Dump Truck directional valve technical standards and requirements: 1, This standard specifies the general requirements for dump truck reversing valve, performance requirements, test conditions, test equipment, test methods, type test and factory test, inspection rules and Signs, packaging, transportation, storage. This standard applies only to hydraulic oil as the working medium for dump truck lifting system with manual, pneumatic and hydraulic directional valve (hereinafter referred to as valve). 2, the reference standard: QC / T460 dump truck - hydraulic cylinder technical conditions; QC / T484 automotive paint coating; GB / T3766 hydraulic system general technical conditions; GB / T2828 batch inspection count sampling procedures and sampling table. 3, the general requirements: 1) The valve should be consistent with the provisions of this standard, and in accordance with the procedures approved by the drawings and technical documents. 2) All parts must be qualified by the quality inspection department before assembly. 3) The nominal pressure of the valve should be selected according to QC / T460 "dump truck - hydraulic cylinder technical conditions" of the relevant provisions. 4) The valve inlet and outlet ports and other parts should be taken rust, dust and other protective measures. The remaining surface paint by QC / T484 Table 1 TQ6 provisions of the paint. 5) All seals, dust-proof parts in the assembly should be coated with oil or thin layer of grease, and should ensure that no damage to the seal. 6) casting surface should be smooth, not sticky sand, cracks, burrs and other harmful defects. 7) The valve should be cleaned before assembly. 8) Manually operated valves should meet the relevant requirements of GB / T3766. 4, the performance requirements: 1) test run: the valve in the nominal pressure, rated flow conditions should be flexible to the direction of abnormal sound should not occur, the pressure oil conversion direction should be accurate. 2) Pressure loss: Under rated flow conditions, the pressure loss of each channel of the valve shall not exceed 0.3MPa. 3) Internal Leakage: The internal leakage test, the valve leakage per minute shall not exceed 0.6% of the rated flow. Note: The specified value of the internal leakage of any working position when the total leakage of each measuring port. 4) pressure: pressure test, the valve shall not rupture, all parts may not appear abnormal phenomena such as oil dripping. 5) Durability: After the durability test, the requirements of 4.2 and 4.3 shall be met.