RU2072884C1 - Magnetic filter - Google Patents

Abstract

FIELD: deep cleaning of high-temperature gases from ferromagnetic and nonmagnetic dust at low hydraulic pressures and high velocities accompanied by heat recovery. SUBSTANCE: filter has horizontal filtering chamber, elbow-shaped chamber being preferable, device for forming two-curtain falling flow of nonmagnetic spheres of similar size (1 to 2 mm) which consists of downslide adjustable fire grate with one stationary fire bar and two movable fire bars, acceleration chamber where magnetized filter material is accelerated in two-passage inclined duct by two gastight curtains intersecting the contaminated gas flow in chamber; cleaning the gas from diamagnetic and ferromagnetic dust is effected due to dynamic processes arising in flowing and due to attractive action of magnetized spheres. Process is rapid, it takes fractions of second. Falling flow enters curvilinear bell-mouth 25. During motion in bell-mouth in section where electric coil is located, flow of spheres is subjected to demagnetization under action of variable magnetic field after which it enters rotary motor which sets it in rotation; vibration exciter which causes vibration of sieve is set in rotation through step-up gearing. After flow has been cleaned from dust it rolls down over inclined branch pipe to diamagnetic pipe of linear induction motor-conveyer; under action of electromagnetic forces the flow gets magnetized and rises, then it returns to hopper through inclined branch pipe being cooled in tubular heat exchanger and then it is again admitted to fire grate. EFFECT: enhanced efficiency. 3 cl, 7 dwg

Description

 The invention relates to techniques for dry cleaning of gases in industries where there is a need to simultaneously capture ferromagnetic dust.

 The predominant field of use is the purification of high-temperature gases in metallurgical industries.

 A cyclone-type dust collector is known in which a ferromagnetic granular material is used as a filter material located in a diamagnetic cassette, and an electromagnet is installed to loosen the filter layer during regeneration, which is supplied with direct and alternating current in a pulsed mode. Regeneration is carried out by air, while the gas supply is stopped, which is the main disadvantage of this device (1).

Known closest in purpose to the proposed magnetic dust collector with a constant magnetic field, designed to clean dusty streams from particles of Fe, FeO, Fe ₃ O ₄ , Ni, etc. in which porous ferrospheres with a diameter of 15 to 20 mm are used as a filter element.

Low productivity (V _r 5-60 thousand m ³ / h), limited upper temperature limit (from 80 to 250 ^o C), the cyclical nature of the filter, the inability to use the physical heat of the exhaust gases, limit its use for cleaning large volumes of gases high temperatures characteristic of metallurgical industries (2).

 The purpose of the invention is to increase the productivity, quality and technological stability of the gas purification process, increase economic efficiency due to the beneficial use of the physical heat of the exhaust gases, reduce metal loss from entrainment.

 This goal is achieved by the fact that in the filter device system a continuous flow of the filtering element of the magnetized small fraction of the same diameter within the size of 1 to 2 mm is made of chemically resistant ferromagnetic material having a large specific gravity, for example, of alloyed cast iron.

 Fraction magnetization occurs in a linear electromagnetic field during its rise by transport, which is a linear asynchronous motor (LAD).

 To sift out the ferromagnetic particles, the ball flow together with the dust is demagnetized by an alternating electromagnetic field created by an electric coil mounted in front of the vibrating screen.

 To extract metal particles from dust, it is enough to pass it through the known magnetic separators.

 For heat recovery during cooling of the flow of balls, a 3-turn horizontal tubular surface type is installed, a heat exchanger with a checkerboard arrangement of brass tubes.

In FIG. 1 shows a General view of the installation, a longitudinal section along a vertical plane; in FIG. 2 section along aa of figure 1; in FIG. 3 is a cross section of the conveyor according to B - FIG. one; in FIG. 4 device mechanism for automatically closing the gate; in FIG. 5 device mechanism for automatically opening and closing the valve bell; in FIG. 6 device for demagnetizing the flow of balls node In figure 1; in FIG. 7 the device of the control peep with light with a partition from dazzle, section GG of FIG. 6;
The magnetic filter contains a filter chamber 1 with a hole 2 for supplying contaminated gas and a hole 3 for removing purified gas, a hopper 4 for placing balls, a surface-type tube heat exchanger 5 for cooling balls, a grate with one fixed grate 6 and two movable grates 7 installed in the frame 8. Each movable grate is connected to two adjusting screws 9, screwed into the holes with thread of the bosses of the frame 8. On the heads of the screws 9 are made disc indicators for the width of the longitudinal gap between the grates kami. The clearance can be set between 0-25 mm.

 To enable the flow of balls there is a gate 10, which is equipped with a mechanical drive for automatic closing when the power supply of the installation is turned off. To reduce the magnitude of the gate stroke, a groove 11 is made, which, when the gate is closed, is blocked by a stationary grate 6.

 The gate drive mechanism has a rotary shaft 12, at the ends of which bushings with levers 13 and 14 are planted on the veneers, which are pivotally connected to the gate and springs 16 by rods 15.

 To keep the gate open, there is a hinge lever 17 with a tooth that engages with the gate of the gate and is held by the electromagnet 18.

 When the electromagnet is de-energized, the spring 19 will release the lock, and the springs 16 will close the gate. An electromagnet is included in the power supply circuit of the LAD.

An acceleration chamber 20 is located under the grate, in which a rotary box 21 with two guide channels is installed. Due to the hinge 22 and two screws 23, the box can be installed with a slope of up to 5 ^o towards the flow of gas.

 The accelerating box is necessary to increase the speed and maintain the compactness of the flow of balls before free fall in the filter chamber. This need is also associated with a significant velocity of the gas flow in the chamber, which distorts the flight of the balls at mutual intersection.

 The adjustment of the slope of the box and the accuracy of the movement of gas-permeable curtains, consisting of freely falling balls, are controlled through illuminated viewing windows (peers) 24 located on the side walls of the filter chamber.

 The filter chamber is connected by a bell 25 with a rotary mover 26 installed in the trough of the vibrating screen 27 located in the hopper of the dust collector 28 having a screw 29 for removing dust.

 The rotary mover through a closed gear located on 2 sides on the outside of the walls of the trough (not shown in the drawing) is connected to the vibration exciter 30 and gives it increased speed, while the unbalance shaft is placed in the pipe welded into the cheeks of the trough. To prevent dust back-up during compression of the ball flow, swirls 31 are made on the bend section of the bell, below which an demagnetizing AC electric coil 32 is located, and for automatically turning the bell on and off, a rotary valve 33 with an electromagnetic actuator is installed, which includes: gear 34, mounted on the end of the rotary valve shaft, a gear rotary sector 35, a spring 36 with a tension screw and an electromagnet 37 with a retractor core, the coil of which is parallelly connected in the electric troskhemu conveyor (LAD). On the inclined pipe 38, the fraction rolls into the conveyor. To prevent dust from entering the conveyor, seals are made in the form of curtains (brushes) 39, drawn from heat-resistant synthetic threads or very thin steel wire.

 As a conveyor, a linear asynchronous motor (LAD) was used, consisting of a trough-shaped aluminum case 40, a magnetic circuit 41 with grooves for a multi-pole winding, a diamagnetic overpass (aluminum pipe) 42, which are interconnected by step ladders (clamps) 43. The overpass has a hatch 44, a winding the stator is protected by an aluminum fence 45 (Fig. 2 conditionally removed).

 The engine may be air or water cooled. In FIG. 2 shows a variant of controlled water cooling, best of all with natural circulation in chamber 46, a system including an expansion tank and a self-cooling radiator.

 Cold water cannot be used due to possible condensation of moisture and dampness of the winding (dew point).

 To install the conveyor under any slope, the support heel 47 has a swivel connection to the motor housing.

 The upper head of the conveyor overpass is connected by a pipe 48 to the hopper 4. For uniform filling of the hopper, there are fan-shaped ribs 49 on the lower inclined wall of the pipe, and a hatch 50 is made on the upper wall for filling with balls.

 Before screening the ferroparticles, the fraction stream is subjected to demagnetization by an alternating magnetic field created by an electric coil 32 fed through a packet switch and a voltage regulator.

 However, the exposure time of the coil to magnetization reversal is short due to the high velocity of the flow of balls. In order to increase the exposure time of the coil, a plug is created in the area of its location, for which a chamber 51 is made along the entire width of the socket, in which a rotary valve 52 is placed, the tilt angle of which can be changed by the rotary lever 53 with a tension screw 54 and create some support.

 The control when setting the height of the cork level is carried out through the viewing window 55. To do this, a backlit peeler is installed on the end wall of the socket 25, consisting of a housing 56, a hinged door 57, glass 58 on a soft strip of rectangular frame 59 made of sheet steel, and a viewing lamp 60 with a partition 61 (from blinding). The box has a flange around the perimeter, is inserted from above and is held on three sides by a guide frame 62. The box can be inserted upside down.

 The filter is tight, eliminates any air leaks.

 The filter works as follows.

 Before the filter is put into operation, the volumes located above the grate, including the heat exchanger 5 and the hopper 4, are filled with shot through the hatch 50 in sufficient quantity for continuous reverse movement, taking into account the reserve to increase the flow.

 Rotate the screws 9, on the disk pointer on the control ruler, move the movable grates 7 to the desired size of the failure gap.

 Using screws 34, establish an approximate slope of the accelerating box 21 with subsequent correction of falling gas-permeable curtains when observing through viewing windows with backlight 24.

 By turning on the batch switch, voltage LAD and an electromagnet 18 are supplied; by turning on another bag, a voltage is supplied to a demagnetizing electric coil 32 and a voltage regulator.

 By turning the lever 14 "toward you", i.e. counterclockwise, the gate 10 opens, the lever 17 engages, holding the gate. The flow of balls through the gaps between the grates rushes into the channels of the accelerating duct 21, picks up speed and in free fall crosses the gas flow in the filter chamber with two gas-permeable curtains, enters the socket 25, passes the location of the electric coil 32, which creates an alternating magnetic field in which it subjected to demagnetization. The demagnetization effect is enhanced by creating a plug of a given height by supporting the flow of balls with a rotary valve 52.

 From the bell, the demagnetized fraction enters the rotary mover 26, drives it into rotation, which, through an upward gear transmission, drives the vibration exciter 30 mounted on the sieve 27 and informing him of the vibration.

 The portioned ejection of the shot onto the spring-loaded sieve additionally creates vertically-throwing vibrations, which is very important for the sieving efficiency.

 The sifted fraction through the pipe 38 enters the shaped pipe (overpass) 42 of the vertical conveyor, which is a linear induction motor, and under the influence of a multipolar linear magnetic field of the 3-phase stator winding, it is captured by it, rises and magnetizes.

 From the conveyor along the inclined pipe 48, the magnetized fraction returns again to the hopper 4.

When the temperature of the water in the chamber 46 reaches approximately 20 30 ^o C by thermometer, it is necessary to turn on the natural circulation of the engine cooling, for which it is necessary to open the valve on the circulation pipe.

 The filter refers to the high-speed type of dry granular magnetic filters, in which the cleaning process is based on the interaction of intersecting high-speed gas flow flows and the flow of falling magnetized balls in the form of gas-permeable curtains.

 Two forces are involved in the cleaning: dynamic, in which, as a result of collision and the presence of rarefied zones during the flow around the suction phenomenon, dust particles receive directed acceleration towards the flight of the balls, the dust is washed out by the flow of balls, and magnetic, which captures and carries away from the gas stream, possessing energy of movement (manpower), particles of magnetic metals.

 Based on this method, it is possible to create filters of other modifications, for example, a filter with a vertical filter chamber with a "flying granular layer", wet filters.

Claims (3)

 1. A magnetic filter for dry cleaning of gases from dust and metal particles, comprising a filter chamber with nozzles for supplying contaminated gas and removing purified gas, a loading hopper, a screening and dust removal system, a filter material return device, characterized in that it is provided with the filters arranged in series under the loading a bunker with a heat exchanger, a failed grate, a gate with a drive and an accelerating chamber, the filter chamber is connected to a screening and dust removal system by means of a raster BA having the bottom of the demagnetization apparatus of continuous filter material, wherein the device for returning the filter material is designed as a vertical conveyor, which consists of trough-shaped casing with slots for the magnetic multipole coil and the diamagnetic pipe, which are interconnected collars.  2. The filter according to claim 1, characterized in that the drive of the gate interrupts the flow of filter material, made in the form of a rotary shaft with rigidly fixed at the ends of the sleeves, which are pivotally connected by rods with the gate and springs, while the filter is equipped with an electromagnet and an articulated lever with a tooth interacting with a gate.  3. The filter according to claim 1, characterized in that the bell is equipped with a rotary valve with an electromagnetic actuator with a spring, consisting of a gear mounted on the end of the rotary valve shaft, and a gear rotary sector, pivotally connected to the electromagnet and the spring.

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