Knife gate valves

MSW Feed System, The MSW feed system consisted of a sealed weigh hopper supported by load cells, a 10,2 cm diameter by 102 cm long screw feeder powered by a variable speed DC motor, and a 7.6 cm diameter feed chute fitted with an expansion bellows and a knife gate valve. An air cooler was installed to keep the feed chute near the combustor from overheating. 

Plexiglas cubes 15-30 cm on a side with an open top or a fast-shuttered knife gate valve at the top. 

FIGURE 2-21 Slurry knife-gate valve cross-sectional drawing. (Courtesy of Red Valve Company, Carnegie, PA, U.S.A.)... 

Knife gate valves for slurry flows (Figures 2 21 and 2-22) feature a metal gate sand-... 

Suppression or containment systems can be operated in conjunction with rapid-acting explosion isolation systems that isolate several interconnected vessels so an explosion in one vessel does not propagate through ducting to initiate an explosion in another vessel. Two types of isolation systems are used (1) mechanical and (2) extinguishing, both based on a fast-acting knife gate valve principle. For details, please refer Reference 38. 

Solids Metering The control valves described earlier are primarily used for the control of fluid (liquid or gas) flow. Sometimes these valves, particularly the ball, butterfly, or sliding gate valves, are used to throttle dry or slurry solids. More often, special throttling mechanisms such as venturi ejectors, conveyers, knife-type gate valves, or rotating vane valves are used. The particular solids-metering valve hardware depends on the volume, density, particle shape, and coarseness of the solids to be handled. 

The simplest functionality of a gate valve is a linear stem that raises and lowers a plate across the ports of the valve. FuU conduit valves such as expanding and slab gates provide protection for the seat in the fully open position. Knife and wedge gates permit circulation across the seats in the open position. Valves are available with pressure preferences for fail open or fail closed requirements. 

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