Selection and use of mechanical seals for pumps

Pump mechanical seals are one of the most precise and complex mechanical basic components, and are the key components of various pumps, reaction synthesis kettles, turbo compressors, submersible motors and other equipment. Its sealing performance and service life depend on many factors, such as model selection, machine accuracy, correct installation and use, etc.

Installation and usage requirements

1. The requirements of mechanical seals for machine accuracy (take mechanical seals for pumps as an example)

(1) The radial runout tolerance of the shaft (or shaft sleeve) where the mechanical seal is installed shall not exceed 0.04~0.06MM.

(2) The axial movement of the rotor does not exceed 0.3MM.

(3) The runout tolerance of the positioning end of the sealing cavity combined with the sealing end cover facing the surface of the shaft (or shaft sleeve) shall not exceed 0.04～

0.06MM.

2. Confirmation of mechanical seal for pump

(1) Confirm that the installed seal is the same as the required model.

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

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

3. Installation of mechanical seal of water pump

The installation method varies with the type of mechanical seal and the type of machine, but the installation methods are almost the same.

and the caveats are as follows:

During installation, the installation size of the mechanical seal should be guaranteed according to the product instruction manual or sample.

(2) Before loading, the shaft (sleeve) and gland should be free of burrs, and the bearing should be in good condition; the seals, shaft, sealing cavity and gland should be cleaned. To reduce frictional resistance

Force, the part where the mechanical seal is installed on the shaft should be coated with a thin layer of oil for lubrication, taking into account the compatibility of the rubber O-ring

If it is not suitable to use oil, you can apply soapy water. The structure of floating static ring without anti-rotation pin should not be oiled, and should be installed in the gland dry.

(3) Install the static ring together with the gland on the shaft first, being careful not to collide with the shaft, and then install the moving ring assembly. Spring seat or drive

The set screw of the seat should be evenly tightened several times. Before the gland is not fixed, push the compensation ring by hand for axial compression, and then compensate after loosening.

The ring can automatically spring back without jamming, and then lock the gland bolts evenly.

4. Use of pump mechanical seal

(1) When the temperature of the conveying medium is too high, too low, or contains impurity particles, flammable, explosive or toxic, take corresponding resistance measures.

sealing, flushing, cooling, filtering and other measures.

(2) Turn the car by hand before running, pay attention to whether the torque is too large, whether there is friction and abnormal sound.

(3) Pay attention to the direction of rotation, whether the coupling is centered, whether the addition of lubricating oil in the bearing part is appropriate, and whether the piping is correct.