Ball valve door, double eccentric hemisphere feasibility of alternative gate valve gate and globe valves
Double eccentric hemisphere ball valve door instead of the feasibility of gate valve gate and globe valves ball valve gate is the fastest developing speed in recent years in China type gate valve, in addition to the hard seal ball valve door, double eccentric hemisphere ball valve door also got rapid development. Double eccentric hemisphere ball valve door is in carefully weigh the ball valve, butterfly valve, gate valve and gate valve door door advantages under the premise of the introduction of Germany hemisphere valve products and development of the localization of products, a conclusion pointed out: & hellip; In some respects on the using performance of more is better than that of gate valve gate, globe valve and ball valve door of similar products, can be applied in petroleum, chemical, electric power and metallurgy industries & hellip; , double side of an eccentric valve door design is unique, novel structure, order scope expands unceasingly, indeed in different occasions to replace the ball valve, butterfly valve gate valve and gate valve door gate, the structure of the double eccentric hemisphere ball valve door advantages specific have: one gate, cricket ball valve structure using chocking eccentric principle. Rotary valve body and valve core center ( The valve stem axis) And sealing in the valve core of spherical geometry center offset a radial size, also with the valve seat sealing surface in the valve body is a channel axis offset size, sealing pair under external force for the metal to metal contact, self-locking valve door relies on two eccentric close, the reasonable choice of eccentric locking Angle is less than the friction Angle, Angle of self-locking chosen too small to shut down easy, open, difficult point selected, while the open force is small, but close the torque increases rapidly, the test-bed of trial and error, determine the two reasonable collocation of eccentricity is essential, reliable self-locking performance to ensure the sealing tightness. This is the core of the eccentric hemisphere valve technology, from the structure principle, through the manufacturing methods to achieve the best sealing, ball valve, butterfly valve door door, gate valve, globe valve and so on is inferior. Second, the hemisphere valve is easy to implement and maintain zero leakage for a long time. The valve core and valve seat sealing is spherical line contact, by eccentric realize self-locking, seal the opening and closing the whole process of little contact, only at the instant of the opening and closing, will contact and brake tight zero leakage, ensure no leakage point of dynamic and static seal. Scaling or other debris on the valve seat, valve core in the process of contact with the valve seat, has a strong ability to remove fouling. And gate valve sealing surface of the door opening and closing of frequent reciprocating motion, the mixed flow medium scale deposition in the lower part of the valve body cavity, the cut-off valve is completely dependent on positive pressure sealing, the valve seat of scaling without cleaning ability, the packing often repeated wear cause inside leaking outside the gate valve gate, globe valve leakage. Ball valve door seal is rely on long-term extrusion on the spherical valve seat, it must wear the hemisphere valve fast, butterfly valve door seal is rubber for mediation, it is the hemisphere valve, ball valve, gate valve door door metal hard seal performance. After long-term use of hemisphere of the valve, the valve seat can have traces of wear, it will continue to be used, by adjusting the valve stem and packing in the process of opening and closing the valve rod just rotate it 90 & deg; , when there were signs of leakage, pressure packing gland bolts touch again, packing can be realized without leakage, while the other valve door is still a small leak reluctantly, big leaks in the valve gate. Three, double eccentric hemisphere ball valve door operation is extremely light. The whole process of double eccentric side door opening and closing of valve, sealing pair in the undamped idling state, almost all the external force is only in the opening and closing moments from or pressure, and the valve rod just rotate it 90 & deg; Light and fast, convenient operation, of course. Ball valves in the process of opening and closing door is on both ends of the holding force of the valve seat and operate, it is the hemisphere valve opening and closing torque, nominal diameter larger open-close torque, the more obvious difference, the butterfly valve door opening and closing is to overcome the deformation of the rubber, torque is bigger. The gate valve gate, globe valve operating time is long and difficult. Four, double eccentric hemisphere valve long service life. Sealing pair belongs to bimetal, different USES of surfacing alloy on the mother, after special heat treatment on the mechanical properties of the sealing pair and the physical and chemical indexes reach the best state, to satisfy different working conditions, Strong wear, wash quickly, severe corrosion medium etc. ) The need, the valve gate valve seat just below the valve core hardness, different material and different heat treatment process, need to seal the deputy of hardness can reach more than HRC53, also can be 560 ℃ high temperature resistant. Practice has proved that its ability to resist corrosion and anti-seizure six times that of stainless steel seal, door opening and closing of the valve without failure, tens of thousands of times longer service life. Five, the double eccentric hemisphere ball valve door wide scope of application. Eccentric side mounted hemisphere valve series varieties are widely used in non-ferrous smelting, the pulverized coal injection of gas natural gas, iron and steel slag and dust removal, electric power, coal pulverizing coal conveying system, harmful gases, Hydrogen sulfide, phosgene, etc. ) And oil ( Heavy fuel oil, crude oil, residual oil, etc. ) Smelting and transmission. Hemisphere valve has wide scope of application, mainly because the seal can be different alloy welding, make it a double metal, valve body, valve stem and other main parts adopt the needed materials, to meet the needs of different working conditions.