Industrial Turbine Flowmeter NT

flanged nt meter


Our range of turbine meters offers high accuracy and high reliability. Over 30 years, thousands of units have been sold to all classes of industry, and the meters have an excellent reputation for durability.
Many leading flowmeter companies in the U.K. and abroad have the confidence to put their name on our range of turbine flowmeters, a sign of the high regard in which the product is held.
The range has been modified and extended over the last few years to provide a reasonably priced general purpose flow transmitter. Our turbine flow meters are now produced at the factory entirely in-house to control quality and availability. The range is available on short deliveries, and popular sizes are held ex-stock.Available in a wide variety of body sizes and styles, all NT flowmeters possess an electrical pulse output directly proportional to flowrate, based upon the operating principle described in this publication. Remote flowrate indication, alarms, totalising and batch control functions are available utilising our wide range of secondary electronic instruments.
The flowmeters are suitable for use on lubricating or non-lubricating liquids of low to medium viscosity and are largely insensitive to density variations, pressure or temperature fluctuations. Contact parts are produced from 316 stainless steel, except rotors which must possess good magnetic qualities, and here 431 stainless is used or Ferralium alloy depending upon the corrosive properties of the liquid.
Standard end connections are screwed BSP parallel thread with included 30 degree internal cones to BS5200, but Ermeto threads are also available. Flanged meters are normally to ANSI 150 or BS4504 (DIN) standards, but older type flanges to BS10 tables D-H may also be fitted.
A unique feature of the design is the use of helically milled rotors cut from solid in sizes up to 65mm. Bearing bushes are of PTFE/Carbon HY49 or similar, or tungsten carbide depending upon the nature of the metered fluid. In all cases, the spindle is of tungsten carbide with Cobalt binder, and thrust balls of tungsten carbide. Stainless steel ball races are used in the smaller sizes.
The electrical signal is a sinusoidal pulse of minimum height 50mV peak at lowest flowrate, rising to 800mV peak at max flowrate. For normal transmission distances pre-amplifiers are not essential since pulse shaping and conditioning are carried out in the appropriate electronic readout unit. In cases where heavy electrical noise is present or where transmission distances are over 500 metres, pre amplifiers of standard or intrinsically safe design are available as head mounted weatherproof units and loop powered.
Performance and other details are listed on Technical Data tables on pages 2 & 3.

Technical Data

  • Linear Accuracy - ±0.5% over 10:1 range
  • Repeatability - ±0.1% of reading
  • Response Time - 50 millisecs for 50% step change in flowrate
  • Output Signal - Sinusoidal pulses 50mV - 800mV peak varying with flowrate
  • Operating Pressure - Twice the pressure drop across the meter plus vapour pressure of liquid
  • Pressure Drop - 0.2 - 0.5 bar depending on meter size
  • Flow Range - 10:1 as standard
  • Temperature Wider ranges possible -30°C min - 150°C max (standard coil), 400°C special design, 120°C intrinsically safe
  • Transmission Distance - 500 metres max without pre-amplifiers for low noise environment
  • Mounting Altitude - Horizontal or vertical (flow upwards) or inclined
  • Maximum Pressure - Limited only by end fittings

parts and material

Parts and Material

  • Parts and Material
  • 1 Housing 316 Stainless Steel
  • 2 Bearing Hanger 316 Stainless Steel
  • 3 Rotor 431 Stainless Steel
  • 4 Spindle Tungsten Carbide
  • 5 Bearing Bushes PTFE/Carbon filled or Tungsten Carbide
  • 6 Thrust Ball Tungsten Carbide
  • 7 Pick off coil Stainless Steel body
  • 8 Collar 316 Stainless Steel
  • 9 Circlip 302 Stainless Steel

Sizing Table

Type NumberFlow Range (Linear) Ltrs/MinFlow Range (Linear) I.G.P.M.Approx K-Factor LtrApprox K-Factor Imp GallLinearityStandard End Fittings BSPStandard End Fittings Screwed ANSI or BS10 E FlangeStandard End Fittings DIN Flange
NT3245-4509.9-99135613±0.5%1 1/4“1 1/2”ND40
NT3865-65014.5-145117530±0.5%1 1/2“1 1/2”ND40
NT65200-200044-4401882±0.5%3“2 1/2”ND65

Operations Principle

A ferritic stainless steel rotor revolves within a non-magnetic housing on the outside of which is located a pick off coil containing a permanent magnet. As the rotor blades pass the tip of the permanent magnet, the reluctance of the magnetic circuit is changed, and a small a.c. voltage is generated in the coil. The frequency of the a.c. voltage is proportional to flowrate, and the total number of pulses produced represents total flow passed through the meter.
The flowmeter may be located some considerable distance from the associated secondary instrument, and remote flowrate indication, total flow, and remote batch control are thus possible.

Installation and use
For best results the flowmeter should be installed well away from heavy current carrying cables and with control valves etc. located downstream of the meter.
A length of straight pipe of bore equal to the meter inlet should be provided, preferably 10 diameters in length, and if possible containing flow straightening vanes at the inlet end. Turbine meters are sensitive to swirl present upstream may cause a change in meter factor.
Strainers should be provided to minimise the risk of damage due to small solids in suspension. Meters may be installed in any attitude, but the flow direction and mounting attitude should be advised at the order stage if other than horizontal.
Varying densities have no appreciable effect on the accuracy of axial flow turbine meters so far as volumetric flow is concerned. If readout is required in mass flow terms, we can supply density or
temperature compensation equipment to automatically correct for density variation. All turbine meters are to some extent sensitive to viscosity changes and any likely viscosity variation should be advised at the order stage.
Servicing may be carried out by our service engineers in the field, but meters should be returned to our factory wherever possible for repair. Bearing replacement can be effected on site by a skilled fitter, and instructions will be provided on request.  When requesting service visits or spares the full serial number should be stated, which immediately gives us access to the original order files for the installation.



Allow an extra 50 mm height on dimension 'D' for pick off coil connector


If you require further information on this product or would like a quotation, please contact dp-flow on:

sales +44(0)1865 600245