RU2207186C1 - Centrifugal mixer - Google Patents

Abstract

FIELD: devices for continuous preparation of loose material mixtures with their subsequent thinning; applicable in food, chemical and other industries. SUBSTANCE: centrifugal mixer has vertical cylindrical body, conical receiving-guiding device with holes, cover with branch pipes for supply of initial materials, spraying disk, bottom with branch pipe for mixture discharge, drive shaft with unloading blades and rotor in form of disk on which three thin- walled truncated cones are installed with increasing height from central part to periphery and angle of inclination of cone generator. Mixer design provides for presence of leading flows of materials in process of their mixing. Direct recirculation and also uniform and stable distribution of materials are ensured by presence of windows in lower part of rotor cones. Windows are confined from below by disk surface. For accomplishment of successive thinning, located on receiving-guiding device are two rows of holes through which a part of inlet flow passes and is laid on material flow passing over cones. EFFECT: intensified mixing process and smoothed fluctuations of inlet flows. 2 dwg

Description

 The invention relates to devices for the continuous preparation of mixtures of bulk materials and can be used in food, chemical and other industries.

 Known mixer [1], comprising a housing with a rotor located on it on a vertical shaft, which is three hollow truncated cones, which are concentrically mounted on the disk. In this case, the height and angle of inclination of the generatrix of each cone to the rotor disk increase from the central part to the periphery. Mixing in the specified mixer occurs as a result of successive passage of the material on the surfaces of three cones under the action of centrifugal forces. However, insufficient rarefaction of flows and lack of recirculation does not allow to obtain high-quality mixtures.

 A known mixer [2], containing three cones, in which the height and angle of inclination of the generators to the base increase from the central part to the periphery, while on the surfaces of the inner and middle cones there are windows through which part of the material moving along the inner conical surface, ahead of the flow hits the surface of the subsequent cone. In addition, a reflector is installed above the cones in the form of a volumetric spiral of Archimedes, which provides a partial return of material coming off the cone.

 When researching the operation of this mixer, its design flaws were revealed. Thus, the bypass windows of the inner and middle cones are arranged in such a way that they are bounded on all sides by a conical surface, as a result of which the material flow moving from bottom to top at the moment of descent from the bottom edge of the window has a speed that is tangential to the surface of the cone. This leads to the fact that part of the flow of material descended from the edge of the window, again falls on the surface of the subsequent cone above the window, not having time to slip into it. In addition, the lower parts of the surfaces of the middle and outer cones are not involved in the mixing process. In addition, it should be noted that the descent of the material from the surface of the reflector does not occur in a circle, but in a spiral line, which leads to an uneven distribution of the material on the surface of each cone.

 The purpose of the invention is the intensification of the process of mixing bulk materials with a ratio of the starting components of 1: 500 and higher, followed by their dilution, increasing the smoothing ability of the mixer and, as a result, improving the quality of the resulting mixture. Achieving this goal is ensured by the fact that on the surface of the receiving-guiding device there are two rows of holes: upper and lower. These holes contribute to the separation of the input stream into three parts: the first part passes through the upper row of holes, the second through the lower row of holes, and the remaining part through the central hole of the receiving-guiding device. Also, the goal is achieved due to the presence of guide rings over the inner and middle cones, which make it possible to direct the bulk mixture coming down from the cone to the base of the next. All these constructive solutions ensure the organization of stable leading flows within the apparatus.

 Figure 1 shows a General view of a centrifugal mixer continuous operation with an indication of the direction of movement of the mixture in the apparatus; figure 2 shows the receiving-guiding device (top view).

 The mixer consists of the following elements: a vertical cylindrical body 1, in which a conical receiving and distributing device 2 is located, having two rows of openings: an upper 3 and a lower 4, covers 5 with inlet pipes 6, bottoms 7 with a discharge pipe 8, a drive shaft 9 Unloading blades 10, a rotor 11 and a feeding plate 12 are attached to the shaft 9. The rotor is a disk with three hollow truncated truncated thin-walled cones 13, 14, 15 concentrically mounted on it, which face down with smaller bases. The height and angle of inclination of the forming cones to their bases increase from the central part to the periphery. On the surfaces of the inner 13 and middle 14 cones there are windows 16 bounded from below by the surface of the rotor disk. Guide rings 17 are located above the inner and middle cones. Reflectors are attached to the lower surface of the receiving and guiding device 2. The drive shaft 9 is mounted in the bearing units 18 and 19 and is driven by a V-belt drive 20 from the electric motor 21.

 Centrifugal mixer operates as follows.

 Bulk components are dispensed through the loading nozzles 6 and hit the surface of the supply plate 12, where, under the action of inertia, they are sprayed with a thin layer on the receiving and distributing device 2. Sliding along it, the components of the mixture are evenly poured through holes 3, on the basis of the outer cone 15 and through holes 4, on the base of the middle cone 14. As a result of this, the main flow going along the cones is superimposed with the flow entering the cone through holes 3 and 4. The part of the stream that fell on the rotor disk is black of the annular gap between the outlet of the receiving-guide device 2 and the drive shaft 9 under the action of inertia forces, spreads over the surface of the disk, wherein the flow path relative to the disc (as well as the cones) is twisted in the opposite direction of rotation. Using windows 16, only part of the flow passes to the surface of the inner cone 13, and the other through the windows 16 moves to the middle cone 14. Next, the mixture moving along the surface of the inner cone 13 is discharged to the surface of the guide ring 17, where it is leading through the holes 4, with respect to to the main stream, the mixture is poured, located on the receiving and distributing device 2, i.e. overlay occurs. The total flow is poured from the surface of the guide ring 17 onto the inner surface of the middle cone 14. Here again, the total flow descended from the guide ring 17 is superimposed with the material passing through the windows 16 of the inner cone 13 onto the surface of the middle cone 14. Then the mixture is again divided into two parts. One of them passes through the windows 16 onto the surface of the outer cone 15, and the other moves along the surface of the middle cone 14, where, under the action of centrifugal forces, it is discharged from its surface onto the guide ring 17. On the surface of which there is an overlap of the flow coming off the edge of the middle cone 14, to the stream passing along the surface of the guide ring 17 through the holes 3 of the receiving and guiding device 2. Next, the total mixture is poured from the guide ring 17 onto the inner surface of the outer cone 15. Here again, the flow of material passing through the windows 16, the middle cone 14, onto the surface of the outer cone 15, with the total flow coming off the guide ring 17. After this, the finished mixture enters the bottom of the mixer 7, where the discharge blades 10, through the discharge pipe 8, is removed from the mixer.

 The mixer will work in the optimal mode if 15-20% of the input flow passes through the upper row of windows 3 of the receiving and guiding device 2, and 30-40% of the input flow through the lower row of windows 4 of the corresponding device. The remaining part of the material 40-55% passes through the annular gap between the inlet of the receiving and guiding device 2 and the drive shaft 9. This distribution of the input stream can be achieved due to the fact that on the receiving and distributing device 2 in the upper row three there are 4 holes, and there are four - 8 holes in the bottom row (i.e. twice as many).

 The intensification of the mixing process and smoothing of fluctuations in the input flows is achieved by redistributing the input stream over three cones with the organization of leading flows both in the rotor and in the receiving-guiding device, with their subsequent pairwise overlapping.

Sources of information
1. Copyright certificate SU 1546120 A1, 1971, B 01 F 7/26.

 2. Copyright certificate RU 2132725 C1, 1999, B 01 F 7/26.

Claims (1)

 A centrifugal mixer comprising a housing with a rotor located on it on a vertical shaft, which is three hollow truncated cones mounted concentrically on the disk, while the height and angle of inclination of the generatrix of each cone to the rotor disk increase from the central part to the periphery, a receiving and distribution device, characterized in that the reception and distribution device has two rows of holes, with four holes in the upper row and eight in the lower row and to the lower surface of the distribution The guides are attached to the ring.

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