Magnetic pump will n pairs of magnets (n is even) according to the law arranged in the magnetic drive on the inside and outside the rotor, the magnet part of each other to form a complete coupling of the magnetic system. When the inner and outer two poles are in opposite polarities, that is, the displacement angle between the two poles is Φ = 0, the magnetic energy of the magnetic system is the lowest. When the poles rotate to the same poles, that is, the displacement angle Φ = 2π / n, the magnetic system at this time the maximum magnetic energy. After removing the external force, due to the mutual exclusion of the magnetic poles of the magnetic system, the magnetic force will restore the magnet to the state with the lowest magnetic energy. So the magnet produces the movement, drives the magnetism rotor to rotate.
Structural Features 1. Permanent Magnet Valve Permanent magnet made of rare earth permanent magnet has a wide range of operating temperature (-45-400 ℃), high coercivity and good anisotropy in magnetic field direction. When demagnetization will not happen, is a good source of magnetic field.
2 isolation sleeve valve In the use of metal isolation sleeve, the isolation sleeve in a sinusoidal alternating magnetic field, the cross-section perpendicular to the direction of the magnetic flux induced eddy current and converted into heat. The eddy current is given by: where Pe-eddy current; K-constant; n-pump rated speed; T-magnetic drive torque; F- pressure inside the spacer; D- spacer inner diameter; resistivity of a material; Tensile strength. When the pump is designed, n, T is given conditions, to reduce eddy current only from the F, D and other considerations. Selection of high resistivity, high strength non-metallic materials made isolation sleeve, the effect of reducing eddy current is very obvious.
3. Cooling fluid flow control pump operation, you must use a small amount of liquid on the inner rotor and the isolator between the ring gap region and the sliding friction bearing pair was washed and cooled. Coolant flow is typically 2% to 3% of the pump design flow, and the annulus area between the inner magnet rotor and the isolation sleeve generates high heat due to eddy currents. When the cooling fluid is not enough or flushing hole poor, blocked, it will lead to the medium temperature is higher than the permanent magnet operating temperature, the magnetic rotor gradually lost magnetism, the magnetic actuator failure. When the medium is water or water-based liquid, the annulus area can be maintained at 3-5 ℃. When the medium is hydrocarbon or oil, the annulus area can be maintained at 5-8 ℃.
4 sliding bearings
Magnetic pump sliding bearing materials impregnated graphite, filled with PTFE, engineering ceramics. As the engineering ceramics have good heat resistance, corrosion resistance, abrasion resistance, so the use of magnetic bearings multi-purpose sliding bearing made of engineering ceramics. As the engineering ceramics are very brittle and the expansion coefficient is small, so the bearing clearance must not be too small, in order to avoid the occurrence of axial accidents.
As the magnetic pump sliding bearings to the lubrication of the media, it should be based on different media and the use of conditions, the use of different materials made of bearings.
5. Protective Measures When the driven parts of the magnetic actuator operate under overload or the rotor is stuck, the main and driven parts of the magnetic actuator will automatically slide off to protect the pump. In this case, the permanent magnet on the magnetic actuator will generate eddy loss and magnetic loss under the action of the alternating magnetic field of the active rotor, causing the temperature of the permanent magnet to rise and the magnetic actuator to slip off.
Advantages of Magnetic Pumps Compared to centrifugal pumps that use mechanical seals or packing seals, magnetic pumps offer the following advantages:
1. The pump shaft becomes a closed static seal from the dynamic seal, completely avoiding media leakage.
2. Without independent lubrication and cooling water, reducing energy consumption.
3 by the coupling into a synchronous drag drive, there is no contact and friction. Low power consumption, high efficiency, damping and vibration damping effect, reducing the impact of motor vibration on the pump and pump cavitation vibration on the motor.
4. Overload, the relative rotation of the rotor inside and outside, on the motor, pump protection.
Structural Features 1. Permanent Magnet Valve Permanent magnet made of rare earth permanent magnet has a wide range of operating temperature (-45-400 ℃), high coercivity and good anisotropy in magnetic field direction. When demagnetization will not happen, is a good source of magnetic field.
2 isolation sleeve valve In the use of metal isolation sleeve, the isolation sleeve in a sinusoidal alternating magnetic field, the cross-section perpendicular to the direction of the magnetic flux induced eddy current and converted into heat. The eddy current is given by: where Pe-eddy current; K-constant; n-pump rated speed; T-magnetic drive torque; F- pressure inside the spacer; D- spacer inner diameter; resistivity of a material; Tensile strength. When the pump is designed, n, T is given conditions, to reduce eddy current only from the F, D and other considerations. Selection of high resistivity, high strength non-metallic materials made isolation sleeve, the effect of reducing eddy current is very obvious.
3. Cooling fluid flow control pump operation, you must use a small amount of liquid on the inner rotor and the isolator between the ring gap region and the sliding friction bearing pair was washed and cooled. Coolant flow is typically 2% to 3% of the pump design flow, and the annulus area between the inner magnet rotor and the isolation sleeve generates high heat due to eddy currents. When the cooling fluid is not enough or flushing hole poor, blocked, it will lead to the medium temperature is higher than the permanent magnet operating temperature, the magnetic rotor gradually lost magnetism, the magnetic actuator failure. When the medium is water or water-based liquid, the annulus area can be maintained at 3-5 ℃. When the medium is hydrocarbon or oil, the annulus area can be maintained at 5-8 ℃.
4 sliding bearings
Magnetic pump sliding bearing materials impregnated graphite, filled with PTFE, engineering ceramics. As the engineering ceramics have good heat resistance, corrosion resistance, abrasion resistance, so the use of magnetic bearings multi-purpose sliding bearing made of engineering ceramics. As the engineering ceramics are very brittle and the expansion coefficient is small, so the bearing clearance must not be too small, in order to avoid the occurrence of axial accidents.
As the magnetic pump sliding bearings to the lubrication of the media, it should be based on different media and the use of conditions, the use of different materials made of bearings.
5. Protective Measures When the driven parts of the magnetic actuator operate under overload or the rotor is stuck, the main and driven parts of the magnetic actuator will automatically slide off to protect the pump. In this case, the permanent magnet on the magnetic actuator will generate eddy loss and magnetic loss under the action of the alternating magnetic field of the active rotor, causing the temperature of the permanent magnet to rise and the magnetic actuator to slip off.
Advantages of Magnetic Pumps Compared to centrifugal pumps that use mechanical seals or packing seals, magnetic pumps offer the following advantages:
1. The pump shaft becomes a closed static seal from the dynamic seal, completely avoiding media leakage.
2. Without independent lubrication and cooling water, reducing energy consumption.
3 by the coupling into a synchronous drag drive, there is no contact and friction. Low power consumption, high efficiency, damping and vibration damping effect, reducing the impact of motor vibration on the pump and pump cavitation vibration on the motor.
4. Overload, the relative rotation of the rotor inside and outside, on the motor, pump protection.