Kelly W Hedegard

US Patent:

RE358746, Aug 25, 1998

Filed:

Jul 6, 1994

Appl. No.:

8/271041

Inventors:

Timothy A. Neeser - Savage MN
Kelly W. Hedegard - Scottsdale AZ

Assignee:

Minnesota Valley Engineering, Inc. - New Prague MN

International Classification:

F25B 1900

US Classification:

62 7

Abstract:

The delivery system of the invention consists of a pair of LNG fuel tanks mounted on a vehicle. A solenoid valve associated with each tank allows the vehicle operator to select the tank from which LNG is to be delivered to the engine. An automatic override system is provided whereby if the pressure in the non-selected tank rises above a predetermined level, the operator's tank selection is overridden and gas from the non-selected tank is used until the pressure falls below the predetermined level. This override system eliminates the need to vent gas to the atmosphere to avoid pressure building up and thereby eliminates waste of the LNG. Each tank is also provided with a pressure building capability such that the gas will always be delivered to the engine with sufficient pressure. The system is designed such that LNG from a stationary low pressure storage tank can be delivered at high pressure to refuel the tanks. Finally, a variable insulation barrier is provided in the fuel tanks to minimize heat transfer between the LNG and gas head.