Method and apparatus for inhibiting air infiltration into fuel dispensing lines
AssigneeMarley Pump
InventorRussell L. Broline
Life of this patent
Estimating the term…
Abstract
A device used in liquid fuel dispensing systems to inhibit the infiltration of air into the product dispensing line due to thermal contraction. A fluid tight container is connected with the product line and supplied with fuel in an amount sufficient to make up the liquid volume loss caused by thermal contraction. A siphon line in the container opens near its bottom. A vent for the container is normally closed by a valve under normal pressures of the dispensing system. When thermal contraction reduces the product line pressure far enough to create a vacuum, the valve opens the container vent so that the fuel in the container can flow into the product line to keep it full of liquid and avoid drawing air into the line.
Claims19
In an apparatus having a fuel storage tank, a fuel dispenser, a product line which extends from the storage tank to the fuel dispenser and which is normally maintained at a normal operating pressure and a pump for pumping fuel from the tank to the dispenser, the improvement comprising:
- a reservoir adapted to contain fuel, said reservoir having a liquid port connected with said product line and a vent connected with a low pressure below the normal operating pressure;
- and
- valve means for opening and closing said vent in response to the pressure applied to the reservoir through said liquid port, said valve means being arranged to maintain said vent closed at the normal operating pressure and to open said vent when the pressure in the reservoir drops to a predetermined level below the normal operating pressure, said valve means being arranged to close the vent again when the pressure in the reservoir rises to the normal operating pressure again.
In a fuel dispensing system having a tank adapted to contain liquid fuel, a dispenser for dispensing the fuel, a product line extending from the tank to the dispenser and subject to losing liquid volume due to thermal contraction, a pump for pumping fuel through the product line at a normal operating pressure of the pump, and a leak detector in the product line for detecting fuel leakage therefrom, the improvement comprising:
- a substantially fluid tight reservoir adapted to contain fuel in an amount sufficient to make up for thermally induced fuel contraction in the product line;
- a siphon line opening into said reservoir and connected with the product line to subject the reservoir to a pressure substantially the same as the product line pressure;
- a vent opening into said reservoir and connected with a low pressure lower than said normal operating pressure of the pump;
- and
- a valve element responsive to the pressure in said reservoir, said valve element being arranged to close said vent at said normal operating pressure of the pump and to open said vent when the pressure in the reservoir drops to a predetermined level below the normal operating pressure, thereby allowing the fuel in the reservoir to flow into the product line to make up the liquid volume lost due to thermal contraction.
A method of compensating for thermally induced volume loss of a liquid fuel pumped from a storage tank to a dispenser through a product line which is normally maintained at a normal operating pressure, said method comprising the steps of:
- supplying the fuel to a substantially fluid tight container in an amount sufficient to make up the volume loss of the liquid in the product line due to thermal contraction;
- connecting the container with the product line to allow the fuel to flow therebetween;
- maintaining the container in an unvented condition when the pressure in the product line ms at or above the normal operating pressure;
- and
- venting the container when the pressure in the product line drops to a predetermined low level below the normal operating pressure, thereby allowing the fuel in the container to flow into the product line to make up the thermally induced liquid volume lost therein due to thermally induced contraction of the fuel in the product line.
Dependencies are inferred from the claim text.