ISO 10770-2:2012 pdf download – Hydraulic fluid power -Electricallymodulated hydraulic control valves —Part 2: Test methods for three-port directional flow-control valves
ISO 10770-2:2012 pdf download – Hydraulic fluid power -Electricallymodulated hydraulic control valves —Part 2: Test methods for three-port directional flow-control valves.
g) pressure gain versus input signal (8.1,9);
h) pressure null shift (8.1.10);
i) faa-safe function test (8111).
8.1.2 Proof pressure tests (optional)
Proof pressure tests may be earned Out to examine the Integrity of the valve before conducting further tests.
184.108.40.206 P, A and X ports test procedure
In the test, a proof pressure is suppl.ed to the pressure and control ports, and the external pilot supply port of the valve with the return pod open. Carry out the test as follows,
a) Apply a proof pressure of 1,3 times the rated pressure to the pressure and control port, and the X port for at least 30 s. For approximately half of this period apply the maximum input signal and for the remainder of the test apply the minimum input signal.
b) During the test examine the valve for evidence of external leakage
c) After the test examine the valve for evidence of permanent deformation.
d) Record the proot pressure used in the test.
220.127.116.11 T port test procedure
Carry out the test as follows,
a) Apply a proof pressure of 1,3 times the T port rated pressure to the valve tank port for at least 30 s.
b) During the test examine the valve for evidence of external leakage.
C) After the test examine the valve for evidence of permanent deformation.
d) Record the proof pressure used in the test.
8.12.4 Pilot drain Y port
Do not apply a proof pressure to any external pilot drain port.
8.1.3 Internal leakage and pilot flow test
The internal leakage and pilot flow test shall be carried out to establish:
a) the combined leakage and pilot flow rate;
b) the pilot flow rate in the case of valves configured for external plot drain.
18.104.22.168 Test circuit
Perform the internal leakage and pilot flow test with a hydraulic test circuit conforming to the requirements of Figure 1, initially with valves SI, S3 and S6 open and all other valves closed
Adjust the valve supply pressure and pilot pressure to 10 MPa (100 bar) above return pressure, or at the
manufacturers rated pressLwe If this Is less than 10 MPa.
Carry out the test as follows.
a) Immediately before the leakage nieasurernents are to be taken, operate the valve over its full input signal range several times, ensuring that the oil passing through the valve is within the specified viscosity range.
b) Close valves S3 and S6. open valve S2 and then close valve Si.
C) Record the leakage flow from the T port as the input signal is swept slowly over its full range (see Figure 3) The flow recorded by transducer 10 will represent mainstage leakage plus pilot leakage. The characteristic shown in Figure 3 is typical for a servo valve Other valve types would have a different characteristic.
d) With a constant input signal, the flow recorded by transducer 10 will represent the steady-state mainstage and pilot leakage.
For valves configured for external pilot drain, open valve Si and close valve S2. Record the leakage flow from the Y port with the Input signal set to zero. The flow recorded by transducer 10 will represent the pilot flow.
These tests may. if required, be repeated at additional pressures up to the maximum supply pressure of the valve under test.
8.1.4 Metering tests
The objective of this test is to determine the metering characteristics of each metering path of the main spoolat a constant pressure drop.Record flow, using flow transducer 11, in each metering path in turn versus inputsignal (see Figure 4).
22.214.171.124 Test circuit
Flow transducer 11 needs to able to measure over a wide flow range, at least 1 % to 100 % of rated flow.lt can be necessary, especially if the flow metering near zero flow is to be measured accurately, to replacetransducer 11 by two separate flow transducers: one to measure higher flows, the other to measure low flowsand having overlapping working flow ranges.