Stac, Inc.

Jeffrey Mark Merth

Shawn Auxier

A hydraulic fan powered in a branch of a vehicle-carried working load hydraulic circuit helps cool hydraulic fluid in a cooler. A switching block has a bypass mode which kicks in whenever sensed hydraulic fluid temperature indicates an overheat condition. The bypass mode shuts off hydraulic fluid to all the working loads of the system, while circulating hydraulic fluid as fast as possible through the cooler and running the cooling fan at a slower rate. After the hydraulic fluid cools below the overheat threshold temperature, a start button must be pressed before the switching block will again power the working loads and run the fan at a higher speed.

Pump fan control circuit and block for truck mountable hydraulic system

Separate from the vehicle's engine, a self-contained internal combustion engine supplies hydraulic power to drive a product pump on a bobtail. The self-contained engine, which can itself run on propane, is provided as part of a preassembly which includes the hydraulic pump, the hydraulic fluid tank, a heat exchanger, and a solenoid controlled start-up valve. The preassembly is mounted as a unit to the side of the bobtail in front of the rear wheels, powering the product pump at the rear of the bobtail while the vehicle's engine is off.

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Oakdale, MN, United States of America

Jeffrey Mark Merth