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Mechanical Industry Standard of the People's Republic of China
JB/T7393-1994
Piston Pressure Gauge
Published on August 23, 1994
Implemented on May 1, 1995
Published by the Ministry of Machinery Industry of the People's Republic of China Subject Content and Scope of Application
Mechanical Industry Standard of the People's Republic of China
Piston Pressure Gauge
JB/T7393-1994
This standard specifies the basic parameters, technical requirements, test methods, inspection rules, marking, packaging and storage of piston pressure gauges. This standard applies to piston pressure gauges (hereinafter referred to as pressure gauges) that apply load to the piston directly or through a load-bearing device (rod). Reference standards
GB1031
GB1146
GB1184
GB8170
ZBY002
ZBY003
Method for determination of acid value of petroleum products
Method for determination of kinematic viscosity of petroleum products and calculation of dynamic viscositySurface roughness parameters and their values
Level
Shape and position tolerance, rounding rules for specified figures without tolerancebzxZ.net
Basic environment and test methods for transportation and storage of instruments and metersGeneral technical conditions for packaging of instruments and meters
Types and basic parameters
The types of pressure gauges are divided into 06, 6, 25, 60, and 250 according to their upper limit values of measurement. 3.2 Accuracy level
The accuracy level of pressure gauges is 0.05 and 0.2. 3.3 Basic parameters
The basic parameters of the pressure gauge shall comply with the provisions of Table 1. Table 1
Parameter name
Upper limit of measurement
Upper limit of measurement
Approved by the Ministry of Machinery Industry on August 23, 1994
Implemented on May 1, 1995
Parameter name
Nominal area of piston
Nominal mass of piston with chassis device
Nominal mass of special base code
Number of special base code
Technical requirements
4.1 Normal working conditions
Ambient temperature: 10~30;
Relative humidity is not more than 80%:
Atmospheric pressure: 86-106kPa.
4.2 Reference working conditions
JB/T7393-1994
Continued Table 1
The vertical position deviation of the axis of the pressure gauge piston should not be greater than 5\; a.
There is no accumulated gas in the working fluid;
The initial angular velocity of the piston rotating freely in the clockwise direction is 30~60／minThe ambient temperature, relative humidity and atmospheric pressure should comply with the provisions of Table 2: Table 2
Accuracy level
Ambient temperature
20 ±2
e. The chassis device is adjusted to the scale line of the working position indicator: 9
Relative humidity
Weather pressure
86~106
f. The mass of the special base weight and the piston with chassis device should take into account the influence of the gravity acceleration value at the place of use (testing); 5
Note: The standard gravity acceleration value is 9.80665m/s2 or the gravity acceleration value at the place of use specified by the user, see Appendix E (reference). When the deviation value of the gravity acceleration value at the place of use (testing) is within the range specified in Table 3, its mass may not be corrected.
Accuracy level
Allowable deviation value
8. The special rank weight of the 250 type pressure gauge should be stacked on the supporting end face of the chassis device in the order of numbering. 4.3 Basic error
JB/T7393-1994
The basic error limit of the pressure gauge shall comply with the provisions of Table 4. Table 4
Accuracy level
4.4 Verticality
When the pressure value is below 10% of the upper limit of measurement, ±0.05% of the upper limit of measurement
±0.2% of the upper limit of measurement
When the pressure value is between 10% and 100% of the upper limit of measurement, ±0.05% of the actual pressure value
±0.2% of the actual pressure value
The supporting end surface of the chassis device should be perpendicular to the piston axis, and the deviation should not be greater than 5'. 4.5 Piston rotation duration
When the pressure gauge is under the load condition of 50% of the upper limit of measurement, and the initial angular velocity of the piston rotating freely in the clockwise direction is 120±10r/min, the piston rotation duration should not be less than the provisions of Table 5. Table 5
Piston drop speed
Piston rotation duration
Special magnetic code outer diameter is not greater than
The pressure gauge under the load condition of measuring the upper limit value, the piston drop speed should not be greater than the provisions of Table 6. Table 6
4.7 Sensitivity limit
Parameter name
Plug drop
mm/min
JB/T7393-1994
The pressure gauge under the load condition of measuring the upper limit value, the sensitivity limit should not be greater than the provisions of Table 7. Table 7
Piston effective area
Parameter name
The allowable range of the average value of the piston nominal area and the piston effective area of the pressure gauge and the relative error between the average value and the individual value shall comply with the provisions of Table 8.
Nominal area of piston
4.9Mass error
Allowable range
0.996~1.004
0.496~0.504
0.198~0.202
0.099~0.101
0.0495~0.0505
Relative error
For the special code of the pressure gauge and the piston with chassis device, the relative error between the actual mass value after adjustment and the mass value calculated by the effective area of the piston should not be greater than that specified in Table 9. Table 9
Accuracy level
Mass error
4.10Sealing
The pressure system of the pressure gauge should be subjected to a 10-min sealing test under the rated pressure conditions specified in Table 10. The pressure drop value after 5min4
JB/T7393-1994
should not be greater than the value specified in Table 10. Table 10
4.11 Working fluid
Rated pressure
The kinematic viscosity and acid value of the working fluid used in the pressure gauge should comply with the requirements of Table 11. Table 11
Parameter name
Upper limit of measuring range
4.12 Special code and chassis device
Kinematic viscosity at 20C
9001100
Pressure drop value
Acid value not greater than
mgKOH/g
For the same type of pressure gauge, the special base code of equal mass shall have the same shape and size; a.
b. The supporting end faces of the special brick code and the chassis device shall be parallel to each other, and their parallelism shall comply with the provisions of Class 8 in Appendix 3 of GB1184;
The surface roughness Ra value of the supporting end faces of the special code and the chassis device shall comply with the provisions of GB1031, and the sampling length c.
shall not exceed 3.2#m within 2.5mm;
d. On the special code and chassis device, there should be a device for the user to adjust the mass. 4.13 Indicator
a. The pressure gauge should be equipped with a piston working position indicator; b. The pressure gauge should be equipped with a piston limit travel limiter. 4.14 Level
The pressure gauge should have a horizontal device and a horizontal adjustment position. a. The level bubble used in the horizontal device should be a circular level bubble with a nominal angle of 8' selected from GB1146, and should meet the requirements of Article 4.2, item a;
b. The horizontal adjustment device should be flexible and stable when adjusting the level, and there should be no free stringing phenomenon. 4.15 Appearance
The parts of the pressure gauge must be made of corrosion-resistant, non-oil-immersed materials, or coated (plated) with an appropriate anti-corrosion layer. The anti-corrosion layer should be smooth, beautiful, uniform and firm. There should be no obvious processing marks, exposed bottom, burrs and scratches on its visible surface; the markings should be complete and clear. 4.16 Transport environment resistance performance
JB/T7393-1994
The pressure gauge should be subjected to the transport environment resistance performance test specified in ZBY002 under transport packaging conditions. The test items and condition parameters are: 40t for high temperature test; -25℃ for low temperature test; free fall height is 100mm. 5. Test method
The pressure gauge test sequence shall be in accordance with the provisions of Appendix A (Supplement). 5.1 Test conditions
In addition to the reference working conditions in Article 4.2, the following requirements must also be met: 3.
Fill the pressure system with the gas in accordance with Article 4.11. Working fluid with parameters specified in Table 11 of Article 11; b. Adjust the pressure gauge to a horizontal position:
c. When the chassis device is adjusted to the scale line of the working position indicator, the piston should be able to rotate freely; d. In the absence of jumping, superimpose the special magnetic code on the chassis device. 5.2 Standard instrument
Use a piston pressure gauge with an accuracy level of 0.02 or 0.05. 5.3 Inspection method
The pressure gauge under inspection is compared with the standard instrument using the hydraulic static balance method. 5.4 Sealing test (Article 4.10)
Close the valve leading to the piston cylinder, and evenly and slowly pressurize to the specified value of Table 10 of Article 4.10. Withstand pressure for 10 minutes. Use a stopwatch to calculate the time from the 6th minute. At this time, the pressure drop value of the pressure system should be observed on a pressure gauge with an accuracy level of not less than 0.4 (5 minutes).
5.5Verticality test (Article 4.4)
Adjust the piston of the pressure gauge to the position specified in Article 4.2, Item e. Place the tubular vial with an angle value of 2 on the chassis and try to keep it in the middle of the chassis. Adjust the level adjustment device so that the bubble is in the middle. Then, rotate the tubular vial 90' (the chassis does not move), and use the same method to adjust the level adjustment device so that the bubble is in the middle. Repeat the adjustment of the level adjustment device until the bubble is in the middle when the tubular vial is placed in these two positions. Then place the tubular vial at the 0, 90\ and 45 positions respectively (the 0 position can be placed arbitrarily for the first time). At each position, the chassis should be rotated 90 and 180°. At this time, the deviation of the bubble from the middle position should not be greater than 5°.
Each time the level device is adjusted to any position, the deviation of the bubble in the circular vial device on the base from the middle position should not be greater than 5.
5.6 Piston rotation duration test (Article 4.5) Under the conditions specified in Items a, b, d, e of Article 4.2 and Article 4.5, let the piston rotate freely and determine the initial angular velocity. When the number of revolutions measured in 10s is 20±1 revolution, it is the initial angular velocity. At this time, start counting the time with a stopwatch until the piston stops rotating completely. The piston rotation duration can be measured three times, but two times must be qualified. 5.7 Piston descent speed test (Article 4.6) Under the conditions specified in Items a, b, c, d, e of Article 4.2 and Article 4.6, turn off the pressure system. Put the probe of the dial indicator at the center of the special code, measure the piston descent distance, and use a stopwatch to calculate the time. The piston descent speed must be measured three times, and the time of each measurement should not be less than 1 minute.
5.8 Sensitivity limit test (Article 4.7)
Under the conditions specified in Items a, b, c, d, e of Article 4.2 and Article 4.7, balance the pressure between the pressure gauge under test and the standard instrument. After the pressure is balanced, place a value not greater than the sensitivity limit specified in Table 7 (converted to mass value, see Table 12) on the pressure gauge under test to see if the pressure balance is destroyed. The sensitivity limit test can be carried out simultaneously with the test of the effective area of the piston. Precision
Parameter name
5.9 Piston effective area test (Article 4.8) JB/T7393~1994
Under the conditions specified in Items a, b, c, d, e of Article 4.2 and Article 4.8, test the effective area of the piston according to the test method of Article 5.3.
a. Connect the pressure gauge to be tested with the standard instrument (or install the piston of the pressure gauge to be tested on the pressure system of the standard instrument) to balance the pressure system:
b. Select the starting balance point at a pressure of about 15% of the upper limit of the pressure gauge to balance the pressure system. If it cannot be balanced, a small weight can be applied to the pressure gauge with the rising piston until it is balanced. To determine whether the pressure system is balanced, the two pistons remain unchanged in the working position, or decrease at the same insignificant speed; c. Select inspection points within the measuring range of the pressure gauge to be tested, and they should be evenly distributed. Perform the pressure balance inspection of each inspection point according to the inspection method of item b of Article 5.9. For the 0.05-level pressure gauge, four points should be inspected when the pressure is increased and reduced; for the 0.2-level pressure gauge, only four points should be inspected when the pressure is increased:
d. After the inspection of this project is completed, the starting balance point must be re-inspected (according to the inspection method of item b of Article 5.9). The difference between the two times should not be greater than 0.005% and 0.01% of the balance point pressure for 0.05 and 0.2 pressure gauges, respectively. If the tolerance is exceeded, the initial pressure balance and the effective area of the piston should be re-measured;
e. The calculation of the individual value, average value and error of the effective area of the piston shall be in accordance with the provisions of Appendix B (Supplement); f. The number of digits retained by the average value of the effective area of the piston after the numerical rounding shall comply with the provisions of Article B.5 of Appendix B (Supplement), and the average value after rounding is the effective area of the piston. 5.10 Quality error inspection (Article 4.9)
. The mass of the special code, the piston with chassis device and its connected parts shall be weighted according to the effective area of the piston, the gravity acceleration (or standard gravity acceleration) at the place of use (inspection) and the buoyancy of air; b. The weighting and error of the mass shall be calculated according to the mass error in Appendix C (Supplement). Then the mass weighting shall be carried out according to the inspection instrument specified in Appendix D (Supplement). 5.11 Inspection of working fluid (Article 4.11) Kinematic viscosity shall be inspected according to the method specified in GB265. Acid value shall be inspected according to the method specified in GB264. 5.12 Inspection of special base weight and chassis device (Article 4.12) a. Parallelism of the supporting end faces of the special magnetic weight and chassis device: inspected with a dial indicator; b. Surface roughness of the supporting end faces of the special magnetic weight and chassis device: compared with surface roughness comparison sample blocks; c. Others shall be inspected visually.
5.13 Inspection of indicating device, level bubble and appearance (Articles 4.13 to 4.15)7
Visual inspection.
5.14 Inspection of resistance to transportation environment performance (Article 4.16) JB, T/393-1994
Inspected according to the requirements of Article 4.16 and the method specified in ZBY002. After all the tests, the inspection shall be carried out in accordance with Articles 5.4-5.8 and Items a and c of Article 5.12 of this standard.
6. Inspection rules
6.1 Factory inspection
6.1.1 Inspection items
The inspection items shall be in accordance with the provisions of Table 13:
6.1.2 Sampling and judgment rules
Inspection items
Verticality
Continuous time of piston rotation
Piston descending speed
Number limit
Piston effective area
Quality error
Sealing
Indicating device
Level bubble
Inspect each unit according to the factory inspection items specified in this standard. If one of the inspection items of a pressure gauge fails to meet the requirements, the pressure gauge shall be judged as a defective product; it can only be judged as a qualified product after all the specified factory inspection items are qualified. Qualified products shall be accompanied by a certificate of conformity before leaving the factory.
6.2 Type inspection
6.2.1 Inspection items
In any of the following cases, the pressure gauge shall be subjected to type inspection in accordance with all technical requirements and test methods of this standard: a.
Test and identification of new products;
Regular inspection of pressure gauges produced in batches;
When there are major changes in design, process and materials; e.
d. When the pressure gauge that has been discontinued is produced again. 8
JB/T7393-1994
Note: For the two cases of b and d, Articles 4.10, 4.13 and 4.16 can be exempted. 622 Sampling and judgment rules
In the two cases of item a and c of Article 6.2.1, three pressure gauges from the trial products shall be randomly selected as the samples to be inspected; in the two cases of item b and d of Article 6.2.1, three pressure gauges from the same batch of products shall be randomly selected as the samples to be inspected. The inspected samples shall pass the type inspection only when all the specified inspection items meet the requirements of this standard. If one inspection item of a pressure gauge does not meet the requirements, items ac shall be deemed as failed inspection, and items b and d shall be doubled for re-inspection. The re-inspected samples shall only inspect the unqualified items of the inspected samples; if all the inspections are qualified, the type inspection shall be passed, otherwise it shall be deemed as failed. 7. Marking, packaging and storage
7.1 Marking
The code, number and name of this standard shall be indicated on the pressure gauge or in its instruction manual or outer packaging. The metal nameplate should be fixed on the base of the pressure gauge. The nameplate should generally indicate: 7.1.1
Manufacturer name or trademark;
Name or model;
Accuracy grade;
d. Measuring range.MPa;
Manufacture year, month and product number.
7.1.2 The special code and chassis device should print the pressure value, MPa. 7.1.3 The product number should be printed on the special base code, chassis device and piston cylinder. The special base code should be printed with a sequential number. The serial number printed on the special base code of the
250 type pressure gauge should be consistent with the mass calculation sequence of the special magnetic code. 7.2 Packaging
The packaging of the pressure gauge should comply with the corresponding provisions of ZBY003, and the protection type of the packaging can be determined by the manufacturer. 7.3 Storage
The pressure gauge should be stored in a ventilated and dry room. The room should be clean and free of corrosive impurities. 9
JB/T7393-1994
Appendix A
Test sequence
(Supplement)
Indicator, vial, appearance, marking, sealing
Verticality
Duration
Descending speed
Effective area, sensitivity limit
Mass error
Transportation environment resistance
Before inspection, the dynamometer should be placed
under reference conditions for no less than 4h
This item can be
conducted separately
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