Industry News
Globe valve sealing structure---2009-11-06
Globe valve structure is simple, both to spin around and through the stem of the principle of lift to reach the globe valve to open or cut off, and to ensure that the globe valve seals and the sealing function. Since the principle of the special structure of the movement, but also result in the valve between the force on the seal pair extremely adverse consequences (the formation of both the vertical seal is needed between the Deputy pressure, there seal pair relative slippage between the friction). Practice shows that valves open and close the upper seal often only a few times because Sealing leakage caused by abrasion between. Take apart repair minor scratches, abrasions serious damage were scrapped due to such effects will not only increase the enterprise's manufacturing costs, but also affected the performance of the valve. To address such issues on the seal of the valve structures and materials was tested and improved.
¢Ù the upper stem seal parts will be moved to the aortic valve (purpose is to force the process, so that aortic valve sealing surface of the upper lid on the relative valve sealing surface of a stationary no-slip state). This improvement may well enhance the life of the seal, but due to the increase of a flap valve between the valve cover and valve seal makes the structure more complex and less cost-effective.
¢Ú Deputy material change in the seal. Stem seal surfacing in the cone on the good performance of anti-abrasion stellite alloy, although this method has achieved good results, but on the one hand because of the cost of stellite alloy is too high, and partly because stem the basic material for the 13Cr martensitic stainless steel, weldability is poor, surfacing to be preheated before welding, after welding, insulation and welding complex. In addition, to ensure the accuracy of stem size, but also increase the roughing process. Comprehensive analysis, in addition to special requirements, this program whose cost is not good.
Practice has proved that the hardness increase stem taper seals to improve the life of cut-off valve on the possible solutions.
¢Ù the upper stem seal parts will be moved to the aortic valve (purpose is to force the process, so that aortic valve sealing surface of the upper lid on the relative valve sealing surface of a stationary no-slip state). This improvement may well enhance the life of the seal, but due to the increase of a flap valve between the valve cover and valve seal makes the structure more complex and less cost-effective.
¢Ú Deputy material change in the seal. Stem seal surfacing in the cone on the good performance of anti-abrasion stellite alloy, although this method has achieved good results, but on the one hand because of the cost of stellite alloy is too high, and partly because stem the basic material for the 13Cr martensitic stainless steel, weldability is poor, surfacing to be preheated before welding, after welding, insulation and welding complex. In addition, to ensure the accuracy of stem size, but also increase the roughing process. Comprehensive analysis, in addition to special requirements, this program whose cost is not good.
Practice has proved that the hardness increase stem taper seals to improve the life of cut-off valve on the possible solutions.
