6.1.2 The location of the outlet pressure measurement point downstream of the test valve, the distance from the test valve should be not less than 10d. 6.2 Temperature measurement point downstream of the outlet pressure measurement point, and the exit pressure measurement point distance should not be less than 5d. 6.3 Measurement flow point temperature measurement point downstream, and the distance between the temperature measurement point should not be less than 5d. 6.4 The tubing used should be straight and the diameter of the holes in the axial direction should be approximately the same. 6.5 The size of the tubing and related fittings used should be adapted to the size of the inlet and outlet ports of the valve, and the tubing should be installed as horizontal as possible. 6.6 Pressure Testing Hole 6.6.1 The diameter of the pressure testing hole should be not less than 1mm and not more than 6mm. 6.6.2 The length of the pressure-measuring hole should be not less than 2 times the diameter of the pressure-measuring hole. 6.6.3 The centerline of pressure measuring hole should be perpendicular to the centerline of the tubing. The crossing angle between the inner surface of the tubing and the pressure measuring hole should be sharp, but there should be no burr. 6.6.4 Pressure measuring point and the connection between the measuring instrument pipe diameter should not be less than 3mm. 6.6.5 When the pressure measurement point is connected with the measuring instrument, the air in the connecting pipe should be excluded. 7 Test Methods 7.1 Test run In the nominal pressure, rated flow, the valve 20 consecutive commutation, should meet the requirements of 4.1. 7.2 Pressure loss test 7.2.1 Full flow range pressure loss test Adjust the test system to make it from zero flow to rated flow, from which at least 4 points to measure the pressure loss from the inlet to the outlet, draw the flow , Pressure loss curve. 7.2.2 Pressure Loss Test at Rated Flow Rate Pressure loss of the flow valve at rated flow from inlet to outlet, inlet to working and working ports to outlet. Note: In the pressure loss test its outlet pressure must be above 0.1MPa. 7.3 Internal Leak Test Adjust the test system so that the valve inlet pressure is the nominal pressure, according to the test valve spool valve function and structure, respectively, from the working port and the return port to measure the valve under test at any working position Internal leakage should meet the requirements of Article 4.3. Note: â‘ In the internal leakage test, the pressure on the outflow side is atmospheric pressure. â‘¡ pressure must be increased within 15s from atmospheric pressure to nominal pressure. 7.4 Pressure test The working oil port blocked, from the inlet port of the valve to apply pressure on the action position, when the nominal pressure is not greater than 16MPa, the nominal pressure of 1.5 times the pressure applied; when the nominal pressure is greater than 16MPa, applied 1.25 times the nominal pressure of the pressure. Continued 3min assessment of ministries of oil spills and so on. In the test, the pressure of the oil outlet is atmospheric pressure, the test result should meet the requirements of 4.4. 7.5 Durability test Sliding valve in the nominal pressure, rated flow, continuous commutation 100,000 times, assess the pressure loss and leakage performance indicators. 8 Inspection rules 8.1 Type test 8.1.1 Type test refers to a comprehensive test valve quality and performance tests. 8.1.2 Type tests shall be carried out under any of the following conditions: a) trial-manufactured directional valves (including conversion of old products); b) when the design, process or material of the valve changes to affect the product Performance; c) has been established in the pilot valve and the type test conducted before the results of impermissible deviations occur; d) batch production of the valve should be conducted once every three years type test. Test and test items: a) commissioning test; b) full flow range pressure loss test; c) internal leakage test; d) pressure test; e) durability test. 8.1.3 Type test The number of samples for the provisions of 3 (pieces), one of them to do the whole project test, the rest of the performance test, there are unqualified items in the test, the project should be doubled the number of retest If the item is still unqualified, then the sample type test is unqualified. 8.2 factory test products factory test should be done before leaving the factory after passing the inspection. Test and test items: a) commissioning test; b) pressure loss test at rated flow rate; c) internal leakage test; d) pressure test. 8.3 Decision Criteria 8.3.1 The pilot valve factory test items must be sub-test and test two categories, sampling methods according to GB / T 2828. 8.3.2 The ordering unit reserves the right to re-check the reversing valve according to the factory test items and requirements. The re-sampling method is according to GB / T2828. 8.3.3 Special order requirements of the valve, the test conditions and rules by the design, manufacture and demand-side units jointly developed. 9 Marking, packaging, transportation, storage 9.1 Sign reversing valve Nameplate should be on the product and indicate the following: a) product name, model and symbol; b) the main technical parameters of the product; c) the name of the manufacturer; d )Date of manufacture. 9.2 Packing The valve should be moisture-proof packaging materials. The packing box shall be firm and reliable, and its outer wall shall be clearly and neatly marked with the following contents clearly: a) the name, type and quantity of the product; b) the total mass, kg; the net weight, kg; c) the name, address and arrival station Station name; d) packing date. 9.3 Transport The reversing valve should be light and light when transported, stacking height is strictly prohibited more than 1m. And should be moisture-proof, rainproof. 9.4 Storage The reversing valve should be stored in a ventilated, dry room during storage. It is forbidden to mix with chemicals. 9.5 Accessories Annex includes the following: a) product certification; b) product instructions; c) spare seals and dust-proof parts; d) packing list. Additional note: This standard proposed by the State Bureau of Machinery Industry. This standard by the National Automotive Standardization Technical Committee. This standard was drafted: Qingdao Special Purpose Vehicle factory.
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