RU2096002C1 - Apparatus for producing food powder - Google Patents

Abstract

FIELD: food-processing industry. SUBSTANCE: apparatus has horizontal housing divided by vertical wall into two sections, where heat-carrier branch pipes are mounted. Hollow perforated rotor is mounted on two hollow semiaxles within housing. Exhaust pipe is extending through cavity of one semiaxle. Disk is fixed on one end of exhaust pipe within rotor in spaced relation to rotor wall in common plane with dividing wall. Radial blades are fixed within rotor with space between blades and rotor wall at the side adjacent to exhaust pipe. EFFECT: increased efficiency, simplified construction and improved quality of powdered product. 5 cl, 9 dwg

Description

 The invention relates to techniques for producing food powders from fluid food products.

 A known installation for the production of food powders, containing a series-connected digester and an ultrasonic spray dryer (A. Stern, A. Study of commodity qualities, conditions for the production and storage of tomato powder spray drying. Abstract of dissertation, Ph.D. M.MINH, 1959, p. 3 11).

 The disadvantages of this installation are the design complexity and low quality of the powder obtained in it.

 Also known is an apparatus for producing food powders containing a vacuum evaporator and a vortex spray dryer connected in series (Mikhailenko A.A. Study of the process of vortex spray drying of liquid products of starch and syrup production. Abstract of dissertation, candidate of technical science M. MTIPP, 1978, p. 5 10).

 This installation allows you to slightly improve the quality of the resulting powder, but retains the complexity of the design.

 Devices for concentrating a liquid food product before spray drying to obtain a powder are not known in the art.

 The technical result of the invention is the creation of a single device that allows spray drying after preliminary concentration of liquid food products.

 The technical result according to the invention is achieved in a sectional device for producing food powders, comprising a horizontal casing, divided by a vertical partition into two sections, containing coolant supply pipes, a hollow perforated rotor installed in it on the hollow axles, an exhaust pipe passing through the cavity from the axles, mounted on it the end of the disk, placed with a gap in the cavity of the rotor in the plane of the partition wall of the housing, and radial blades, fixed with a gap in the rotor and placed in section of the housing from the side of the exhaust pipe.

 This design ensures that in one device sequentially the operations of concentration and spray drying of liquid food products in a continuous stream.

 In a preferred embodiment, it is possible to make holes in the perforation of the rotor in the form of Laval nozzles in at least one of the sections of the housing.

 This allows you to intensify heat and mass transfer processes by creating phases of ultrasonic vibrations in the contact zone.

 In this case, it is possible to supply the nozzle holes of the rotor with swirls installed at the inlets in at least one of the sections of the housing, or to supply the device in at least one of the sections of the housing, or to supply the device with at least one placed in the section of the housing in the contact zone with the rotor, in which the rotor perforation holes are made in the form of Laval nozzles perforated by the stator, the perforation holes of which are made with rotor perforation holes in the same planes along coaxial circles with unequal and ekratnym circumferential step and provided zavihriteljami installed in them.

 This makes it possible to increase the energy intensity of the phases of ultrasonic vibrations generated in the contact zone.

 In another preferred embodiment, the device is equipped with at least one perforated stator located in the section of the housing in the contact zone with the rotor, the perforation holes of which are arranged with the holes of the rotor perforation in the same planes along the coaxial circles with unequal and non-multiple circumferential pitch.

 This makes it possible to intensify heat and mass transfer processes in the phase contact zone by creating or increasing the energy intensity of the ultrasonic vibrations generated in it.

 In FIG. 1 shows a longitudinal section of the proposed device; in FIG. 2 shows a cross section of a device with a stator in the coolant supply zone; in FIG. 3 to 9 show embodiments of the heat transfer medium inlet assembly.

 The sectional device for producing food powders contains a horizontally located case 1, divided by a vertical partition 2 into sections 3 and 4, containing tubes 5 and 6 for supplying gaseous coolant, installed in the case 1 on two hollow half shafts 7 and 8, a hollow perforated rotor 9, holes 10 perforation which can be made in at least one of the sections 3 or 4 in the form of Laval nozzles, which in turn can be equipped with exhaust swirls 11 installed at the inputs, passing through the cavity of the axle shaft 7 the pipe 12, communicated with holes 13 with the cavity of the rotor 9, with a disk 14 fixed at its end, placed with a gap 15 in the cavity of the rotor 9 in the cavity of the partition 2, and radial blades 16, fixed with a gap 17 in the rotor 9 and placed in section 3 The device can also be equipped with a stator 18 located in sections 3 and / or 4 in the contact zone with the rotor 9, the perforation holes 19 of which are placed with holes 10 in the same planes along coaxial circles with an unequal and non-multiple circumferential pitch, and in the case of adjacent holes 10 nozzle shape Laval can be equipped with swirlers 20 installed in them.

 The device operates as follows.

 Through the cavity of the semi-axis 7 in the rotor 9 serves a liquid food product. The rotation of the rotor 9 ensures the distribution of the product in the form of a film on the inner surface of the rotor 9, flowing in the direction from section 3 to section 4 of the housing 1 through the gaps 17 and 15. At the same time, in the sections 3 and 4 of the housing 1 through the nozzles 5 and 6 serves a gaseous coolant under excess pressure.

где Q расход газообразного теплоносителя, кг/с;
q расход жидкого продукта, кг/с;
R внутренней радиус ротора 9, м;
μ_г, μ_ж вязкость газообразного теплоносителя и жидкого продукта соответственно, Па•с;
ω угловая скорость вращения ротора 9, c^-1;
r_ж плотность жидкость продукта, кг/м³,
полученной эмпирическим путем, задают расход газообразного теплоносителя через патрубки 5 и 6 таким образом, чтобы его значение в патрубке 5 не превышало расчетное, а в патрубке 6 было больше него, с учетом изменения характеристик жидкого продукта в процессе концентрирования. Это гарантирует незначительный вынос брызг в секции 3 и полное диспергирование продукта в секции 4 корпуса 1.According to the formula

where Q is the flow rate of the gaseous coolant, kg / s;
q flow rate of the liquid product, kg / s;
R is the inner radius of the rotor 9, m;
μ _g , μ _g viscosity of the gaseous coolant and the liquid product, respectively, Pa • s;
ω the angular velocity of rotation of the rotor 9, c ^-1 ;
r _{W the} density of the liquid product, kg / m ³ ,
obtained empirically, the flow rate of the gaseous coolant through the nozzles 5 and 6 is set so that its value in the nozzle 5 does not exceed the calculated value, and in the nozzle 6 it is greater than it, taking into account changes in the characteristics of the liquid product during the concentration process. This ensures a slight removal of the spray in section 3 and complete dispersion of the product in section 4 of the housing 1.

 With the periodic coincidence of the holes 10 of the rotor 9 and the holes 19 of the stator 18 in the presence of the latter, or continuously through the holes 10 in its absence, the gaseous coolant enters the film of the liquid product. The holes 10 in the shape of Laval nozzles or the presence of a stator 18 at the time of overlapping of the holes 10 provides a disruption of the flow of gaseous coolant at the outlet of the holes 10, accompanied by the formation and collapse of cavitation cavities with an ultrasonic frequency, especially intense when the abovementioned design features are combined. In the presence of swirls 11 or 20, the supersonic flow of gaseous coolant in a certain section of the trajectory has a barrel-shaped shape and creates regular shock waves, i.e., the second zone of generation of ultrasonic vibrations, intensifying heat and mass transfer processes at the concentration stage in section 3 and / or at the spray drying stage in section 4 housing 1.

 In section 3 of housing 1, when the gaseous coolant flow rate is not more than the value obtained by formula (1), its bubbles float in the liquid product film under the action of inertia and Archimedean buoyancy forces and when the field of centrifugal and friction forces is counteracted. Under such conditions, tangled flows occur in the liquid product film, and toroidal gas movement occurs in the bubbles, which ensures accelerated updating of the phase contact surface and intensive passage of heat and mass transfer processes. The spent coolant together with the vapor leaves the film of the liquid product, taking with it a small amount of spray. Sprays are collected by the blades 16 rotated together with the rotor 9 and filtered off on the surface of the exhaust pipe 12 and returned to the product film under the action of the centrifugal force field. The slip of the waste coolant saturated with vapors into the section 4 of the housing 1 is excluded by the formation of a hydraulic shutter at the disk 14, so it enters through the openings 13 into the exhaust pipe 12, through which it is removed from the device.

 The concentrate through the gap 15 enters the section 4 of the housing 1, where when the flow rate of the gaseous coolant is greater than the calculated value according to formula (1), it is completely dispersed and dried in the direct flow of the coolant. The field of centrifugal forces contributes to the release of large droplets from the flow and their return to the surface of the rotor 9. Small droplets that can give the necessary amount of moisture are dried in flight and removed together with the waste coolant flow from the device through the cavity of the axle shaft 8 for subsequent separation from the flow in the separators, for example, cyclone type.

 Thus, the proposed device allows, upon receipt of food powders from fluid products, to combine the concentration and spray drying operations sequentially carried out in a continuous flow while improving the quality of the finished product due to the intensification and acceleration of concentration and more uniform drying with increasing monodispersity during spray drying.

Claims (5)

 1. Device for producing food powders, characterized in that it contains a horizontal casing, divided by a vertical partition into two sections, containing coolant supply pipes, a hollow perforated rotor installed in it on two half shafts, an exhaust pipe passing through the cavity of one of the half shafts with an attached exhaust pipe at its end, a disk placed with a gap in the cavity of the rotor in the plane of the partition wall of the housing, and radial blades fixed with a gap in the rotor and placed in the section of the housing from the side Nia exhaust pipe.  2. The device according to claim 1, characterized in that the perforation holes of the rotor are made in the form of Laval nozzles in at least one of the sections of the housing.  3. The device according to claim 2, characterized in that the nozzle holes are equipped with swirlers installed at the inlets in at least one of the sections of the housing.  4. The device according to any one of claims 1 to 3, characterized in that it is equipped with at least one perforated stator located in the housing section in the contact area with the rotor, the perforation holes of which are located with the rotor perforation holes in the same planes along coaxial circles with unequal and in multiple circumferential steps.  5. The device according to claim 2, characterized in that it is provided with at least one located in the housing section in the contact zone with the rotor, in which the perforation holes of the rotor are made in the form of Laval nozzles, a perforated stator, the perforation holes of which are made with rotor perforation holes in identical planes along coaxial circles with an unequal and non-multiple circumferential pitch and equipped with swirlers installed in them.

Images