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Variable-area flow meter / for liquids / plastic tube / flange
PG/PGU Roxspur Measurement & Control


  • Technology:


  • Fluid:

    for liquids

  • Other characteristics:

    plastic tube, flange

  • Process pressure:

    Min.: 0 bar (0 psi)

    Max.: 10 bar (145.04 psi)

  • Process temperature:

    Min.: 0 °C (32 °F)

    Max.: 80 °C (176 °F)

  • Volumetric flow rate:

    Min.: 0.7 m³/h (24.72 ft³/h)

    Max.: 1500 m³/h (52972 ft³/h)


Gapmeters type PG and PGU are low cost direct reading variable area flowmeters for liquids or gases, in pipe sizes ½” or 1”. The shatterproof TPX moulded tapered indicator tube has a 100mm linear flow scale with a 10:1 flow range. The stainless steel or Dural float rises with the flow to an equilibrium position - flow rate is read from the top of the float. Standard air and water scales are etched directly onto the plastic flow tube high float visibility, easily read at a distance.

Type PG is a lightweight, open construction ideal for surface mounting or portable use. For alternative process liquids or conditions, external laminated scales are provided positioned in front of the flow tube. Type PGU has a rigid diecast housing with a Perspex window, giving complete protection from random damage: this flowmeter is suitable for unsupported mounting in process pipework. TPX plastic tubes are available with air or water scales etched into the flow tube. Glass tubes are also available, which can be supplied with custom scales to suit process conditions, in the PGU housing.

The PG/PGU meters are installed vertically, with flow upward. End connections are either ½” or 1” BSPP standard: units with plated brass connections use Nitrile O-ring seals, with stainless steel connections the seals are Viton. Type PGU is also available with stainless steel flange connections, using Viton seals for the flow tube.
TPX plastic has excellent resistance to most chemicals and gases - it is also non-toxic and boilable.


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