| 摘要 |
A hydraulic system for operating equipment for removing snow and/or ice from surfaces having a plow, and a spreader for spreading traction enhancing materials onto the surfaces comprises a fixed displacement pump, a priority valve for receiving all of the hydraulic fluid from the pump and directing it to a loa d sensitive spreader valve and a plow valve. The priority valve is mechanically biased t o direct the hydraulic fluid primarily to the spreader valve. The pressure from the fluid directed to the spreader valve is used to oppose the mechanical bias while t he load pressure from the spreader valve is used to augment the mechanical bias, suc h that the spreader valve receives the amount of hydraulic fluid required for its operation. The system further includes an orifice connected to a load sensing line in the spreader valve to bleed fluid from the line. The spreader may include a conveyor and/ or an auger and a spinner for spreading materials, as well as a dispenser for liqu id materials. The metering devices for operating the components in the spreader may be solenoid or mechanically operated; the metering devices for operating the plow may be solenoid, air, hydraulic or mechanically operated.
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