Therefore, in the design and production of flue valve, the material and mechanical properties, thermal expansion and thermal alternating of valve plate are considered first. The general temperature below 450℃ can choose 16 mn steel plate, the temperature is 450~600℃ choose 1 stainless steel plate, at the same time, the thickness and structure form of valve plate should be considered, and the thickness and structure form of valve plate of valve body is also an important factor of deformation and wear. 

    Second, the valve plate stuck or bite, the main reason is that the valve caliber large valve plate weight, valve plate due to gravity and droop caused. For the media temperature above 400℃, the common positioning guidance structure is unreliable. We use the external bearing structure to ensure the positioning and support of the valve plate, which can avoid the influence of internal high temperature on the guide structure. Bearing and valve plate positioning, using "day" type positioning can play a very good role in positioning, support and protection, can ensure the valve plate in the longitudinal accurate positioning, avoid valve plate due to gravity and droop caused by blocking, offset, resulting in unilateral jam or bite. Since the use of pipe negative pressure (generally 7000~8000 pa), valve plate vibration, dust, high temperature characteristics, the use of rolling bearings, lubricating oil is easy to dry, dust easy to enter, action is not flexible, increase the opening and closing torque, actuator load is large, bearing should choose high temperature resistant sliding bearing. The front and rear axle neck of the valve adopts internal seal, and the special seal packing is used to seal well, without leakage and high temperature resistance. 

    it is difficult to achieve high cutting performance under high temperature conditions, and conventional high performance sealing methods are difficult to achieve. at present, in order to prevent the problem of blocking caused by material expansion in high temperature, the sealing gap is usually left large. As a result, in order to achieve the valve leakage rate is small, must change the valve structure, we use in the valve body welding stainless steel ring, forming valve body convex platform, valve plate sealing surface surfacing welding wear-resistant alloy process, forming a circular line sealing surface, to achieve a good sealing effect, leakage rate is only 10-3~10-4, with better sealing reliability, service life can be extended, at the same time in the cement line without shutdown, the power plant can be maintained and overhauled as usual.