Wouter Witzel butterfly valves from AVK Southern Africa provided substantial cost-savings and reduced personnel requirements for KwaZulu Natal-based Umfolozi Sugar Mill (USM). The savings enabled the company to redistribute finance to other plant instrumentation upgrades and negated the need for specialized valve maintenance personnel. This facilitated the redeployment of these personnel to other plant maintenance tasks. The Wouter Witzel DN700 butterfly valve, installed to regulate flow in one of the plant’s pan discharge applications, remained unaffected by the severity of the production process for more than six years without any maintenance.
USM runs on a seasonal basis and maintenance, therefore, is conducted during the off-season plant shutdown. The maintenance inspection subsequent to this valve installation included valve removal, damage inspection and functional scrutiny, which it passed with flying colours. It proved the valve’s durability compared to the wear and tear that competitor valves underwent.
Based on these findings, USM took the decision that future maintenance inspections for this specific valve would be reduced to a liner inspection and water test only. The water test is used to determine if there is any seal leakage, and none was ever found.
Wouter Witzel butterfly valves are heat-resistant, using NBR, EPDM or FPM rubber lining, which offer heat resistance up to 90, 110 or 200° C respectively. High-quality construction materials like ductile iron or cast steel on a single bodied valve; and a Rilsan, Epoxy or Halar coated duplex stainless steel disc contributes to enhanced durability. The disc, centre to the valve’s design, is thinner than conventional valve discs which facilitate increased flow capacity and smaller actuators if actuation is required. This contributes to increased pump efficiency resulting in lower power requirements.
