise the calibration shall be repeated. The difference between the magnetic code and the simple piston is allowed to be proportional to the constant K, and the value is calculated according to the formula (AMETROLOGY where K.
The value of the proportional constant K at the i-th measuring point: IS
Differential piston
-After the initial balance, the code mass added to the i-th calibration point of the differential piston relative to the balance point, kg; After the initial balance, the code mass added to the i-th calibration point of the simple piston relative to the balance point, kg. The average value of the proportional constant K value is calculated according to formula (2): K flat meat
In the formula: K average average value of the proportional constant K: n
JJG159—2008
Number of measurements (0.02 level, n=10; 0.05 level, n=6). The maximum error of the proportional constant K value is calculated according to formula (3): Ok
In the formula: 8k-the absolute value of the maximum error of the proportional constant K; AK-the maximum absolute value of the difference between the average value and the single value of the proportional constant K. 6.3.9 Verification of discrimination
The verification of discrimination of double piston pressure vacuum gauge is carried out during the K value verification. When the simple piston and the differential piston are balanced at the starting balance point, the minimum code that can destroy the balance of the two pistons is added to the differential piston, and the quality of the code is the discrimination of the double piston pressure vacuum gauge. 6.3.10 Verification of effective area of differential piston
As shown in Figure 1 or Figure 2, connect the double piston pressure vacuum gauge to be tested with the standard instrument, open all valves of the gas and oil circuits, and adjust the horizontal position. Then close the valve to the atmosphere, add a magnetic code that can produce a pressure equivalent to 0.1MPa on the differential piston to be tested and the piston of the standard instrument as the starting balance point, start the motor to rotate the piston: pressurize with the gas source, adjust the pressure with the gas pressure regulating gas, so that the differential piston to be tested and the piston of the standard instrument (if the standard instrument is a double piston pressure vacuum gauge, use the differential piston) are both in the working position. If it is unbalanced, add a small base code on the rising piston until it is balanced.
Yujiu production
Figure 1 Schematic diagram of differential piston effective area measurement Figure 1 (a): Tested double piston pressure vacuum gauge (b)
1-simple piston; 2-differential piston side hole; 3-differential piston, 4, 9-gas line valve; 5, 10, 12, 15-atmospheric valve: 6-pressure air inlet: 7-oil and gas isolator, 8-pressure pipe; 11-gas source; 13-gas pressure regulator; 14, 17-oil line valve; 16-oil pressure gauge Figure 1 (b): High-grade standard piston pressure gauge 1-oil and gas isolator; 2-oil cup: 3-piston pressure gauge; 4-pressurizer; 56, 7 valves To determine whether the two pistons are balanced, it should be observed whether they remain stable in the working position or drop at the same insignificant speed.
After confirming that the two pistons are balanced, add a pressure that can produce an equivalent of 8 on the differential piston to be tested and the piston of the standard instrument respectively.
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