Globe valve seal structure and material improvement

Globe valve has simple structure, can through the principle of the valve rod rotation and lifting the valve door open or truncation, and ensure that the valve door seal and seal function. Due to the special structure of movement principle, and also causes stress between the valve door seal is extremely adverse consequences ( Form both the sealing pair must be vertical pressure, and the relative slip between vice friction sealing) 。 On the practice has proved that the valve door seal tend to open/close a few times, just because the sealing pair of scratches and cause leakage. Scratch slightly open repair, abrade serious were damaged and destroyed, so the consequences of not only increases the manufacturing cost, and the impact on the performance of the valve gate. To solve such a problem on the valve door sealing structure and materials tested and improved. 1) move on the valve rod sealing parts on the valve disc ( Is in the process of loading, designed to make the valve disc on the sealing surface relative to the valve sealing surface in the state of static no slip on the cover) 。 The improved though can increase the seal life, but due to increased along the valve disc cover and seal between the valve disc makes structure more complex, with low price. (2) change the seal material. Surfacing on the valve stem seal cone abrasion resistance good department too hard alloy, although this method obtains a good effect, but on the one hand, because the company too alloy cost is too high, on the other hand because the valve rod basic material for 13 cr martensitic stainless steel, poor weldability, welding preheating before welding, when the complex heat preservation after welding and welding process. In addition, to ensure the dimensional accuracy of the valve rod, but also increase the rough machining process. Comprehensive analysis, in addition to the special requirements, which the price is not good. Practice has proved that to improve the valve rod cone hardness is a feasible way to improve the globe valve seal life.