Hengaode instrument analysis electromagnetic pump? Sensor principle

Electromagnetic pump, a pump that flows in a magnetic field in a certain direction under the action of electromagnetic force. A device that uses the interaction of a magnetic field and an electric current in a conductive fluid to cause the fluid to be subjected to an electromagnetic force to generate a pressure gradient, thereby promoting the movement of the fluid. Most of them are used to pump liquid metal in practice, so they are also called liquid metal electromagnetic pumps.

Introduction

The electromagnetic pump has no mechanical moving parts, simple structure, good sealing, reliable operation, and no shaft seal is needed. Therefore, it is used to transport some toxic heavy metals such as mercury and lead in the chemical industry and printing industry for nuclear power plant Liquid metal (sodium or potassium, sodium-potassium alloy) as a heat carrier is also used to transport molten non-ferrous metals in casting production. The flow rate can reach 13000m / h, the pressure can reach 1.7MPa, and the temperature can reach 1200 ℃.

Electromagnetic pump can be divided into AC pump and DC pump according to the form of power supply.

According to the current feeding method in liquid metal, it can be divided into conductive (conductivity) electromagnetic pump and inductive electromagnetic pump. Conductive electromagnetic pumps use direct current (Figure 1) or alternating current (Figure 2). It has a tube made of non-magnetic refractory metal (see picture), around the tube is a magnet, and the lines of magnetic force are perpendicular to the tube. When a current perpendicular to the tube and the magnetic field lines is passed, a mechanical force is generated to press the conductive fluid out of the tube according to the left-hand rule. The conductivity type is generally a small pump, used for low pressure and small flow. In the conductive electromagnetic pump, the current is directly conducted to the liquid metal by the external power source through the electrodes on both sides of the pump trench. In induction pumps, the induction type uses multiphase alternating current. The current is induced by an alternating magnetic field. The latest type of induction type electromagnetic pump is a linear induction pump, equipped with a flat, linear stator winding, the induction force is axial, and the size is large. Large flow pumps are of this type.

According to different structure, it can be divided into plane, screw pump and cylindrical pump. In induction pumps, the liquid metal current is induced by an alternating magnetic field (single-phase or three-phase). Fig. 3 is a schematic diagram of an induction type flat pump, and Fig. 6 is a schematic diagram thereof. The working principle of the three-phase induction type electromagnetic pump is similar to the ordinary induction motor. A three-phase winding (the current of which is shown in FIG. 6 curve 1) in a planar or cylindrical iron core generates a traveling wave magnetic field (curve 2 in FIG. 6 is the magnetic induction intensity curve of the traveling wave magnetic field) or a rotating magnetic field. This magnetic field induces a current in the liquid metal (Figure 3, curve 3). The interaction between the induced current and the magnetic field generates a magnetic force, which creates a pressure difference at the pump inlet and outlet that drives the movement of the liquid metal. For DC electromagnetic pumps, the above pressure difference â–³ p can be written as:

Where σ is the conductivity of the liquid metal being transported; Q is the volume flow: a is the half height of the channel; b is the half width of the channel; L is the effective length of the channel; B is the magnetic induction intensity. For induction electromagnetic pumps, the pressure difference can be written as:

Where Bm is the magnitude of the magnetic induction intensity; va is the velocity of the traveling wave magnetic field; va = 2tf, t is the pole distance of the magnetic pole, f is the frequency of the power supply; u is the flow velocity;

The above-mentioned differential pressure formula is derived from the simplest model. If considering the influence of other practical factors (usually making the differential pressure smaller), a corresponding correction factor must be introduced. These practical factors are mainly the armature reaction to the DC pump (the uneven magnetic field distribution caused by the magnetic field induced by the current through the liquid metal), the current flow (the uneven current distribution caused by the current shunt on both sides of the magnetic field area), the magnetic pole Air gap magnetic leakage at the edge, etc .; for induction pumps, it is mainly the lateral end effect (caused by part or all of the induced current in the liquid metal in the limited width channel forming a loop) and the longitudinal end effect (caused by the finite length of the core) Caused by an open magnetic circuit).

A device that uses the interaction of a magnetic field and an electric current in a conductive fluid to cause the fluid to be subjected to an electromagnetic force to generate a pressure gradient, thereby promoting the movement of the fluid. Most of them are used to pump liquid metal in practice, so they are also called liquid metal electromagnetic pumps. Electromagnetic pumps can be divided into AC pumps and DC pumps according to the form of power supply; according to the current feeding method in liquid metal can be divided into conductive electromagnetic pumps and inductive electromagnetic pumps; according to different structures can be divided into flat pumps and cylindrical pumps. In the conductive pump, the current is directly conducted to the liquid metal by the external power source through the electrodes on both sides of the pump trench; in the induction pump, the current is induced by the alternating magnetic field. The electromagnetic pump has no rotating parts, simple structure, good sealing and reliable operation. Therefore, it is used to transport some toxic heavy metals such as mercury and lead in the chemical industry and printing industry; it is used to transport particularly active chemical properties in the atomic power industry Metals, such as sodium, potassium, and sodium-potassium alloys; can be used to make quantitative pumps for active metals such as aluminum and magnesium in foundry enterprises, but they are now mainly used by military and other large enterprises. The disadvantage of electromagnetic pump is lower efficiency,

The disadvantage of the electromagnetic pump is its low efficiency, which has not been widely adopted in the smelting and casting industries.

The electromagnetic pump is similar to the ordinary solenoid valve. It uses alternating current as the working power. The current forms an alternating fixed magnetic field through the electromagnetic winding, and interacts with the movable pump body to drive the pump body to vibrate and promote the liquid output.

principle

Conducted electromagnetic pump principle

The principle of the conductive electromagnetic pump is: the conductor in the magnetic field, through the current, the conductor will be thrust by the magnetic field, the three directions are perpendicular to each other, the magnitude of the thrust is F = I × B × L.

The conduction electromagnetic pump does not have any rotating parts, which solves the problem of mechanical pump wear and forms a maintenance-free welding machine. However, due to the adhesion and shielding of the slag on the electrode during the process of conducting current to the liquid metal by the high-current electrode in contact with the liquid metal, the wave crest is unstable, and even the ups and downs cannot be stabilized. The domestically imported Swiss model Almost 50 units have been discontinued.

Induction electromagnetic pump principle

The principle it uses is to use a single-phase C-shaped open electromagnet. Due to the magnetic path difference between the inner and outer rings, the phase difference of the inner and outer ring magnetic fields is generated, thereby forming a forward magnetic field component, that is, a forward magnetic field component that points from the leading phase to the lagging phase. The liquid metal solder in the forward magnetic field component cuts the magnetic field lines, so it receives a forward induced force to achieve the purpose of pumping the liquid metal solder.

Since the magnetic path difference is used to generate a phase difference to form a forward magnetic field component, the forward magnetic field component is very limited. Most of it is a pulsating magnetic field that does not generate forward thrust. A wide peak (300mm ~ 400mm peak width) as shown in the figure should be created. Ultra-high peaks (40mm height) are very difficult.

working principle

The working principle of the three-phase induction electromagnetic pump is similar to the asynchronous motor, and the structure mainly includes the stator core and the winding. After the winding is energized, it generates a traveling magnetic field and the liquid metal in the pump trench generates an induced current. The liquid metal in the pump trench becomes a current-carrying conductor. It interacts with the traveling wave magnetic field to generate electromagnetic force to drive the metal solution to flow directionally.

Pros and cons

Because the inherent phase difference of the three-phase power supply is directly used, the synthetic magnetic field basically has no pulsating magnetic field components, and all are synthetic magnetic fields that generate forward force. They are completely the same as the principle of the electromagnetic gun, so the efficiency is high, up to 70% or more. In addition to all the advantages of induction electromagnetic pumps, the wave soldering machine composed of phase asynchronous induction pumps, such as the superposition of acoustic frequency perturbation vibration waves, enhances the welding ability and climbing ability, without any rotating parts, no wear, maintenance-free, The structure is simple, etc. It also has a strong peak height and can obtain an ultra-high peak 40mm and a wide peak 300-400mm width.

The company's main stainless steel water collector, vacuum detection box for tank bottom welding seam, reading instrument, eight-level air microbial sampler, relay comprehensive tester, dual-wavelength scanner, coating thickness gauge, soil grinder, tempered glass surface Flatness tester, sound sensor, portable electric water level meter, network port flowmeter, corrosion rate meter, portable scratch tester, freezing point tester, water quality tester, online ammonia gas tester, coating thickness gauge, coating Thickness gauge, soil crusher, digital thermometer, gas sampling pump, ceramic impact tester, automatic crystallization point tester, drug freezing point tester, reed switch tester, constant temperature water bath, gasoline root transfer, gas Sampling pump, tempered glass tester, water quality tester, PM2.5 tester, respirable particulate matter tester, high frequency heat sealer, strain control triaxial instrument, milk body cell tester, helium concentration tester, soil moisture conductivity Rate tester, field strength meter, collection box, transmittance tester, capillary water absorption time tester, redox potentiometer vibration tester, carbon monoxide carbon dioxide detection , CO2 analyzer, oscilloscope polarimeter, slime content tester, car starting power supply, automatic potentiometric titrator, portable thermometer, zirconia analyzer, reed switch tester, precision conductivity meter, TOC water quality analysis Instrument, microcomputer plasticity measuring instrument, wind direction station, automatic spotting instrument, soil redox potentiometer, digital thermometer, portable total phosphorus tester, corrosion rate meter, constant temperature water bath, residual chlorine detector, free expansion rate meter , Centrifugal cup, concrete saturated vapor pressure device, particle strength tester, Gauss meter, automatic coating machine, safety valve grinding tool, weather station, kinesthetic azimuth instrument, dark adaptation instrument, odor collector, rain gauge, four-in-one Gas Analyzer, Emulsion Concentration Meter, Dissolved Oxygen Meter, Temperature Measuring Instrument, Thin Layer Spreader, Temperature Recorder, Aging Instrument, Noise Detector, Constant Temperature and Humidity Chamber, Split Resistivity Tester, Initial Tack and Holding Tack Tester, infrared carbon dioxide analyzer, hydrogen lamp, kinesthetic azimuth meter, constant temperature animal operating table, cooling fan, grease acid value detector, viscosity number analyzer, colony counter, Meteorological station, rain gauge, Kjeldahl nitrogen analyzer, fluorescent whitening agent, the company adhering to the "customer first, forge ahead" business philosophy, adhere to the "customer first" principle to provide our customers with quality services. Welcome to patronize!

Bathtub Caddy

Bathtub Caddy,Bath Shelf Caddy,Tub Caddy,Tub Tray

Jiangmen Sunbond Houseware Manufacturing CO.,LTD , https://www.jmsunbondhw.com