The Oval Gear meters are positive displacement fl owmeters where the passage of liquid causes two oval gears to rotate within a precision measuring chamber and with each rotation a fi xed volume of liquid passes through the meter. Magnets embedded within the gears initiate a high resolution pulse train output. The pulse output can be wired directly to proc-ess control and monitoring equipment or can be used as an input to instruments supplied with or fi tted directly onto the meter.
The fl owmeter is available as a blind transmitter with pulse output capable of interfacing to most monitoring and control instrumentation or the meter can be fi tted with or supplied with instruments such as totalisers, rate totalisers or batch controllers. These instruments also have monitoring and con-trol output options including 4-20 mA, scaled pulse, fl owrate alarms and batch control logic (preset metering).
This technology allows precise fl ow measurement and dis-pensing of most clean liquids regardless of their conductivity, with other liquid characteristics having no or minimal effect on meter performance. This metering technology does not re-quire fl ow profi le conditioning or straightline runs as required with alternative fl ow technologies making the installation rela-tively compact and low cost.
Positive displacement fl owmeters are an inexpensive means to accurately meter high viscosity clean liquids as high as 1 million centipoises however, the appropriate meter must be sized so that the pressure drop across the primary measu-ring elements (oval rotor), does not exceed the maximum capability of either.