The hydraulic system is comprised of electrical control switches, hydraulic pumps, control valves, hoses, motors and hydraulic cylinders. Energy is transmitted from the sweeper’s auxiliary engine to the dual output hydraulic pump unit by means of a direct-drive gear. The pump unit circulates pressurized fluid through hoses and control valves throughout the system. The hydraulic system is controlled by electrical switches mounted on the control panel in the truck’s cab and on the front side of the power module. Technically, these switches control the hydraulic directional valves mounted the manifold, which route the flow of high pressure hydraulic fluid.
The two 2-stage manifolds are internally configured with the directional valves positioned in series. The directional valves control hydraulic functions for the hopper, sweeping head, right gutter broom and left gutter broom. If the unit is equipped with a Mechanical-Pneumatic Powerhood or hydraulic hand hose, a third single-stage manifold is added.
An auxiliary hydraulic unit, consisting of a 12 volt hydraulic pump and control switches, enables the sweeper’s hydraulic devices to function when the power module engine is not operating. The unit is mounted to the sweeper frame just behind the power module and connected to the sweeper’s hydraulic system. It uses the truck’s 12 volt battery to power the electric motor that drives the auxiliary hydraulic pump. The truck’s engine does not have to be running to activate the system. However, because of the electrical load generated by the unit, it is best to run the truck engine whenever possible. This auxiliary system is intended to be used for maintenance applications and in emergency conditions.
The auxiliary hydraulic pump is needed if the power module engine runs out of fuel or when an emergency shutdown situation occurs. Without it, the sweeper head, brooms and any other device which normally function when the power module engine is running would not operate. The 12-volt auxiliary unit can be used to power the broom out or in, raise the sweeper head, raise the hopper or open the hopper door for maintenance or cleaning. Under normal sweeper operating conditions, the main hydraulic unit mounted on the power module should be used to operate these hydraulic devices.