The installation sequence of mechanical seals can be carried out in a certain order after the installation preparation work is completed, completing the installation of stationary components inside the end cover and rotating components on the shaft, and finally completing the overall assembly installation of the seal. Taking the centrifugal pump with a single end face internally installed unbalanced mechanical seal shown in Figure 1 as an example, the installation sequence is introduced as follows:

1. Installation of stationary components

Insert the anti rotation pin (1) into the corresponding hole of the sealing end cover, and then insert the static ring auxiliary sealing ring (2) from the tail of the static ring (3). If a V-ring is used, pay attention to its installation direction. If an O-ring is used, do not roll it. Then align the anti rotation pin groove on the back of the static ring with the anti rotation pin and install it into the sealed end cover. The height of the anti rotation pin should be appropriate, with a gap of 1-2mm between it and the stationary ring, and should not be placed on top of the stationary ring. Finally, measure the distance A from the static ring end face to the sealing end cap end face. After installing the static ring into the end cap, it is also necessary to check the perpendicularity between the sealing end face and the centerline of the end cap, as well as the flatness of the sealing end face. For pumps transporting liquid hydrocarbon media, the verticality error should not exceed 0.02mm, and for media such as oil, it can be controlled within 0.04mm.

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Figure 1 Installation Example of Mechanical Seal

2. Determine the installation position of the spring seat on the shaft

The installation position of the spring seat should be determined based on adjusting the relative position between the rotating shaft and the sealing chamber housing. First, draw a correct reference line on the pump shaft along the sealing chamber end face. Then, according to the sealing working length marked on the sealing assembly drawing, adjust the compression amount of the spring to the design specified value based on the positioning size of the spring seat. The positioning size of the spring seat (see Figure 1) can be obtained by the following formula: B=L - (A+S) in the formula:

B - Distance from the back end face of the spring seat to the reference line

L - total height of the working position of the rotating component, L=L '- H;

H - spring compression amount;

A - The distance from the end face of the static ring to the end face of the end cover after the static ring is assembled into the sealed end cover;

S - Thickness of sealing end cap gasket.

3. Assembly of rotating components

Insert the two ends of the spring (8) in Figure 1 onto the spring seat (9) and the push ring (7) respectively, and ensure that the flattened ends of the spring are in close contact with the flat surfaces on the spring seat and push ring. Insert the auxiliary sealing ring (5) of the dynamic ring into the dynamic ring (4) and combine it with the push ring to form a whole. Then, fit the assembled rotating parts onto the shaft (or shaft sleeve) so that the back end of the spring seat is aligned with the specified position. Tighten the screws (10) evenly in several times, and press the dynamic ring backwards with your hand to see if it can float axially.

4. Installation of stationary component components

Install the sealed end cap of the stationary component onto the sealing chamber, evenly press the end cap, and use a feeler gauge to check the gap between the end cap and the sealing chamber end face without deviation. The error should not exceed 0.04mm. Check the radial clearance between the end cap and the stationary ring on the shaft, with an error of no more than 0.1mm at each point along the circumference.