RU2286843C1 - Mixer for powders - Google Patents

Abstract

FIELD: equipment for mixing of powdered materials in chemical and other branches of industry.

SUBSTANCE: mixer for powders has immovable horizontal cylindrical casing, rotor with blades, and drive equipped with distribution box comprising auxiliary low-power electric engine whose shaft is connected through reducing transmission with rotor shaft. Driven gear of reducing gear is fixed relative to rotor shaft of toothed coupling. Movable member of toothed coupling is connected with pneumatic cylinder through change-over and fixing mechanism comprising cam roll with two slots spaced apart along generatrix and change-over fork with two protrusions cooperating with respective slots of roll.

EFFECT: increased efficiency of mixer by reduced time of component charging operation, reduced consumption of power, increased safety and enhanced reliability in operation of mixer.

2 cl, 3 dwg

Description

The present invention relates to the field of devices for mixing powdered materials in the chemical and other industries. In many cases, batch mixers are used to obtain powder mixtures. The starting components are loaded into the mixer, mixed for a certain time, and then the finished mixture is discharged to the next process phase.

Typically, the total volume of components loaded into the mixer is ~ 0.6 of the volume of the mixer. As a rule, mixers with a horizontal cylindrical body usually have up to three loading hatches located in the upper part of the body or on a common lid. More hatches are difficult to constructively. These features lead to the fact that when loading components, the amount of which in the mixture is a significant part, the powder, accumulating, forms a cone with an angle at the base close to the angle of repose of the material. This cone grows upward, occupying a relatively small volume of the mixer, and partially or completely blocks the entrance hatch, making further loading difficult. In the case of loading several components into different hatches, the presence of a rotor with blades aggravates loading difficulties, since the blades are mounted on the shaft with angular displacement to create intensive mixing conditions, and the blade may stop near the hatches, partially blocking the loading hole and contributing to clogging of the hatch during loading. The above is especially evident when working with powders that have poor flowability, clump, adhere to the surface of the apparatus.

In well-known mixers with slow-moving rotor-mixers (A.G. Kasatkin. The main processes and apparatuses of chemical technology. - M.: Chemistry, 1971, pp. 756-757; Mixers for bulk and paste-like materials. Catalog TSINTIKHIMNEFTEMASH, M. , 1985, pp. 17-22) this problem is solved simply - during the loading of the components of the mixer include, and they distribute the powder throughout the volume of the mixer. The disadvantage of such mixers is their low productivity.

In high-performance plow-type mixers (such mixers are also called vortex mixers) there is one high-speed rotor with blades in the form of plows (Mixers for bulk and pasty materials. Catalog TSINTIHIMNEFTEMASH, M, 1985, pp. 33-36). During mixing in a vortex mixer, the powder moves with great speed throughout the entire volume of the mixer and uniformity of the mixture is quickly achieved. This mixer is adopted as a prototype.

The disadvantage of the prototype is that when loading the components you can not turn on the rotation of the rotor, because the powder is intensively scattered in all directions, it also enters the loading hatches and complicates the loading process. Therefore, the loading is carried out in parts, periodically stopping the supply of components and including for a short time the rotation of the rotor. At this time, the loaded powder is distributed in the mixer body. Then the rotation of the rotor is stopped and the loading of components is continued again. Such stops increase the load time of the mixer and, thus, reduce the performance of the mixing phase of the components.

The technical problem, the solution of which the invention is directed, is to increase productivity and profitability, as well as to increase safety and reliability.

The technical result is achieved in that the powder mixer, comprising a fixed horizontal cylindrical body, a rotor with blades and a drive, has a junction box with an auxiliary electric drive, the shaft of which is connected via a reduction gear to the rotor shaft, and the driven reduction gear is fixed relative to the shaft rotor gear clutch. Thus, the rotor drive has a junction box with two input shafts, one of which is connected to the main electric motor operating during the mixing operation, and the second is connected to the auxiliary electric motor of lower power and transmits rotation to the rotor through the reduction gear during component loading. As a result, when loading, the powder is simultaneously distributed inside the mixer by a slowly rotating rotor, i.e. loading operation is performed without interruption.

Improving the safety and reliability of the mixer during the processing of explosive and fire hazardous powder materials is achieved by providing remote switching of the movable element of the gear coupling with a pneumatic cylinder, while the movable element of the gear coupling is connected to the pneumatic cylinder through a switching and fixing mechanism containing a cam roller with two recesses spaced apart along the generatrix and a switching fork with two protrusions interacting with the corresponding recesses of the roller. The plug converts the rotational movement of the cam roller into the translational motion of the movable element of the gear coupling when switching from loading to mixing and vice versa. Moreover, in extreme positions, the fork is fixed by a cam roller due to the output of the interacting protrusion of the fork from the recess on the cylindrical surface of the roller. This fixation allows you to remove air pressure from the cavities of the pneumatic cylinder after the operation of switching the coupling.

The indicated design features of the mixer allow loading components without manual operations, without stopping the rest of the equipment of the technological phase.

The essence of the invention is illustrated by the following drawings.

Figure 1 schematically shows the proposed mixer.

1 - housing;

2 - rotor;

3 - gear;

4 - junction box;

5 - main electric motor;

6 - auxiliary electric motor;

7 - hatch;

8 - shutter;

9 - gear;

10 - gear;

11 - gear coupling half;

12 - pneumatic cylinder;

13 - lever;

14 - a conducted shaft;

15 - movable gear coupling half.

Figure 2 shows the mechanism of switching and fixing the gear clutch.

10 - gear;

15 - movable gear coupling half;

16 - a switching plug;

17 - cam roller;

18 - axis.

Figure 3 shows a top view of the switching mechanism and fixing the gear clutch.

13 - lever;

16 - a switching plug;

17 - cam roller;

18 - axis.

The mixer consists of a fixed horizontal cylindrical body 1, a rotor 2 with blades and a rotor drive. The rotor drive contains a gear 3, a junction box 4, the main 5 and auxiliary 6 motors. The body of the mixer is equipped with hatches 7 for connecting communications supply of the source components and for inspection. In the lower part of the housing there is an unloading hole, which is locked during operation by a shutter 8 with a pneumatic actuator. When unloading the mixer, the shutter 8 is opened and when the rotor 2 is rotated by the engine 5, the finished mixture is unloaded.

During the mixing operation, the electric motor 5 operates, transmitting the rotational moment to the driven shaft 14 through the gear half-coupling 11 and the movable gear half-coupling 15. To transmit the rotational moment, the movable half-coupling 15 is fixed relative to the driven shaft with a key that does not prevent the half-coupling 15 from moving in the axial direction. In the right position of the coupling half 15, the rotation of the driven shaft is transmitted from the engine 5, in the left - through a reduction gear bevel gear from an auxiliary electric motor of lower power 6.

Switching the movable coupling half 15 from one position to another is done by the pneumatic cylinder 12 through the lever 13, the cam roller 17 and the switching fork 16.

The cam roller 17 has two recesses spaced along the length of the roller. With these recesses during switching, two protrusions on the switching fork 16 interact.

The process of loading and mixing the components is as follows. When the manhole covers 7 are open, flexible hoses are connected connecting the working cavity of the mixer with the metering devices. Dosing devices are weighed and feed the components in a predetermined ratio to the mixer. The components can be supplied in a continuous stream or in several portions. When components are loaded, the electric motor 6 is turned on, which rotates the driven shaft 14 and rotor 2 through the reduction gears 9 and 10 through the coupling half 15. Rotating, the rotor continuously leveles the loaded powder with its blades, allowing the next portions of components to freely enter the working chamber of the mixer. In this case, the rotor speed is several times less than with stirring. In a particular case, the speed is taken four times less. The power of the engine 6 is also four times less than the power of the main engine 5. Since the loading operation lasts in many cases longer than the main mixing operation, the use of an auxiliary engine of lower power gives significant energy savings.

After loading is complete, engine 6 is turned off. Air is supplied to the left cavity of the pneumatic cylinder 12, its rod moves to the right, turning the cam roller 17 counterclockwise through the lever 13. The lower recess of the cam roller 17 interacts with the lower protrusion of the switching fork 16, rotates it about the axis 18 clockwise, moving the coupling half 15 to the right extreme position. In this case, the coupling half 15 disconnects the output shaft from the auxiliary engine and connects through the coupling half 11 to the main engine 5. The engine 5 is turned on, the rotor starts to rotate at the speed necessary for quick and high-quality mixing of the components. After a specified period of time, the mixing operation ends, the shutter 8 opens, and when the rotor rotates, the finished mixture is unloaded. After unloading, the engine 5 is turned off, the shutter 8 is closed and the mixer is ready for the next cycle of operation.

The presence of a junction box with two input shafts, one of which is connected to the main engine, and the other to the auxiliary engine, which transmits rotation to the rotor through a reduction gear, allows to increase the mixer performance by reducing the time of the component loading operation. The use of an auxiliary electric motor of lower power compared to the main one saves energy.

The use of remote switching of a gear coupling by a pneumatic cylinder rotating a cam roller with two recesses that interact with two protrusions of the switching fork and move it, and then fix the movable coupling element when switching from loading to mixing and vice versa, improves the safety and reliability of working with the mixer during operation with fire and explosive powder materials.

Tests of the mixer in experimental conditions confirmed its high performance. It is planned to be introduced into production in 2006.

Claims (2)

1. A powder mixer comprising a fixed horizontal cylindrical body, a rotor with blades and a drive, characterized in that the drive is equipped with a junction box with an auxiliary electric motor, the shaft of which is connected via a reduction gear to the rotor shaft, while the driven reduction gear is fixed relative to the rotor shaft gear coupling. 2. The powder mixer according to claim 1, characterized in that the movable element of the gear coupling is connected to the pneumatic cylinder through a switching and fixing mechanism comprising a cam roller with two spaced apart recesses and a switching fork with two protrusions interacting with the corresponding recesses of the roller.

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