Closed loop flow control
February 2013
Valves, Actuators & Pump Control
Proportion-Air F-Series flow monitors are the heart of its new real-time flow control system and the electro-pneumatic controls can be electronically reconfigured to accept feedback from its F-Series flow monitors. This combination of components provides a complete flow control package for a wide spectrum of flow ranges. Because the feedback is real-time, the result is a series of flow controllers that respond instantly to change in command or system fluctuations. This fast response allows manufacturers and machine builders to use flow control in applications using high cycle rates. Real-time response allows increased cycle rates and thus higher productivity.
The servo valve and flow transducer are plumbed in a directional valve so that it can control the cap-end or the rod-end of the cylinder’s speed. Speed is adjustable on the fly with a command signal. Speed is visual unless an LVDT is used and velocity is monitored via a PLC: this is not common, but the capability is available. Repeatability is excellent with the flow control package. If the correct speed is achieved, with 5 VDC, for example, one can be assured that speed results with a 5 VDC command will be repeatable.
Ramped speed is easily achieved as well. So if a ramped command is given to a device, it will track that command with a ramped velocity. This is typically done when the user wants to throttle back speed just before reaching the end of the actuator’s stroke. Proximity sensors could be mounted on the actuator to the switch signal sent back to the PLC to start the ramp function.
Force is a concern for most engineers when this system is explained. Of course it is the force that moves the load attached to the cylinder. But force is not what drives speed, flow does that. So, users should pre-set supply pressure for the pressure required to move the heaviest load. The speed control package will manage the flow at the pressure set to ensure velocity is maintained. The best explanation is a heavy pressure vessel lid mounted so as to pivot like a dancer cylinder. The load changes as the lid is lifted and without control, the change in force past centre point causes the cylinder to want to run away. The flow controller helps keep runaway from taking place. If users need to adjust pressure on the fly to adjust force, the system would be able to deal with that as well: just account for the range of pressure.
Further reading:
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.
Read more...
ENERGYValves expands operations
Valves, Actuators & Pump Control
ENERGYValves is expanding its operations with a new facility in Cape Town. The new premises will significantly enhance the company’s capacity to serve the Cape Town market and surrounding areas.
Read more...
Revolutionising slurry management in mining operations
Valves, Actuators & Pump Control
Dynamic Fluid Control has launched the Vent-O-Mat Slurry Air Release Valve, designed to set new standards in performance and technology for the mining industry.
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...
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...
New system improves performance of magnetic drive pumps
Valves, Actuators & Pump Control
KSB Pumps and Valves has introduced its ground-breaking MagnoProtect system for the local petrochemical, chemical and general industry markets ,to enhance the safety and performance of its magnetic drive pumps.
Read more...
Emerson software optimises maintenance
Emerson Automation Solutions
Valves, Actuators & Pump Control
Emerson has announced the Plantweb Insight Valve Health Application, a powerful software tool that combines Fisher control valve expertise with advanced analytic algorithms. The new app makes it possible for users to visualise an entire connected fleet of valves, while prioritising actions based on the health index of each valve.
Read more...
Inline pumps for space-saving applications
Valves, Actuators & Pump Control
Pump manufacturer, KSB Pumps and Valves has introduced its latest EtaLine range of inline pumps, including the advanced EtaLine Pro for diverse applications such as HVAC, industrial recirculation, and heating systems.
Read more...
printer friendly version