This paper describes the principle of magnetic seals and their applications.
I Profile difference between magnetic sealed shaft and mechanical sealed shaft
The main sealing forms of reaction kettle are packing seal, mechanical seal and magnetic seal.
In comparison, the packing seal price is low, the sealing performance is not good.
The magnetic seal sealing performance is good, no leakage, the defect price is high.
The mechanical seal is in the middle.
How do I know if a reactor uses mechanical or magnetic seals?
An easy way to do this is to look at the appearance of their mixing shafts.
Mechanical seal shafts are hollow, while magnetic seal shafts are solid.
As shown in the figure below：
Magnetic seal reactor is configured for reactors with strict sealing requirements. The reactor adopts the sealing principle of "static seal", which can theoretically achieve "zero leakage" of the reactor during the mixing process of chemical materials.
II Magnetic seal principle
The magnetic seal is a sealing method that uses magnetism as the sealing force and consists of two mutually attractive magnets.
One magnet is fixed to the rotating part of the equipment, and the other is fixed to the stationary part.
When the machine rotates, a highly confined space is formed between the two magnets due to the magnetic force, resulting in an effective seal effect.
Specifically, the magnetic sealing principle involves the following aspects.
2.1. Magnetic field effect:
When two mutually attractive magnets are close together, a strong magnetic field is formed between them. This magnetic field will have an effect on the surrounding environment, including attraction and repulsion of other objects, etc.
2.2. Magnetic balance:
In a magnetic seal, since there is a certain distance between the rotating part and the static part, it is necessary to achieve a balance between the two magnets by designing a suitable shape and size.
The balance between the two magnets needs to be achieved by designing the right shape and size. This ensures that there will be no deflection or loss of balance during operation.
2.3. Airtightness:
Since a highly confined space is formed between the two magnets, liquid or gas leakage can be effectively prevented during operation. This airtightness is very important, especially in industrial production when some dangerous or volatile substances need to be handled.
III Advantages of magnetic seal
The magnetic sealing principle uses the action of magnetic force to achieve an effective seal. It has many advantages, such as not being easy to damage, long life, and simple maintenance.
Magnetic reactor adopts magnetic sealing technology in high temperature, high pressure, flammable and explosive media, compared with packing seal and mechanical seal technology.
It has the advantages of easy operation, no leakage, easy maintenance, reduced maintenance cost, energy saving, safety and reliability, and good overall benefits, etc.
Magnetic sealed technology is widely used for the reactors with hazardous reaction, such as
hydrogenation factors, dangerous medium reactors, and so on.
It can be widely used in old chemical plants and new chemical plants.
IV Operation notices
The magnetic reactor is a high-pressure product, so safety should be put in the first place, so the staff should have strict training before they start working, so as to avoid the situation due to improper operation.
4.1
Stop the rapid cooling and heating to prevent the magnetic reactor body from forming cracks due to excessive temperature stress. After the operation of the magnetic reactor is finished, it can be cooled by water (exothermic reaction) or air-cooled.
4.2
The needle valve is a line seal, only need to quietly shift the valve needle, press the tight cover, that can reach outstanding sealing, stop using too much force to avoid damage to the sealing surface. After the reaction is finished, cool down first, then release the high pressure gas in the kettle, make the pressure drop to normal pressure, then unload the bolts symmetrically and equally.
4.3
In the process of unloading the cover of the magnetic reactor, special attention should be paid to maintaining the sealing surface. At the end of each operation, the residues on the kettle body and cover should be eradicated.
All sealing surfaces on the magnetic reaction kettle should be cleaned regularly and kept dry, no hard objects or soft objects with a rough appearance should be used for cleaning, and the stirrer should be unloaded and cleaned.
4.4 Other notices:
4.4.1. Periodically inspect the pressurized components of the magnetic reactor by flaw detection and calibrate the instrument.
4.4.2、The needle valve is out of order, it can be disassembled and cleaned, the valve needle can be replaced, and the hydraulic test can be conducted before the magnetic reactor can be installed and used.
4.4.3、The magnetic reactor and instrumentation box must be grounded.
4.4.4、To know what material the magnetic reactor used is, when choosing the medium, it should be within the corrosion resistance of such material.
4.4.5、The reaction of toxic or flammable and explosive materials that are harmful to the human body should be taken at the safety valve to drain outward.
