Mechanical seal device, application requirements1

Mechanical seal device, application requirements

The mechanical seal is a high-precision mechanical equipment component. Its performance and service life are greatly related to the operating conditions, accuracy and sealing device of the host. Therefore, it is necessary to follow the following requirements when installing and using: 1. Precautions before installation 1. Correctly select the appropriate type of mechanical seal and material combination according to the working conditions and host conditions; 2. When the pump with mechanical seal or other similar rotating machinery is operating, the axial string momentum of the rotor is less than or equal to 0.3mm 3 . The step of the shaft (or shaft sleeve) of the mechanical seal part of the device must have a chamfer of 3 × 10°, and the transition is smooth, and its roughness Ra≤1.6. 4. The surface roughness of the shaft (or shaft sleeve) of the mechanical seal part is Ra≤1.6, the runout tolerance is less than or equal to 0.04mm, and the standard tolerance is h6. 5. The surface roughness of the contact part between the sealing end cover of the mechanical seal static ring and the auxiliary sealing ring is Ra≤1.6, the standard service is H8, and the straightness of the positioning end facing the shaft is ≤0.04mm. 6. When installing a mechanical seal, it is necessary to clean the seal cavity of the shaft (or the shaft sleeve), the seal end cover and the mechanical seal itself to prevent any impurities from entering the seal. 7. When installing the ring, especially the carbon graphite ring, it is necessary to press in with extra care. 8. When the temperature of the conveying medium is too high, too low, or contains impurity particles, flammable, explosive, toxic, etc., the corresponding methods of blocking, flushing, cooling, filtering, etc. shall be adopted according to the API682 specification. 9. According to the device operation manual or sample, ensure the device size of the mechanical seal. 10. For the mechanical seal driven by the tension spring, the rotation direction of the tension spring should be selected reasonably. Generally, when viewed from the motor end to the impeller end, when the rotating shaft is clockwise, the right-handed tension spring should be selected, otherwise, the left-handed tension spring should be selected. 11. During the operation of the double-end mechanical seal, the pressure of the blocking fluid is 0.05-0.2MPa higher than the pressure of the medium in the sealing chamber. 2. Precautions for installation 1. The installation process should be carried out in a dry, dust-free and clean working environment, and the parts of the sealing chamber and the sealing parts should be kept clean. 2. In order to reduce the conflict resistance, when installing, apply a layer of clean lubricating oil or grease to the contact surface of the auxiliary seal. But it is necessary to pay attention to when choosing ethylene-propylene rubber as auxiliary seal, do not touch with mineral oil or grease, it can be cleaned and smooth with water or soapy water; 4. The working height of the spring must reach the product sample or installation drawing. the height of the device shown. 5. It is forbidden to bump or hit the seal during the installation process; when the sealing device is finished, it is not allowed to knock or hit the shaft, shaft sleeve, sealing end cover, etc., so as to avoid damage to the mechanical seal conflict pair and cause the seal to fail. 3. Matters needing attention when the sealing device is finished and the equipment is turned on 1. It is necessary to exhaust the air in the sealing chamber, especially the double-end seal with sealing liquid, and pay more attention to exhausting the air. When starting from scratch, the suction valve should be opened first, and the motor should be turned on after the liquid (medium) enters the sealed cavity. For those media with crystals, when starting the vehicle from scratch, the crystals on the sealing surface, springs and other related structural parts should be washed with washing liquid before starting the vehicle. 2. Before starting the device, check that the resistance of the rotating shaft is normal and even, and no jamming is allowed. 3. Before the operation of the equipment, the sealing cavity must be filled with medium, maintain good smoothness, and prevent dry interference, which will lead to sealing failure.