The Design For Big Size Exhausting Butterfly Valve Used For Feed Water Pump Turbine In Large-Scale Thermal Power Units

With the rapid development of power industry in our country, the thermal power unit constantly promotes in the direction of large scale and high parameters. Because the small steam turbine driving feed water pump has the higher economic value and reliability than motor driven feed pump, now large capacity steam turbine units are mostly driven by this way. And feed water pump turbine exhaust butterfly valve which is the key equipment in connecting the small turbine exhaust steam with the main condenser, whose importance is self-evident, has become an indispensable important equipment of large thermal power plant. Feed water pump turbine exhaust butterfly valve which is installed between the small turbine exhaust steam and the main condense acts as the function of cutting off. Under the normal operating conditions, it is in the fully open position. When you need to repair the small steam turbine, this valve is closed and isolated, which can make sure the main condenser in vacuum. In the past, this kind of valve depends on import and the price is expensive. With the need of high parameters and high performance valve localization, the development of this kind of valve has become very urgent.In this paper, the author studies on exhaust butterfly valve with the triple eccentric metal seal structure. According to the triple eccentric butterfly valve sealing principle and characteristics, we design the main sealing parts of the butterfly valve, establish the self compensation institution, uniform sealing pressure and ensure the two-way sealing performance. The stem part needs to think about the filling and also the compaction device, to establish the self compensation institution, to control the vacuum degree from the radial direction and axial direction to ensure the good sealing effect. Using numerical simulation technology to design the valve and Using theoretical analysis and numerical simulation technology to analyze and verify the valve sealing parts and the key parameters can optimize the design. We need to make testing program according to the task and verify the design scheme by test. This design provides the basis for the quantitative production of ultra supercritical thermal power unit feed water pump turbine exhaust butterfly valve.