Dynamic fluid control company Aveng Manufacturing Dynamic Fluid Con-trol (DFC) reports that its upgraded mechanically operated RF pinch valve, which was introduced in March 2011, has been well received by the market.

Aveng Manufacturing executive director Pat Stander tells Engineering News that the RF pinch valve, which uses the pinch bar mechanism to achieve shut-off, became part of the company’s product range when it bought RF Technologies in May 2010, adding that RF Technologies was at the time a US-based pinch-valve manufacturer with an established global presence.

“This acquisition was in line with Aveng Manufacturing DFC’s strategy of accelerating its presence in the international mineral processing valves market,” explains Stander.

The RF pinch valve, which uses compressed air to provide the pressure required to shut off flow through the valve, was then redeveloped by Aveng Manufacturing DFC at its Benoni facility, on the East Rand.

“The company redeveloped the RF pinch valve sleeves and body casting to enable it to function effectively in Africa’s harsh and abrasive mining conditions,” he points out.

Additionally, the company changed the body lining of the RF pinch valve from a fab- ricated body lining to a metal casting, which supports the upgraded sleeves on the valve.

Stander explains that the RF pinch valves are on/off valves, which contain full port identity documentation (ID), meaning that the ID of the valve matches the ID of the pipeline for unobstructed and 100% full flow.

He adds that the valves are designed to manage higher flow rates at higher than normal pressures, making them well suited to mining trends producing larger volumes of ore and processing the ore at higher pressures and velocities. They also achieve lower energy and main-tenance costs, over the lifetime of the facility.

Moreover, Stander says RF pinch valves are engineered to meet specific application requirements across a range of process condi-tions and actuation modes.

“The specification process starts with the submitting of valve data and process con-ditions and includes a review of available elastomer qualities, which are especially important when users have specific material preferences,” he states.

Stander explains that the on/off valves are available as manual, electric, pneumatic, hydraulic or air-actuated valves.

The pinch valves are available in many configurations and with an assortment of accessories, including solenoid and air valves, filters, regulators, limit and proximity switches, air-operated hydraulic pumps, the SmartValve Wear indicator wire and Monsys Alarm Box, fail close actuators, a manual handwheel override and lockouts.

The company also introduced a new range of Insamcor stainless steel lugged-wafer (LW) knife-gate valves in 2011.

Stander explains that the Insamcor LW full knife-gate valve is specifically designed for use in chemical and/or corrosive applications, where a leaching process occurs, for example, in copper mining.

The Insamcor LW knife-gate valve’s mech-anically moulded body seal contains a valve gate guided through the full length of the valve’s stroke and also possesses self-cleaning flush-out corners to prevent deposit build-up in its sealing area.

Further, the valve contains a full-bore unrestricted flow area, without seat pockets or cavities, and a bidirectional leakproof sealant.

The valve includes a 150 psi, or 10 bar, pressure rating for all sizes; an adjustable stuffing box and gland design, which ensures leakproof sealing to atmosphere temperature; and a secondary transverse seal that increases the wear life of the primary seal.

Moreover, its built-in polytetrafluoro-ethylene scrapers keep the blade free from any foreign matter over the width of the blade during operation, while the valve’s yoke design allows for easy mounting and boasts limit switches, which provide visual and remote electrical indication of a valve’s position and also include lockouts in the open and closed position.

“The mounting plate is designed to accept manual, pneumatic or electric actuation,” he concludes.