What are the cause of damage of pneumatic valve? How to prevent?

Pneumatic valve has been widely applied in the field of gasification coal chemical device, due to the use condition of containing solid particles, ash, sulfur and other special medium, should reach wear resistance, corrosion resistance, resistance to erosion, fouling prevention and action, rapid opening and closing, buckle and frequent requirement, at the same time has good sealing, implementation device of high efficiency, low energy consumption and safe and reliable operation. Valve, pneumatic valve leakage cause analysis after a period of time of using the unsmooth, switch does not reach the designated position, etc. , main valve sealing surface body, seat severe erosion, sealing surface is damaged, more serious, the body and the valve cavity parts damaged, inside the valve leakage; Stem and packing gland clearance increases, lead to valve leakage. 。 Pneumatic valve leakage: according to various kinds of gasification technology, media, the process of comprehensive analysis of the key parts of the valve, not only because of the influence of the solid content in the medium, at the same time the valve switch frequency is higher, is affected by the structure of throttling valve design flow, when the medium flows through the valve, the flow velocity is amplified, before and after the valve pressure difference is bigger, lead to flush valve, wear especially serious; Part of the valve producted by high temperature medium, because of the effect of surface tension, forming a large number of small particles, increase the valve and sealing surface erosion wear; Seat spring cavity into powder or filled with dust, turn disable spring, spring, etc. ; Valve and valve seat grinding precision is not up to standard, the concentricity is poorer, less surface coarse degree, prone to leakage. Metal material is commonly forging stainless steel valve body, surface spray chromium carbide processing, the thickness is only. ~。 Mm, hardness of HRC ~, the influence of grinding effect in the frequent switch, a sealing surface strain, the valve seat and valve wear serious, time grows, also prone to wear-resisting layer is worn off, easy to cause serious leakage of the valve. 。 Leakage of pneumatic valve: the valve stem packing structure design is unreasonable, the valve body and valve stem alignment error and unreasonable factors such as material selection, stem from the valve in the process of switch, valve stem and packing wear increased, stem and packing mating surface wear serious, lead to stem diameter decreases, eventually the valve leakage along the valve stem axial flow passage medium. Pneumatic valve, improvement measures. , sealing structure transformation in hard skiving structure is used to seal valve seat design, make the body and seat in the switch process has self-cleaning function, effectively prevent particle precipitation and adhesion between body and seat, ensure the valve movements smooth continuous BuKa resistance; Deputy seat and body as well as the main, the seat of both the use of special structural design, packing to add metal ring, further increasing rigidity and toughness of the packing to prevent impurities into the seat at the back of the spring chamber, ensure the long-term effective work, spring spring using cylindrical spring at the same time, can realize the seat force uniform, avoid eccentric wear on sealing surface, prolong the service life of the sealing surface. 。 Outside the valve stem seal structure transformation, the end face adopt bearing positioning, the valve stem have relative rotation, and play a guiding role, guaranteed the valve stem and body alignment requirements, packing, upper with disc springs, guarantees the packing sealing pre-tightening force design for live load form, the sealing effect is good, can ensure the service life of sealing material. 。 To adopt new technology, new material: according to different conditions, can the valve body adopts ceramic metal composite or surface coating materials such as tungsten carbide, zirconium carbide, valve seat sealing surface using supersonic spraying hardening technology, hardness HRC or above, above the maximum of HRC, the valve can adapt to the vast majority of the harsh conditions of resistance to erosion wear resistance. Through above to improve the inside and outside sealing structure, improve the ability of valve sealing surface abrasion and packing sealing performance and prolong the service life of the equipment, pneumatic valve sealing structure is relatively reasonable, meet the requirements of working condition.