• Steam and Mining Industries

Check Valves

SMI/Swastik check valves are designed to close the valves automatically by back pressure of the flow in order to maintain the flow in one direction, and to prevent flow reversal. The valves are made of cast steel. These are two kinds of check valves: "swing" type and "lift" type. The lift type is mostly used for smaller pipelines, and the disc is normally of "piston" type and occasionally "ball" type: barb are designed for the forged steel valves. Swing check vrlves are so constructed that one end of the disc is fixed totbe body with a hinge pin, permitting it to open freely in onedircction. As opposed to the lift type, the swing type check valve is widely installed both horizontally or vertically. When the swing check valves are fitted in vertical pipelines, special attention should be paid so as to secure a force to lift up the disc. Swing check valves are normally of cast steel and mostly available in large sizes. Construction: the bodycover connection is usually of bolted cover type. but pressure seal type is available for high pressure service. Seats arc of the flat type, jointing with the body being either screwed, welded or integral. The eye bolt is particularly designed to the cover of the larger sizes to facilitate carriage. The following special designs for check valves are available: Counter-weighted-counterweight fixed to the rotating pin of disc to control the disc movement; shock-absorbed; forced closing, swing type reverse current check; and tilting disc type-swing check valves for higher pressure service.