The static seal replaces the dynamic seal, so that the flow passage parts of the pump are completely sealed, which completely solves the unavoidable defects of running, falling, dripping and leaking of other pump mechanical seals. The materials of pump body and flow passage parts are made of corrosion resistant stainless steel, corundum ceramics, tetrafluorographite and other materials.
working conditions
1. Permanent magnets: Permanent magnets made of rare earth permanent magnets work in a wide range of temperatures (-45-400 degrees Celsius).
High tenacity, good anisotropy in the direction of magnetic field, and no demagnetization occurs when the same pole is close to each other.
2. Isolation sleeve: When using metal isolation sleeve, the isolation sleeve will be in a sinusoidal alternating magnetic field, in the vertical.
The eddy current is induced on the cross section of the magnetic line direction and converted into heat. After the oil pump is designed, the rated speed and magnetic driving moment of the pump are given by the working condition. To reduce the eddy current, we can only consider the pressure in the separator and the inner diameter of the separator. High resistivity and high strength non-metallic materials are selected to make the isolator to reduce the eddy current. Flow effect is very obvious.
3. Sliding bearing: The material of sliding bearing includes impregnated graphite, engineering ceramics, filled PTFE, etc.
Engineering ceramics have the advantages of heat resistance, corrosion resistance and friction resistance, so the sliding bearings of magnetic pump are mostly made of Engineering ceramics. But the engineering ceramics are brittle and have small expansion coefficient, so the bearing clearance should not be too small, in order to avoid shaft holding accident. Because the sliding bearing of the magnetic pump is lubricated by the medium it conveys, bearings of different materials should be selected according to different media and working conditions.
4. Control of the flow rate of cooling lubricant: When the pump is running, a small amount of cooling fluid must be used to flush and cool the annulus area between the internal magnetic rotor and isolation sleeve and the friction of sliding bearing. The flow rate of cooling fluid is usually 2%-3% of the designed flow rate of the oil pump. The annular gap area between the internal magnetic rotor and isolation sleeve has high heat due to eddy current. When the cooling fluid is small or the flushing hole is not smooth and blocked, the medium temperature will be higher than the working temperature of the permanent magnet, which will gradually make the internal magnetic rotor lose its magnetism and the magnetic drive will fail. When the medium is water or water-based liquid, the annular temperature can be maintained at 3-5 C, and when the medium is hydrocarbon or oil, the annular temperature can be maintained at 5-8 C.
5. Protection measures: When the driven parts of the magnetic drive are running under overload or the rotor is stuck, the main and driven parts of the magnetic drive will fall off automatically, thus protecting the oil pump. Under the action of alternating magnetic field of the active rotor, the permanent magnet on the magnetic drive will produce eddy loss and magnetic loss, which will cause the temperature of the permanent magnet to rise and the sliding failure of the magnetic drive.