Universal upstream-downstream flowmeter tester

Claim 1

A circuit simulating the electrical signal response of a flowing fluid whose velocity is to be measured by an upstream-downstream flowmeter with fixed transducers comprising, input means for acquiring electrical transmit signals from a flowmeter of the type having upstream and downstream transducers which convert electrical transmit signals to acoustic signals, a gated first oscillator connected to receive and be gated by the electrical transmit signal and having first counter means connected to said oscillator for receiving the gated oscillator output signal and dividing down said signal to the extent said divided signal electrically simulates in time a signal having almost the mean transit time of an acoustic pulse between upstream and downstream transducers in said flowmeter, pulse means for incrementing the almost mean transit time signal by preselected amounts of time representing upstream and downstream pulses with respect to an exact mean transit time signal simulating, in time, signals received at said upstream and downstream transducers due to flow in a hypothetical pipe carrying a known fluid whose velocity is to be measured, a second oscillator connected for triggering by said upstream and downstream pulse simulation signals and having second counter means connected to said oscillator for receiving the oscillator output signal and producing in response thereto mimicking output signals shaped to simulate upstream and downstream received signals at respective upstream and downstream acoustic transducers, and injector means for directing said mimicking output signals to said upstream and downstream transducers.