Nowadays, there are many kinds of centrifugal pumps in the industry, which have different classification in different aspects. For example: we according to the tree impeller mechanical seal is not the same, the impeller can be divided into single-stage pump and multi-stage pump, single-stage pump refers to the existence of only one impeller in the pump shaft, and multi-stage pump refers to the non-balance type of mechanical seal with two or more impeller; In the process of work, we can also according to the pressure between the water column is not the same, can also be divided into the centrifugal pump low-pressure pump, medium-pressure pump and high-pressure pump; According to the impeller suction method is not the same, we can also be divided into single-side water and double-side inlet pump. Although there are many kinds of centrifugal pumps in industrial production, but the main elements of leakage, the main elements that cause the leakage of production equipment are: first, for the improper selection of sealing materials, so that the working function of the centrifugal pump is very much affected by the import of mechanical seal; Second, the internal parts of the wear is very serious; Third, the unevenness of the cooperation between the moving ring and the static ring is the primary factor of leakage. Fourth, between the static ring and the static ring seat seal is not strict. It can be seen that the choice of materials, the impact of conflict and the damage of parts is the primary elements of mechanical leakage, we should start from these three aspects, talent is very good to deal with the sealing of industrial production.

Mechanical seal material selection

When selecting mechanical sealing materials, the characteristics of materials should be fully considered, such as acid and alkalinity, corrosiveness, granularity, viscosity, temperature, pressure and other elements. According to these elements, the appropriate anti-pair material should be selected to reduce the anti-pair anti-coefficient, so as to reduce the possibility of thermal cracking of the end face. Resistance of vice material should have excellent wear resistance, heat shock, heat conductivity, self lubrication, should be has high mechanical strength and appropriate hardness, so appropriate vice material is resistant mechanical seal safe working conditions, followed by the structure of the mechanical seal way, user can choose according to the practice application situation according to the manual sealing.

Analysis and differentiation of leakage elements

When the equipment is static, the leakage of mechanical seal equipment is tested after static test to inquire the leakage amount. If the leakage amount is small, the o-ring sealing ring with moving ring or static ring is mostly questionable; When the leakage amount is large, it indicates that the dynamic and static ring collision pair is in doubt. On the basis of starting to query the leakage amount and distinguishing the leaking parts, manually turning the car to query, if the leakage amount has no significant changes, then the sealing ring of the moving and static rings have questions; If the leakage amount of significant changes can be distinguished is the conflict side of the question; If the material is sprayed along the axial direction, the o-ring is damaged. If the material is sprayed along the radial direction, it is mostly the static ring gasket failure.

Leakage occurs during the test run. The centrifugal force generated by high-speed rotation during the test run will restrain the leakage of materials. Therefore, the bottom is the damage factor of dynamic and static ring collision pair after cleaning the shaft and end cover seal failure during the test work. The main elements of its conflict pair failure are :(1) due to the pumping, cavitation, pressure, and other abnormal conditions, resulting in a larger axial force, so that the dynamic and static rings respectively; (2) when mechanical sealing of equipment, the tightening amount is too large, resulting in serious loss of collision pair and scratches' o-ring of moving ring is too tight, and the spring cannot adjust the axial floating amount of moving ring; (5) there are errors in the type selection, improper selection of the specific pressure and collision coefficient of the end face, which constitutes the damage of collision pair.

Leakage occurred in the normal work of the centrifugal pump in the work of natural leakage of the bottom chamber is because of working conditions or improper operation of the composition. (1) the centrifugal pump idles for a long time, forming thermal cracking of resistant side; (2) cavitation or pressure holding for a long time; (3) the material liquid is mixed with a lot of granular materials or aggregates and gelling materials, and the mechanical seal itself is not suitable for this material, when the spring compression force is not big, scratch the resistance pair; (4) the media temperature changes greatly or the environment temperature changes dramatically, damaging the machine seal.

Notes in the process of equipment and repairing mechanical seal

(1) the moving ring spring tightening is not the tighter, the better, the appropriate tightening of mechanical seal dynamic, static ring itself adjustment is beneficial, such as the tightening is too large, the possibility of overheating, wear, scratch, directly affect the use of mechanical seal life. (2) the cooperation between the o-ring and the shaft of the moving ring is not as tight as possible. The cooperation between the o-ring and the shaft of the moving ring is too tight to prevent material leakage on the surface. The practice has affected the axial adjustment in the work of the dynamic ring, which is easy to make the end cooperation uneven, and easy to accelerate the wear of the o-ring.

Pump mechanical seal repair in several errors

(1) the greater the spring tightening, the better the sealing effect. The original is not. Too much spring tightening. Can cause the collision pair to wear out rapidly. Flash burn, excessive tightening so that the spring conditioning ring end of the talent. Cause the seal to fail. (2) the tighter the sealing ring is, the better. Original moving ring seal ring too tight harmful. One is to aggravate the wear between the sealing ring and the shaft sleeve, premature leakage; The second is to increase the axial adjustment of the moving ring. Resistance to movement. When the working condition changes frequently, the adjustment cannot be made in time; Three is the spring is easily damaged by excessive fatigue, four is to make the moving ring sealing ring deformation. Affect the sealing effect.

conclusion

It can be seen that in industrial production, the selection and repair of mechanical sealing equipment is very important. Therefore, we in the repair of mechanical sealing equipment, to fully consider all aspects of mechanical sealing equipment elements, so talented all of the mechanical sealing equipment to protect. However, China's technology in this area is still very sophisticated, we have to continue to explore and strive in the future internship.