Mechanical shaft seal with them about

( 1 ) When the mechanical seal pressure medium, the pressure medium due to the end face than the pressure of its adaptation range is exceeded , will lead to film damage , causing heating and abrasion ; high friction deformation easy to make and fragmentation , so that the machine seal failure. Required to work under high friction material must have sufficient stiffness and strength , must be considered carbide , ceramic , ceramic spraying pressure and both high strength and stiffness of the material.
( 2 ) In the case of high- speed , linear velocity as the mechanical seal , the sealing surface to increase the friction heat and wear , the friction material should be a good thermal conductivity low coefficient of friction ceramic leaching copper and graphite .
( 3 ) When the mechanical seal in a hot environment , if not handled properly prone to the aging of rubber , part of the deformation , so that the mechanical seal leakage should be used in high-temperature materials, such as sintered alumina ceramic ( alumina ceramic ) , heap solder alloy and so on.
Machine graphite stationary ring quality does not meet the design requirements
Design requirements resin impregnated graphite stationary ring , but have a certain immersion depth. Sometimes impregnated graphite stationary ring is not deep enough , fixed length plastic strap seal that is impregnated layer remaining after machining rarely ; design requirements face some finish, but often fail to meet requirements spare finish ; design requirements purity graphite texture , and a certain hardness, and spare parts tend to have hard spots , hardness is not enough and so on. Resulting graphite wear very serious.
Improper selection of spring pressure machine
Mechanical seal primary seal point - dynamic seal point , is perpendicular to the axis of rotational movement of the ring end face and the end faces of the stationary ring by bonding together . The sealing end face of the spring clamping force is generated by the spring pressure , the low pressure seal faces is to start , run and stop lamination case always maintain a good prerequisite sealed state . When the seal face wear , by the spring pressure to overcome the friction of the shaft seal to ensure that ring moved axially face wear compensation , ensure the seal .
Since spring pressure value directly affects the size sealing reliability , such as spring pressure is too large ,wire seals the sealing surface overextended , increased wear and tear ; spring pressure value is too small , not well fit the sealing surface , the spring force to resist not within the gas medium pressure or face wear not compensated , resulting in mechanical seal leakage . Therefore, a reasonable choice of spring pressure value is the key to sealing reliability . Spring pressure is not enough, take the following two methods to eliminate leakage : ( a ) in the ring behind padded to compensate for the spring force . ( 2 ) with a spatula and abrasive scraping , sanding sealed chamber and the spring seat and "V" -ring with the Department , so that the spring force acting on the friction pairs tightly closed.