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Premier Control Technologies Fluid Solutions


Why we chose to partner with King Instrument Company

We have been partnered with King Instrument Company since the very early days of our inception. During this time we have watched the range of King flow meters grow and for them to stay true to their mission statement “To produce the finest group of rotameters ever sold”.

King’s range of rotameters are ideally suited to low flow and low pressure applications for both liquids and gases. Dependant on your process and application there will be a suitable model of rotameter. The range includes flow transmitters and flow switches for applications which require a switched output. Various material and seal options exist for general purpose and corrosive applications.

King Instrument Company combines proven measurement technology with high-tech production systems; to build accurate, versatile, economical Rotameters.

Learn more about rotameters

Rotameters can be used for both liquid flow meter and gas flow meter applications. Offering a simplistic form of flow measurement as a visual indication of the flow rate. Some of the rotameters within our range can also be supplied with either an output signal or a switched output.

With an analogue output signal the rotameter can be said to be a flow transmitter as it has a 4 – 20 mA output. Rotameters may also be offered with various switched outputs such as NPN sinking normally open (N.O.) or normally closed (N.C.) or PNP sourcing (N.O. or N.C.).

King rotameters can be supplied with control valves which can be used to manually set flow rates by adjusting the valve opening while observing the scale to establish the required process flow rate.

Choose the right type of rotameter for your application

The King instrument company range of rotameters is comprehensive to cover acrylic, polysulfone, PVC, Kinglass and 316L metal tubed rotameters to fit the right application. Acrylic tubed rotameters offer real value in general purpose applications as well as panel mount versions for OEM use. Acrylic tubed flow meters are available from ¼" line sizes up to 2" and offer flow rates up to 245 SCFM for air and 750 LPM for water - it's an excellent water flow meter. Polysulfone tubed rotameters are ideal for processes which require no metals to be wetted. These are available with PVC and PVDF fittings. PVC type 1, grade 1 tubed rotameters offer excellent chemical resistance in liquid applications.

"King rotameters are excellent water flow meters"

King instrument company also manufacture Kinglass rotameter tubes, which are precision formed borosilicate flow metering tubes. Glass tubed rotameters are available which offer removable glass tubes, low-flow and gas purge models or high chemical resistance models. Flow meters can be ordered with side plated construction complete with polycarbonate shield or all 304 or 316L stainless steel cased flow meters for harsh environments. 316L tubed flow meters offer higher pressure ratings even for low flow applications. Within the stainless range is also a tapered tube design using a float which allows for a longer, more linear scale and provides better point stability as well as up to 40% greater accuracy compared to similar models.

Temperature ratings may also be increased for metal tube rotameters, allowing for temperature ratings beyond 200⁰c.

  • Process Connections

    King rotameters are available with various process connections. Standard port threads are male and female NPT with flanged options available for both vertical and horizontal mounting. Process connection materials include 316L stainless steel, Hastelloy C-276, Brass, aluminium, PVC and PVDF. Other thread or flange types and materials are available on request.

  • O-rings

    O-ring materials offered with King rotameters include EPR, Buna-N, Viton and Kalrez. Dry seal options are also available on some models.

  • Float types

    King instrument company know that there are many different types of application and process where a rotameter maybe used. For that reason, different float types are offered so that float materials and designs fit the application. This can be of benefit as it can extend flow ranges or performance of the rotameter. Floats are offered which allow for viscosity compensation, lower pressure drop or to offer maximum flow.

    Dependant on the float type it will have different edges from where the flow reading should be taken from. Floats are available in 316L stainless steel, Hastelloy C-276, Tantalum, Carboloy, Glass and Sapphire.

  • Scales

    • King rotameters for liquids as standard have scales which are for a specific gravity of 1.0 for use with water. Scales may be created for other liquids if the density and viscosity of the liquid is known.
    • Scales for gases are typically provided in standardised units, the reference conditions have an STP (standard temperature and pressure) of 21.1⁰c (70⁰f) and 14.7 PSIA on air. Scale for gases maybe created against different reference conditions and gases.
    • Correction factors may be used for both liquid and gas scales, to calculate the flow capacity when using a liquid other than water or a gas other than air at STP conditions.
    • Any volumetric flow rate can be printed on the scale.
    • Dual scales may be produced if different volumetric flow rates are required or if more than one process fluid is used with a rotameter.
    • Scales may also be created which relate to a percentage of range.
    • Rotameters may be provided with a factory calibration certificate to NIST standards where required.
  • Accuracy and repeatability

    King have many ranges of rotameters for many different processes and applications. Accuracy specifications vary between models but can be as good as ±2% of full scale and are typically within the ±3% - ±4% of full scale. Repeatability is typically between ±0.5% and ±2% of full scale.

  • Turndown

    King rotameters typically have a 10:1 turndown ratio.

How does a Rotameter work?

Take a moment to read our applications article on how a rotameter works.

If you have any questions about our range of rotameters, please do contact us.

Help and advice

A member of our team will be happy to assist with any questions you may have.

Ask the team