Mechanical seal is composed of two sealing element(static ring and moving ring) perpendicular to the shaft,smooth and straight surface contact with each other, and the relative rotation of the sealing device. It is by the sealing medium pressure in the rotation of the movable contact surface of the static ring (end) was produced on the pressing force properly, so that the two end faceclosely, face to keep a very thin liquid film for sealing.This layer of liquid film with liquid dynamic pressure and static pressure, the lubrication balance force.

Clean sealing 1 machinery and testing

1) the working principle of the mechanical sealmechanical seal without any impurities. Mechanical seal in the assembly to be completely clean before moving ring,a static ring, shaft and other components.

2) check the existence of dynamic and static ring surfacescratches, cracks and other defects, these defects can cause serious mechanical seal leakage. Conditional cancheck the sealing surface is smooth with special tool,sealing surface is not flat, the pressure of water will enter the assembly of the movement after the mechanical seal ring sealing surface, the separation of dynamic and static ring, mechanical seal failure. When necessary,production tooling test pressure before the assembly.

3) check of dynamic and static ring seat whether there are effects of the defective seal. Such as dynamic and static ring seat and the sealing ring with the existence of surface defects.

4) check the mechanical seal spring whethercompensation for damage and deformation, stiffnesschange.

5) check the existence of sealed burr sleeve, groovesand other defects.

6) cleaning check all sealing ring if there are cracks,porosity and other defects, measuring the diameter aprons in the tolerance range.

7) with the pumping mechanism of mechanical seal also check the helix pump whether there is crack, break and other defects.

2 mechanical seal assembly dimensional check

1) measuring static sealing surface ring size. This data is used to verify the radial width of dynamic and static ring,when the friction of different materials, hard surface friction than the radial width should be 1 ~ big soft 3mm,otherwise easy to cause the sharp end embedded in the soft material and hard material surface.

2) clearance inspection of dynamic and static ring and the shaft or sleeve, the inner static ring generally large shaft diameter of 1 ~ 2mm, the moving ring, in order to ensure the floating, large diameter than the shaft diameter of 0.5 ~ 1mm, the compensation axis of vibration and deflection,but the gap can not be too large, otherwise it will make the dynamic ring seal ring is clipped into the damage caused mechanical seal function.

3) mechanical seals tight checking power. We often speak of mechanical seal is tight end edge pressure, end pressure to the right, is too large, will face mechanical seal friction heat, accelerated wear of surface, increases the friction power is too small, easy to leakage. Face pressure in the design of mechanical seals identified, we can only in the assembly is sealed by the measurement of mechanical power to determine tight. The vertical distance measurement method usually makes themeasurement of static ring end to end cap installed, and then measured the vertical distance from the movable ring end to end cap, the difference between the two is thetension of mechanical seal.

4) measuring the length of the compensation spring ischanged. Changes in the spring performance will directlyaffect the mechanical seal face pressure. General springin a long time after the operation will be shortened in length, compensation spring in the reason of dynamicmechanical seal ring will because of centrifugal force anddeformation.

5) Central anti static measurement of the length of sub resellers and pin hole depth, too long to prevent the pinassembly in place can not be static ring. This will damage the mechanical seal.

Grinding 3 movable ring and the static ring face

1) ring removed, after grinding, the first rough grinding,fine grinding after, conditional can be polished.

2) coarse grinding, selection of 80 ~ 160# size of abrasive, abrasive machining marks the first. Then use160# more abrasive grinding, the finish to meet the design requirements. Hard alloy or ceramic ring after fine grinding to polishing machine. Polishing machinedynamics can choose boron carbide M28 ~ M5. Polishedto a mirror. Since agate powder ceramic ring can be usedM5 mill, with chromium oxide.

3) graphite filled PTFE static ring, because the material issoft, kerosene, gasoline or available water lapping,without grinding agent. In the process of running in isresearch, so finish requirements are not too high.

4) grinding method, a grinding machine grinding ingrinding machine, hand grinding method can adopt 8glyphs in flat glass without grinding machine.

The 4 sleeve inspection

1) sleeve maintenance and inspection of corrosion andwear off, if the corrosion or wear is slight, usable finesanding and, if the corrosion or wear serious byelectroplating processing or changing sleeve.

The 5 seal ring

1) seal ring after a period of time after the use, in most cases, loss of elasticity or aging, general need to replace the new ring.

6 spring

1) if not serious spring corrosion, can maintain the original flexibility, can not replace. If a lot of corrosion is more serious or elastic reduced, you need to replace thenew spring.

2) seal on the assembly box machine, the box clean, and check the groove worn or deformation, for correction ofrepair, re grooving or replacement.

3) after repair of mechanical seals, re assembly,assembly after the same pressure testing, and then put into normal operation.