GB/T 8107-1987 Test method for pressure differential flow characteristics of hydraulic valves
Some standard content:
1 Scope of application
National Standard of the People's Republic of China
Hydraulic valves
Pressure differential-flow characteristic test method
Hydraulic power valves-Method of determining pressure-differential flow characteristic This standard applies to the pressure differential-flow characteristic test of hydraulic valves with hydraulic oil (liquid) as the working medium. This standard can also be used to measure the pressure differential-flow characteristics of other hydraulic components with similar working conditions. Symbols, quantities and units
Symbols, dimensions and units are shown in Table 1.
Table 1 Symbols, dimensions and units
Nominal diameter of valve
Volume flow
Flow velocity relative to valve
Flow velocity relative to pipeline
Reynolds number
Valve loss coefficient
Pipeline length
Pipeline friction coefficient
Pipeline inner diameter
Celsius temperature
Kinematic viscosity
Oil density
Note: 1) M
Test device
3.1 Test loop
Mass basis +
Length T.-time,
Temperature.
Figure 1 is a basic test loop. An overflow valve should be set in the loop to prevent the system from overloading. Approved by the State Machinery Industry Commission on July 13, 1987"
MI,-1r-2
UDC 621. 646. 001. 4
GB 810787
Implemented on July 1, 1988 bZxz.net
3.2 Position of pressure measuring point
Class A 50d
GB B107--87
B-levelC-levellU
Figure 1 Pressure difference flow characteristic test circuit
Hydraulic source, 2 overflow valve, 3-stop valve: 4-test valve 5--differential gauge: 6-thermometer, 7-flow meter 3.2.1 Position of the upstream pressure measuring point of the test valve
3.2.1.1 In order to ensure that the flow at the upstream pressure measuring point of the test valve is in a stable flow state, the distance between the upstream pressure measuring point of the test valve and the front-end disturbance source shall comply with the provisions of Table 2.
Table 2 Distance between the upstream pressure measuring point of the test valve and the front-end disturbance source Test level
Distance from the front-end disturbance source
3.2.1.2 Distance between the upstream pressure measuring point of the test valve and the test valve The distance should be 5d. .
3.2.1.3 The sections of pipeline between the disturbance source and the upstream pressure measuring point of the test valve and between the upstream pressure measuring point and the test valve should be straight. 3.2.2 Position of the downstream pressure measuring point of the test valve
To ensure that the pressure can return to normal after the liquid flow is disturbed in the downstream pipeline of the test valve, the distance between the test valve and the downstream pressure measuring point should be 10d, and the pipeline should be straight.
3.2.3 When measuring according to Class C accuracy, if the position of the pressure measuring point does not meet the above requirements, the corresponding correction value should be given. 3.3 Position of temperature measurement point
The temperature measurement point should be located downstream of the downstream pressure measuring point of the test valve, and the distance between the two should be 5d, and the pipeline should be straight. 3. 4 Position of flow measurement point
The flow measurement point should be set downstream of the temperature measurement point, the distance between the two should be 5d, and the pipeline should be straight. 3.5 Requirements for pressure measuring holes
3.5.1 For Class A test accuracy, a pressure measuring joint composed of a pressure measuring ring is used. When the inner diameter of the pipeline is less than or equal to 6mm, the pressure measuring ring should contain 2 evenly distributed pressure measuring holes. When the inner diameter of the pipeline is greater than 6mm, the pressure measuring ring should contain 3 or more evenly distributed pressure measuring holes. Connect these pressure measuring holes with a catheter. The pressure hole is connected to the measuring instrument. 3.5.2 For Class B and Class C test accuracy, a single pressure hole can be used. 3.5.3 The center line of the pressure hole should intersect the center line of the pipeline vertically. 3.5.4 The diameter of all pressure holes should be equal, and its diameter should be less than or equal to 0.14, but not greater than 6mm and not less than 1mm. 3.5.5 The length of the measuring hole shall not be less than 2 times its diameter. 3.5.6 The cross-sectional area of the conduit connected to the measuring instrument shall not be less than half of the total cross-sectional area of the pressure holes. GB 8107-87
3.5.7 All pressure holes shall not be installed under the lowest point of the pipeline. 3.6 Pipes and joints
3.6.1 The inner diameter of the pipe and pipe joint connected to the test valve shall be consistent with the nominal diameter of the valve. 3.6.2 The pipeline should be installed horizontally. When this installation condition cannot be met, the measured pressure value should be corrected. 4 Test cases
4.1 Test oil
In the test report, indicate the brand of oil used in the test, and give the kinematic viscosity (in and density (o) of the oil in the entire temperature range of the test according to the test accuracy level requirements. 4.2 Oil solid contamination level
The solid contamination level of the hydraulic oil (liquid) used in the test system shall not be higher than 19/16. When there are special test requirements, it may be specified separately.
Indicate the installation position, quantity and model of the filter in the test report. 4.3 Test temperature
When testing components with hydraulic oil as the working medium, the oil temperature at the inlet of the test valve is specified to be 50°C. If other oils are used as the working medium or When there are special requirements, other provisions may be made. 4.3.1 When the test results are expressed in dimensioned form, the allowable range of variation of the oil temperature indication value during the entire test process shall comply with the requirements of Table 3.
4.3.2 When the test results are expressed in dimensionless form, it is not required that all tests are carried out at the same control temperature, but only that the oil temperature variation of each test condition complies with the requirements of Table 3.
Table 3 Allowable range of variation of oil temperature during the test Test level
Allowable range of variation
5 Test method
Use the flow regulating device of the test system to adjust the flow rate within the flow range allowed by the test valve, and measure the pressure difference (Ap) when different flow rates (α) pass through the given channel of the test valve. 6 Test measurement
6.1 During the test, when the measured parameter changes within the range specified in Table 4, it is a steady-state condition, and the readings are recorded under steady-state conditions. Table 4 Allowable range of variation of average indication value of controlled parameter Controlled parameter
Flow, %
Pressure, %
Viscosity, %
Test level
6.2 The number of measurement reading points of the measured parameter and the distribution of the readings taken should be able to reflect the performance of the tested parameter within the entire flow range. GB 810787
6.3 When calculating the average value of the measured quantity, the time interval between each measurement should be the same. 6.4 During the test, the measurement system should be selected according to the specified test accuracy level, see Appendix A. 6.4.1 Subtract the pipeline loss from the measured total pressure to calculate the pressure loss of the valve. The calculation method of pipeline loss is shown in Appendix B. 6.4.2 The pressure loss through the test valve joint is regarded as part of the valve loss. 6.4.3 When measuring the pressure difference, the corresponding differential pressure device should be selected according to the requirements of the test accuracy level to measure the inlet and outlet pressure. The pressure difference at the inlet and outlet. If two sets of pressure measuring devices are used to measure the pressure at the inlet and outlet respectively, and then calculate the pressure difference, the system error of the pressure measuring device should meet the requirements of the corresponding test accuracy level, see Appendix A.
6.5 Measurement of density and viscosity
According to the requirements of the test accuracy level, for A and B level tests, the test oil should be extracted from the test tank before the test begins, and its kinematic viscosity () and density (p) values should be determined; for C level measurements, the kinematic viscosity (v) and density (g) values provided by the oil manufacturer can be used. Expression of test results
The measured values and calculation results of all test parameters should be listed in a table and expressed by curves according to the requirements of dimensional expression or non-dimensional expression.
7.1 Dimensional expression
For valves whose internal geometry changes with flow and pressure, the test results are expressed in dimension. The test results are expressed as a curve of flow rate (g-)-pressure difference (A-force), and the oil used in the test, the test temperature, and the kinematic viscosity () and density (p) of the oil at that temperature are indicated. The typical curve is shown in Figure 2.
A to center
P judge A or B
Volume flow rate
Figure 2 Dimensional expression of square valve
7.2 Dimensionless expression
For valves with fixed internal geometry, the test results can be expressed in dimensionless form. At this time, the flow rate is expressed in Reynolds number (R.), and the pressure difference is expressed in loss coefficient (K). A curve of Reynolds number (R.)-loss coefficient (K) is drawn on logarithmic coordinate paper. Reynolds number calculation formula
Loss coefficient calculation formula
The typical curve is shown in Figure 3.
GB 8107—87
Note: When the test results are expressed in dimensionless form,According to the requirements of the test accuracy level, the Reynolds number (R) and loss coefficient (K) values are calculated using the kinematic viscosity (1) and density (0) of the oil at each test condition temperature. AB
P to A or B
Reynolds number R.
Figure 3, dimensionless expression of directional valve
A1 Test level
GH877-87
Attachment A
Test level
(Supplement)
According to the provisions of GB7935 "General Technical Conditions for Hydraulic Components", the test is carried out according to one of the three test levels A, B and C. A2 Error
Any test device and method that has been calibrated or compared with national standards and shows that the system error does not exceed the range listed in Table A1 can be used.
Table A1 Allowable system error of measurement system
Test level
Test only table parameters
Flow rate <, %
When pressure difference Ap<200kPa gauge pressure, kPa
When pressure difference Ap≥200kPa gauge pressure, %
Temperature, ℃
Note: The percentage limit range given in the table refers to the percentage of the measured value, not the maximum value of the test parameter or the percentage of the maximum reading of the measurement system.
Appendix B
Method for calculating pipeline loss
(Supplement)
B1BC level test
B,C level test, connect formula (B1) to calculate pipeline loss: Ap=A.
When calculating, you can first calculate the Reynolds number (R.) value according to formula R,
(where d can be measured with a vernier caliper), then find the friction coefficient ^ value from the R-α curve in Figure B1 according to the calculated Reynolds number (R), and finally substitute the values of ^, L, e, V, d into formula (B1) to calculate the pressure difference (△p).
32A level test
GB 810787
Transition zone
Bacterial number R.
Figure B1 Pipeline friction coefficient
When testing at level A, the calculation formula is the same as above. But the value should be found from the measured R. curve. The method of making the curve is: remove the test valve and pipeline from the test device, and connect a pipeline of the same inner diameter of appropriate length between the two pressure measuring points. The length of the pipeline should ensure that when passing through the minimum flow base, a pressure loss (△β) within the range of the instrument used is generated. Substitute the measured pressure loss (△ force) into formula (B2) to obtain ^. 2·Ap+d
Then make an experimental curve of R,-^ based on the calculated value of the Reynolds number (R.) of the pipeline. Additional notes:
This standard is proposed and coordinated by the National Hydraulic and Pneumatic Standardization Technical Committee. This standard was drafted by the 704th Institute of the 7th Institute of China State Shipbuilding Corporation and Shanghai Jiaotong University. (B2)
Tip: This standard content only shows part of the intercepted content of the complete standard. If you need the complete standard, please go to the top to download the complete standard document for free.