Design And Research A New Combined Main Stop Valve & Over Load Valve Of Turbine

As the market demand for high-capacity,high-parameter Turbo-generator growing in units supporting the maximum flow rate greater than the rated flow conditions in many cases,it is necessary to complement the use of over load valve technology.Using over load valve has two purposes: The first is to make the sliding pressure operation of the unit at the rated flow rate,inlet pressure reaches the rated value;the second is to make the actual operation of the unit,without going through the governor valve can get FM function and avoid throttling losses.Meantime FM reaction fast can reduce the boiler pressure fluctuations.In addition to the above advantages,the use of over load valve technology helps flow capacity of the unit which does not need to design large,which increases the unit in part load economy.One ultra-supercritical steam turbine main technical characteristics of Shanghai Turbine Works is in the form of steam into the structure of the full circle and over load valve.Over load valve technology advantage is self-evident,but any technology has its limitations,over load valve technology also has its disadvantages,mainly this valve put into operating conditions,the rotor vibration levels increased;due to the main steam valve and over load valve located in different layers,over load valve pipe need to escape from other equipment,piping.Arrangement of these works takes a long time to calculate and we need to pay a lot of energy,and often arranged more complicated,and these pipes we are all using good high temperature properties of materials,such as P91,so it really costs too much.In addition,the over load valve technology also involves patent licensing issues.In this paper,through research the phenomenon when over load valve open condition unit vibration rising and according to analyze of the mechanism,it puts forwards creatively to change the ideas of existing over load valve configured independently,in other words the main steam valve and over load valve uses one steam valve joint program body.According to the new design,here builds a joint body of the simulation model for theoretical analysis of the feasibility of a joint body strength characteristics and evaluation of various conditions,and finally completed the design development work.Design and calculation results show that the structure of the joint body can be reduced and the reduction of costs and the corresponding device designed to work together,can improve the efficiency of the valve,improved vibration characteristics of the unit,and can further improve the market competitiveness of products.