Installation sequence of mechanical seals can be carried out in a certain order after the completion of installation preparation. Installation of stationary parts in the end cover and installation of rotating parts on the axis can be completed. Finally, the overall assembly of the seals can be completed. As an example, the non-balanced mechanical seal installed on a single end face of a centrifugal pump as shown in Fig. 1 is introduced in the following installation sequence:

1. Installation of Static Components

Insert the anti-dump pin (1) into the corresponding hole of the sealing end cover, and then insert the auxiliary seal ring (2) from the tail of the static ring (3). If V-ring is used, pay attention to its installation direction, if O-ring, do not roll. Then, the anti-re-pin groove on the back of the static ring is aligned to the anti-re-pin and loaded into the sealed end cover. The height of the anti-reselling pin should be appropriate, and the gap between 1 and 2 mm should be left with the static environment protection, not the top static ring. Finally, the distance A from the end face of the static ring to the end face of the sealing end cover is measured. After the static ring is installed in the end cover, the verticality of the sealing end face and the center line of the end cover and the flatness of the sealing end face should also be checked. For pumps transporting liquid hydrocarbon media, the verticality error is less than 0.02 mm, and the oil and other media can be controlled within 0.04 mm.

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Fig. 1 Installation example of mechanical seal

2. Determine the mounting position of the spring seat on the axle

To determine the installation position of the spring seat, it is necessary to adjust the relative position between the fixed shaft and the sealing chamber shell. Firstly, a datum line is drawn correctly on the pump shaft along the end face of the sealing chamber. Then, according to the seal working length marked on the seal assembly drawing, the compression of the spring is adjusted from the positioning size of the spring seat to the design specified value. The positioning dimension of spring seat (see Fig. 1) can be obtained by following formula: B = L - (A + S):

B - Distance from back end of spring seat to datum line

L - Total height of working position of rotating parts, L = L'- H;

H - spring compression;

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

S - Seal end cover gasket thickness.

3. Assembly of rotating parts

The two ends of the spring (8) in Fig. 1 are respectively sleeved on the spring seat (9) and the push ring (7), and the two ends of the grinding spring are close to the plane of the spring seat and the push ring. Then, the auxiliary seal ring (5) of the moving ring is loaded into the moving ring (4) and combined with the push ring. Then, the assembled rotating parts are sleeved on the shaft (or sleeve), so that the back end of the spring seat can be aligned to the specified position, and the screw (10) is tightened evenly several times, and the moving ring is pressed backward by hand to see if it can float axially.

4. Installation of Static Component Components

Install the sealing end cap of the stationary parts on the sealing chamber, press the end cap evenly, and check the gap between the end cap and the end face of the sealing chamber with a plug ruler, the error is not more than 0.04 mm. Check the radial clearance between the end cap and the stationary ring, and the error along each point of the circle is not more than 0.1 mm.