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Premier Control Technologies Flow, pressure, level and temperature solutions

708 Series Fractional Flow Control Valve

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Express Delivery available, less than 1 week!

  • Express delivery available, less than one week!
  • Most accurate control available within LowFlows fractional control range
  • Pneumatically or electronically actuated

Mark 708 series of LowFlow valve from Richards Industrials is a fractional flow control valve which is able to provide accurate and precise control for your liquid or gas application. In fact it was developed to provide the most accurate control available for fractional control services.

Mark 708 series is a complete range of pneumatically or electronically actuated control valves to allow precision on your most critical micro flow applications. It features as standard the quick change trim, for applications requiring frequent trim changes without disturbing the actuator settings. The secondary stem connection eliminates stroke adjustment when changing trim; facilitating fast, easier trim changes (not available on Cv’s below 0.05)
Cv's range from 0.00001 to 4.0 available in DN8, DN15, DN20 or DN25 sizes (1/4” to 1").

Other features include:

  • Rolling diaphragm which ensures that the effective diaphragm area remains relatively constant, regardless of valve stem position. This increases accuracy of the actuator when positioning the valve by ensuring a linear response to input signal changes.
  • Spring-loaded TFE/Chevron packing to maintain a proper compression, while minimizing excessive friction. This alleviates the need for most field adjusting.
  • The TFE packing is suitable for temperatures to 232°C, while braided or Graphite/Grafoil may be used for higher temperature requirements.
  • Bolted body/bonnet connection provides solid construction and secure connection. This bolting adds ease to maintenance, as bonnet/actuator assembly may be removed with the valve body in-line.
  • The extended orifice and plug guiding are standard and offers improved shutoff and accuracy equivalent to heavy duty trim option of alternative models (not applicable to cv's below 0.05).

Connections and body options

708 series is available with a wide range of process connections including threaded (NPT, BSPT, BSPP), socket weld, tube end or welded flanged (ANSI, DIN, JIS).
Various diaphragm, body/bonnet, trim, actuator and stem materials exist.


Common process applications and industrial uses include:

  • Aerospace Testing
  • Cannabis / Hemp Extraction Supercritical CO2
  • Chemical Injection
  • Dosing systems
  • Hydrogen Fuel Cells
  • Pilot Plants
  • Polymer/Resin Production
  • R & D Facilities
  • Test Stands
  • Venting applications


The 708 Series Fractional Flow Control Valve is widely used in the following industries:

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Richards Industrials