US 3,940,971 AGranted

System for testing flow meters

AssigneeBadger Meter, Inc.

InventorsMarvin W. Krause, Donald H. Strobel, Edward A. Seruga

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Abstract

Liquid is supplied to a meter test stand at a uniform pressure, and the flow through the meters on the stand automatically is directed to each of three receptacles in sequence at three different flow rates during each test cycle. Level sensors in each receptacle actuate cycling controls and actuate sensing and recording components. The latter components monitor the rate of flow registration of the meters on test and provide an accurate comparison by percent of the measured flow rate to the actual flow rate. A high degree of accuracy is achieved through the use of a phase locked loop and digital control system which responds to the level sensing and cycling controls to provide a print-out of the comparison as a measure of accuracy of the meter at each such flow rate.

Claims9

Dependent claims

Apparatus for testing a flow meter comprising:

means for establishing a flow of fluid through the meter being tested at a predetermined rate;
a receptacle for said fluid;
quantitative sensing means associated with said receptacle for generating a pair of signals respectively at the beginning and end of receipt of a predetermined volume of fluid, said signals defining a measuring interval;
transducer means positionable adjacent the tested meter for producing a first rate signal corresponding to the actual rate of registration of the tested meter;
controlled oscillator means responsive to said first rate signal for producing a second rate signal which varies at a frequency proportional to but at least an order of magnitude in excess of said registration rate, said controlled oscillator means including a voltage controlled oscillator having a nominal output frequency at least an order of magnitude in excess of the frequency of registration of said meter, frequency division means coupled to said oscillator for dividing said second rate signal in frequency to produce a phase reference signal having a frequency approximating the desired frequency for said first rate signal, a phase detector for receiving said first rate signal and said phase reference signal and for providing an output signal varying with the difference in phase between said first rate signal and said phase reference signal, and means responsive to said phase detector output signal to provide an oscillator control signal the voltage of which varies with said phase difference to increase or decrease, respectively, said oscillator output frequency as the frequency of said first rate signal becomes greater or less than the frequency of said reference signal;
counting means controlled by said quantitative sensing means for counting the cycles of said second rate signal occurring during said measuring interval;
and an output device for indicating the count in said counting means at the end of said measuring interval.

4 more elements

Apparatus for testing a flow meter comprising:

programmable means for selectively establishing fluid flow through the meter being tested at a plurality of predetermined rates, receptacle means for receiving fluid passing through said meter, quantitative sensing means associated with said receptacle means for generating a pair of signals respectively at the beginning and end of receipt of a preselected volume of fluid, said signals defining a preselected measuring interval, transducer means positionable adjacent the tested meter for producing a first rate signal corresponding to the actual rate of registration of the tested meter, controlled oscillator means responsive to said first rate signal for producing a second rate signal which varies at a frequency proportional to but at least an order of magnitude in excess of said registration rate, counting means controlled by said quantitative sensing means for counting the cycles of said second rate signal occurring during said preselected measuring interval, and an output device for indicating the count in said counting means at the end of said preselected measuring interval.

Dependencies are inferred from the claim text.