The mechanical seal of the pump is a precision component, and the requirements for manufacturing accuracy and installation accuracy are very strict. If the assembly is improper, it will affect the sealing performance. To install it correctly, you must pay attention to the following points:
1. Technical requirements for the coordination of machines, pumps and mechanical seals:
a. The maximum shaft curvature must not exceed 0.05mm.
b. All parts in the assembly meet the requirements of the drawings. b. When tightening the gland, it should be done after the coupling is aligned, and the compression screws should be tightened to prevent the flange surface from deflection. c. The compression of the spring shall be allowed to be within ±2mm according to the drawings.
c. The amount of vibration of the shaft where the mechanical seal is installed shall not be greater than 0.1mm. c. The axial movement of the shaft is not allowed to be greater than 0.5mm. d. The shaft manufacturing tolerance of the part where the mechanical seal is installed is h8, and the finish is 1.6. e. The end of the shaft (sleeve) where the moving ring sealing ring is installed and the end of the sealing gland (or housing) of the quiet ring sealing ring should be chamfered and polished. 2. Installation requirements of mechanical seals for pumps:
d. After the moving ring is installed, it must be ensured that the moving ring can move flexibly on the shaft.
Cooling and flushing of mechanical seals for pumps
1. The first type of cooling is from the outlet or high pressure end of the water pump. The clean medium is directly flushed to the sealed end surface, and then enters the pump cavity. Through the continuous circulation of the medium, the frictional heat on the friction end surface is removed to achieve the cooling effect. .
2. The second cooling method
On the basis of the first form of cooling, a cooling water jacket is added to the back of the static ring, the cooling effect is improved, and it can be flushed to collect the leaked liquid. When the temperature of the sealing medium is >150℃, in addition to cooling in the cooling water jacket through the cooling water and the back of the static ring, forced cooling measures should be taken. That is, the clean medium from the pump outlet should be cooled to 50°C in advance by the heat exchanger. Then enter the sealed cavity for cooling and flushing. This form is the best cooling effect.
3. If the medium contains particles or impurities, filtering measures must be adopted to input the clean flushing fluid at room temperature into the sealed cavity.
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chnical essentials for the installation and use of mechanical seals
1. During installation, the surface in contact with the seal should be coated with a layer of clean mechanical oil so that it can be installed smoothly;
2. The sealing cavity of the equipment should be kept clean during installation, and the sealing parts should be cleaned to keep the sealing end face intact to prevent impurities and dust from being brought into the sealing part;
3. It is strictly forbidden to knock and bump during the installation process, so as to avoid damage to the mechanical seal and cause seal failure;
4. The vigorous runout of the shaft of the equipment should be ≤0.04mm, and the axial runout is not allowed to be greater than 0.1mm;
5. When installing the static ring gland, the tightening screws must be evenly stressed to ensure that the end face of the static ring is perpendicular to the shaft;
6. Push the moving ring by hand after installation, which can make the moving ring move flexibly on the shaft, and has a certain degree of flexibility;
7. After installation, turn the shaft by hand, and the shaft should not feel light or heavy;
8. The equipment must be filled with medium before operation to prevent dry friction and seal failure;
9. For the medium that is easy to crystallize and particles, when the temperature of the medium is >80℃, corresponding washing, filtering and cooling measures should be taken. For various auxiliary devices, please refer to the relevant standards of mechanical seals.
Post time: 2021-12-07
