First, the valve of the common failures and causes Valve in the course of the common faults are: 1. Stem rotation is not flexible or stuck stem rotation is not flexible or stuck, the main reasons are: packing pressed too tight; packing Fill packing box when not in conformity with specifications; stem and stem bushing using the same material or material improper selection; Stem and bushing gap is not enough; Stem bent; thread surface roughness does not meet the requirements. 2. Sealing surface leakage Sealing surface leakage reasons are: sealing surface damage, such as indentation, abrasion, the middle of a broken line; between the sealing surface dirt adhesion or seal connection is not good. Leakage of packing at the packing place Leakage reasons are: packing plate is not pressed; packing is not enough; packing failure due to poor storage; stem roundness exceeds the provisions or the stem surface scratches, engraving, drawing and rough defects ; Filler varieties, structural dimensions or quality does not meet the requirements. 4. The valve body and valve cover leakage at the junction may occur because of the following reasons: uneven flange bolts flange fastening caused by the tilt, or tightness of the fastening bolt is not enough, the valve body and bonnet connection surface Damage; Gasket damage or does not meet the requirements; flange is not parallel to the surface, the flange surface is not good; stem bushing and stem bad thread so that the valve cover tilt. 5. Gate and valve cover interference When the valve is opened to fully open state, sometimes the gate can not be fully open, and the gate and the valve cover interference phenomenon. The reason is: Gate installation is not correct or the valve cover geometry does not meet the standard requirements. 6. Shutter does not close off The main reasons for such cases are: not enough power to close; between the valve seat and the gate into debris; valve sealing surface processing is not good or damaged. 7. Other aspects, such as casting defects caused by trachoma, sealing surface cracks will also affect the normal use of the valve, to take appropriate measures to be resolved. Second, the valve solution to common faults For the above various faults, according to the actual situation to take a different approach to be resolved, the specific solution shown in the table. Third, the conclusion In order to ensure the normal use of the valve, in addition to its fault according to the exact reasons for the determination and analysis, and take appropriate measures to solve, but also should strengthen the management of the valve, make routine maintenance and inspection Work to reduce valve failure and improve the valve intact, making it the greatest utility for the handling of the port.