Multi – way valve test related standards

February 6, 2017 · Posted in Uncategorised · Comment 

As one of the key components of the hydraulic system of the construction machinery, the multi-way valve has an important influence on the control performance, reliability and service life of the machine. How to accurately and comprehensively evaluate the performance and quality parameters of the multi-way valve , The development of multi-way valve, raise the level of technology has an important significance. Therefore, for the multi-valve test also developed the relevant standards and technical conditions, the multi-valve test items, test methods and test conditions, etc. to regulate. As the domestic multi-valve testing in the late start, so for the time being there is no uniform national standards angle machine. After consulting, the current domestic multi-valve test standards are JB / T8729 “hydraulic multi-directional valve” and hydraulic excavator with the overall multi-valve technical conditions (JG / T5116 a 1999). The first two are common multi-valve test methods and technical conditions, the test of all types of multi-valve are applicable, and the last one is the reference to the previous two, combined with hydraulic excavator with the characteristics of the overall multi-valve . The multi-valve integrated test system in this subject is mainly based on the former design, the following main contents are introduced.

metal punching machine 1. Test types and test items
Pressure test, multi-way valve must be carried out before the test pressure test, pressure test, the test port to the pressure test pressure applied, and the pressure test pressure is 1.5 times the maximum working pressure of the test port.
Multi-valve test types are divided into punching machine for sale type tests and factory tests: One type of test is to conduct a comprehensive assessment of the quality of multi-valve, which is mainly developed for the new products, as well as the original product in the structure, materials or technology have more Large changes and other circumstances need to carry out the test, and the factory test refers to the product to be carried out before delivery of the test. The test types and test items of the multi-channel valves specified in the test standard are shown in Table 1.1.
2. Test standard test circuit
The test standard is given in the multi-valve test hydraulic circuit, shown in Figure 1.1; The test circuit mainly by the main test system and auxiliary system composed of two parts, the main test system, including the pump source, the load part and the pressure flow detection device ; The auxiliary system is mainly for the pilot-type multi-valve to provide pilot oil, as well as the step load device to provide control oil.
3. Test methods and their requirements for test systems
Test methods for factory test items
L) the form of oil and spool valve function: multi-valve operation for the switch to observe the oil on-off situation, thus determining the form of multi-channel valve and spool valve function tube drilling machine.
2) commutation performance: Nominal pressure and nominal flow in the tested valve, through manual direct manipulation or through the auxiliary fuel supply system to provide the pilot oil to drive the slide valve for continuous action 10 times or more, check the spool reset and positioning .
3) internal leakage (with neutral position and commutation position within the leakage): Neutral position leakage is to make the multi-valve in a neutral position, from the multi-valve work oil into the oil port, and the system pressure to be tested multi- The nominal pressure of the valve, measured by the return of the corresponding leakage. And the reverse position of the leakage is to make the multi-valve in the commutation position drilling machine, from the multi-port valve P into the oil, the pressure is also the nominal pressure of the test valve, measured by the oil return port leakage.
4) pressure loss: the multi-valve placed in the commutation position, and to be tested through the multi-valve nominal flow, measured by the pressure gauge or pressure sensor P, T, A, B, the pressure was calculated Out of the slide valve corresponding to the pressure loss.
5) the performance of the safety valve: multi-channel valve will be tested all the work port blocked, the system pressure to the nominal pressure higher than the safety valve% Qiao, play a role in safety, and through the nominal flow, and then the main security Valve pressure range, pressure stability, pressure swing and opening and closing characteristics of the test.
6) Other auxiliary valve performance: For overload valve, charge valve and other auxiliary valve multi-valve, should be in accordance with the provisions of the performance of these auxiliary valves tested.
7) back pressure test: back to the oil back pressure to the specified value, the slide valve for 5 times repeatedly pressed for 3 minutes.
Type test items and test methods
L) Steady-state test: test all items in accordance with the provisions of the factory test items and test methods, and draw pressure loss, internal leakage curve and safety valve pressure characteristics curve.

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Internal leakage curve

Internal leakage curve

2) Transient test: through the action of the step load valve, the inlet of the main safety valve of the tested multi-way valve produces a pressure gradient that meets the transient conditions, and record the change of the inlet pressure with the pressure sensor and draw the safety valve instantaneously State response curve. The pilot project requirements in line with the requirements of transient conditions, that is, the safety valve inlet pressure change rate to reach 600-800MPa / s.

Safety valve transient response characteristic curve

Safety valve transient response characteristic curve

Multi - channel valve fretting characteristic curve

Multi – channel valve fretting characteristic curve

3) the pilot test: mainly for manual direct manipulation of the multi-valve, to be tested by the multi-way valve to the nominal flow, and in a certain pressure case, the stem pushed or pulled to the maximum stroke position, And the magnitude of the steering force or torque is measured. For the pilot-type multi-valve does not have this pilot project requirements.
4) Jogging characteristic test: In some way, make the slide valve move slowly to each commutation position, and measure the relation of the corresponding flow or pressure with the displacement. The Jogging Test requires that the test system have means to allow the spool of the slide valve to move slowly and to measure the corresponding displacement.
5) high temperature test: the oil temperature of 80 soil 5 degrees under the conditions, to be tested through the multi-channel nominal flow, and the pressure to its nominal pressure, the slide valve to a certain frequency for continuous semi- Hours. Therefore, the test system is required to be able to control the oil temperature.
6) Durability test: mainly for the multi-valve service life assessment, the nominal pressure and test flow conditions, so that subjects were to a certain frequency of multi-channel continuous reversing, to achieve the required number of times, check subjects The main valve internal components.