Precautions for installation and use of centrifugal pumps

1. Confirmation of seals:

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

(2) Before installation, carefully compare the parts with the general layout to ensure that the number of parts is complete. Check the friction pairs, sealing rings, gaskets, etc. for any scratches or defects. If any abnormalities are found, they must be repaired and qualified before use. Parts that do not meet the requirements shall not be installed.

(3) For mechanical seals utilizing coiled spring transmission, the spring can be either left-handed or right-handed, and must be selected according to the rotational direction of the shaft. If the rotational direction is incorrect, the transmission function will be lost, resulting in seal failure. The method to determine the rotational direction is as follows: looking from the back end face where the stationary ring is installed towards the rotating ring assembly, if the shaft rotates clockwise, a right-handed spring should be used; otherwise, a left-handed spring should be used.

2. Installation:

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

(1) Confirmation of location

The working length for installing the mechanical seal is determined according to the requirements of the general assembly drawing, and the compression amount of the spring depends on the upper positioning dimension of the spring seat on the shaft. Before determining its installation position, the relative position of the rotating shaft and the seal cavity housing must be fixed. Mark the shaft based on the end face of the housing perpendicular to the shaft, and then calculate the positioning dimension of the spring seat.

(2) Installation

Before installation, the shaft (or shaft sleeve) and gland should be free of burrs, and the bearing should be in good condition; the sealing elements, shaft, sealing chamber, and gland should all be cleaned. To reduce frictional resistance, the area on the shaft where the mechanical seal is installed should be lightly coated with oil for lubrication. Considering the compatibility with ethylene propylene rubber, oil should not be used; instead, soap water can be applied. First, install the non-compensating ring together with the gland on the shaft, taking care not to collide with the shaft to avoid damaging the sealing ring; then, install the compensating ring assembly. The fastening screws of the spring seat or transmission seat should be evenly tightened in several stages.

Before securing the gland, check whether there are any foreign objects adhering to the contact end surface of the friction pair. Push the compensation ring with your hand to apply axial compression, and after releasing it, the compensation ring should automatically rebound without any clamping stagnation. Then, evenly tighten the gland screws.