RU2159147C2 - Mixer for powder-like materials with liquid additives - Google Patents

Abstract

FIELD: mixing powder-like materials with liquid additives. SUBSTANCE: mixer includes vertical cylindrical housing with branch pipes for delivery of loose materials and liquid components and discharge of finished product, ring-shaped reflector, drive shaft with rotors, disk-sprayer and knives secured on lower rotor and located one opposite other. Reflector is mounted on inner surface of housing below disk-sprayer. Ends of at least one pair of knives are located above reflector and are bent in parallel with its generatrices copying the reflector shape and then upward in parallel with generatrices of cylindrical housing at length slightly above plane of rotation of disk-sprayer. EFFECT: extended range of powder-like materials to be treated. 7 dwg

Description

 The invention relates to continuous devices for the preparation of compositions of predominantly powdered bulk materials with liquid additives and can find application in food, chemical and other industries.

A device for mixing, containing a vertical cylindrical body with inlet and outlet openings and a hollow drive shaft, the height of which is installed centrifugal plates. On the periphery of the upper centrifugal plate, elastic plates are fixed. The shaft is equipped with conveyor blades located at its end and elastic plates tangentially mounted along its height on the brackets in the holders. The elastic plates are arranged in pairs against one another with a displacement of the underlying pairs relative to the overlying 90 ^o , while the working surface of the plates interacts with the inner surface of the housing [1].

 The disadvantage of this device is the low quality of mixing the second liquid additive and the semi-finished product mixture coming from the upper plate. The liquid sprayed by the lower centrifugal plates inevitably settles inside on the surface inside the housing, and in combination with bulk materials, it creates stable deposits on them, for example, on a shaft, i.e. where the centrifugal force is insufficient to remove sediment. All this limits the scope of the known device for mixing "well-flowing" materials.

 In addition, in the event of fluctuations in the flows of bulk and liquid materials entering the mixer or precipitation breakage, i.e. in case of violation of the recipe, the quality of the finished product decreases.

 The closest technical solution, selected as a prototype, is a mixer containing a vertical housing with nozzles for supplying bulk solids and outlet of the finished product, a drive shaft with rotors made in the form of a base with mixing knives, and a liquid sprinkler, and the upper part of the drive shaft is made with internal cavity and is equipped with a disk with a spherical recess and a conical head placed in it, and the liquid sprinkler is equipped with a supply tube and nozzles, which are made at an angle m vertically to the outputs of the base of the conical head, the solids supply pipe is provided with two concentrically mounted vertically movable conical reflectors [2].

 The disadvantage of this mixer is that with the joint movement of liquid and bulk material over the surface, in this case along a spherical recess of a disk rotating relative to its axis, in most cases complete mixing of the liquid and solid phases is not achieved, since they tend to move in layers, although they form on the surface of a spherical recess a viscous polydisperse system. Since a liquid and a viscous polydisperse system have wettability and viscosity, when drops of liquid and aggregates are removed from particles from the edge of a non-planar disk, they tend to move in the plane of its rotation, while bulk materials slip along them along the imaginary forming surface of rotation. Therefore, to bring the finished product to a predetermined quality, an additional rotating conical reflector is provided here. However, a disk with a spherical recess and a conical reflector have the same angular velocity, therefore, the mixing intensity of granular and viscous on it is minimal and it weakly destroys aggregates from mixture particles formed on the disk. Thus, its presence only complicates the design of the mixer.

 Since the formation of aggregates on the upper stage in the prototype is inevitable, knives are installed on the rotors for their destruction under the disk. But the rotating parts, the disk, the cone, the knives, spin the air inside the apparatus relative to the shaft. It carries with it particles of the mixture and aggregates, which, as heavier ones, are discarded under the action of centrifugal force on the walls of the body and settle down on them down to the outlet pipe of the finished product. Moreover, the mere fact of the presence of knives does not mean that they act on the mixture. In order for them to effectively fulfill their function, it is necessary to stipulate their shape and dimensions, and not just their orientation.

 In addition, during the formation of aggregates on the upper stage and their movement along the walls of the housing, they can form stable growths due to the adhesion forces on the stationary parts of the equipment, which distort the normal mixing process. In addition to the upper stage of the apparatus, on which there is some averaging of fluctuations in the flow of ingredients due to their pouring on the disk and conical reflectors, its lower stage, the system of knives, behaves as an ideal crowding apparatus. Therefore, fluctuations in the flow inside the apparatus, the formation of aggregates and their adhesion on the inner surfaces of the housing reduce the quality of the finished product.

 These disadvantages limit the range of processed powdered bulk materials with liquid additives.

 The purpose of the invention is the expansion of the range of processed powdered bulk materials with liquid additives.

 This goal is achieved due to the fact that a ring-shaped reflector is installed on the shaft under the flat spray disk on the inner surface of the mixer body, which forms a radial clearance between its inner edge and the edge of the spray disk. The ends of at least one pair of knives are located above the reflector, bent parallel to its generatrix, repeating the shape of the reflector, then up parallel to the cylindrical body, with a length slightly higher than the plane of rotation of the atomizer disk, the ends of at least one other pair of knives are bent down in the radial region clearance.

 Figure 1 shows a General view of the mixer (isometry), figure 2 - its frontal section, figure 3 - section along aa, figure 4-7 - manufacturing options for knives and rings, figure 4 - flat ring shaped reflector, in FIG. 5 is a L-shaped reflector; FIG. 6 is a reflector in the form of a reverse truncated cone; FIG. 7 is a reflector in the form of an element of revolution ellipsoid.

 The mixer of powdered materials with liquid additives contains a vertical cylindrical body 1 with nozzles for supplying granular 2 and liquid 3 components and outlet of the finished product 4, the drive shaft 5 with rotors 6 and 7. The rotors have the ability to move vertically along the shaft. A flat atomizer disk 8 is fixed on the upper rotor 6, and at least two pairs of knives 9 and 10 are mounted on the lower 7. The knives in pairs are located opposite one another to reduce imbalance during rotation. However, these pairs can occupy different locations relative to each other on the rotor (angular or in height). An annular reflector 11 is mounted on the inner surface of the body under the knives 9, which forms a radial clearance 1 between its inner edge and the edge of the atomizer disk. The ends of the pair of knives 9 are located above the reflector 11 and bent parallel to its generatrix, repeating its shape, then up parallel to the generatrix of the cylindrical body 1. Their length is slightly higher than the plane of rotation of the atomizer disk 8. The ends of the pair of knives 10 are bent down in the radial clearance zone 1. For regulating the rebound of the finished product to the center of the mixer, the ends of the knives 9 and 10 can be made with a cutting edge in the direction of rotation (figure 3).

 The mixer operates as follows.

 Bulk and liquid components are continuously fed through the corresponding nozzles 2 and 3 to the center of the rotating flat atomizer disk 8, where during their movement along the disk, under the combined action of centrifugal forces and friction forces of the particles against the disk, they are mixed. The resulting semi-finished mixture, consisting of bulk material, liquid and a viscous polydisperse system, is discharged from the disk onto the housing walls. A flat disk-sprayer does not separate into fractions along the height of the body of the mixture of semi-finished product when it is dropped. Pairs of knives 9 and 10 are fixed under the atomizer disk so as not to disturb the mixing process of liquid and granular on it. An annular reflector 11, fixed on the body below a pair of knives 9, prevents its penetration to the pipe outlet of the finished product. This semi-finished mixture, settling on the wall of the housing 1 and on the surface of the reflector 11, falls under the impact of the cutting edges of the knives 9, which move parallel to the generatrix of the cylindrical body and ring. At the moment of cutting it off from the surfaces, aggregates of particles are destroyed and intensive mixing of bulk material, liquid, and a viscous polydisperse system occurs. In fact, the mixture is being refined to its condition, i.e. receiving the finished product. Part I of it is returned to disk 8, thereby forming a recirculation loop, to reduce the influence of fluctuations in the flows of ingredients and their properties on the quality of the finished product. And part II fails to the outlet pipe of the finished product 4. The value of the recycle stream I, in the inventive device, can be set for specific ingredients by choosing the diameter of the flat atomizer disk 8 of the ring 11, its shape (Fig. 4-7), for example, flat, conical and etc., with a radial clearance l between them, the relative position of the disk 8, the knives 9 and the ring 11 in the axial direction of the housing 1 (in height), the angle of the cutting edges of the ends of the knives 9. The ends of the pair of knives 10, bent down in the area of the radial clearance 1 and having bevel (cutting edges) for the end of the finished product to the center of the mixer, mainly needed when installing a number of steps in a single housing, for example, with the sequential introduction of ingredients. In this case, the incoming stream II from the upper stage will fall to the center of the next atomizer disk.

 The design of the mixer allows the expansion of the range of processed powdery bulk materials with liquid additives in the direction of "low-flowing" and high viscosity. The experiments on a prototype mixer showed that one stage of the apparatus is enough to obtain mixtures of a given quality on products such as regenerated milk for feeding young farm animals, consisting of skimmed milk powder, high-viscosity fat-phosphatide concentrate and other components, jelly made from starch, sugar and juice extract. At the same time, the process takes several seconds. The intensity of the mixing process in the inventive mixer is much higher than that used in the production of a worm-blade mixer.

Sources
1. A.S. 707508, cl. B 01 F 7/26, BI N 48, 12.30.79.

 2. A.S. 1042788, cl. B 01 F 7/26, BI N 35, 09/23/83.

Claims (1)

 A mixer for powdered materials with liquid additives, comprising a vertical cylindrical body with nozzles for supplying bulk and liquid components and for discharging the finished product, a reflector, a drive shaft with rotors, a spray disk, knives mounted on the lower rotor and arranged in pairs one against the other, characterized in that the spray disk is made flat and fixed on the upper rotor, on the inner surface of the housing below the spray disk there is a ring-shaped reflector that forms a gap between its by the inner edge and the edge of the atomizer disk, the ends of at least one pair of knives are located above the reflector, bent parallel to its generatrix, repeating the shape of the reflector, then upward parallel to the cylindrical body, with a length slightly higher than the plane of rotation of the atomizer disk, the ends of at least one other pair of knives is bent down in the radial clearance zone.

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