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Mechanical seal maintenance instructions

The mechanical seal of the pump is composed of high-precision parts. Under the correct and reasonable use conditions, the sealing performance can be better. However, due to its complicated use conditions and complicated sealing structure, the mechanical seal performance is very easy. It was damaged, so it is very important to properly repair and disassemble and install mechanical seals.

The first point is the precautions for mechanical seal removal.
The order of removal of the mechanical seal is the reverse of the installation sequence. In the process of dismantling the mechanical seal, it must be careful. It can't be hammered or flat shovel. It can't be beaten. It can't damage the sealing surface of the machine and the static ring. If there is too much dirt due to oil stains, it can't be disassembled. After cleaning with kerosene, remove it, so that the parts of the machine seal can be kept intact.

The second point is the requirements and process of mechanical seal overhaul.
After removing the machine seal, first check the pump body with the organic seal installed, and the following requirements must be met:
1. The maximum bending degree of the shaft is ≤0.05mm, and the axial turbulence is ≤0.05mm;
2. The jump at the moving ring seal ring is ≤0.01mm;
3. The surface roughness of the shaft or sleeve of the machine sealing part is 1.6 μm, and the surface roughness of the contact with the static ring sealing surface is 3.2 μm;
4. Then repair the mechanical seal:
(1) Check the mechanical seal components. All components must be complete and non-destructive. There are no scratches or bumps on the surface of the moving and static ring seals. If damage is found, repair or replace the machine seal;
(2) Check if the spring force of the spring becomes smaller. If it becomes smaller, the spring must be replaced.
(3) Check the inner wall of the seal and the inner surface of the sealed end cap for damage. If problems are found, repair them in time.

The third point is the preparation and precautions for the installation of the mechanical seal.
After the above maintenance work is completed, the machine seal needs to be reinstalled, and must be prepared before installation:
1. If the new machine seal is replaced, it is necessary to check whether the type and specification of the mechanical seal are correct and the quality meets the standard;
2. The anti-rotation groove end of the static ring tail and the top of the anti-rotation pin should maintain an axial gap of 1mm-2mm to avoid buffer failure;
3. The moving and static ring end faces are cleaned with alcohol. The other metal parts are cleaned with gasoline and dried with clean compressed air. Carefully check to ensure that there are no damage to the moving and static ring sealing surfaces. Before assembly, two pieces of “0”-shaped rubber sealing ring should be coated with a layer of lubricating grease, and the moving and static ring end faces are not allowed to be oiled.

The fourth point, the installation sequence and precautions of the mechanical seal.
1. After the relative position of the rotor and the pump body is fixed, determine the installation position of the mechanical seal, and calculate the positioning dimension of the seal on the shaft or the sleeve according to the installation dimension of the seal and the position of the static ring in the gland;
2. Install the machine to seal the ring. After the moving ring is installed, it must be able to move flexibly on the shaft;
3. Assemble the assembled static ring part and moving ring part;
4. Install the sealed end cap in the seal body and tighten the screws.

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