The quality of mechanical seals and normal use will affect the normal operation of vacuum pump and diaphragm pump and affect the service life of the pump. The following are the installation and use requirements of vacuum pump and diaphragm pump mechanical seal:

1. Requirements of mechanical seal on machine precision: (taking mechanical seal of vacuum pump as an example)

(1) The axial movement of the rotor is less than 0.3mm.

(2) The maximum runout tolerance of the locating face of the sealing cavity and the sealing end cover to the surface of the shaft (or shaft sleeve) shall not exceed 0.04 ~ 0.06 mm.

(3) The maximum radial runout tolerance of the shaft (or shaft sleeve) installed at the mechanical seal position shall not exceed 0.04 ~ 0.06 mm.

2. Confirmation of seals:

(1) Before installation, check with the general assembly drawing carefully to see if the quantity of parts is complete.

(2) For mechanical seal driven by parallel coil spring, the spring can be divided into left and right rotation, which must be selected according to the rotation direction of rotating shaft.

(3) Confirm whether the seal installed is consistent with the required model.

3. Installation method of seal: the installation method varies with the type of mechanical seal and the type of machine, but the installation essentials are almost the same. The installation steps and precautions are as follows:

(1) Determination of installation size: during installation, the installation size of mechanical seal shall be ensured according to the product instruction or sample.

(2) Before installation, the shaft (shaft sleeve) and gland shall be free of burr, and the bearing shall be in good condition; the seal, shaft, sealing chamber and gland shall be cleaned. In order to reduce the friction resistance, a thin layer of oil should be applied to the position where the mechanical seal is installed on the shaft for lubrication. Considering the compatibility of rubber O-ring, if oil is not suitable, soap water can be applied. Floating type static ring without anti rotation pin structure, should not be oiled, should be dry installed into the gland.

(3) First, install the static ring and the gland on the shaft, and pay attention not to collide with the shaft, and then install the moving ring assembly. The set screw of spring seat or transmission seat should be tightened evenly in several times. Before the gland is fixed, the compensating ring is pushed by hand for axial compression. After loosening, the compensating ring can automatically spring back without jamming, and then the gland bolts are locked evenly.