Precautions for Installation and Operation of Centrifugal Pumps

1. Seal Verification:

(1) Confirm that the installed seal matches the required model.

(2) Before installation, carefully compare with the assembly drawing to ensure all parts are complete. Check friction pairs, sealing rings, gaskets, etc., for any scratches or defects. If abnormalities are found, repair and inspect them before use; non-compliant parts must not be installed.

(3) For mechanical seals using helical springs, springs come in left-hand and right-hand configurations and must be selected according to the rotation direction of the shaft. Incorrect selection will result in loss of transmission function and lead to seal failure. To determine the correct hand: when viewing from the back side of the stationary ring toward the rotating ring assembly, a clockwise-rotating shaft requires a right-hand spring; otherwise, use a left-hand spring.

2. Installation:

Installation methods vary depending on the type of mechanical seal and machine, but the general principles remain largely consistent. The following steps and precautions should be observed:

(1) Position Confirmation

The working length of the mechanical seal is determined by the assembly drawing requirements, while spring compression depends on the axial positioning dimension of the spring seat on the shaft. Prior to determining the installation position, fix the relative position between the shaft and the seal housing. Use the end face of the housing perpendicular to the shaft as a reference point to mark the shaft, then calculate the positioning dimension for the spring seat.

(2) Installation

Before installation, ensure the shaft (or sleeve) and gland cover are free of burrs and that bearings are in good condition. Clean the seal components, shaft, seal chamber, and gland cover thoroughly. To reduce friction resistance, apply a thin layer of oil to the area where the mechanical seal will be mounted on the shaft for lubrication. Considering compatibility issues with ethylene propylene rubber, oil should be avoided; instead, use soapy water. First, install the non-compensating ring together with the gland cover onto the shaft, taking care not to touch the shaft directly to avoid damaging the seal ring. Then insert the compensating ring assembly. Tighten the securing screws of the spring seat or drive seat gradually and evenly in several stages.

Before fixing the gland cover, check for any foreign matter adhering to the contact surfaces of the friction pair. Manually push the compensating ring axially to compress it; after releasing, it should return automatically without sticking. Finally, evenly tighten the gland cover bolts.