Some standard content:
1 Scope of application
National Standard of the People's Republic of China
Flow control valve
Testing method
Hydraulic fluid power
Testing method of flow control valvesUDC 621.646. 001. 4
GB 8104 87
This standard applies to the steady-state performance and decompression performance tests of flow control valves with hydraulic oil (liquid) as the working medium. The test methods for proportional control valves and electro-hydraulic servo valves shall be specified separately. 2 Terminology
2.1 Bypass throttling
A circuit state in which a part of the flow is diverted to the main oil tank or a circuit with lower pressure to control the input flow of the actuator 2.2 Inlet throttling
A circuit state in which the input flow of the actuator is controlled 2.3 Outlet throttling
A circuit state in which the output flow of the actuator is controlled 2.4 Three-way bypass throttling
Flow control valve itself must have bypass oil discharge! The inlet throttling state. 3 Symbols, dimensions and units
Symbols, quantities and units are shown in Table 1.
Table 1 Symbol Dimension Unit
Nominal diameter of valve
Linear displacement of control element in valve
Angular displacement of control element in valve
Volume flow
Inner diameter of pipeline
Pressure, pressure difference
Mass density of oil reservoir
Kinematic viscosity
Temperature
Etc. Bulk elastic modulus
Note: 1M
.Length
Approved by the State Machinery Industry Commission on July 13, 1987
Temperature.
Kina"
1988-07-01 implementation
4 General
4.1 Test equipment
4.1.1 Test national road
GB 810487
4.1.1.1 Figures 1, 2 and 3 are curved test circuits for inlet throttling and bypass throttling, outlet throttling and bypass throttling respectively. Figure 4 is a typical test circuit for diverter valves
It is allowed to use a comprehensive circuit containing two or more test conditions. 4.1.1.2, the flow rate of the oil source should be adjustable, and the flow rate of the oil source should be greater than the test flow rate of the valve under test. The pressure pulsation of the oil source shall not be greater than 0.5MPa.| |tt||4.1.1.3 A pressure control valve should be installed between the oil source and the pipeline to prevent the circuit pressure from overloading. 4.1.1.4 It is allowed to add components to the given basic circuit to adjust the pressure, flow or ensure the safe operation of the test system. 4.1.1.5 The inner diameter of the pipeline and pipe joint connected to the test valve should be consistent with the nominal diameter of the valve. .4.1.2 Position of the pressure measuring point
4.1.2.1 Position of the inlet pressure measuring point||tt| |The inlet pressure measuring point should be set between the downstream of the disturbance source (such as valve, elbow) and the upstream of the test valve. The distance from the disturbance source should be greater than 10, and the distance from the test valve is 5d.
4.1.2.2 The outlet pressure measuring point should be set 10d downstream of the test valve. 4.1.2.3 When testing 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. 4.1.3 Pressure measuring hole
4.1.3.1 The diameter of the pressure measuring hole The diameter shall not be less than 1mm and shall not be less than 6mm. 4.1.3.2 The length of the pressure measuring hole shall not be less than 2 times the diameter of the pressure measuring hole. 4.1.3.3 The center line of the pressure measuring hole and the center line of the pipeline shall be perpendicular, and the intersection of the inner surface of the pipeline and the pressure measuring hole shall be sharp but without burrs. 4.1.3.4 The inner diameter of the connecting pipe between the pressure measuring point and the measuring instrument shall not be less than 3mm. 4.1.3.5 When the pressure measuring point is connected to the measuring instrument, the air in the connecting pipe shall be removed. 4.1.4 Position of the temperature measuring point
The temperature measuring point shall be set 15d upstream of the pressure measuring point at the inlet of the test valve 4.1.5 Solid contamination level of oil
4.1.5.1 In the test system, the solid contamination level of the hydraulic oil (liquid) used shall not be higher than 19/16. It can be specified when there are special requirements.
4.1.5.2 During the test, if the measured values of the same parameter are inconsistent after several measurements within a certain time interval due to clogging, the time-defect value should be noted in the test report. 4.1.5.3 Indicate the installation position, type and number of filters in the test report. 4.1.5. 4 Indicate the solid contamination level of the oil in the test report, and indicate the method for determining the contamination level. 4.2 General requirements for the test
4.2.1 Test oil
4.2.1.1 Indicate the following points in the test report: Type and brand of test oil:
b: Oil viscosity and density at the test control temperature: c, isotropic bulk elastic modulus,
4.2.1.2 When measuring the effects of different oil viscosities at the same temperature, use the same type of oil but with different viscosities. 4.2.2 Test temperature
4.2.2.1 When hydraulic oil (liquid) is used as the medium test element: the oil temperature at the inlet of the test valve is 50C. When other T is used as the medium or there are special requirements, it can be specified separately. The actual test temperature should be indicated in the test report. GB 810487
4.2.2.2 The oil temperature should be lower than 25℃ during the cold start test. Before the test begins, keep the test equipment and oil temperature at a certain temperature. After the test begins, allow the oil temperature to rise. The relationship between temperature, pressure and flow rate over time should be recorded in the test report. 4.2,2.3 When selecting the test temperature, consider whether the valve needs to be tested for temperature compensation performance. 4.2.3 Steady-state T condition
4.2.3.1 The steady-state condition is when the range of change of the controlled parameter does not exceed the specified value in Table 2. Record the measured values of the test parameters under the steady-state condition.
Table 2 Allowable variation range of average indication value of controlled parameters Controlled parameters
Flow rate, %
Energy, %
Oil temperature, ℃
Viscosity, %
Test level
4.2.3.2 The number of reading points of the measured parameters and the distribution of the readings taken should be able to reflect the performance of the tested valve in the entire range. 4.2.3.3 In order to ensure the repeatability of the test results, the measurement time interval should be specified. 4.3 Pressure test
4.3.1 A pressure test should be carried out before the test valve is tested. 4.3.2 During the repulsion test, a pressure repulsion force is applied to each pressure-bearing oil port. The pressure repulsion force is 1.5 times the maximum working pressure of the oil port, and increases at a rate of 2% of the pressure test pressure per second: maintain the pressure for 5 minutes, and there shall be no external leakage. 4.3.3 During the pressure test, each oil drain port is connected to the oil tank. 5 Test contents
5.1 Flow control valve
5.1.1 Steady-state flow...pressure characteristic test
, the controlled flow and bypass flow should be measured within the full range of the control component setting value and differential pressure as much as possible. 5.1.1.1 Pressure compensation valve
Test the specified pressure and flow from the minimum to the maximum value at the specified increment of the inlet I1 and outlet II pressure (see the curve in Figure 5). 5.1.1.2 Non-pressure compensation valve
Test with reference to the relevant provisions of GB8107-87 "Hydraulic valve pressure difference--flow characteristic test method". 5.1.2 External leakage test
For flow control valves with external leakage ports, the external leakage should be measured, and the test method is the same as 5.1.1. Draw the inlet flow-pressure difference characteristic and the outlet flow-pressure difference characteristic. The difference between the inlet flow and the outlet flow is the external leakage. 5.1.3 Test of the "force" (generally referring to force, torque, pressure) required to adjust the control component. Within the pressure variation range of the inlet and outlet of the test valve, under each set of inlet and outlet pressure settings, change the adjustment setting value of the control component, so that the flow rate increases from the minimum to the maximum (positive stroke), and then returns from the maximum to the minimum (reverse stroke), and measure the corresponding adjustment force under each adjustment setting value. Before each adjustment to the set position, the test valve should be adjusted to the full stroke more than 10 times continuously to avoid the clamping force caused by the plug affecting the measurement. At the same time, the reading should be measured within 60s from the time of adjustment to the set position. After completing more than 0 full stroke operations, when the control component is adjusted to the set position, the direction of the adjustment action should be determined according to the positive or negative direction of the specified stroke.
Note: When the back pressure effect needs to be eliminated, this test can only use the path shown in Figure 1. 5.1.4 Transient characteristic test of flow control valve with pressure compensation Within the adjustment range of the control component: test the flow-time characteristics under each adjustment setting value. CB 8104-87
The test circuit of inlet throttling and three-way bypass throttling is shown in Figure 1, and a pressure step is caused to the outlet of the test valve to conduct the test. The test circuits of outlet throttling and bypass throttling are connected as shown in Figures 2 and 3 respectively, and a pressure step is caused to the inlet of the test valve to conduct the test. The influence of external leakage can be ignored when conducting transient characteristic tests. 5.1.4.1 In Figures 1 to 3, the operation time of valve 9 (see Figure 6) shall meet the following two conditions: a. shall not be greater than 10% of the response time;
b., the maximum shall not exceed 10ms,
5.1.4.2 In order to obtain sufficient pressure gradient, the compression effect of the oil must be limited. The test method is shown in formula (1). de_4·K
The pressure gradient is estimated by formula (1). Where q is the steady-state flow set before the test begins; K is the constant-entropy elastic modulus; V is the connected volume between the test valve 5 and valves 8a and 8b; force is the step pressure (in Figures 1 and 2, read from pressure gauge 4b; in Figure 3, read from pressure gauge 4a). The pressure gradient estimated by formula (1) should be at least 10 times the actual measured result (see Figure 6). 5.1.4.3 Transient characteristic test procedure
. Close valve 9, adjust the control components of the test rack 5, read the steady-state set flow rate 9-adjusting valve 8a from flowmeter 7a, read the pressure difference △ caused by flow rate 9 flowing through valve 8a (subscript \2" indicates the working condition of flow rate 4 passing through valve 8a alone), and calculate using formula (2): Nap
From formula (2), calculate the coefficient K of valve 8a. For Figures 1, 2 and 3, they are the reading differences of pressure gauges 4b and 4c, 4a and 4b, and 4a and 4c respectively.
b. Open valve 9, adjust valve 8h, and read the pressure difference Ap caused by 4% passing through the parallel oil circuit of valves 8a and 8b (subscript \1\ indicates the working condition of flow rate 4e passing through the parallel oil circuit). The reading method of pressure difference force is the same as that of pressure difference:. In the process of writing, when flow rate 9 is formula (3): 4=4=K VAp
can be considered as the starting moment of the response time of the test valve, which is called the starting flow (see Figure 6). c. Operate valve 9 (from open to closed) to cause a pressure step for detection. 5. 1. 4. 4 Test method
Select one of the following methods to perform transient characteristic test: (3)
The first method - indirect method (using a high-frequency response pressure sensor), use the pressure sensor to measure the instantaneous pressure difference A of valve 84, and use formula (41) to calculate the instantaneous flow rate 9=KA
through the test valve 5. Note: In this method, a flow meter with a lower frequency response is allowed because it is used to measure steady-state flow. 4)
h. The first method - direct method (using a high-frequency response pressure sensor and flow sensor), directly use the flow sensor to read Output instantaneous flow. Use a pressure sensor to calibrate the accuracy of the flow sensor phase. Note: The valve 9 operation time can be determined with reference to Figure 6. For the first method, the start time of valve 9 operation is the moment when the flow begins to rise (point B on Figure 6), and the end time of valve 9 operation is the moment when the flow begins to rise (point A on Figure 6). 5.2 Diverter valve
5.2.1 Steady-state flow-pressure characteristic test
Within the range of inlet flow variation, measure the relevant characteristics of the diverter flow of the two working ports A and B to each white pressure difference at each inlet flow setting value.
GB 810487
4. The outlet pressure of port B is achieved by adjusting valve 7a (or adjusting valve 7b at the same time) and valve 7c (or adjusting valve 7d at the same time), and is read by pressure gauges 4b and 4c. After the outlet pressure is adjusted, the inlet pressure of the test valve is determined accordingly and is read by pressure gauge 4a. The pressure difference between ports A and B and the inlet can be calculated.
The diverted flow rates of ports A and B are read by flow meters 8a and 8h respectively, and the sum of the diverted flow rates of the two outlets is the inlet flow rate. According to the provisions of Table 3, the outlet pressures of ports A and B are adjusted, and the inlet pressure and outlet flow rate at each inlet flow rate are measured within the specified inlet flow range.
For valves with equal or unequal flow rates at two diverted ports, the diverting ratio should be indicated. Table 3 Outlet pressure provisions
5.2.2 Transient characteristic test
Pmin pmx- pm
Paia+ prr- pmi
Peda+pma
pmin→trir+pmir
Pun. + Pauas +Pnin
pmin- pma paia
Measure the time-related characteristics of each diversion flow rate under different pressure step conditions generated when valves 6a and 6b perform different coordinated operations (simultaneous or non-simultaneous operations) within the range of inlet flow changes. The operating time of valves 6a and 6b in the test loop is the same as that of valve 9 in 5.1.4.1, and the requirements for the pressure gradient of the loading part of the loop are the same as those in 5.1.4.2. The diversion ratio of the valve should be indicated.
5.2.2.1 Test procedure
Close valves 6a and 6h, adjust valve 7a and valve 7c respectively, make the outlet pressure of A and B II to the highest load force (at this time, the pressure of port A is expressed as force, which is read by pressure gauge 4b, and the outlet pressure of port B is expressed as pressure, which is read by pressure gauge 4c), read the steady-state flow rate 4vsA and qvsB of port A and port B respectively by flow meter, and read the pressure force and force by pressure gauges 4d and 4e. Calculate by formula (5) and formula (6): A=P
Calculate p2a and Apze (△gaApu respectively represents the pressure difference formed by qvs passing through valve 7a alone vs the pressure difference formed by passing through valve 7t alone).
Calculate the coefficient K of valve 7a and the coefficient KB of valve 7c by formula (7) and formula (8). KA—qv5A/
（7）
：（8）
b. Open valves 6a and 6b, and adjust valves 7b and 7d to make the outlet pressure of port A and port B the minimum load pressure. At this time, the outlet pressure of port A is represented by p, which is read by pressure gauge 4b, and the outlet positive pressure of port B is represented by , which is read by pressure gauge 4c). The pressures 4 and 8 are read by pressure gauges 4d and 4e respectively.
Calculate by formula (9) and formula (10):
A=—PA
GB B104—87
A represents the pressure difference formed by avs through the parallel oil circuit of valves 7a and 7b, and Ap represents the pressure difference formed by qvse through the parallel oil circuit of valves 7c and 7d.
Use formula (11) and formula (12) to obtain the va of the flow rate qvin at the start of the transient characteristic response. AVA=GVIA=KAVAPIA
ve -gVir-Ke VAbu
c, operate valve 6a and (or) 6h, generate pressure step, the operation sequence is shown in Table 4. Table 4 Valve 6a and 6b operation sequence
5.2.2.2 Measurement method
Select one of the following methods for transient characteristic test:
Start to open
Always open
a The first method is the indirect method (using high-frequency response pressure sensor). The instantaneous pressure difference △pa of valve 7a is calculated from the readings of pressure sensors 4b and 4l, and the fault pressure difference △ of valve 7c is calculated from the readings of pressure sensors 4c and 4e. The instantaneous flow rate 9 and vB of A and B ports are calculated respectively by formula (13) and formula (14)
4VA- KA VAPA
(14)
b. The first method is direct method (both flow and pressure instruments use high-frequency response sensors). The instantaneous flow rates VA and 4vB at ports A and B are read out by flow sensors 8a and 8L respectively. The instantaneous pressure differences △P and Pu can be read out by the corresponding pressure sensors to verify the phase accuracy of the flow sensor.
6 Test report
6.1 The test data and results should be reported, and the symbols and units used shall be as specified in Table 1. 6.2 Test related data
The data on the test valve and its test conditions agreed before the test should be written in the report, including at least the following items: 6.2.14
Data required for each valve type
"Manufacturer" name:
Manufacturer's nameplate (model, serial number, etc.); "Manufacturer" description of the relevant valve;
Detailed list of valve connecting pipes and pipe joints, manufacturer's requirements for filtration;
Accuracy of the filter installed in the test circuit; Actual solid contamination level of the test oil, test oil (brand and description),
Kinematic viscosity of the test oil;
Density of the test oil;
Equivalent bulk elastic modulus of the test oil;
Temperature of the test oil;
m. Ambient temperature.
6.2.2 Additional information required for diverter valves
Minimum flow:
Given diverter ratio.
6.3 Test results
GB 810487
All test results shall be presented in tables and graphic curves and written in the report. 6.3.1 Bed resistance
Record the withstand pressure value
6.3.2 Flow control valve
Steady-state flow-pressure characteristics (within the specified setting range) (see Figure 5); h.
The "force" required to adjust the control component, that is, force, torque and pressure; transient characteristics under the set pressure and flow conditions (see Figure 6), (A) Flow-time transient characteristics: or pressure-time characteristics and the calculated flow-time characteristics (both expressed in graphs): (B) Response time and transient recovery time:
(C) The ratio of flow overshoot to the final steady-state flow. 6.3.3 Diverter valve
Steady-state flow-pressure characteristics;
b At each pressure and flow at port A and port B Although the transient characteristics under the value (see Figure 6), that is: (A flow-time transient characteristics, or pressure-time characteristics and the calculated flow-time characteristics (both expressed in graphs); () transient recovery time:
(C) the ratio of flow overshoot or diversion error to the final steady-state flow. L
Test circuit diagram when the flow control valve is used as inlet throttling and three-way bypass throttling
1 Liquid source: 2 overflow valve; 3 thermometer: 4 force gauge (high-frequency response pressure sensor is used when doing transient test), 5 test object: 6 · accumulator (added when necessary and possible): 7 flow meter (high-frequency response flow sensor is used when the first method of off-state test is adopted); 8 throttling: 9 two-position two-way reversing valve GB 8104-87
Figure? Test circuit for flow control valve used as outlet throttling-Hydraulic source, 2-Relief valve: 3-Thermometer; Hydraulic meter (high frequency response pressure sensor is used for transient test); 5-Test valve; 6 Accumulator (additional if necessary and possible): 7-Flowmeter (high frequency response sensor is used when the second method of transient test is adopted); 8 Throttle valve: Note: Valve 5 and valve 8 are connected by a hard pipe, and the volume between them should be as small as possible. Position-through reversing valve|| tt||Figure 3 Test circuit when flow control valve is used as bypass throttling 1-Hydraulic source; 2 Overflow valve; 3-Thermometer: 4 Pressure gauge (High-response limit force sensor should be used in transient test); 5-Test valve; 6-Accumulator (additional when necessary and possible); 7-Flowmeter (High-frequency response flow sensor should be used when transient test method is adopted): 8 Throttle valve: 9-Two-position one-way valve Note: Valve 5 and valve 8 are connected by hard pipe, and the volume between them should be as small as possible. GB 8104—87
Figure 4 Diverter valve test circuit
1—Hydraulic source; 2—Relief valve; 3—Thermometer; 4—Pressure gauge (High-frequency response positive force sensor should be used in transient test); 5—Test valve; 6—Two-position two-way valve; 7—Throttle valve; 8—Flowmeter (High-frequency response flow sensor should be used in transient test second method)
Maximum setting value
Minimum setting value
Figure 5 Steady-state characteristic curve of flow control valve
Starting flow area
Response time
GB 8104—87
Temporal recovery time
Figure 6 Transient characteristic curve of flow control valve
—Instantaneous flow, 9—Pressure difference 4bwww.bzxz.net
Measured pressure table Bao. Calculate d
Time by the slope of the line connecting point BC!
Final steady-state flow rate α
A1 Test level
GB 8104—87
Appendix A
Test level
(Supplement)
According to the provisions of GB7935--87 General Technical Conditions for Hydraulic Components, test 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.
Allowable system error of test system
Test level
Test only table parameters
Flow, %
Pressure difference p200kPa gauge pressure.kPa
Pressure difference p≥200kPa gauge pressure, %
Temperature, C.
Note: The percentage 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.
Additional instructions:
This standard is proposed and managed by the National Hydraulic and Pneumatic Standardization Technical Committee. This standard is drafted by Shanghai Railway Institute and the 704th Institute of the 7th Institute of China Shipbuilding Corporation.C Test at one of the three test levels A2 Error
Any test device and method that does not exceed the range of system errors listed in Table A1 after calibration or comparison with national standards can be used.
Allowable system error of test system
Test level
Test only table parameters
Flow, %
Pressure difference p200kPa gauge pressure. kPa
Pressure difference p≥200kPa gauge pressure, %
Temperature, C.
Note: The percentage 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.
Additional remarks:
This standard is proposed and managed by the National Hydraulic and Pneumatic Standardization Technical Committee. This standard was drafted by Shanghai Railway Institute and the 704th Institute of the 7th Institute of China Shipbuilding Corporation.C Test at one of the three test levels A2 Error
Any test device and method that does not exceed the range of system errors listed in Table A1 after calibration or comparison with national standards can be used.
Allowable system error of test system
Test level
Test only table parameters
Flow, %
Pressure difference p200kPa gauge pressure. kPa
Pressure difference p≥200kPa gauge pressure, %
Temperature, C.
Note: The percentage 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.
Additional remarks:
This standard is proposed and managed by the National Hydraulic and Pneumatic Standardization Technical Committee. This standard was drafted by Shanghai Railway Institute and the 704th Institute of the 7th Institute of China Shipbuilding Corporation.
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