AS-1574 Double Cartridge Mechanical Seal Made As Per Drawing

AAS-1574 Double Cartridge Mechanical Seal Made As Per DrawingS-1574 double cartridge mechanical seal is dual seal made as per drawing

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Discussion on the installation and commissioning of mechanical seals of large submersible axial flow pumps （2）
This article describes how to improve the pass rate of the pump shaft seal（mechanical seal） air tightness test by strictly controlling the perpendicularity between the stationary seat end face of the mechanical seal and the shaft based on practical experience in the installation and maintenance of submersible pumps, thereby ensuring the reliability of the motor insulation and oil chamber seal（mechanical seal） and saving money.

IV Installation and debugging of mechanical seal
1.Inspection and measurement before installation (1) Check that the surface of the mechanical seal is free of defects such as pores, pitting, cracks, scratches, eccentric wear and flash. (2) The gap between the inner diameter of the rotary face and the shaft diameter should be 0.2~0.40mm to avoid poor floating performance of the sealing ring. Measure the thickness of the stationary seat and the depth of the static ring seat to ensure that the static ring is installed in place. The height of the boss of the moving ring should be ≥1 mm to avoid affecting heat dissipation.(3) The degree of freedom of the measuring spring should be consistent, and the two end faces of the spring should be kept parallel to avoid unilateral wear of the end face due to unbalanced spring force. The outer surface of the spring is clean and free of rust. The allowable error of the free length of the spring is <0.5mm, and the required error of the compression amount is <±2mm.

2.Key processes for mechanical seal installation
（1） Perpendicularity between the end face of the stationary seat and the shaft .Mechanical seals for pumps require verticality ≤0.06mm when the shaft diameter is >50~120mm. Practical experience shows that strictly controlling the verticality within the range of 0.01~0.02mm can significantly improve the pass rate of the air tightness test after the mechanical seal is installed.

(2)End face specific pressure
After the verticality adjustment is qualified, install the rotary face on the shaft, install the O-type rubber sealing ring in the inner groove of the rotary face, and then press the compensation ring of the mechanical seal. Determining the axial position of the compensation ring involves adjusting the end face pressure ratio. If the specific pressure on the end faces of the mechanical seal is too large, it will accelerate the wear of the friction pair; if the specific pressure is too small, it will easily leak.
Adjusting the specific pressure is actually adjusting the compression size of the spring and axially positioning the compensation ring of the mechanical seal. The submersible pump can be adjusted inward by 1mm based on the original mark (the axial position mark of the original compensation ring when the water pump was disassembled), combined with the axial position size of the mechanical seal marked on the water pump drawing, taking into account that the spring will become fatigued and loose after long-term operation. And the spring seat cannot be deflected, which can be ensured by measuring the distance error between the circumferential points of the compensation ring end face of the mechanical seal and the shaft body stop. After passing the test, tighten the set screw of the compensation ring diagonally. At this time, push the ring by hand to compress it axially. After letting go, the rotary face of the mechanical seal should automatically rebound without sticking.

3.Air tightedness test
The method of applying soaping solution at the sealing site for a static pressure test combined with an artificial crane to detect the vitality of the cavity of the mechanical seal.
(1) Leakage analysis and judgment
The leakage volume of the mechanical seal is small, mostly there are problems with the rotary face or stationary seat sealing ring; when the leakage volume of mechanical seal is large, there are problems with the two sealing rings friction. On the basis of preliminary observation of leakage and judging the leakage site, then manually do the crane. If there is no obvious change in the leakage of the mechanical seal, there is a problem with the two sealing rings. If the leakage medium is sprayed along the axial direction, there are mostly problems with the rotary face of the mechanical seal and the leakage medium is leaked from the surroundings, and most of them are invalidated by the stationary seat of the mechanical seal

(2)Air tightness test
After installation, use an air compressor to pressurize the motor cavity and oil cavity of the mechanical seal to 0.2MPa, close the relevant air path gate valves to maintain the cavity pressure. Apply soap solution to the joint between the stationary seat and the stationary seat seat, the joint between the rotary face and the stationary seat and between the compensation ring and the shaft of the mechanical seal. Turn the machine to check whether there is foaming. At the same time, monitor whether the value of the inner cavity pressure gauge changes.

The mechanical seal in the 10KV submersible axial flow pump structure of this station's pump gate adopts turning measurement during installation and adjustment. The method of controlling the verticality of the stationary seat end face and the shaft is ≤0.02mm. It has been verified by the installation practice of 6 water pumps of the same model that only one or two adjustments can be made to achieve the sealing chamber pressure of the mechanical seal maintaining pressure of 0.2MPa, with no obvious leakage (≤0.01MPa) for 12 hours, which meets the requirements, improves efficiency, and saves man-hours.