SU884840A1 - Electromagnetic shot blasting apparatus - Google Patents

Description

(54) ELECTROMAGNETICIFL POBEMETHOE DEVICE

I

The invention relates to metallurgy in the continuous casting of steel can be used to improve the quality of the ingot and improve the performance of the process by introducing ferromagnetic dispersed materials into the jet of liquid metal, as well as in engineering when processing the surface of products with ferromagnetic abrasive to remove scale, rust, paint and cold working .

A device is known for introducing ferromagnetic fibrous materials into a liquid metal containing a blinker, a piping system and an electromagnet that generates a directional magnetic field for pulling ferromagnetic particles from the nozzle of the pipeline and introducing them into the metal stream at a given angle.

However, in this device, on the core of an electromagnet, build-ups of ferromagnetic bulk material are created, which shunt and distort

the field of an electromagnet, which leads to the spillage of the material particles on the mirror of the liquid metal.

The closest to the proposed technical essence is a device for introducing ferromagnetic dispersed materials into a jet of liquid metal, containing an electromagnetic thrower in the form of a single accelerating solenoid encompassing an inclined pipeline, inside which acceleration of the ferromagnetic material occurs, dispensing from the hopper by means of dispenser 2 .

A disadvantage of the known device is that when a portion of the ferromagnetic material is accelerated by the throwing solenoid, some particles acquire insufficient speed to penetrate the metal and drop - the metal mirror, forming a crust, reducing the effect of the particles penetrating into the liquid metal. Installing a twin-magnet electromagnet at the output of the throwing solenoid reduces the performance of the device and does not solve the problem of the formation of a crust. In addition, when supplying a propelling solenoid without a magnetic core with rectangular voltage pulses, its magnetic field energy is not efficiently used. The purpose of the invention is to increase the speed of departure of ferromagnetic granular material in electromagnetic shot-blasting devices, increasing their productivity and reducing energy intensity. The goal is achieved by the fact that in an electromagnetic accelerator of ferromagnetic dispersed materials containing a feed bin with a sloping pipe along which the pulsed electromagnetic dose is sequentially expanded: the torus of the ferromagnetic material is a two-winding electromagnetic magnetic clamp of the initial position of the material and the propelling solenoid with its control system, the throwing solenoid is equipped with a stacked magnetic circuit, successively by the main throwing solenoid along the pipeline along d The accelerated material is fitted with an auxiliary metatal solenoid with a magnetic core, and the control system contains a chain consisting of a series-connected capacitor and a diode connected in parallel with the main propelling solenoid, a chain consisting of a series-connected thyristor, an auxiliary propelling solenoid, and an additional resistor connected in parallel to the capacitor, and the control circuit. nor thyristors. Fig, 1 shows the device, a general view; in fig. 2 - section of accelerating solenoids with magnetic core, section; FIG. 3 is a circuit for feeding solenoids; Fig. 4 shows plots of voltage and current versus time for various; The power supply circuits in FIG. Figures 5 and 6 show the dynamics of the movement of a ferromagnetic volatile material at different lengths of the current angle and exponential current pulses of the accelerating solenoid. Electromagnetic shot-blasting device (fig) contains loading hopper 1 5 inclined direction of pipe 2 of non-ferromagnetic non-conductive material, electromagnetic metering device 3, electromagnetic two-winding lock 4 of initial fraction, main accelerating solenoid 5 and auxiliary accelerating solenoid 6 with magnetic cores 7 stacked type The main accelerating solenoid 5 is placed in the magnetic core 8 of the stacked type, and the auxiliary solenoid 6 is placed in the magnetic conductor 9. Between the solenoids there is a ferromagnetic plate 10. The solenoids cover the non-ferromagnetic non-conducting pipeline 2, which is fixed in the axial direction by means of wedges 1I from textolite . A section of two solenoids is assembled using fastening pins 12. The solenoid power circuit (Fig. 3) contains a thyristor unit 13 of a three-phase full-wave alternating current rectifier for powering the main solenoid 5, a chain consisting of a series-connected capacitor 14 and a diode 15 and connected in parallel to the main accelerating solenoid, a circuit consisting of series-connected thyristor 16, auxiliary solenoid 6 and resistor 17 and connected in parallel with capacitor I4, as well as the thyristor control circuit 18 i.Tiristorny unit 13 comprises a thyristor 19 and the diode 20. The electromagnetic sledukmtsim shot-blasting device is operating properly. From the hopper 1, a mobile ferromagnetic weight (cast iron or steel shot, steel wire chaff, etc.) is fed through conduit 2 to a pulsed electromagnetic metering unit 3 (Fig. 1) .. A detached portion of ferromagnetic material moves by gravity along the pipeline, captured by a magnetic field latch 4 and takes its original position at the input of the main accelerating solenoid 5. One of the two windings of the latch is powered by an adjustable voltage source and creates a magnetic field necessary for fixing the flowing material, and the other winding is connected in series with the coil 5 creates a magnetic field neutralizing, removing material at the time of fixation accelerant slew force solenoid floor. The main accelerating solenoid 5 accelerates the ferromagnetic granular material to the required speed.

FIG. Figure 5 shows graphs of the speed of a ferromagnetic granular material and its position as a function of time for different durations of rectangular current pulses flowing in a solenoid of relative length 2.0 (ratio of the length of the solenoid to its average radius). The solution of the equation of motion of the material is performed on the Nairi-2 digital computer.

Depending on the duration of the rectangular current pulse flowing around the solenoid, it is possible to obtain different in magnitude of the speed of movement of the load in the forward and even in the opposite direction. The greatest speed in the direction of the ragon can be obtained when the current is turned off in the solenoid when the load passes the center of the solenoid, as a result of which the magnetic forces hindering its movement are impeded by the magnetic field of the solenoid and the load is decelerated only by mechanical resistance forces caused by friction.

However, the considered problem is idealized, since in real conditions it is necessary to consider the exponential nature of the narstines and the current decay in the solenoid.

FIG. Figure 6 shows the dynamics of the movement of a ferromagnetic material in the field of a previously considered solenoid with an exponential current and different duration of supply voltage pulses.

It is seen from the graphs that the slowly falling current of the solenoid after it is disconnected from the source creates a decelerating force field and the ferromagnetic load loses the previously obtained velocity, as a result of which the steady-state load speed at the output is several times lower than the maximum.

To accelerate the current decay in the main solenoid and, consequently, to obtain higher output velocities of the bulk ferromagnetic material, as well as to more rational use of the magnetic field energy of this solenoid, the power supply unit of the fractional unit is used (Fig. 3).

The control scheme works as follows.

At zero time, when the load is loaded, the initial position at the input of the main accelerating solenoid 5 is when the thyristors 19 are turned on and the solenoid is affected by a voltage equal to DO (Fig. 4a). The current in the solenoid circuit increases exponentially (the section from the curves in Fig. 4e) and the force field of the solenoid rae drives the abrasive up to the maximum speed. At time t, when the abrasive is near the center of the solenoid, the thyristors 19 disconnect the solenoid from the source. If only diode 5 is present in the circuit, the solenoid current is slowly reduced exponentially (section mn of the curves. Fig. 4d) producing a braking effect on the load. When turned on, in series with the diode 15 of the capacitor 14 of the corresponding capacitance, the current 15 will begin to decrease according to a periodic law (section mcd), however, due to the diode, the appearance of negative current values is impossible

and the current decay process is limited to the part of the mc curves (Fig. 46). Thus, the use of capacitance 4 leads to a rapid decrease in current in the main accelerating solenoid 5. At the same time, the magnetic field of the solenoid minus the heat losses is transferred to the electric field of the capacitor.

At time t, the voltage on

the maximum capacitor (Fig. 4c). At this moment, the thyristor 16 is turned on and the capacitor 14 is discharged through the auxiliary accelerating solenoid 6. By switching on the add-on resistor 17, the discharge is aperiodic in the auxiliary solenoid circuit (Fig. 4b). The current ID of the auxiliary solenoid creates a field representing the second stage of abrasive acceleration. The parameters of the systems must be chosen in such a way that at the moment of occurrence of the strongest field of the auxiliary solenoid the ferromagnetic material is under the influence of its positive accelerating forces.

Claims (2)

After the disappearance of the current If of the auxiliary solenoid, the collation begins. a new portion of ferromagnetic material in the field of the main accelerating solenoid. The thyristor control unit 18 allows adjusting both the current pulse duration and the frequency of their sledging. The use of a stacked type magnetic core made of ST-3 steel leads to an increase in the driving forces of the propelling solenoid 2.5-4 times, which allows to obtain higher speeds of ferromagnetic material at the output of the electromagnetic shot-blasting device compared to that without a magnetic core. The use of an auxiliary nuclear solenoid, which is fed by the energy stored in the magnetic field of the main accelerating solenoid and which serves as an additional stage of acceleration of the ferromagnetic material, will significantly improve the speed and energy performance of the electromagnetic fractional device. The proposed solenoid power supply scheme not only provides the necessary sequence of power supply to the solenoids, but also allows a faster current decrease in the main accelerating solenoid to be realized after it is disconnected from the source, which also results in a higher emission velocity of the material. Claims of Electromagnetic Blast; A device for introducing ferromagnetic di. 8 persistent materials into a jet of liquid metal containing a feed bin with a sloping pipeline, along which the dispenser of ferromagnetic material is successively placed, an electromagnetic lock of the initial position of the material and a propelling solenoid with a control system that covers the pipeline, in order to increase the rate of departure of the ferromagnetic bulk material, increasing plant capacity and reducing energy consumption, the propellant solenoid additionally; The receiver is supplied with stac-type wire, an auxiliary throwing solenoid with a magnetic core is installed in series with the main propelling solenoid along the pipeline along the accelerated material, and the control system contains a chain consisting of a series-connected capacitor and a diode connected in parallel with the main propelling solenoid, as well as a circuit consisting of a series-connected thyristor, an auxiliary propellant solenoid and resistors connected in parallel nsatoru. Sources of information taken into account during the examination 1. USSR author's certificate number 416150, cl. B 22 D 11/10, 2. USSR author's certificate number 533445, cl. At 22 D 11/10. / Z Fm.z Fig.Z