Positive Displacement Flow Meters

SMART MEASUREMENT – Positive Displacement Flow Meters

Positive Displacement Flowmeters, which employ one of the oldest-known flow measurement techniques, are widely used in industry and have one of the largest install bases of any flow meter technology. Positive Displacement Flowmeters feature two precisely machined rotating members inside a measuring chamber of known volume which may be used to accurately determine volumetric flow rate as a function of the rotors’ velocity.

The advantages that the Positive Displacement Flowmeter provides over other technologies are numerous. These advantages include high accuracy (up to 0.1% of reading), excellent repeatability, wide turndown ratios, high temperature operation, high viscosity operation, no upstream or downstream straight pipe requirement, the ability to be used with mechanical registers which require no electrical power, and readings which are immune to changes in viscosity. This combination of features and advantages makes the PD meter an ideal choice for applications that can be found in many different industries including food & beverage, paint & coatings, oil & gas, and fluid power.

Bi-Rotor Positive Displacement Flow Meter, ALBRPD

  • Superior accuracy – to 0.1% of reading over 30:1 turn-down
  • Uniform rotation means low pressure loss
  • No metal-to-metal contact provides for long service lifetime
  • Self-lubricating
  • Very low noise and vibration
  • Reduced number of parts reduces maintenance requirements
  • Rugged double case construction prevents loss of calibration due to changes in pressure or temperature
  • NIST traceable calibration certificate

Gear Positive Displacement Flow Meter, ALGPD

  • High output frequencies resulting in good resolution and suitable for pulsating flows.
  • Reverse-flow detection and pulse multiplication functions
  • Ex-protection E Ex ia IIC T6/T4
  • Resistance to high voltage from 50 kV up to 120 kV
  • Special meters with high-pressure connectors for service up to 690 barg (10,000 PSIG).
  • Heated versions are available on request
  • The K-factor (no. of pulses per liter) is nearly constant over a wide range.

Oval Gear Positive Displacement Flow Meter, ALOVPD

  • Superior accuracy – to 0.5% of reading with ±0.03% repeatability
  • Elliptical gear design provides low pressure loss
  • Meter body is available in CS (Std), 304SS or 316SS
  • Bearings are available in CS (Std), 304SS or 316SS as well as Alnico
  • Will accommodate pressures of up to 870 psig (60 bar)
  • Will accommodate viscosities of up to 1000 cP

Helical Positive Displacement Flow Meter, ALHPD

  • High accuracy and wide turndown ratios; up to 400:1
  • Suitable for pressures up to 5800 psig (400 bar)
  • Low pressure drop compared with other positive displacement meters
  • Double pulse rate and reverse-flow detection possible
  • Pulsation-free measurement, readings unaffeted by pulsating flows
  • High quality materials and bearings provide superior corrosion resistance
  • Low operating noise
  • Ex-protection E Ex ia IIC T6 for zone 1

Micro Flow Positive Displacement Flow Meter, ALMPD

  • The relative simplicity of the ALMPD makes it far less costly than other PD flowmeters desigined for low-flow rate measurement.
  • Reduced susceptibility to wear versus other PD technologies as a result of the following design features:o Micro-machined components with reduced size resulting in lower relative velocities amongst the moving partso Any forces acting on one side of the
  • Since the moving parts are not rigidly attached to each other or the motion detection mechanism, the ALMPD is capable of service in fluids less filtered than other devices which may be capable of measuring similar low flow rates.
  • Should the MICRO FLOWMETER become clogged with debris, it can be easily disassembled, cleaned and reassembled with reasonable care in the field.