The only wetted part is the elastomer sleeve, so abrasive slurries, powders and corrosive liquids never touch metal. Open, it is a straight full-bore tube with no pockets for solids to pack into. Air-operated versions pinch the sleeve by pressurizing the housing around it, while mechanical versions use a bar or pinch mechanism. Sleeve wear and fatigue set the maintenance interval.
Tailings line chewed through another pinch valve sleeve, put a spare on the next truck up.
Related terms
Diaphragm valve
A valve that closes by pressing a flexible diaphragm down onto a weir or the body floor, with no stem packing.
Knife gate valve
A gate valve with a thin, sharp-edged blade that cuts through slurry, pulp or solids as it closes.
Body
The main pressure-containing shell of a valve, carrying the flow passage and the end connections.