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NFX Glass Tube Variable Area

The Nixon NFX Glass tube Variable Area Flowmeter is available in a full range of lengths and is available scaled for liquid or gas measurement. Customised scales match the meter to specific conditions.

There is a choice of three scale lengths for optimum readability or compact installation. Repeatability is better than 0.5% of reading to improve process control. An optional needle valve is available for precise control at reduced cost.

The tubes are removable from the frame for easy cleaning/ replacement. Angled or straight connections allow for flexible pipe layout. The meters can be simply mounted to reduce installation costs.

The instruments have a retained polycarbonate cover to ensure operator safety in the event of a breakage. The units are aesthetically styled to suit integration into original equipment. 

Technical Data

  • Flow ranges: gas range 20 cc/min—115 l/min (air equivalent)
  • Liquid ranges 2.0 cc/min-4.6 l/min (water equivalent)
  • Scale length options - 140 mm / 100 mm / 30 mm
  • Accuracy Class - % 1.6 / 2.5 / 4 VDI/VDE
  • Temperature range - -15°C to +20°C
  • Maximum pressure - 20 Bar Non shock
  • Connections - Stainless Steel or Nickel plated brass
  • 1/4” BSP Female
  • Seals- Viton 
  • Flow tube - Borosilicate glass
  • Float- Stainless Steel, Anodised Aluminium


Variable Area Flowmeter. Displacement of a float in a conical, Borosilicate glass tube.

Applications: Commonly used in industry to measure the flow for:

  • Water treatment.
  • Chemical processes.
  • Industrial Refrigeration & Air Conditioning.
  • Research Laboratories.
  • Gas Burners.
  • Pilot Plants.
  • Annealing Furnaces.


  • Easy Installation, no straight pipe required.
  • Low pressure drop.
  • Scaled directly in l/h ,l/m, kg/h, %, mm, etc.
  • Adjustable alarms, in all scales, operated magnetically or with infra-red light.
  • Measuring tube in Borosilicate glass.
  • Steel construction, coated with Polyamide 11.
  • Connections in Steel, AISI-316, PVC & PTFE.
NFX Glass Tube Variable Area




  • Low/Medium flow of Liquids and Gasses
  • Compact, Standard and long versions available
  • Direct reading indication
  • Optional Needle control Valves
  • Custom scales
  • Alarm and 4-20mA options