Problem-Solving Application: MAXUM™ Rotary Control Valves for Kaolin Slurries

DeZURIK MAXUM™ Rotary Control Valves (RCV) Offer Extended Service Life in Abrasive Kaolin Slurry Applications

Faced with a failing valve in a critical – and demanding – Kaolin slurry application, engineers at a large U.S. pulp and paper mill had to find a cost-effective solution that could handle high-temperature abrasives while requiring minimal maintenance and attention. Used in one of the mill’s jet cookers (a paper coating process), the valve had to throttle abrasive, 320°F (160°C) Kaolin slurry with 60% solids at 50 gpm (3 L/S), while managing a healthy 70 psi (480 kPa) pressure drop.

Two previous valves weren’t up to the task. The first, a 3" (80mm) plug valve, suffered fractured plug-to-shaft legs and failed outright. Its replacement, a 3" (80mm) rotary valve, performed adequately but required extensive maintenance. The slurry quickly abraded its ball and seat surfaces and technicians were worried about the valve’s ultimate reliability.

Engineers found the solution to the jet cooker problem in DeZURIK’s MAXUM™ Rotary Control Valve (RCV), with its tungsten carbide coated trim components (Rockwell C68), accurate throttling and high flow capacity. The RCV is designed for exceptional performance in abrasive slurries, scaling cooking liquors, and digester gas-off applications. The RCV offers superior performance, reduced maintenance, less downtime and greater productivity. These values can’t always be measured in the lab, but they make a big difference in the bottom line.

After more than two problem-free years of continuos service, the DeZURIK RCV pictured here was in like-new condition. It showed no substantial wear on plug or seat surfaces. Installed in the flow-to-close direction, the 2" (50mm) valve with high capacity trim replaced a competitor’s 3" rotary valve that was failing after only six months of service.

Engineers also noted that the improved control and throttling accuracy of the RCV led to significant process savings. DeZURIK RCV’s may soon replace other control valves used in the plant’s coating area.