How to ensure the sealing performance after the pump mechanical seal is installed

As the key equipment to ensure the airtightness of the equipment, the pump mechanical seal has relatively complicated maintenance operations. In order to better ensure that the assembled seals do not leak, it is necessary to master the verification of the corresponding technical dimensions.

1. Detect the length of the anti-rotation pin of the static ring and the depth of the pin hole to prevent the pin from being too long and the static ring cannot be assembled in place. This condition can damage the seal.

2. Measure whether the length of the compensation spring has changed. Changes in the spring function will indirectly affect the specific pressure of the sealing end face. In general, the length of the spring will increase after running for a long time, and the compensation spring will deform due to the centripetal force on the moving ring.

3. Measure the size of the sealing surface of the moving ring and the static ring. It is used to verify the radial width of the dynamic ring. When different friction materials are selected, the radial width of the friction surface of the hard material should be 1-3mm larger than that of the soft material, otherwise it is easy to cause the edges and corners of the end surface of the hard material to embed the end surface of the soft material.

4. Test the end face specific pressure of mechanical seals used in pumps. If the end face specific pressure is too high, it will cause the friction surface of the seal to heat up, reduce the wear of the end face, and reduce the friction power; if it is too small, it will easily leak. The specific pressure of the end surface is determined according to the design, and we can only determine it by measuring the tight force of the seal during assembly. The usual measurement method is to measure the vertical distance from the installed static ring end face to the end face of the gland, and measure the vertical distance from the end face of the moving ring to the end face of the gland. The difference between the two is the tight force of the seal.

5. Check the gap between the moving ring, the static ring and the shaft or bushing. The inner diameter of the static ring is usually 1-2mm larger than the shaft diameter. For the moving ring, in order to ensure the floatability, the inner diameter is 0.5-1mm larger than the shaft diameter. To compensate the vibration and deflection of the shaft, but the gap should not be too large, otherwise the moving ring seal ring will be stuck and the seal function will be damaged.

In terms of ensuring the tightness of the mechanical seal used in pumps, the above-mentioned methods can be used for operation, so as to achieve the purpose of verification and ensure its efficiency.