Product Description   the air control tipping valve in the hydraulic tipping system of dump truck, plays up , stop , down and the proportion of slow-down function.  1.Built pilot relief valve:You can set the system security pressures.  2. The proportion of slow-down function:With proportional control valve used in conjunction ,Adjust different control pressure,When operating the lowering operation, to achieve proportional control the lowering speed.  3.The relief pressure can be set according to user requirements.