LNG dispenser

摘要

A method is provided for verifying integrity of a recirculation valve in a recirculation line of an LNG dispenser. The method includes: closing the recirculation valve and a fill valve in a supply line that supplies LNG; monitoring a mass of the LNG flowing through the recirculation line to ensure that the mass flowing therethrough is less than an acceptable threshold; and aborting any pending sales if the mass of the LNG flowing therethrough is not less than the acceptable threshold. According to another embodiment, a method is provided for verifying integrity of a vent valve in an LNG dispenser. The method includes: closing the vent valve and opening a fill valve in a supply line that supplies LNG; monitoring the pressure of the LNG within the fill hose to ensure that the pressure remains steady; and aborting any pending sales if the pressure does not remain steady.

主权项

1. An LNG dispenser comprising:
a supply line through which LNG is supplied from a natural gas farm to a vehicle tank; a mass flow meter provided for measuring a mass of LNG flowing through said supply line; a recirculation line branching from said supply line downstream of said mass flow meter for recirculating LNG from said supply line back to the natural gas farm; a recirculation valve located in said recirculation line for controlling a flow of LNG through said recirculation line; and a controller for controlling said recirculation valve, wherein said controller verifies integrity of said recirculation valve by closing said recirculation valve and monitoring the mass of the LNG flowing through said mass flow meter to ensure that the mass of the LNG flowing therethrough is less than an acceptable threshold, and wherein, if the mass of the LNG flowing through said mass flow meter is not less than the acceptable threshold, said controller halts any sales.