RU220675U1 - Industrial vertical mixer for the production of emulsion explosive compositions - Google Patents

Abstract

The utility model relates to mixing devices. A vertical mixer for the production of explosives, containing a base in the form of a disk-shaped support platform located above the supporting surface on racks, between which a container is placed. An electric motor is mounted on the base with the shaft directed downwards. Connected to this shaft is a vertically oriented shaft, on which disk mixers are mounted at a distance from each other along the length of the shaft, each of which on the peripheral contour is equipped with rectangular-shaped blades along the circumference of the disk, oriented transversely to the disk. Some of the blades are directed upward from the disk along the shaft, and the blades located between the upwardly directed blades are directed downward from the disk along the shaft. Each disk is made on the periphery with teeth repeating the shape of a ratchet gear with asymmetrical teeth of normal design, and on each disk the blades directed up and down from the disk are attached to the end walls of each tooth and are located vertically oriented. The disk with blades, located at the free end of the shaft with disk mixers, is made with a diameter smaller than the diameter of other disks with blades. The electric motor is mounted on a separate platform, which is connected to a vertically oriented shell mounted on a disk-shaped support platform. This shell houses the rotation shaft of the electric motor and the end of the shaft with disk mixers brought inside the shell. The other end of the shaft with disk mixers is located at a height above the supporting surface, greater than the height of the container. The electric motor shaft and the shaft with disk mixers are connected to each other in the cavity of the shell, which is separated along the longitudinal axis into two parts by a bushing, which covers the adjacent ends of the shafts, followed by fastening the parts of the bushing with bolted connections. 9 ill.

Description

The utility model relates to mixing devices and can be used in the mining and processing industry for mixing the components of emulsion explosives (EME) in order to create a homogeneous chemically active environment.

An emulsion is a system of two liquid phases, where in one liquid there are tiny droplets of another liquid suspended. A system in which one substance is distributed in the form of small particles in another substance is called a dispersed system, and the distributed substance is the dispersed phase of the system, and the surrounding substance is a dispersed medium. Emulsions are classified as coarse systems, since the dispersed phase of the emulsion consists of relatively large particles. Emulsions based on ammonium nitrate as an oxidizing agent and machine oils as a fuel are widely used in the preparation of explosives.

In general, the composition of emulsifiers looks like this (the components are arranged in order of decreasing concentration): oxidizing phase (inorganic salts, water, combustible phase (solid and liquid fuels), emulsifiers and aerating and modifying additives.

All types of explosives are characterized by a uniform distribution of components over the mass of the substance and a noticeably large contact area between the oxidizer and the fuel. Their peculiarity is that in emulsion explosives, liquid fuel (liquid fuel - diesel fuel) covers drops of a saturated solution of ammonium nitrate (AM) (sometimes mixed solutions of AM and sodium nitrate) with a thin film, forming a so-called “water in oil” reverse emulsion. The emulsification process is carried out in mixers with a rapidly rotating stirrer in the presence of emulsifiers.

A large interfacial surface is formed between the water and oil phases. Inside there is a highly concentrated ammonium nitrate solution saturated and stabilized by the interface, and the surrounding shells at the points of contact of the droplets consist of fuel with a very high calorific value.

The basis of all compositions is a matrix emulsion, formed by mixing in special apparatus a solution of an oxidizer and a flammable liquid phase, where the external phase is formed by various petroleum products.

The technology of emulsion explosives is fundamentally different from the technology for producing powdery, granular explosives. If their production involves physical and chemical processes (crushing, drying, mixing components, capping), then the production of explosives, consisting of a highly concentrated aqueous solution, AS and liquid diesel fuel or industrial oil), is based on hydromechanical processes. The AC solution, heated to 60-90°C, is dispersed in the oil product due to intensive mixing. An emulsifier is added to the resulting mixture for stabilization, and the mass acquires the properties of a stable emulsion, in which each drop (globule) of the AC solution is covered with a thin film of petroleum product (water-in-oil emulsion).

Thus, a vertical mixer for the production of emulsion explosive compositions is known, containing a base on which an electric motor is mounted with the shaft directed downwards, a vertically oriented shaft connected to the electric motor shaft, on which disk mixers are fixed at a distance from each other along the length of the shaft, each of which is on a peripheral contour is equipped around the circumference of a rectangular disk with blades oriented transversely to the disk, with one of the blades directed upward from the disk along the shaft, and the blades located between the blades directed upward are directed downward from the disk along the shaft - a staggered arrangement along the perimeter of the disk (CN 217663023, B01F 27/1152, B01F 27/171, B01F 27/172, published 10/28/2022).

This solution was adopted as a prototype.

In a known mixer, the blades on each disk are attached tangentially (the radius of the disk is perpendicular to the surface of each blade) and slightly inclined towards the center of the disk. Essentially, these blades act as a dispersant and a homogenizer at the same time. But when the disk rotates, only part of the mixture moves centrifugally towards the blades: particles of the mixture accumulate at the wall of the mixer container and are slowly pressed through the gaps between the blades in the same direction. Tilt of the blades towards the center of the disk is not enough to mix the mixture; these blades act as dispersants. In this regard, on the field of the disk itself in the zone between the blades, additional inclined elements are fixed, which mix that part of the mixture that is located not at the peripheral zone, but in the hone closer to the rotation shaft of the disk mixer. But these additional inclined elements do not act as dispersants. These are, in fact, elements of the direction of the mixture flow from the center to the periphery. The result is a rather complex design of a disk mixer, in which the mixed mixture is constantly in contact with the guide surfaces (increasing the process of friction of the mixture against the metal). To obtain emulsion explosives, friction, as a parasitic phenomenon, is unacceptable due to the fact that some ingredients of the emulsion explosive mixture accumulate static electricity. To mix emulsifiers, it is necessary that the mixture is mixed without moving. Only in this case is it possible to obtain a hydromechanical process of a stable emulsion, in which each drop (globule) of the AC solution is covered with a thin film of petroleum product.

Another disadvantage of the known solution is that the shaft with disk mixers has a cantilever mounting directly through the coupling. When mixing products consisting of liquid and solid or close to solid phases, dispersion of the solid phase occurs, during which lateral forces of unequal vectors and different loading forces act on the blades. This leads to the appearance, as a result of all the forces on the blades, of a lateral component acting on the shaft and deflecting the shaft from the vertical axis. Shaft runout appears, which at high speeds begins to destroy both the bearing assembly and the coupling. And in an electric motor, the rotor moves relative to the windings. This significantly reduces the durability of the mixer.

The utility model is aimed at achieving a technical result consisting in increasing the durability and reliability of the mixer at high speeds by eliminating the runout of the disk mixer shaft when mixing the emulsion explosive mixture in the hydromechanical process mode.

The specified technical result is achieved by the fact that in an industrial vertical mixer for the production of emulsion explosive compositions, containing a base on which an electric motor is mounted with the shaft directed downward, a vertically oriented shaft connected to the electric motor shaft, on which disk mixers are mounted at a distance from each other along the length of the shaft , each of which on the peripheral contour is equipped along the circumference of the rectangular disk with blades oriented transversely to the disk, with one of the blades directed upward from the disk along the shaft, and the blades located between the blades directed upward are directed downward from the disk along the shaft, the base is made in in the form of a disk-shaped support platform and is located above the supporting surface on racks, the space between which is intended to accommodate a glass-shaped container, the electric motor is mounted on a separate platform, which is connected to a vertically oriented shell, mounted on a disk-shaped support platform, to accommodate the rotation shaft of the electric motor in the cavity shell, into which the end of the shaft with disk mixers is brought out, the other end of the shaft with disk mixers is located at a height above the supporting surface, greater than the height of the glass-shaped container, the electric motor shaft and the shaft with disk mixers are connected to each other in the cavity of the shell, which is separated along the longitudinal axis into two parts with a sleeve that cover the adjacent ends of the shafts with subsequent fastening of the parts of the sleeve with bolted connections, each disk is made on the periphery with teeth repeating the shape of a ratchet gear with asymmetrical teeth of a normal design, and on each disk blades directed up and down from the disk are attached to the end walls of each tooth and are located vertically oriented, while the disk with blades located at the free end of the shaft with disk mixers is made with a diameter smaller than the diameter of the other disks with blades.

In this case, technological windows can be made on the wall of the shell, closed with removable grilles for access to the sleeve connecting the ends of the shafts and to the bearing assembly of the shaft carrying the disk mixers. And on the side of the support platform facing the disk mixers, elements for securing a glass-shaped container raised to this platform can be made. In addition, a technological window can be made on the support platform, closed with a hinged lid, for supplying mixture components to the container.

These features are essential and are interrelated to form a stable set of essential features sufficient to obtain the required technical result.

This utility model is illustrated by a specific example of execution, which, however, is not the only possible one, but clearly demonstrates the possibility of achieving the required technical result.

In fig. 1 - view of the mixer from one side;

fig. 2 - view of the mixer from the other side;

fig. 3 - shows a mixer with a container before it is lifted to the disk mixers;

fig. 4 - shows a mixer with a raised container and disk mixers inserted into its cavity;

fig. 5 - disassembled mixer;

fig. 6 - connection unit for the shaft with disk mixers and the electric motor shaft;

fig. 7 - bushing for connecting the ends of the shafts in a disassembled state;

fig. 8 - view of the installation of gratings on the shell for access to the bearing assembly;

fig. 9 - shaft with disk mixers.

According to the claimed utility model, the design of an industrial vertical mixer for the production of emulsion explosive compositions (EMCs), in which a drop (globule) of an AC solution is covered with a thin film of petroleum product (water-in-oil emulsion), is being considered.

An industrial vertical mixer for the production of explosives (Fig. 1-4) contains a base made of a support platform 1 and vertical posts 3 located above the support surface 2, attached from below to the support platform 1 (the posts can be dismantled). The space between the racks 3 is intended to accommodate a glass-shaped container 4. On the side of the support platform 1 facing the disk mixers 5 and the support surface 2, there are elements 6 for fastening a glass-shaped container 4 that is lifted up to this platform 1. The mechanism for lifting the container 4 to the elements 6 of its attachment to the support platform 1 is not shown. The racks attached to the supporting surface are made of the appropriate cross-section and, for example, have an open box-shaped cross-section to ensure reliable retention of the support platform 1 on them and to prevent its transverse displacements when the disk mixers 5 operate in the cavity of the suspended container 4.

In the space between the racks there is a vertically oriented shaft 7, on which disk stirrers 5 are mounted at a distance from each other along the length of the shaft. The freely hanging end of the shaft with disk stirrers is located at a height above the supporting surface 2, greater than the height of the glass-shaped container 4. And the other end of the shaft 7, through a hole in the support platform 1, is brought out to the other side of the platform and secured in the bearing unit 8 so that its free end comes out from this unit (Fig. 6). The bearing unit 8 is mounted on the upper surface of the support platform 1, on which a vertically oriented shell 9 is fixed, which carries on the other side a disk element 10 (Fig. 4), on which an electric motor 11 is mounted. The electric motor is mounted on a separate platform, which is connected to a vertically oriented shell . The shaft 12 of the electric motor 11 is brought into the cavity of the shell 9. To connect the ends of the shafts 12 and 7 in the cavity of the shell, a cylindrical sleeve 13 stretched along the length is used, consisting of two halves - half-bushes 14 and 15, obtained by cutting the sleeve along its longitudinal axis and connected along the longitudinal planes (Fig. 7). The half-bushings are connected to each other by bolted elements through coaxial transverse holes 16 in the body of each part of the bushing. The design of this bushing repeats the design of a longitudinally folded coupling in accordance with GOST 23106-78 (longitudinally folded couplings are intended for connecting cylindrical shafts without softening dynamic loads and compensating for displacements). With this fastening, shafts 7 and 12 are rigidly positioned along the longitudinal axis of the sleeve and become connected into one unit, which eliminates runout of one shaft or its misalignment relative to the other shaft due to the fact that shaft 7 is fixed in the bearing assembly 8, and shaft 12 - in motor housing support. When lateral loads appear on the blades of the disk mixers, the resulting force from these loads acts on the shaft 7 and is compensated by the self-installation of the rolling elements in the existing bearing gaps. In fact, we can assume that shaft 7 is fixed in a two-support system: the first is the bearing assembly 8, the second is the electric motor, in which, during its operation, the rotor is positioned due to displacements by the mutual influence of the fields of the electric windings. For this reason, shaft 7 does not have angular or transverse displacements when disk mixers operate in the environment of a stirred mixture of emulsifiers.

To eliminate axial shifts of the shafts 7 and 12, an annular groove 17 is formed in the cavity of the sleeve 13 (Fig. 6), into which support washers are installed (not shown). When installing shafts in parts of the bushing, these shafts are inserted into the washers until they stop, and then the parts of the bushing are connected.

To access the bushing, a technological window is made on the shell wall almost along the height of the shell, closed by a removable grille 18. And to access the bearing unit 8, another technological window is made on the opposite wall of the shell, closed by a removable grille 19 (Figs. 5 and 8). Grilles 18 and 19 differ in size and height. The grid 18 is made of a higher height to allow access to the connecting sleeve 13 for the purpose of its installation or replacement or tightening of the bolts holding the half-sleeves together. Through the grille 19, access to the bearing unit 8 is provided to monitor its condition and lubrication. At the same time, the grilles provide air exchange between the shell cavity and the external environment to remove warm air released when the bearing unit 8 is heated.

On shaft 7, disk mixers 5 are located distantly along the height of the shaft (Fig. 9). Each disk mixer is a disk 10, which on the peripheral contour is equipped with rectangular blades 21 and 22, oriented transversely to the disk. Some blades 21 are directed upward from the disk along the shaft 7, and blades 22, located between the blades 21 directed upward, are directed downward from the disk along the same shaft. That is, the blades in the form of rectangular plates in plan around the circumference of the disk are arranged in a checkerboard pattern.

Each disk is made on the periphery with teeth that repeat the shape of a ratchet gear with asymmetrical teeth of normal design. In this case, on each disk, the blades 21 and 22 are attached to those end walls of each tooth, which along the length of the end surface are greater than the length of the end surface of the other tooth stolon. In addition, all blades with such fastening are located vertically oriented.

Top-mounted disk mixers are made of the same diameter (these mixers are located along the side wall of container 4). And the disk with blades located at the free end of shaft 2 under the top-mounted mixers is made with a diameter smaller than the diameter of the other disks with blades.

The arrangement of disk mixers at a distance from each other on a vertical shaft is known from the prototype and, in principle, repeats the classic design of disk mixers. A feature of the claimed solution in this part of the mixer design is the location of the blades 21 and 22 on the disks 20 and the design of the last mixer disk at the free end of the shaft with a smaller transverse dimension.

The use of a layout of flat blades at an angle to the tangential line of the disk, directed towards the center of the disk, ensures the return of the mixed mixture in the direction of the shaft 7. That is, when mixing the mixture (AC and DT), under the action of centrifugal forces, the mixture particles are directed to the periphery of the disk 20 and fall on the shoulder blades 21 (facing upward). On the surface of these blades, a distribution of pressure forces occurs, as a result of which the mixture changes its vector and flows around the circumference of the disk with a return to the shaft. Part of the mixture passes through the gaps between the blades 21 and falls down, where it lands on the surfaces of the blades 22 (facing down). The process of rejecting the mixture is repeated. Under the influence of gravity, the particles fall and fall onto the surface of the underlying disk, where the algorithm for changing the vector of motion of the stirred mixture is repeated. The peculiarity of such mixing is that laminar flow is present only in the shaft zone, and in the rest of the cavity there is a turbulent movement of the mixture, which leads to the fact that the mixed particles return to the zone in which there is part of the mixture with unmixed or insufficiently mixed particles and are added to this part. The process of mixing the mixture has a rotational component, but the latter is formed in the area of the walls of the container 4. Otherwise, the mixing process is not similar to simple mixing of the mixture with rotation in a circle, in which the mixture begins to swirl along the wall of the container with the formation of a funnel in the center, but is similar to the process of swirling , when the mixture from below or from the side is moved up and back. With this mixing algorithm, the pressure forces on the blades constantly change in magnitude and direction, which leads to virtually no resultant forces that cause the shaft (especially its free end part) to shift (imbalance mode).

This is facilitated by the fact that the last disk mixer has smaller transverse dimensions. Part of the homogenized mixture, under the influence of its own weight, is collected in a sufficient volume in the bottom area of the container. The space for this volume is ensured by the fact that the disk 20 of this mixer is smaller than the size of the other disks 20. In this case, the shape of the container is glass-shaped, that is, it has a flat bottom, from which the side wall can extend either at a right angle or with a smooth transition. In this zone, as a rule, a compacted part of the mixture is formed in the form of a homogenized sediment. When the lower mixer rotates, this volume is mixed, eliminating the presence of lumps or non-dispersed particles in the mixture that have passed through the gaps of the blades of other mixers and settled in the bottom area of the container. Since the distance between the side wall of the container and the lower stirrer is greater than that of other mixers, the accumulated volume of the mixture begins to act as resistance for the rotating stirrer, which, according to Pascal’s law, balances the position of the free end of the shaft in this area of the container.

When the mixer operates, a special algorithm is used to load the container with components in a certain sequence. Therefore, at the initial stage of creating emulsifiers, they can first be mixed with simultaneous dispersion, for example, AS with a petroleum product (DP). And then, after reaching a certain size of the AC granules and obtaining the effect of enveloping them with a DF film, antistatic components, aluminum powder or microsphere powder, gunpowder, etc. are added. The addition is carried out without interrupting the mixing process. For this purpose, a technological window is formed on the support platform for access to the cavity of the container 4. This window is closed by a receiver 23, that is, a fence around the technological window having a rotating lid 24 (Figs. 3 and 4). Thus, the technological window made on the support platform 1 is closed with a hinged lid.

This utility model is industrially applicable and can be manufactured using general mechanical engineering technologies. The practice of using the claimed mixer has shown a reduction in the time to obtain a homogenized mixture of explosives, both without additives and with additives, and has made it possible to increase the reliability of the mixer in media of different liquid viscosities without the appearance of an imbalance on the shaft with disk mixers, which has increased the service life of the mixer bearing unit by high speeds and by eliminating the runout of the disk mixer shaft when mixing the emulsion explosive mixture in the hydromechanical process mode.

Claims (4)

1. An industrial vertical mixer for the production of emulsion explosive compositions, containing a base on which an electric motor is mounted with the shaft directed downwards, a vertically oriented shaft connected to the electric motor shaft, on which disk mixers are fixed at a distance from each other along the length of the shaft, each of which is on a peripheral contour is equipped around the circumference of the disk with rectangular blades oriented transversely to the disk, with one of the blades directed upward from the disk along the shaft, and the blades located between the blades directed upward are directed downward from the disk along the shaft, characterized in that the base is made in the form of a supporting platform and is located above the supporting surface on racks, the space between which is intended to accommodate a glass-shaped container, the electric motor is mounted on a separate platform, which is connected to a vertically oriented shell, mounted on a disk-shaped support platform, to accommodate the rotation shaft of the electric motor in the cavity of the shell, into which the end of the shaft with disk mixers is brought out, the other end of the shaft with disk mixers is located above the supporting surface at a height greater than the height of the glass-shaped container, the electric motor shaft and the shaft with disk mixers are connected to each other in the cavity of the shell, which is separated along the longitudinal axis by a sleeve into two parts, which cover the adjacent ends of the shafts with subsequent fastening of the bushing parts with bolted connections, each disk is made on the periphery with teeth repeating the shape of a ratchet gear with asymmetrical teeth of a normal design, and on each disk the blades directed up and down from the disk are attached to the end walls of each teeth and are located vertically oriented, while the disk with blades located at the free end of the shaft with disk mixers is made with a diameter smaller than the diameter of the other disks with blades. 2. The mixer according to claim 1, characterized in that there are technological windows on the shell wall that are closed with removable grilles for access to the sleeve connecting the ends of the shafts and to the bearing assembly of the shaft carrying the disk mixers. 3. The mixer according to claim 1, characterized in that on the side of the support platform facing the disk mixers, there are elements for fastening a glass-shaped container raised to this platform. 4. The mixer according to claim 1, characterized in that the support platform has a technological window, closed with a hinged lid, for supplying mixture components to the container.

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