Pump controller program

Abstract

A method for operating a pump controller to pressurize a liquid product line for thermal stabilization during a leak test is accomplished as follows. A microprocessor controlled timer is installed in a petroleum service station product dispensing system that includes a pump relay, a pump, a dispenser, and a leak detection monitor. The timer activates pump relays to pressurize a liquid product line that runs from a tank to the dispenser at predetermined intervals to compensate for thermal contraction during product line leakage testing. Prior to activating pump relays, the timer has circuitry and program determines if product is currently being dispensed. If product is being dispensed, the timer waits until dispensing has halted then starts a timer to provide a delay before activating pump relays to pressurize the product line. Also prior to activating pump relays, the timer has circuitry and program determines if pump operation should be inhibited and if so halts before activating pump relays. Optical isolation is used between the timer and pump relays and a dispenser switch.

Dependencies are inferred from the claim text.