Pneumatic positioners match the particular current valve setting with the set-point signal as a control value. The control air, as the input quantity, generally corresponds to a unit signal of 0,2 to 1 bar. Positioners are also volume boosters that convert the control air at a minimal pressure to a proportional, high control pressure for the positioning of the valve.
However, control valves with large volume, pneumatically operated, part-turn and piston actuators, usually need several seconds for large positioning processes or to close or open fully. Concerning valves from DN 150 upwards, this can often result in restrictions in control quality. Now, with the newly developed, high precision 4090 pneumatic volume booster from Schubert & Salzer Control Systems, it is possible to amplify the air strength of the set-point signal from positioner to actuator such that these control valves – depending on nominal valve size – operate up to four times faster without any further modification.
Pneumatic volume booster
The pneumatic volume booster is based on a diaphragm system with which the pressure and volumetric flow of the control air are increased up to 6 bar through the controlled insertion of supply air. In the volume booster, the control air is fed through an adjustable bypass to the actuator. By controlling the flow rate in the bypass, the switching threshold for activating the amplifying air can be controlled precisely. This ensures that the pneumatic volume booster applies the default amount of supply air to the actuator with small changes in pressure, i.e. small control interventions. When the adjustable bypass pressure threshold is exceeded, the pneumatic volume booster is activated and releases the additional pressure amplification for the control air so that the adjustment of the valve stroke or, respectively, the part-turn actuator is substantially faster.
In the venting also of the actuator, the pneumatic volume booster adopts the same function and makes a vent valve operate when the supply air pressure is reduced. An exhaust air filter fitted here minimises sound emission.
The 4090 pneumatic volume booster enables significant reductions in switching times both in the closing as well as the opening of a valve. Using a DN 300 ball sector valve for a direct comparison, the closing time for a single-acting actuator falls from 43 seconds to 21.5 seconds with a standard setting and to just 10 seconds with an ‘aggressive’ bypass setting on the booster. This new pneumatic volume booster not only shortens switching times significantly but also optimises the control quality particularly for control valves in the larger nominal sizes.
The volume booster can also be connected retroactively with ease to G 1/4” inline linear actuators and to part-turn actuators with a Namur (1/4”) interface.
High-flow solenoid valve Emerson Automation Solutions
Valves, Actuators & Pump Control
Emerson has introduced the new ASCO Series 327C solenoid valve, which features a direct-acting, high-flow design that provides superior flow-to-power ratio. It permits high flows at minimum power levels, making it ideal for use in power plants, refineries, and chemical processing facilities.
Read more...Proportional cartridge valve series is the fastest in its class
Valves, Actuators & Pump Control
Parker Hannifin is introducing the enhanced version of the proportional cartridge throttle valve series, TFP. The new pilot valve further reduces the step response times by up to 30%, making the TFP the fastest valve in its class.
Read more...Proportional cartridge valve series is the fastest in its class
Valves, Actuators & Pump Control
Parker Hannifin is introducing the enhanced version of the proportional cartridge throttle valve series, TFP. The new pilot valve further reduces the step response times by up to 30%, making the TFP the fastest valve in its class.
Read more...Inspection system for leak detection in valves in hazardous areas Extech Safety Systems
Valves, Actuators & Pump Control
Leaking valves in industrial plants not only lead to loss, safety risks and possible contamination and pollution, but also result in high economic costs. Therefore, valves in hazardous areas require regular proper inspection and preventive maintenance to ensure their functionality.
Read more...Control head for automation of hygienic process valves Burkert South Africa
Valves, Actuators & Pump Control
Burkert’s Type 8681 control head is optimised for decentralised automation of hygienic process valves. Thanks to its universal adapter, it can be combined with all normal commercial butterfly valves, ball valves and single- and double-seated valves.
Read more...Hydroformed tube valve body Burkert South Africa
Valves, Actuators & Pump Control
One of the most common necessities for manufacturing pharmaceuticals, cosmetics, food and beverages are diaphragm valves. What used to be a dull two-way race between forged and cast body variants is now being challenged by an exciting, ground-breaking technology. The hydroformed, light-weight diaphragm tube valve body will change the way you think about plant design and operation.
Read more...Global pumping giant ready to support hydrogen economy
Valves, Actuators & Pump Control
With abundant sunshine and wind, southern Africa is perfectly positioned to become a global powerhouse in green hydrogen production. Two key projects are already in advanced stages of development in Namibia. KSB has identified the vast potential of these types of projects in southern Africa, and through its KSB Pumps and Valves subsidiaries in Namibia and South Africa is investing heavily in bringing the right skills to the region.
Read more...Compact valve position indicator Emerson Automation Solutions
Valves, Actuators & Pump Control
Emerson’s new TopWorx DVR Switchbox is an entry-level addition to the DV Series of valve position indicators. It combines a durable resin enclosure, compact size, and a patented cam design that provides a reliable valve position feedback for water and wastewater systems, food and beverage production lines, and industrial utilities.
Read more...Precision, control and performance in regulators and control valves Valve & Automation
Valves, Actuators & Pump Control
Cashco has long been a trusted name in industrial control solutions, offering a broad range of regulators and control valves designed to meet the rigorous demands of various industries. There are two key Cashco product lines, its regulators and the Ranger QCT control valve.
Read more...Advanced solutions for valves Bearing Man Group t/a BMG
Valves, Actuators & Pump Control
BMG delivers state-of-the-art valve solutions to diverse industries across Africa, in collaboration with InterApp, a global leader in the design and manufacture of high-quality valves.
printer friendly version