Sales director for Dual Products Stephen Van Rensburg explains that the company has been exporting the product for the past 21 years but that only recently has it begun to notice a significant increase in international trade.
“Two years ago 40% of our turnover was in the international market, now it’s nearly 60%,” explains Van Rensburg.
He tells Engineering News that the company attributes the increase in business to the fact that customers are finally finding it necessary to replace the valves which were installed twenty years ago. “We have also found that we are receiving wider exposure within the various industries as more and more people recommend our products,” says Van Rensburg.
The combination of replacement and maintenace as well as new work has seen the company’s turnover increase dramatically. So much so that Dual Products is currently searching for new, larger premises from which to conduct its business.
“Things are developing so quickly recently that we aren’t sure just how much space we will need; we have already taken over the factory next door and even this is proving to be inadequate,” explains Van Rensburg.
The increased awareness of the company throughout the world has seen Dual Products expand into a number of industries in which the company previously had no presence. “We recently sold valves to a sewerage company in Melbourne Australia, and are also exporting our valves to companies in Iran, Ghana and Russia,” says Van Rens-burg.
The company’s growth is expected to continue as Warman International recently announced that the Dual Products valves will be packaged with all of its slurry pumps. “This is important news for us as Warman International is the largest slurry-pump company in the world. We expect noticeable significant growth to arise from this one deal alone,” reports Van Rensburg.
According to him, weakness in the pins in swing-check valves has also allowed Dual Products to thrive as more and more com- panies move from swing-checks to ball checks.
“Our customers have been so impressed with our work that, as the old swing checks give in, we have been tasked with the replacement of these valves with our ball checks,” says Van Rensburg.
The secret to the company’s success is the patented rotary-disc valve which was originally designed for use in heavy slurries, such as ash, and can turn through this sludgy material without sticking. As the handwheel is opened or closed, the disc rotates. This happens due to the pressure which pushes against the disc and causes the disc to touch the valve body and to rotate. As the valve is cycled, the disc rotates 100 mm, seating in a different position each time. The valve body has a cutaway behind the disc which clears debris and ensures that the disc closes and seals.
The very nature of fabrication allows a maximum of flexibility in customisation to meet specific materials pressure-rating configuration needs. The bonnet is usually made of carbon steel but can be made out of different materials to suit the individual customer. The bonnet houses the rotating disc and seals around the spindle. All types of actuators can be fitted, including electric, gearbox, hydraulic, pneumatic and hand- wheel. The rotary-disc valve is available in two variations, as a rising or a nonrising spindle, and as high- or low-pressure valves.
The rugged design also aids with the overall effectiveness in abrasive environments. Flanges are typically made in carbon or stainless steel and drilled to customer require- ments. For Europe, flanges are made to DIN standards. The valves are capable of operat- ing under standard working pressures of 10 up to 500 bar and under temperatures up to 80