The pressure at the user end is measured and a feed back is provided to the control system. The control system works on a closed loop feedback mechanism. There are basically two types control valves a) Diaphragm, b) Passing/Throttle Valve, that controls the flow of steam at a preset pressure accommodating the seasonal variation of turbine load. A partial steam flow is drawn out of the turbine at a constant pressure as per the process requirement. It provides a constant pressure steam through a controlled extraction at various loading conditions of the turbine based on seasonal variations.Ī control valve integrated with the steam path is provided at a predetermined stage. One of the most versatile setup in terms of operation and intricate in terms of design. Its utility is found mainly in LP heating requirements like de-aerator, LP/HP Heaters or some processes This tap is provided before the controlled extraction in the steam path of turbine. In some cases a nozzle/port is provided at a predetermined stage and an un-controlled high-pressure steam flow/bleed is drawn out of the turbine. This setup is applied for processes where the steam pressure is a critical parameter. Based on this error signal the feedback control system actuates a control valve designed to vary the area of the valve aperture and thereby regulate the pressure.

There are basically two types control valves a) A Grid Valve, b) Bypass Valve, which control the flow of steam at preset pressure accommodating the seasonal variation of turbine load. In a controlled extraction type, a control valve integrated with the steam path is provided at a predetermined stage and the steam is allowed to escape the turbine at desired constant pressure based on the process requirement. A controlled extraction at various loading conditions of the turbine based on seasonal variations.

Extraction condensing steam turbine pdf