Abstract: A lubrication system for the block and bleed valve seat of a gate valve. Lubrication is provided to the seat through tubing which communicates with the exterior of the gate valve to supply the lubricant and the interior channels of the valve seat. Seals in the valve seat maintain the lubricant within the interior channels of the seat. The lubrication system allows the user to test each seat for integrity without exposing the entire valve to atmosphere by increasing lubricant pressure through the valve seat.

Abstract: A slurry gate valve incorporating dual gates for the positive interruption of fluid flow through a pipeline associated with the valve. The dual gate valve is movable through three positions: a fully open position, a half open position, and a full closed position. The valve includes a main leader gate and a follower gate each having selectively alignable fluid passageways. An interlock mechanism selectively connects the dual gates for simultaneous travel once the gates have reached the half open position. The dual action gate valve reduces wear on the downstream resilient seals associated with the valve by shielding the seal against the fluid flow through the main passageway of the valve.