【 Weak current College 】 magnetic pumps working principles and considerations-Power By 【 China power house network 】

Magnetic pump consists of pump, magnetic actuator, motor made up of three parts. Key components of the magnetic actuator by external magnetic rotor and rotor and not within the magnetic permeability of isolation set. When the motor driven external magnetic rotor rotates, the magnetic field can penetrate the air gap and non-magnetic material, led and impeller are connected within the magnetic rotor for synchronous rotation, the implementation of the contactless transmission, the dynamic seal into static sealing. Due to the magnetic rotor shaft, is within the pump body, isolated set of complete closure, to solve the "run, run, drip, leak" issue, eliminating the oil chemical industry inflammable, explosive, toxic, harmful media through pump seal leakage in security risk, effectively ensured the workers ' physical and mental health and safety.

1. high-temperature magnetic force pump operating principle

N on magnets (n is an even number) are arranged according to the law of the magnetic actuator Assembly of internal and external magnetic rotor, composed of the magnet parts mutually full coupled magnetic system. When the inner and outer two poles in different polar opposite, namely the two poles of displacement angle Φ = 0, in which case the magnetic system of magnetic energy; when turning to the magnetic pole with a relative, that is, the two poles of displacement angle Φ = 2 π/n, magnetic system of magnetic energy Max. To remove the external force, due to the magnetic system of magnetic pole mutually exclusive, so that the magnet will be restored to the State of minimum energy. So the magnet generates movement to bring the magnetic rotor spinning.

Second, the structure features

1. magnet valve

By rare-earth permanent magnetic material magnet operating temperature range (-45-400 ° c), high coercivity magnetic field direction has good anisotropy, at the same time very close to never happen demagnetization phenomenon, is a good sourceof magnetic field.

2. isolation sleeve valve

Set in a metal isolation, quarantine, set in a sinusoidal alternating magnetic field, in the direction perpendicular to the magnetic induction of the section out of the Eddy-current and converted into heat. Eddy current expression:. With Pe-Vortex; K — constant; n-pump rated speed; T-magnetic transmission torque; F-sleeve pressure inside; D-sleeve diameter; an electrical resistivity of materials; — material tensile strength. When the pump design, n, T is the condition given to reduce the Eddy-current only from F, D, and so on. Choosing high resistivity, high strength of non-metallic materials production, reducing the isolation of Eddy current aspects of the effects are clear.

3. coolant flow control

Pump operation, you must use a small amount of liquid on the magnetic rotor and isolation of ring gap between set regional and sliding bearing friction for flushing and cooling. Coolant flow typically pump flow rate of 2%-3%, the magnetic rotor and isolation of ring gap between set regions due to Eddy current and high heat. When coolant flush holes or poor, plug, will lead to the medium temperature is higher than the working temperature of the magnet, the internal magnetic rotor magnetic, gradually loses its magnetic transmission failure. When the medium is water or water-based liquid, you can make ring gap regional temperature remained at 3-5 ℃; when the media is a hydrocarbon or oil, to make the ring gap region of temperature rise at 5-8 ° c.

4. plain bearings

Magnetic pumps sliding bearing material has impregnated graphite, filled PTFE, ceramic, etc. Because of Engineering Ceramics has good heat resistance, corrosion resistance, resistance to friction performance, high-temperature magnetic force pump of plain bearings use engineering ceramics production. Due to very fragile ceramics and expansion, thus bearing clearance may not be too small in order to avoid hold axis accident.

Due to the high-temperature magnetic force pump of plain bearings to the conveying media lubrication, so should be based on different media and use conditions, the selection of different materials to make bearings.

5. protection measures

When a magnetic actuator from dynamic components run in overload or rotor card death magnetic actuator of the master, slave dynamic components automatically spondylolisthesis, protection of the pump. At this point magnetic actuators on magnet in active rotor alternating magnetic field, will result in loss of damage, magnetic Vortex, causing permanent magnet temperature, magnetic actuator slippage.

III. advantages of magnetic force pump

With the use of mechanical sealing or packing seal of centrifugal pump, magnetic drive pump has the following advantages.

1. pump shaft seal by moving into closed static sealing, completely avoiding the media leaks.

2. no independent lubrication and cooling water, reducing energy consumption.

3. the coupling drive into sync, no contacts and friction. Small power consumption, high efficiency, and has a damping effect, reducing motor effect of vibration on the pump and the pump cavitation vibration effect on the motor.

4. overload, internal and external magnetic rotor relative spondylolisthesis, motor, pump has a protective effect.

IV. operation precautions

1. prevent particles entered

(1) are not allowed to enter the ferromagnetic impurities, particles and magnetic actuator bearings friction pairs. (2) transportation easy Crystal or precipitation of the media to timely cleaning (stop after instillation to pump water, emissions clean after running 1min) to protect the bearing service life. (3) sent and contained the solid particle medium when the pump flow tube entrance filtering.

2. prevent demagnetization

(1) the magnetic torque is not designed to be too small. (2) should run under a defined temperature conditions, is strictly prohibited to medium temperature exceeded. Available in high-temperature magnetic force pump isolation set exterior installation platinum resistance temperature sensor detection ring gap region of temperature rise, so that when the temperature overrun alarm or downtime.

3. prevent dry friction

(1) No idling. (2) no media time. (3) in a outlet valve is closed, the pump continuous operation time must not exceed 2min, prevent magnetic actuator for heat loss.