US 5,360,139 A · Liquified natural gas fueling facility

Abstract

An automated fueling facility allows untrained persons to safely dispense homogenous phase liquid methane from a cryogenic storage tank into a motor vehicle. The fueling facility automatically maintains pressure on the liquid methane within a predetermined safe operating range using methane gas trapped in the cryogenic storage tank. The pressure on the liquid methane is at least set equal to a set pressure equal to the sum of the saturation pressure of the liquid methane plus an additional amount to help to ensure that it remains in a fully saturated condition after absorbing any heat during pumping from the storage tank. A pump is cooled by placing it in the storage tank and circulating liquid methane through the pump and back into the storage tank. A dispenser, including nozzle for connecting to a motor vehicle, is cooled by circulating liquid through the nozzle and back to the storage tank through a receptacle on the dispenser to which the nozzle is connected. No dispensing of liquid methane into a motor vehicle tank is allowed to begin without the pressure of the liquid methane being within the operating range and the pump and nozzle pre-cooled. No additional pressure is built in the storage tank than is necessary to bring the pressure of the liquid methane to the set pressure.

Claims23

Dependent claims

A method of automatic operation of a facility for dispensing liquid methane into a motor vehicle through a dispenser system from a supply stored in a cryogenic storage tank comprising the steps of:

measuring pressure of the liquid methane near an outlet of a cryogenic tank with a pressure sensor and communicating a signal indicative of the pressure to a controller;
measuring temperature of cryogenic fluid near the outlet of the cryogenic tank with a temperature sensor and communicating a signal indicative of the pressure to the controller;
determining with the controller, in response to the signal indicative of temperature, a set pressure for the liquid methane, the set pressure substantially equal to a sum of a liquid saturation pressure for the liquid methane at the indicated temperature and an additional compression, the compression of the liquid methane being supplied by methane gas trapped in the cryogenic tank;
and
enabling the dispenser system to permit a user to dispense on demand liquid methane into a vehicle only if a signal from the pressure sensor indicates that the pressure of the liquid methane is substantially at or above the set pressure, thereby tending to assure that homogenous phase liquid methane is dispensed into a motor vehicle.

2 more elements

A system that dispenses fuel as a cryogenic liquid for accurately measuring the mass of fuel dispensed into a tank, the system having a dispensing line for coupling to an inlet of a tank, through which liquid flows into the tank, and a vent line for coupling to a vent outlet of the tank for, through which vapor displaced from the tank flows, the system including an apparatus for terminating liquid flow into the tank when the tank is full including:

a liquid flow meter for sensing the mass flow rate of the cryogenic liquid through the dispense line for calculation of the total mass of fuel dispensed into a tank;
a vapor flow meter for sensing the mass flow rate of vapor through the vent line for determining the mass of fuel displaced from the tank during dispensing;
an apparatus for calculating the total amount of fuel dispensed into and retained in the tank from information provided by the liquid flow meter and the vapor flow meter;
and
a valve in the vent line that is biased open, wherein a flow of vapor at rates expected during dispensing exert insufficient force to close the valve and a flow of liquid through the vent line when the tank is full exerts a force sufficient to close the valve, the closing of the valve closing the vent line to a flow of vapor and liquid through the vent line.

2 more elements

Dependencies are inferred from the claim text.

Liquified natural gas fueling facility

Life of this patent

Liquified natural gas fueling facility

Life of this patent

Abstract

Claims23