Sludge valves are used for complete draining of reservoirs and tanks, being cast into the floor as illustrated.

They can be supplied in cast iron or cast steel, or, as is usual for the larger sizes, they can be fabricated from stainless steel, corrosion-resistant steel, or mild steel. Bronze/Neoprene is standard for the seats, with stainless steel being used where specially required.

Normal operation is by means of a handwheel, but hydraulic or pneumatic operation can be utilised if necessary.