What is the Characteristics and Selection Method of Micro DC Pump?

Definition of a micro DC pump: A micro DC pump is a device that generates electromagnetic force through a DC power supply and can move a liquid or gas from one place to another. The principle is based on the Lorentz's law, which means that when a current passes through a conductor, it creates a magnetic field that acts on any conductor in the space it is in. In a miniature DC pump, the power supplies a current and then uses a liquid or gas to build a magnetic field, creating an electromagnetic force that eventually pushes the liquid or gas flow.

The technical parameters to measure pump performance include flow, suction, head, shaft power, water power, efficiency, etc. It can be divided into volume pump and blade pump. Volume pump uses the change of studio volume to transfer energy; the interaction of rotary blade and water to transfer energy, including centrifugal pump, axial flow pump and mixed flow pump. According to the control principle, the centrifugal pump can be divided into AC pump, brushed DC pump, brushless DC motor and brushless DC magnetic isolation pump.

Voltage range: DC 4.5v-12v; Head range: 0.4m-3m; Flow rate range: 100-250L / H (DC40 series. Voltage range: DC 6v-24v; head range: 1.5m-7m; flow range: 246-620L / H DC50 series Voltage range: DC 12v-24v; head range: 1.5m-16m; flow range: 1030-3500L / H The brushless DC pump through electronic direction, without the need to use carbon brush, magnet rotor and stator silicon steel sheet have multistage magnetic field, when the magnet rotor rotates one Angle relative to the stator, will automatically change the direction of the magnetic pole, so that the rotor always maintains the same rejection, so that the brushless DC magnetic isolation pump has a high speed and efficiency. The stator of the magnetic isolation pump is completely isolated from the rotor, which completely avoids the liquid leakage problem existing in the traditional motor-type brushless DC pump. And can be completely diving use and completely waterproof, effectively improve the service life and performance of the pump. When the metal sleeve is used, the sleeve is in a sinusoidal alternating magnetic field, and the vortex current is induced in the section perpendicular to the direction of the magnetic line and converted into heat. The expression of the eddy current is: Pe-eddy; K-constant; n-rated speed of the pump; T-magnetic transmission moment; F-pressure in the sheath; D-inner diameter; the resistivity of the material; -the tensile strength of the material. When the pump is designed, n and T are given by the working condition, and the vortex reduction can only be considered from the aspects of F and D. The non-metallic material with high resistivity and high strength is selected to make the isolation sleeve, which has a very obvious effect in reducing the eddy current. Because the brushless DC magnetic isolation pump is driven by the electric coil rotating the rotor to work, rotation in order to maintain the smooth rotation of the rotor and noise, the use of high performance ceramic shaft and shaft sleeve, can achieve high accuracy, effectively reduce the rotation resistance and noise.

When the driven part of the magnetic drive is running under overload, the driven part of the magnetic drive will slip on the shaft, effectively protecting the motor. When the pump is running, a small amount of liquid must be used to rinse and cool the annular gap area between the internal magnetic rotor and the isolation sleeve and the friction pair of the sliding bearing. The flow rate is usually 2% -3% of the designed flow rate of the pump, and the annular gap area between the internal magnetic rotor and the isolation sleeve generates high heat due to eddy currents. When the cooling lubrication fluid is not enough or the flushing hole is not smooth and blocked, the medium temperature will be higher than the working temperature of the permanent magnet, and the internal magnetic rotor will gradually lose its magnetism and the magnetic drive will fail. When the medium is water or water base liquid, the temperature rise can be maintained at 3-5℃; when the medium is hydrocarbon or oil, the temperature rise can be maintained at 5-8℃.

Make the type and performance of the selected pump meet the requirements of the device flow, head, pressure, temperature and other process parameters, the most important is to determine the voltage, the highest head, and how much flow rate when the head is high. Please refer to the head-flow curve graph for more details. Must meet the requirements of the medium characteristics of the pump conveying flammable, explosive, toxic or valuable media, the shaft seal is reliable or using no leakage pump, such as magnetic drive pump (no shaft seal, using isolated magnetic indirect drive). For pumps conveying corrosive media, convection parts are required to use corrosion resistant materials, such as fluorine plastic corrosion resistant pumps. For the pumps containing solid particle medium, the convection parts are required to use wear-resistant materials, and the shaft seal should be washed with clean liquid when necessary.

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