Fuel feeding device for a heating unit, especially for vehicles

摘要

Fuel feeding apparatus is provided for a vehicle heater of the type having a combustion air fan connected by a combustion air feed line to a heater combustion chamber. A venturi tube is arranged in the feed line downstream of the combustion air fan and a fuel feed line and fuel nozzle opens into the air feed line at the venturi tube. A diaphragm pump is provided which has a first chamber, a fuel supply line inlet and an outlet at the fuel feed line to the venturi tube and a second chamber communicated with the air feed line at a position spaced from the venturi tube. A check valve is provided in the fuel feed line and a closure valve is provided at the fuel supply line leading to the first chamber. Movement of the diaphragm in the pumping direction is controlled exclusively by a pressure difference at the venturi tube and at the air feed line upstream of the venturi tube, while the suction stroke is controlled by an electromagnet. Switch means are provided for switching the electromagnet on at the end of the pumping stroke and off at the end of the suction stroke.