Common operations of mechanical seals
Sep 29, 2022
Installation operation of mechanical seals
I. In order to make the mechanical seal have good sealing performance, the equipment for installing the seal should meet the following requirements.
1. Installation of mechanical seals parts of the shaft (or sleeve) outside diameter size tolerance of h6, surface roughness Ra value is not more than 3.2um.
2. When the outer diameter of the shaft (or sleeve) where the mechanical seal is installed is not greater than 50mm, the radial runout tolerance shall be ≤ 0.04mm; the outer diameter shall be greater than 50mm ≤ 0.06mm.
3. The axial runout of the rotor of the equipment where the mechanical seal is installed is ≤ 0.3mm.
4. must be installed when the shaft, seal cavity (pump cover), mechanical seal itself clean, to prevent impurities into the seal installation parts.
Second, the installation of mechanical seals
The installation of mechanical seals is carried out in the process of pump assembly. When the pump shaft is installed on the bearing box, after the sealing components of the bearing box are installed, install the mechanical seals according to the following steps.
1. Before installation, confirm that the product type and specification are consistent with the equipment requirements.
2. Apply oil evenly to the shaft, cavity and gland where the seal is installed and in contact with the auxiliary seal (Note: for ethylene propylene rubber, or where the medium does not allow injection of lubricating oil, vegetable oil or soapy water may be applied.
3. Put the mechanical seal on the shaft and install it in place according to the designed working height.
4. Tighten the entire seal to the sealing chamber (pump cover) with a bolt through the gland through-hole, using diagonal cross-tightening.
5. When the mechanical seal is equipped with an auxiliary system, connect the pipeline correctly according to the label.
Third, the mechanical seal test drive
1. After the above steps are completed, manually drive the car and observe the change in torque and any abnormal rubbing sound to determine whether to reinstall and adjust.
2. Open the valve, seal the cavity into the sealing medium, discharge all the air from the sealing cavity so that the sealing cavity is fully filled with medium, and observe whether there is any leakage in the seal.
3. Confirm that the above two are correct after the test run.
Fourth, mechanical seals operating precautions
1. When the equipment is running, attention should be paid to observe whether the control instrument is normal, and whether the equipment has any strange noise and overheating and other phenomena.
2. At the beginning of operation, pay attention to the leakage of the seal, in general, the initial leakage may be large, but after a period of running together, the leakage will be reduced or even close to zero.
3. During the trial run, attention should be paid to the vibration and sound changes of the equipment. Due to the difference in thermal expansion of the shaft and housing, the machine may vibrate, in which case a seal failure can be induced. In this case the machine should be stopped and the piping, couplings, ground screws and other parts should be adjusted and strengthened again.
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