Local valve designer and manu- facturer Dual Products International reports that it now exports 80% of its products to a number of countries across the world.
The company produces valves for the mining, sands, steel, power, chemicals and paper industries worldwide and has exported valves to more than 25 countries.
Dual Products International member Stephen van Rensburg adds that the company has a number of ongoing contracts for the supply of a range of valve products to new mining plants in foreign countries, including the Ukraine, Australia, Canada, and Zambia.
“We have just received a new contract in Ghana, and we are working on a R16-million contract for the Ukraine and Russia,” says Van Rensburg.
The company supplies a range of slurry and abrasion-resistant valves, including rotary disc valves, double nonreturn valves, pinch valves, ball check valves and knife gate valves, besides others, for a number of mining projects.
Further, Van Rensburg says the company has been supplying Eskom with polyurethane-lined rotary discs with 305-mm face-to-face, free-flow ball check and Dual valves used on the ash slurry lines. The cast slim-line ball check is used on ash water lines in place of the swing check valve owing to the pin wearing out and the discs dislodging. The products are being standardised at all Eskom power stations.
“These polyurethane-lined valves are used on wet ash systems, and have been installed at power stations, such as Camden, Matla, Kriel, Arnot, Hendrina and Duvha, across the Mpumalanga highveld,” says Van Rensburg.
He adds that the valves can be repaired and used over and over again.
The company also offers a urethane-lined version of its Dual Valve product.
The Dual Valve operates on the discharge side of a pump. It is a maintenance-free slurry valve with a rotating and floating ball, which self-adjusts to the flow of slurry.
It is self-cleaning, owing to its freely rotating ball, and the seat and ball can be inspected or replaced without removing the entire valve from a pipeline.
In addition, its range of cast steel Dual Rotary Disc Valves is also now being lined with urethane. The valve is a rotating gate valve used for heavy abrasive and corrosive slurries. The design allows the valve to operate in heavy slurries without sticking. Dual delivered two on-meter 16-bar valves to the Norilsk Nickel mill a year ago through Weir Minerals, Dual Products International’s agent in the Ukraine.
There are two types of this pro-duct, namely rising and nonrising spindle, and high-pressure or low-pressure valves.
Moreover, Dual Pro- ducts International has designed its new Dual Pump Protec-tion Valve for slurry pumps, which is espe-cially effective in releasing the excessive fluid temperature rise, within the pump housing.
The Pump Pro-tection Valve uses a simple design, a urethane ball and a compressed helical spring to seal the valve. As the pressure in the pump builds up past the manufacturer-designed pressure rating, the ball is pushed backwards, allowing fluid or steam to flow through into the bypass line of the valve.
As pressure falls back to normal levels, the ball will reseal the valve, hence, protecting the pump against damage and an explosion which could cause bodily harm and even death.
“This product has been specified for use at all Anglogold mines. The valves are available in 40 mm and 80 mm,” says Van Rensburg.
He adds that the company will market the new product to all countries with large mining interests, including Russia, Canada, the US, Jordan, Angola and Fiji. It also serves China through its Australian agent, Dual Valves Asia Pacific.
The company has also changed the design of the sleeve on its range of pinch valves. “The new design eliminates the amount of hydraulic closing force required to close the valve, which means it is easier to close when manual operation is required,” explains Van Rensburg.
Lastly, the company also manufacture sleeves for other makes of pinch valves in alternative materials, providing chemical and abrasive resistance to most media, including a urethane-lined sleeve.