In chemical production, the mechanical seal material of the out-of-stock special pump is very important. The choice of mechanical seal material due to the difference in the pumping medium and the different structure types should be decided according to the specific situation. The material selection method of the mechanical seal of the out-of-stock pump is usually very complicated, and the selection of the dynamic and static ring materials is also different according to the different media, and the installation of the mechanical seal also has its technical requirements.
Technical requirements for the installation and use of mechanical seals for out-of-stock pumps
1) When the diameter of the shaft or sleeve of the mechanical seal is generally ￠10~50mm, the radial runout tolerance is 004mm, when it is greater than 50~120mm, the radial tolerance is 006mm. Under the premise of meeting the technical standards, the outer diameter tolerance of the surface roughness of the shaft or sleeve is h6
2) The axial movement of the transmission shaft is light rain or equal to 02 mm.
3) The end face of the shaft, the sleeve and the end face of the sealing cavity must have chamfers. Under normal circumstances, the shaft diameter is less than Φ30 mm, it is 3×10°; and when the shaft diameter is greater than Φ30mm, it is 4×10°.
4) Once the conveying medium is prone to spontaneous combustion and explosion due to the problem of fluctuating temperature, or inclusion of other impurities, toxic particles, and prone to spontaneous combustion and explosion, the following methods must be urgently adopted to solve the problem: filtration, flushing, cooling, and blocking ,and many more
5) For mechanical seals that rely on spring transmission, attention should be paid to the direction of rotation of the spring. In other words, the spring direction should be tighter and tighter under the sealed condition. The way of spring rotation is generally: from static ring to moving ring, the shaft rotates clockwise with a right-handed spring, and when it is turned counterclockwise, a left-handed spring should be used.
Out-of-stock special pump mechanical seal installation requirements
1) The sealing performance of the equipment should be tested and cleaned before the mechanical seal is installed. If the sealing performance is good, it should also be prevented from being infected by dust and impurities. Check whether the end faces of the dynamic and static rings of the mechanical seal are intact, whether there are scratches, cracks, etc. The flatness deviation shall not be greater than 0.004mm.
2) During the installation process, the sealing surface should be kept clean and it is forbidden to use hard objects and utensils to strike and other actions between the sealing surfaces to avoid functional failure due to damage to the sealing.
3) When installing, apply lubricating oil such as molybdenum disulfide on the junction of the seal ring and the shaft to facilitate the installation.
It should be emphasized that for mechanical seals of different materials, the lubricating oil used is not the same. It is necessary to prevent the deterioration of the degree of aging caused by the wrong selection of Run Huanyou, or the occurrence of O-ring immersion oil expansion, thus Ensure effective sealing.
4) When installing the static ring, the static ring should be pressed into the static ring seat steadily and evenly, and the static ring section should be kept horizontal. During installation, keep the sealing surface of the static ring perpendicular to the center line of the gland hole. In addition, for static ring glands with positioning pins, attention must be paid to the alignment of the positioning pins and the bayonet on the static ring during installation.
5) When the static ring gland is installed, the screws must output evenly during the screwing process, once to ensure that the axis line and the end face of the static ring are perpendicular.
6) After installation, the best condition is that the movable ring can run elastically and easily without pressure on the shaft.
7) Under the premise of being full of medium, the equipment can run normally without friction to ensure the effectiveness of the seal.
8) When the granular medium is easy to crystallize, and the temperature of the medium is above 80 ℃, it must be washed, cooled and filtered to ensure its tightness.
