The opening or closing of control valves is done by means of electrical, hydraulic or pneumatic systems. Positioners are used to control the opening or closing of the actuator based on electrical or pneumatic signals. These control signals were traditionally based on 3-15psi (0.2-1.0bar) but 4-20mA signals are now more commonly used for industry. With the introduction of "Smart" systems; HART, Fieldbus Foundation, & Profibus are the more common communication protocols available.

The primary function of a control valve is for throttling which is achieved by varying the restriction caused by the internal trim components. Various control valve trims are available in order to deal with certain process requirements such as characterisation, anti-cavitation and low noise.

• In-line Globe, Angled Globe, Butterfly, Control Ball, Eccentric Disc
• Manual, Pneumatic, Electric or Hydraulic Actuation
• Trim style options – parabolic plug, multi-hole cage, multiple cages, high duty labyrinth
• Trim features – low flow, anti-cavitation, low noise, erosion resistant, high energy dissipation
• Trim coatings – Silicon carbide (Hyc 20), Hard Chrome, Tungsten Carbide
• Erosion resistant upgrades – Stellite weld overlay, Solid Tungsten Carbide Inserts, Solid Ceramic Inserts
• Characteristics – Linear, Equal Percentage, Quick Opening
• Hydrostatically body tested to ANSI B16.34
• Seat leakage tested to ANSI FCI 70-2
• Specialised gas, low temp and cryogenic testing options
• Positioner options – pneumatic, electro-pneumatic, electronic digital SMART
• Operating temperature and fluids suitability – further information available on request
• Modification service available for all stock options

• ANSI 150, 300, 600, 900, 1500 & 2500lb - Flanged RF, RTJ, Butt-Weld and Hub ends
• Others available on request