Hydraulic control system for vacuum sweeper trucks

摘要

A hydraulic control system for a vacuum sweeper truck including a hydraulic pump coupled to the truck's engine, a reservoir of hydraulic fluid, a hydraulic fan motor, a hopper actuator, and a valve assembly having three operative positions. In a first position the hopper actuator is deactivated and full power goes to the vacuum fan motor. In a second position the hydraulic fluid is diverted to the hopper actuator to raise the hopper and the vacuum fan motor is run at a reduced speed by hydraulic fluid returning to the reservoir. In a third position, the hydraulic fluid is again diverted to the hopper actuator to drive the hopper in a second direction, and again the fan motor is run at a reduced power level. A compensator is coupled to the hydraulic pump and is responsive to a cut-off setting and to the hydraulic pressure produced by the pump. A pressure adjustment means is provided in the cab of the truck which is coupled to the flow regulator to permit the truck operator to vary the cut-off setting of the flow regulator.