Continuous development in the design and manufacture of plastic valves has created an opportunity for these valves in the potable-water market that was previously dominated by metal valves, says Cape Town-based piping systems company Alprene Plastic Products.

The company imports Swiss-made Georg Fischer products for distribution in Southern Africa.

Alprene director Niccoló Gericke tells Engineering News that several Georg Fischer valves are currently accredited by the German Technical and Scientific Association for Gas and Water (DVGW) as safe to use in applications for potable water and gas.

The polyvinyl chloride (PVC) union ball valve is a compact type of valve featuring full flow and axial pipe load block, with microadjustment of the ball seat. This valve ranges in size from 16 mm to 110 mm and it is suitable for applications in water treatment, swimming pools, water systems, food products, potable-water pipelines and low-aggressive chemical liquids.

Alprene also offers the unplasticised PVC (PVC-UH) one-flow directional valves that facilitate easy disassembly from a network by simply unscrewing two union nuts.

Further, a new-generation butterfly version of the PVC-UH valve from Georg Fischer offers reliability, safety and high performance. There are also butterfly versions available with lever-operated, hand-wheel-operated, pneumatic and electric actuators, as well as pre- assembled valves with free flanges. These valves are available in diameters from 75 mm to 200 mm.

The polyethylene (PE) series ball valves can be used in applications of up to 16 bar water pressure (with a safety factor improved three times) and applications of up to 10 bar gas pressure. This range is available in sizes of up to 225 mm, with PE spigots suited for electrofusion, butt fusion and mechanical jointing. These valves are also relative to the size of the pipe to enhance flow.

PE ball valves from Georg Fischer are DVGW W364-certified for use in potable- water applications.

Georg Fischer regularly launches new-generation piping systems onto the worldwide market, made available in South Africa by Alprene. These new diaphragm valves have several advantages, including enhanced materials handling capabilities, safety and efficiency. Safety and efficiency are enhanced through an improved use of appropriate plastics that are suited for specific applications, such as large bores, simplified installation and high-pressure ratings.

The diaphragm valves are suited for applications in the gas, water distribution and chemicals industries.

“The new-generation diaphragm valves have been accepted well in the Southern African market,” Gericke says, adding that, in many other countries, these valves are standard products in gas distribution networks. “Large European gas suppliers work with our high- quality products.”