Features of mechanical seal for kettle

In terms of sealing principle, the machinery used in the kettle and the discharge chute is the same as the mechanical seal used in the pump, but the mechanical seals used in the pump have the same operating conditions and operating technology. The mechanical seal is different and has its own characteristics:

1. The inner diameter and axial movement of the mixing shaft are large.Φ178 andΦ120mm, the mechanical seal arm of the hanging kettle is long. During mixing, the eddy current produced by the material will not only move horizontally, but also circulate in the up and down direction, thus causing the radial oscillation of the mixing shaft. In addition, the axial thrust generated by the mixing, the self-weight of the mixing shaft and the superimposed axial load of the material pressure cause the axial movement. These unfavorable factors can easily lead to poor sealing of the sealing end face, unstable liquid film, and sometimes The soft sealing environment is cracked, resulting in the failure of the mechanical seal of the reactor.​​

2. Most of the sealed medium of the gas-phase sealed kettle and the discharge chute mechanically sealed is in gas, not liquid. Since the material in the kettle is usually not full of the kettle, as long as the material is full of the kettle, it is liquid. Under severe conditions, the sealing end face is often in a state of gas-phase dry conflict, which increases the wear of the sealing end face.​​

3. Operation under variable working conditions The material undergoes chemical reaction in the kettle. The process is that the temperature and pressure are reduced from high temperature and high pressure to normal temperature and pressure; when new materials enter the kettle, the temperature and pressure in the kettle return to high temperature and high pressure from the beginning. Repeated changes in pressure and temperature will bring bad luck to the seal, and it is easy to cause hydraulic deformation and thermal deformation of the end face of the mechanical seal, resulting in leakage of the seal end face. At the same time, repeated changes in temperature and pressure also tend to accelerate the aging and deformation of the auxiliary seal ring, resulting in seal failure.​​

4. The sealing assembly and disassembly should be convenient. The reaction kettle is usually a vertical equipment, and its installation method: electric type—reducer—frame—Reactor. The mechanical seal is between the flange of the kettle mouth and the coupling of the frame, so that when the mechanical seal is replaced, it can be extracted from the axial neutral between the two shafts. The mechanical seal used in the kettle is a cartridge type, which is assembled with a flange, a shaft sleeve, a short shaft and a mechanical seal. There is no neutral space between the shaft of the discharge chute and the transmission shaft. The mechanical seal is directly installed on the shaft, and the upper end of the seal is supported by two thrust bearings. When assembling and disassembling, the motor and frame should be removed, and then the mechanical seal should be installed. It is clumsy and requires lifting equipment to carry out, and the assembly and disassembly of the mechanical seal is labor-intensive and time-consuming.