Long regarded as a leading brand in abrasive slurry applications, Krebs Technequip knife gate valves now allow less stockholding of spares through the enhanced interchangeability of components. Most of the components are standard across the range, explains Herman Britz, Regional Product Line Manager for Pumps, Cyclones and Valves at FLSmidth. The upgrade of the legacy products has ensured that customers need to keep a smaller variety of parts in their inventory.
“While the bodies of the flange-type valve and the wafer-type valve will differ, for instance, other components like the gate, actuator and wiper blades are standard,” says Herman. “This means that the components for a 200mm flange valve, for instance, will also fit on the 200mm wafer-type valve.”
The focus of the design was for harsh, abrasive applications where these valves have proved their worth globally. In sizes from 50mm up to 1,3m in diameter, the valves match the pipe sizes in the market and are designed to deal with a wide range of pressures and process conditions. Herman highlights the ‘full port’ nature of the valve, reflecting that the valve’s inside diameter will be the same as the pipe when the valve is fully open.
“This reduces any pressure loss as the material passes through the valve, and ensures that there is no turbulence, which also reduces the wear rate,” he explains. “The gate removes itself completely from the flow of material, which is a key differentiating factor.”
He also points to the valves’ push-through or self-cleaning design. This is essentially a self-flushing function which eliminates the need for a packing gland. As the gate closes during actuation, material is ejected out of the bottom of the valve, ensuring that there is full closure of the gate and a reliable seal is created. Another vital contributor to the valves’ durability and performance is the internal wear sleeve.
“The wear sleeves on our knife gate valves are the only surface that is in direct contact with the slurry,” says Herman. “By protecting the other parts from wear and tear, the sleeves reduce the need for replacement of parts.”
A bubble-tight seal ensures that there is no spillage, whether the valve is open or closed. Importantly, the sleeves can also be replaced in the field, so there is no need to take the valve to a specialised workshop.
“On our flange-type valve, a technician can simply remove the retainer flange and take out the sleeve, replacing it with a new part and returning the retainer to its position. This is certainly a stand-out feature when compared with most products on the market, and helps our customers avoid undue downtime,” Herman concludes.