Valves › Control Valve
Control Valve Overview
Control Valves are valves used to control conditions such as Flow, Pressure, Temperature and Liquid Level. The range of valves used for these purposes is extensive and varied, so this section is only representative of the type of valves that we can supply-but is by no means complete.
The accuracy of control is determined by the type of control valve selected, the correct calibration of the type of positioning device and correct valve “sizing”. “Sizing” control valves is essential and relies on obtaining and inputting all of the various application data…pressure, temperature, SG, viscosity and the min/normal/max flow control ranges. We have excellent sizing programs to assist us with these calculations.
We have decided to present this section by starting with the simplest type of self acting valves and progressing through to more sophisticated valves that are generally operated by a pneumatic actuator and positioned by a pneumatic or electro-pneumatic positioner, which receives a 3-15 psi or 4-20mA signal from a PLC or other control instrument.
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Maric Flow Control Valve
Maric Flow Control Valves provide a fixed constant flow rate irrespective of pressure differential across the valve over a wide range. Precision Series (differential range 140-1,000 kpa) offers to control the stated flow range with +/-10% and high pressure models HP1 (differential range 140-1,500 kpa) or HP2 (170-2,000 kpa) +/-20% accuracy.
The principle is simple…the bodies are made to rigid engineering standards in DR Brass, Chromed Brass, Gunmetal, PVC or 316SS and are fitted with a control rubber in either Nitrile (std), EPDM (opt) or Viton (opt). As the pressure differential increases, the control rubber deforms to restrict the flow rate to the pre-set setting (which is also stamped on the valve body). For larger flow rates than cannot be handled by 2” screwed valves, wafer type valves are available up to 12” (multiple control rubbers can be inserted into machined recesses in the plate)
This type of flow control device is automatic (self acting), self cleaning and maintenance free and is available in the following materials and flow ranges (refer to data sheet for all flow rates available for each valve type and size).
DR Brass & Chromed Brass (screwed)
¼”→ 2” F x F BSPP, numerous flow ranges between 0.4 LPM → 342 LPM
½” → 1” F x M or M x F BSPP, numerous flow ranges between 0.4 LPM → 114 LPM
316ss (screwed)
¼”→ 2” F x F BSPP, numerous flow ranges between 0.4 LPM → 233 LPM
¼” (F x M), ½” & 1” F x M or M x F BSPP, numerous flow ranges between 0.4 LPM → 114 LPM
PVC (screwed)
¼”→ 2” F x F BSPP, numerous flow ranges between 0.4 LPM → 342 LPM
Gunmetal or 316ss (wafer type for Table D flanges)
1”→ 12” numerous flow rates from 0.4 LPM to 8,854 LPM
3-8 V-Port Ball Valve with Positioner
Standard full or reduced port Ball Valves are unsuitable to use for modulating control due to their large Cv’s and can result in poor control through most of their opening/closing range. However, a V-port or V-notch Ball valve has significantly reduced Cv values and, when used in conjunction with an actuator and I/P positioner, can be used as an economically priced control valve for modulating duty.
Components for modulating assembly are:-
Valve- Apex 3-8T, 3-piece 30° or 60° V-port, 1,000 psi (69 bar) Ball Valve, ISO5211 direct mount, 316ss body/ball/stem, TFM1600 seats, PTFE seals, bsp ends (SW or BW optional)
Sizes- ½” (DN15) → 2” (DN50)
Actuator- Prisma PA series DA or SR (if fail open/close required)
Positioner- YT-1000R (positions in response to 4-20mA signal)
Piping- generally ¼” st/steel tube with Hylok tube fittings (nylon tube with plastic fittings optional), Filter Regulator and Pressure Gauges
Series 2000 Angle Seat Control Valve (on/off)
Series 2000 is one of Burkert’s extensive range of general purpose Control Valves. The standard valve and actuator is suitable for on/off duty but it can be fitted with other control heads and parabolic plug so that it can function as a modulating control valve. This valve is an angle-seat design and is operated by a single or double acting pneumatic actuator (either PA or PPS material, depending on ambient temperature) which is rotatable and with visual indicator. Valve is 2-way, normally closed and is available in sizes 3/8” (Kv3.7) → 2 ½” (Kv90) with threaded ends female BSP.
Body materials: Gunmetal or 316L
Seal material is PTFE (NBR, FKM, EPDM on request).
Can be ordered with flow direction above (gas & steam) or below the seat (liquids).
Series 2012 is the flanged version of the same valve
Options: Different Control Heads (8691, 8690, 1062), banjo pilot valve, actuator for high ambient temperature, normally open valve (see data sheet for all options)
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