JJG 49-1999 Verification Procedure for Bourdon Tube Precision Pressure Gauges and Vacuum Gauges JJG49-1999 Standard download decompression password: www.bzxz.net
This procedure applies to the initial verification, subsequent verification and in-use inspection of the series bourdon tube precision pressure gauges and vacuum gauges with an upper limit of the measuring range of (-0.1~250)MPa.

Verification Regulation of the Bourdon TubePrecise Pressure Gauge and Vacuum GaugeJJG49—1999Replaces JJG49—1987JJG 636—1990
This regulation was approved by the State Administration of Quality and Technical Supervision on December 22, 1999, and came into force on April 1, 2000. Responsible unit: National Technical Committee on Pressure Metrology. Drafting unit: Shanghai Testing Technology Institute, Shanghai Institute of Metrology and Testing Technology. Drafting unit: Shanghai Automation Instrument Factory No. 4, Shanghai Testing Technology Institute.
This regulation is entrusted to the National Technical Committee on Pressure Metrology for the interpretation of this regulation. Main drafters:
Xuan Jiarong (Shanghai Testing Technology Institute)
Dai Xiaohua (Shanghai Institute of Metrology and Testing Technology) Additional drafters:
Yuan Defang (Shanghai Automation Instrument Factory No. 4) Dai Gendi (Shanghai Testing Technology Institute)
1 Scope
2 Overview
3! Measuring performance requirements…
3.1 Accuracy grade and allowable error of precision gauges and their relationship 3.2 Accuracy grade and metrological performance requirements of 300-grid precision gauges 4 General technical requirements
4.1 Appearance
4.2 Zero adjustment device
4.3 Micrometer
5 Control of measuring instruments:
5.1 Initial calibration, subsequent calibration and inspection during use 5.2 Picking up parts
5.3 Calibration items and calibration methods
5.4 Processing of calibration results
5.5 Calibration cycle
Appendix A Calibration record sheet for precision pressure gauges (or vacuum gauges)| |tt||Appendix B 300-grid precision pressure gauge (or vacuum gauge) calibration record Appendix C Inner page format of precision gauge calibration certificate, Appendix L Notice of failure in precision gauge calibration [Inner page format Appendix F List of calculated values ​​of allowable errors for precision pressure gauges 1074
: 1076
Verification procedures for spring tube precision pressure gauges and vacuum gauges This procedure refers to the International Organization for Legal Metrology International Recommendation No. 109 "Precision pressure gauges and vacuum gauges with non-elastic sensitive elements (standard instruments)", and adopts some contents that are in line with my country's national conditions, and retains the effective contents of the original regulations JJG49-1987 and JJIC636-1990.
1 Scope
This regulation applies to the initial calibration, subsequent calibration and in-use inspection of spring cylinder precision pressure gauges and vacuum gauges (hereinafter referred to as precision gauges) with a measuring range upper limit of (-0.1-250) MPa: 2 Overview
Precision gauges are mainly used to calibrate general pressure gauges, and can also be used for precision measurement of pressure or vacuum. Working principle of precision gauges: Under the action of pressure and vacuum, the spring tube produces elastic deformation, causing the displacement of the tube end. The displacement is amplified by the mechanical transmission mechanism and transmitted to the pointer device, and then the pointer indicates the measured pressure or vacuum value on the dial engraved with the legal unit.
Precision pressure gauges used to calibrate sphygmomanometers and sphygmomanometers can use kPa and mmHg dual scales. 3 Metrological performance requirements
Accuracy grade and allowable error of precision gauges and their correlations 3.1
The accuracy grade and allowable error of precision gauges and their correlations are shown in Table 1. 1
Accuracy level
Allowable error% (calculated as a percentage of the upper limit of measurement) = 0.06
3.1.1 Indication error
Accuracy level
Allowable error% (calculated as a percentage of the upper limit of measurement) = n.25
Within the measurement range, the indication error of any calibration point shall not be greater than the allowable error. 3.1.2 Return error variation]
Within the measurement range, the return error of any calibration point shall not be greater than the absolute value of the allowable error. 3.1.3 Tap displacement
After tapping the case, the change in the pointer indication shall not be greater than 172% of the absolute value of the allowable error. 3.1.4 Pointer deflection stability
Within the measurement range, the pointer deflection shall be stable, without jumping or jamming. 3.2300-grid precision meter accuracy grade and metrological performance requirements 300-grid precision meter accuracy grade and metrological performance requirements are shown in Table 21074. Performance requirements: The deviation of the position before and after calibration is not greater than the calibration point. The difference between the maximum and minimum indications is less than the value after tapping the shell. The change of the push needle indication value is not more than the upper limit of measurement. When the pointer indicates the true half of the position within 0.092.M, the nonlinearity of the indicator position is stable. General technical requirements: 4.1 Appearance 4.1.1 Appearance Accuracy grade Cabinet 207~3010 grid | |tt||At the beginning of 273--276
the difference between the maximum and minimum values ​​of the interval between any two corresponding calibration points should not be more than [/10] of the nominal value of the interval between the two calibration points. There should be no vibration or sticking.
The parts of the precision meter should be firmly assembled without looseness: 4.1.1.1
4.1.1.2 The coating of the newly manufactured precision meter should be uniform and smooth without obvious residue. 4.1.2 Marking
The dial of the precision meter should have the following markings: manufacturing unit or trademark: product name: measurement unit and number; measurement instrument manufacturing license mark and number: vacuum (-) number or negative letter: accuracy grade: factory number. 4.1.3 Reading part
The glass should be colorless and transparent, and should not have defects and damage that hinder reading; the scale plate should be flat and smooth, and the markings should be clear and visible; the indicating end of the pointer knife should be perpendicular to the scale plate and be able to measure 1/4 to 3/4 of the shortest scale line. The distance between the pointer and the plane of the scale plate should be within the range of (0.5 to 1.5) mm; the width of the indicating end of the pointer knife should not be larger than the width of the scale line. 4.1.3.4
4.1.4 Measurement upper limit value number
The measurement upper limit value number should conform to one of the following series: 1×10″1.6×10″, 2.5×10″, 4×10\6×10 where: is a positive or negative integer or zero. wwW.bzxz.Net
4.1.5 Graduation value
The graduation value shall conform to one of the following series
1×10″, 2×10″, 5×10*.
Wherein: n is a positive, negative integer or zero
4.1.6 Accuracy grade
The accuracy grade conforms to one of the following series-
0.060.10.16, 0.25, 0.4, 0.6.
4.2 Zero adjustment device
For precision meters with zero adjustment device, the zero adjustment range shall not be less than 2% of the measuring range: 4.3 Fine adjuster
For precision meters with pressure fine adjuster, the fine adjuster shall be flexible and shall not fall off during adjustment, and shall be able to play a good fine adjustment role. 1075
5 Control of measuring instruments
5.1 Initial calibration, subsequent calibration and in-service inspection The metrological performance and technical requirements of precision meters for initial calibration, subsequent periodic calibration, calibration after repair and in-service inspection shall comply with the requirements of 3.1, 3.2 and 4.
5.2 Verification conditions
5.2.1 Standard instrument
S.2.1.1 Error requirements for standard gauges
The absolute value of the allowable error of the standard instrument shall not be greater than 1/4 of the absolute value of the allowable error of the precision gauge to be verified. Note:
1 To verify the 0.16-level precision gauge, a second-class standard pressure gauge with the corresponding measuring range can be selected. 2. To verify the 0.06-level precision gauge, a first-class standard pressure gauge with the corresponding measuring range can be selected. 5.2.1.2 The available standard instruments are as follows: a. Piston pressure gauge:
b. Active pressure vacuum gauge:
c. Liquid pressure gauge;
d. Other pressure measuring standards that meet the error requirements of standard instruments. 5.2.2 Auxiliary equipment
5.2.2.1 Pressure source, vacuum source.
5.2.2.2 Pressure regulator.
Oil-gas, oil-water separator.
S.2.3 Environmental conditions
Environmental temperature
0.06, 0.1, 0.16, 0.25 precision meters: (20=2)C. 0.4, 0.6 precision meters: (20=3).
Relative humidity: not more than 85%,
Environmental pressure: atmospheric pressure.
Precision meters should be calibrated at least 24 hours under the environmental conditions of 5.2.3.1, 5.2.3.2, 5.2.3.3, 5.2.3.4
5.2.4 Working medium for verification
For precision gauges with a measurement upper limit value of no more than 0.25 MIA, the working medium shall be clean air or a light-toxic, harmless and chemically stable gas.
For precision gauges with a measurement upper limit value greater than 0.25 MIA, the working medium may be a non-corrosive liquid. 5.2.4.21
For precision gauges with a measurement upper limit value of no more than 2.5 MPa, which are actually used to measure gas pressure, gas is also used as the working medium during verification.
5.3 Verification items and verification methods
5.3.1 Appearance
Observe visually to see if it meets the requirements of 4.1. 5.3.2 Indication error: The precision gauge for calibration of range error (variation) and tapping displacement shall be installed on the calibration device according to the working position and shall be tight and leak-free: 5.3.2.1
When selecting a precision gauge with a standard piston pressure gauge and an upper limit value of no more than 0.6MPa, make sure that the pointer shaft of the precision gauge is on the same horizontal plane with the lower end surface of the active part. Otherwise, the pressure value caused by the height difference of the liquid column must be corrected, and the pressure correction value should be calculated according to the following formula:
Ap = h'g+h,Pa
Where: 0——Working medium density kg/im (density of transformer oil at 2U β-.86×103kg/mr)\-—Gravitational acceleration at the calibration location m/s: It is the height difference between the center axis of the meter being tested and the lower end face of the piston m.(1)
When the pointer axis of the precision meter being tested is higher than the lower end face of the piston, △ is corrected, and a small code corresponding to the pressure value should be added to the bearing plate of the piston pressure gauge for correction. 5.3.2.3 The precision indication error calibration points should be no less than 8 points (excluding zero value): The calibration points should be evenly distributed within the measurement range as much as possible.
5,3.2.4 During the calibration, the pressure should be raised or lowered steadily from zero position, and each calibration point should be calibrated. When the indicated value reaches the upper limit of measurement, the pressure source (or vacuum source) should be cut off, and the pressure should be withstood for 3tnL, and then the pressure should be lowered and raised steadily according to the original calibration point for re-testing. Impact and return should be avoided when raising or lowering the pressure. For each calibration point, two readings should be taken when raising and lowering the pressure. The first reading should be taken before tapping the case; the second reading should be taken after tapping the case (estimated at 1/10 of the scale value), and the reading after tapping and the pointer change caused by tapping the case before and after should be recorded in the calibration record (see Appendix A, B). 5,32.5 In some low-pressure areas, the pressure resistance calibration should be carried out according to the air voids of more than 90% of the air pressure in the area. 5.3.2.6 For 0.06 and 0.1 precision meters, the method of 5.3.2.4 shall be used for three consecutive times; for 0.16 and 0.25 precision meters, the method of 5.3.2.4 shall be used for two consecutive times; for 0.4 and 0.6 precision meters, the method of 5.3.2.4 shall be used for one consecutive time; for 300-division precision meters, the method of 5.3.2.4 shall be used for two consecutive times. Adjustment of the precision meter is not allowed during the entire calibration process. 5.3.2.7 Indication error:
For each calibration point, during the step-up (or step-down) and step-down (or step-up) calibration, the difference between the indication and the standard value before and after tapping the case shall meet the requirements of 3.1.1. 5.3.2.8 Return error (variation)
For the same calibration point, the difference in the indication after lightly melting the case during the pressure increase (or pressure reduction) and pressure reduction (or pressure increase) shall meet the requirements of 3.1.2. 5.3.2.9 Tap and shift
For each calibration point, the change in the pointer indication caused by tapping the case during the pressure increase (or pressure reduction) and pressure reduction (or pressure increase) calibration shall meet the requirements of 3.1.3. 5.3.2.1 Stability of pointer deflection
During the indication error calibration process, the deflection of the pointer shall be observed visually and shall meet the requirements of 3.1.4. 5.3.2.1After the 1300-division precision meter is calibrated, it shall meet the requirements of 3.2. 5.4 Handling of verification results
5.4.1 Precision meters that have been verified to have a lower accuracy level than the original level may be downgraded for use, but the mark of the accuracy level must be changed: Precision meters that have been verified to have a higher accuracy level than the original level shall not be upgraded. 54.2 A "Verification Certificate" shall be issued to precision meters that have passed the verification, and the qualified accuracy level shall be given. The verification certificate for 300-point precision meters shall give the verification results (see Appendix C), and the verification value shall be the arithmetic mean of the 4 readings after tapping the case. Precision meters used for mandatory verification shall be accompanied by a seal mark. 5.4.3 For precision meters that have failed the verification, a "Verification Failure Notice" shall be issued, and the unqualified items and contents shall be indicated (see Appendix D)
5.5 Verification cycle
The verification cycle of precision meters shall generally not exceed 1 year. 1077
Drum inspection form: Use single diameter
Standard instrument used: Name
Standard instrument
(or direct empty value)
Light hub picked up value
First calibration
Certificate number:
Second calibration
Correction:
Calliance:
Calliance officer:
Upper limit of measurement
Measurement range
Appendix A Calibration record form for precision pressure gauge (or vacuum gauge) MPa Accuracy level
MPa Accuracy grade
Change of indication of the pointer before and after light tapping
First calibration
Year Month Day
Second calibration
Difference between the maximum and minimum values ​​of the indication at the calibration point
Reviewer:
Manufacturer
Average value of the minimum readings at the control point
Year H Day
Check point
The maximum value of the marked value at the point
Note: 1. For precision meters of grade 0.06, grade 0, and grade 1, add one calibration record in the columns of the value indicated by the instrument after tapping and the change of the indication of the needle before and after light tapping. 2. Heart.4 test, 0., 6 successive precision thank you table in "after tapping, only indicate the value\ and\ before and after light acid, indicate the change of the value, each column is reduced by 1 time. Test delay record, test working medium
test time room temperature
test result
1. The difference between the maximum value and the minimum value (including zero point) of the indication
allowable value
2. Maximum indication of pointer
Variation
Additional value
3. Maximum deviation of each reading of the calibration point and the marked value of the point
Additional value
Calibration result:
Conformity level
Instrument to be tested: Unit of use
Instrument used: Name
Instrument
Pressure value
(or vacuum value)
Indication of the instrument to be tested after tapping
First calibration
First calibration
Calibration certificate number:
Instrument technician:||t Appendix B Calibration Record Sheet for (300-grid Precision Pressure Gauge or Vacuum Gauge) Upper Limit of Measurement Rate
MTaAccuracy Grade
MI'aAccuracy Grade
Change in Indication Value of Gauge before and after Tap Calibration Point Indication First Calibration
Difference between Maximum and Minimum Values ​​of First Calibration
Inspector:
Manufacturer
Calibration Point Changes
: 30U Gradient Precision Gauge
Minimum Reading
Average Value
Time of Each Phase Calibration
Point According to the value
Control working medium
Verification time and temperature
Verification results
1. The maximum and minimum values ​​of the indicated value (including zero point)
Allowed value
2. The pointer expansion
Allowed value
3. The maximum and minimum values ​​of the range between any two adjacent verification points of the 300-division precision meter
Allowed value
Verification results:
Conformity level
Upper limit of measurement
Verification temperature
Format of the inner page of the verification certificate of precision meter
Allowable error
Calibration medium
Calibration data
Standard pressure value (single diameter:
Calibration value (unit:
Note: 1.300-division precision meters must be used according to the values ​​in the calibration certificate. If there is no pressure (filling) value given in the certificate, a linear internal table must be compiled.
2. When the precision meter is used, the temperature deviates from the calibration temperature (20±2)℃ (0.06, 0.1, 0.16, 0.25 level) to (20±3) (0.4, U.6 level). The error of the indicated value should meet the following requirements:
D=1 (8+K-20)
In the formula; 8——absolute value of allowable error%: (r2-tt):
2\--Environmental saturation [5.-40t) any value between; when 2 is higher than or lower than 22℃ or 23℃, take 22℃ or 23℃; when 2 is lower than or lower than 18℃ or 17℃, take 18℃ or 17℃; K
Temperature coefficient: ±0.04%Representation method of data in 1 and basic difference
Name of calibration standard instrument:
Accuracy grade:
Factory number:
Calibration lens:
Calibration working medium:
Qualified items and contents:
Appendix D
Precision gauge calibration failure notice inner page formatCalibration results
Upper measurement limit
Appendix E List of calculated values ​​of allowable error of precision pressure gaugeAccuracy grade
± 0. 0H0036
1 0.00096 | | tt | | ±D.IXI96 | ±0.000625
± 0.0016
+ (1.(H)24
±01.0036
=0,0096
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