Special check valve KOS-400-1M2,5

Backflow valve KOS is installed on the steam extraction pipeline from the turbine and serves to protect the turbine during load shedding from the reverse flow of steam contained in the pipelines and apparatuses connected to the turbine.
The valve consists of a housing in which the valve shut-off organ (plate) is located and a servomotor mounted on top of the housing cover The plate moves freely in the vertical plane around the axis of its mounting in the housing. The servomotor is not rigidly connected to the valve plate and acts on it via the stem and lever.
The valve is opened by the direct steam flow from the turbine. The valve is closed by the reverse steam flow, which occurs during load shedding. The servo motor insures the valve closure by creating additional force on the shut-off organ - the plate.