RU2796979C1 - Cavitation-vortex disperser for magnetic materials - Google Patents

Abstract

FIELD: ferromagnetic industry.

SUBSTANCE: cavitation-type devices for grinding solid materials, breaking molecular bonds used for grinding ferromagnetic materials. The cavitation-vortex disperser for ferromagnetic materials consists of a pump and a liquid movement accelerator made in the form of a cyclone collector, containing a shell, a first end wall connected by a central hole to the suction pipe of the pump, a second end wall equipped with an outlet transit pipe, a tangential inlet pipe connected to the discharge nozzle of the pump, the suction nozzle of which is equipped with an inlet transit pipe. The tangential inlet pipe of the cyclone in the end projection is made in the form of a part of the ring, the inner arc of which is connected to the shell according to the law of external interface. The cyclone collector shell is equipped with an inductor concentrically covering it, consisting of a power supply, windings, a magnetic circuit, in which a hole is provided for accommodating a tangential inlet pipe.

EFFECT: increasing the efficiency of grinding magnetic materials.

2 cl, 6 dwg

Description

The invention relates to cavitation-type devices for grinding (dispersing) solid materials, destroying molecular bonds, and can be used in particular for grinding ferromagnetic materials intended for the preparation of magnetorheological fluids used in vibration and shock damping systems, as well as in shaft sealing devices and non-contact type rods controlled by an external magnetic field.

A grinding device is known, a ball mill (Shinkorenko S.F. Handbook for the beneficiation of ferrous metal ores. - Moscow: Nedra, 1980. - 527 s), containing a hollow drum with a rotation drive, inside which balls-weights and the crushed material are placed. The disadvantage of this design is its low performance [Vershinin N.P. Process activation settings. “Use in industry and agriculture. Ecology". - Rostov-on-Don, 2004, p. 22].

Known apparatus of the vortex layer (ABC), containing a flowing cylindrical part with an internal sleeve-shaped coaxial insert and metal needles covered by an inductor, including a magnetic circuit, a winding and a power source [Vershinin N.P. Process activation settings. “Use in industry and agriculture. Ecology". - Rostov-on-Don, 2004, p. 42]. This device in the grinding operation is 200 times more productive and 150 times less energy-intensive compared to the ball mill discussed above. These advantages are achieved due to the rotation of the needles from the rotating magnetic field of the inductor. At the same time, they become magnets-dipoles, creating an uneven magnetic field with ultra-high intensity gradients, creating electrical discharges when connecting and disconnecting the needles (high emf is induced in them when closed loops are formed from the needles). When these needles rotate in the liquid, they break it, creating cavitation caverns that instantly collapse, creating shock waves, energy density at the point of collapse, causing multiple changes in energy forms and deep deformation of the liquid.

However, the presence of metal needles in the working process and their impact interactions lead to their wear and clogging of the ground product with their fragments. In addition, the cavitation process in such a device occurs chaotically and incompletely, the cavities have an elongated shape (not spherical), as a result of which, during the collapse, there is a non-focused and non-frontal impact of the opposite walls of the cavities - the cavitation efficiency is low.

The closest technical solution to the claimed, selected as a prototype, is a vortex cavitator containing a fluid accelerator made in the form of a cyclone, the first end wall of which has a central outlet, the second end wall is blank, and the shell is equipped with a tangential inlet pipe, a vane pump with impeller, suction and discharge nozzles, connecting pipeline, as well as inlet and outlet nozzles, the cyclone is coaxially connected directly with the suction nozzle of the vane pump by the central outlet, and the inlet tangential nozzle of the cyclone and the discharge nozzle of the pump have an opposite orientation and are connected by a connecting pipeline.

In the vortex cavitator under consideration, the liquid flow leaving the pressure pipe of the vane pump enters the tangential inlet pipe of the cyclone, then, having made almost a complete revolution along the shell in the cyclone, it interacts with its later section at the connection point of the tangential pressure pipe. The interaction of competing flows intersecting at an acute angle and blocked from three sides causes a periodic process of changing the direction and parameters of the resulting flow. In this case, on the area of the sector of change in the direction of the resulting flow (Fig. 1), as a function of time, the pressure changes from gauge to vacuum values. In this case, the fronts of elastic perturbations propagate in the direction of the cyclone outlet, therefore, periodic cavitation occurs in the interaction zone and in the direction of propagation of the elastic perturbation. In the vacuum phase, when the pressure is reduced to a value below the saturated vapor pressure of a given liquid, it, the liquid, breaks on the nuclei with the formation of empty cavities. In the manometric phase, external pressure and surface tension forces cause the collapse of the cavity with a total speed of the counter-movement of the walls exceeding 3000 m/s, which leads to the creation of an ultra-high energy density at the collapse point (T=6000°, pressure 50-100 MPa) In addition, after the collapse there is the formation of secondary elastic waves with a higher amplitude of pressure changes, which, interacting with each other, also create similar caverns. The combination of these processes leads to deep deformation of the liquid, including the solid components of the liquid, high stress gradients in solid inclusions, their local heating, vibrations, sound-capillary effects, etc. As a result, solid inclusions are destroyed into smaller fragments and thus the dispersion of solid components in the liquid occurs. However, in the device under consideration, the solid component is distributed arbitrarily along the inlet flow and, therefore, only a part of the total amount enters the interaction zone. This is especially evident along the wall of the tangential discharge pipe, which is mated with the shell. The area of the flow interaction sector does not overlap this wall (Fig. 1), therefore, a part of the inlet flow is not subject to cavitation, and the solid component present in the liquid flow is not subject to cavitation. This circumstance reduces the efficiency of the crushing operation. Another significant circumstance is that this device does not exhibit the physical effects realized in the above-considered analogue - the vortex layer apparatus (ABC).

The aim of the invention is to increase the efficiency of the vortex cavitator when grinding magnetic materials.

To achieve this goal in a well-known vortex cavitator, including a pump and an accelerator of fluid movement, made in the form of a cyclone, containing a shell, the first end wall connected by a central hole to the suction pipe of the pump, the second end wall equipped with an outlet transit pipe, a tangential inlet pipe connected to the discharge pipe of the pump, the suction pipe of which is equipped with an inlet transit pipe, the tangential inlet pipe of the cyclone in the end projection is made in the form of a part of the ring, the inner arc of which is connected to the shell according to the law of external conjugation, and the cyclone shell is equipped with an inductor concentrically covering it, consisting of a power supply source, windings, magnetic core, in which there is a hole for accommodating a tangential inlet pipe.

In this case, the magnetic circuit of the inductor can be made open and additionally covering the convex part of the tangential inlet pipe.

The execution of the tangential inlet pipe of the cyclone in the end projection in the form of a part of the ring, the inner arc of which is connected to the shell according to the law of external conjugation (Fig. 2) causes the bending of the flow and the manifestation of centrifugal forces in it. In this case, the solid components of the flow, most often heavier than the liquid, due to centrifugal forces, move to large radii to the confluence line of the considered inlet and circumferential flows along the cyclone shell, that is, to the sector of the cavitation process. This circumstance increases the proportion of solid particles of the flow that are subject to the cavitation process, moreover, in a more intense zone of its impact. As a result of this measure, the productivity and efficiency of grinding in the vortex cavitator is increased.

The supply of the cyclone shell with a concentrically enveloping inductor, consisting of a power supply, windings, a magnetic circuit, in which a hole is provided for accommodating a tangential inlet pipe, gives the vortex cavitator additional capabilities similar to those of the ABC (vortex layer apparatus). In this case, the magnetic components are analogues of needles, and they cause the following factors to appear:

- magnetization of solid components by an external magnetic field causes their interaction with each other;

- movement with all degrees of freedom of solid components and their collision cause the appearance of acoustic waves, cavitation contributing to the destruction of solid material;

- the energy of collisions of solid components is sufficient for the formation of charges on them;

each solid component is a micro-electrolyzer, the continuous operation of which saturates the working area with ions of different polarity, which contributes to the acceleration of redox reactions;

- when magnetization reversal of magnetic components occurs, the phenomenon of magnetostriction occurs, therefore, each solid magnetic component during its movement continuously emits force impulses of large destructive force, affecting neighboring solid inclusions;

- for a short time there are closed circuits of electrically conductive solid materials, in which an external magnetic field induces strong currents initiating micro-arcs.

As a result of magnetostrictive pulses, cavitation, induced currents, microarcs and other factors, solid components are effectively and more completely crushed [Vershinin N.P. Process activation settings. “Use in industry and agriculture. Ecology". - Rostov-on-Don, 2004, p. 21-22].

Another circumstance of the process under consideration is the interaction of the solid component and the liquid phase. The rotating magnetic field of the inductor (when power is applied to it) affects the magnetic particles, streamlines and stabilizes their movement. In addition, the additional effect of the rotating magnetic field on the magnetic particles of the solid phase is realized in the effect of a linear induction pump, which makes it possible to reduce the drive power of the vane pump. Moreover, the controlled additional effect of the magnetic field on the particles of the magnetic material makes it possible to separate the particles by size during processing and thereby obtain a more stable powder fraction.

As a result, as a result of the proposed measures, the productivity of the dispersion process, the quality of the resulting product, the uniformity of its fractional composition increase, the energy intensity of the process decreases, which allows us to state a general increase in efficiency.

The development of technological progress involves both the development of known technologies and devices, and the creation of new ones. One of the promising and relevant areas is the creation of vibration and shock damping systems (magnetorheological transformers - MRT), both in transport systems and in other industries. Another very relevant direction is the creation of sealing devices in technical systems with rotational and linear sealing interfaces. In both devices, it is very promising to use magnetorheological fluids (MRF) consisting of a liquid phase and a solid magnetic component. In magnetic fluid seals, such a liquid is placed in the gap between the movable and fixed elements and is held in it by an external magnetic field. In such devices, there is no direct contact between the elements of a moving pair, there is no wear, the energy intensity of movements is reduced, and manufacturing requirements are reduced. In magnetorheological transformers, the magnetic fluid is placed in two cavities connected by channels surrounded by magnetic field sources. External mechanical action causes the flow of MRF from one cavity to another. The magnetic field, the intensity of which is controlled by this mechanical action, changes the viscous properties of the fluid (MFR), changing the amount of flow through the connecting channel and, thus, changing the degree of damping.

In the considered technical systems, as well as in many other devices used by the GRM, its characteristics must meet high requirements, in particular, in terms of size and uniformity. For the preparation of the solid component of the MRM, the proposed invention is proposed. Ensuring the required quality of MRM can give impetus to the further development of magnetorheological devices and their varieties.

The essence of the invention is illustrated by drawings:

Fig. Fig. 1. Scheme of the formation of elastic signals in the vortex cavitator cyclone.

Fig. Fig. 2. Scheme of organizing the movement of a solid magnetic component in a cavitation-vortex disperser for magnetic materials.

Fig. 3. Cyclone of a vortex cavitator equipped with an inductor.

Fig. 4. Cyclone of a vortex cavitator equipped with an open inductor.

Fig. Fig. 5. Frontal section along the cyclone and the inductor of the cavitation-vortex disperser for magnetic materials. Section B-B according to the image A-A.

Fig. Fig. 6. Meridian section along the inductor of the cavitation-vortex disperser for magnetic materials. Section A-A according to the image B-B.

The cavitation-vortex disperser for magnetic materials includes a pump 1 and a fluid movement accelerator made in the form of a cyclone 2, containing a shell 3, the first end wall 4, a central hole 5 connected to the suction pipe 6 of the pump 1, the second end wall 7, equipped with an outlet transit branch pipe 8, the tangential inlet pipe 9 connected by a pipeline 10 to the discharge pipe 11 of the pump 1, the suction pipe 6 of which is equipped with an inlet transit pipe 12, the tangential inlet pipe 9 of the cyclone 2 in the end projection is made in the form of a part of the ring, the inner arc 13 of which is connected to the shell 3 according to the law of external conjugation, and the shell of the cyclone 3 is equipped with an inductor concentrically covering it, consisting of a power supply 14, windings 15, a magnetic circuit 16, in which an opening 17 is provided to accommodate the tangential inlet pipe 9. The inductor is placed in the housing 18.

In this case, the magnetic circuit 16 of the inductor can be made open and additionally covering the convex part of the tangential inlet pipe 9 (Fig. 4).

Cavitation-vortex disperser for magnetic materials works as follows. First, the cavitation-vortex disperser is filled with water through the transit pipes 8, 12 and the pump 1 is turned on. From the pump 1, water through the pressure pipe 11 and then through the pipeline 10 enters the tangential inlet pipe 9 and then into the cyclone 2, making a vortex motion in it. At the same time, the replenishment of the cyclone with water causes an overflow from it into the suction pipe 6 through the central hole 5 into the pump 1. After the regime is stabilized and air is released from the device through the outlet transit pipe 8, then water pulp of magnetic material with grain sizes up to D = 5 mm is supplied (after preliminary mechanical grinding) through the inlet transit pipe 12 to the pump 1 and the power supply 14 is connected.

In the pump 1, the pulp receives energy in the form of pressure and flow velocity and enters the cyclone 2 through the tangential inlet pipe 9. Moreover, due to the implementation of the tangential inlet pipe 9 curvilinear, that is, in the end projection in the form of a part of the ring, the solid component under the action of centrifugal forces moves away from wall 13 and, passing to large radii, is collected along its opposite wall. At the confluence of this input stream with the circumferential one in cyclone 2, their interaction takes place, which is expressed in periodic mutual squeezing with the intersection of the directions of their initial outflow. In this case, in the sector of the highest intensity of the interaction of flows, the highest concentration of the solid component, especially large fractions, takes place. The largest range of pressure changes during the interaction of flows generates the greatest intensity of cavitation, causes the largest amount of energy stored in each of the cavities, a high level of energy released during the collapse of cavities. The cumulative effect of caverns, shock waves from collapse, shock wave interference, sound-capillary effects, deep and detailed deformation cause the destruction of solid components, that is, their grinding. After passing through the zone of interaction of the flows, the pulp is divided into fractions - larger inclusions due to the greater mass are centrifugally carried to the periphery to the shell 3. Smaller fractions under the action of viscosity forces are carried away by the flow to the center to the central transit outlet pipe 8 and further into the container of the finished product ( not shown in the figures). The other part of the circumferential flow in the cyclone 2 through the central hole 5, the outlet pipe 6 goes to the pump 1 and then to the next processing cycle.

At the same time, the inclusion of an inductor in the working process, consisting of a power supply 14, windings 15, and a magnetic circuit 16, further intensifies the crushing process. The inductor creates a rotating magnetic field similar to the rotating magnetic field in the stator of an electric motor, the rotation speed of which can be controlled either by the frequency of the electric current or by the number of pole pairs to be switched on. This moving field acts on magnetic solid particles, providing them with an additional momentum of movement. These poorly streamlined bodies with sharp edges break the continuity of water, create cavitation caverns throughout the volume of the cyclone. The collapse of these caverns cause an increase in the volume of cavitation treatment, therefore, its productivity increases. Moreover, the operation of this part of the device causes the emergence of closed chains of conductive particles. They disintegrate as quickly as they arise. In the presence of an external alternating field, pulsed electric currents are induced in these circuits, which greatly heats up all the circuits, and when they break, electric arcs are formed. In addition, magnetic particles and a rotating magnetic field in a liquid cause the following factors to appear:

- additional magnetization of solid components by an external magnetic field causes their interaction with each other;

- movement with all degrees of freedom of solid components and their collision cause the appearance of acoustic waves, another type of cavitation contributing to the destruction of solid material;

- the energy of collisions of solid components is sufficient for the formation of charges on them;

- each solid component is a micro-electrolyzer, the continuous operation of which saturates the working area with ions of different polarity, which contributes to the acceleration of redox reactions;

- when magnetization reversal of magnetic components occurs, the phenomenon of magnetostriction occurs, therefore, each solid magnetic component, during its movement, continuously emits force impulses of large destructive force, affecting neighboring solid inclusions.

As a result of magnetostrictive pulses, cavitation, induced currents, microarcs and other factors, solid components are effectively and more completely crushed [Vershinin N.P. Process activation settings. “Use in industry and agriculture. Ecology". - Rostov-on-Don, 2004, p. 21-22].

To increase the length of the magnetic effect on the magnetic particles, it is advisable to extend the inductor to the inlet tangential pipe 9 of the cyclone 2. In this case, the action of the moving magnetic field on the particles of the pulp will be carried out before the cavitation effect on it, to the zone of competing merging of flows, which is even more will increase the volume of the working area of the device with the same initial dimensions and thereby increase its productivity, and hence efficiency.

An additional effect of a moving magnetic field on the magnetic particles of the solid phase is realized in the effect of a linear induction pump, which makes it possible to reduce the drive power of pump 1.

Moreover, the controlled additional effect of the magnetic field on the particles of the magnetic material makes it possible to separate the particles by size during processing and thereby obtain a more stable powder fraction.

As a result, as a result of the measures taken, the productivity of the dispersion process, the quality of the resulting product, the uniformity of its fractional composition increase, the energy intensity of the process decreases, which allows us to state a general increase in efficiency.

The socially beneficial positive effect of the proposed technical solution lies in the fact that, firstly, the problem of import substitution is solved, since until now this powder has been imported from the USA. Secondly, the use, and subsequently further development of this dispersant design, will make it possible to further improve progressive and promising directions for the creation of highly efficient vibration-damping supports that adapt to external operating conditions, as well as highly efficient magnetic fluid non-contact seals. As a result, taking into account the development of related and other branches of technology, the resource of manufactured machines will increase, productivity will decrease, the cost of products manufactured using this technology will decrease, and the well-being of the population will increase.

Claims (2)

1. A cavitation-vortex disperser for ferromagnetic materials, including a pump and an accelerator of fluid movement, made in the form of a cyclone, containing a shell, a first end wall connected by a central hole to the suction pipe of the pump, a second end wall equipped with an outlet transit pipe, a tangential inlet pipe, connected to the discharge pipe of the pump, the suction pipe of which is equipped with an inlet transit pipe, characterized in that the tangential inlet pipe of the cyclone in the end projection is made in the form of a part of the ring, the inner arc of which is connected to the shell according to the law of external conjugation, and the cyclone shell is equipped with an inductor concentrically covering it , consisting of a power source, windings, a magnetic circuit, in which a hole is provided for accommodating a tangential inlet pipe. 2. Cavitation-vortex disperser for ferromagnetic materials according to claim 1, characterized in that the magnetic circuit of the inductor is made open and additionally enclosing the convex part of the tangential inlet pipe.

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