SU918749A1 - Dryer - Google Patents

Description

I

The invention relates to the technique of drying wet materials and can be applied in the food, chemical, medical, and especially in the microbiological industry for drying enzyme preparations and amino acids.

Spray dryers for thermolabile solutions and suspensions are known that contain a cylindrical chamber with sprays and gas distributors installed along its axis opposite one another, supply and discharge connections for heat-transfer agent and air-cleaning equipment.

However, heat and mass transfer in these dryers is not effective enough.

An acoustic spray dryer is also known, in which three-channel acoustic nozzles are installed in the spray zone to improve the mixing of the components. . combined with metering devices, a predetermined ratio of components and a uniform spray of liquid S2.

(54) DRYER

The disadvantages of this dryer are the moisture density of the drying volume, which leads to an increase in the dimensions of the dryer, especially when drying thermosensitive materials, when the heat transfer fluid has a low temperature, complexity and high cost of dispersing devices, the need to use additional means to prevent material from sticking. walls of the dryer.

Also known is a dryer containing a vertical gas path to create a vacuum, associated with the outlet

15 hole in the case of the feeder 3L

However, this dryer also has a number of significant drawbacks. Thus, the residence time of particles of a wet material in the gas path, which is

20 drying chamber, small due to the small linear dimensions of the Veituri tube. In addition, the material adheres to the walls because of the absence of a gradient of aavlenii in the cross section of the chamber. These factors explain the low intensity of the drying process in the above dryer. Closest to the proposed technical essence and the achieved result is a dryer containing a self-vacuuming vortex tube with a nozzle inlet of compressed gas, a diaphragm having a central hole to which a funnel is connected to suck the material being dried, and a slotted diffuser. The vortex tube also has a nozzle for the output of the holoz stream 4. However, this dryer has limited heat carrier flow and does not ensure stable weighing of the material layer. The purpose of the invention is the intensification of heat and mass transfer. The goal is achieved by the fact that the funnel is installed in the diaphragm with a gap for air leaks, and an air channel is made along the axis of the funnel, the diffuser being located on the side opposite to the nozzle inlet, and the diaphragm serves as the outer wall of the diffuser. 0 In addition, the central opening of the diaphragm can be located eccentrically relative to the longitudinal axis of the vortex tube. Such an embodiment of the dryer allows creating a vacuum in its central part, which intensifies the drying process at lower temperatures of the drying agent. The latter circumstance is especially significant when drying thermo-labile substances. Making the central aperture of the diaphragm eccentric relative to the longitudinal axis of the vortex self-vacuum tube creates a precision movement of the material, which also intensifies the heat exchange between the wet material and the drying agent. The presence of radial pressure drop in such a dryer prevents material from falling on its walls. The temperature separation of the drying agent prevents the material from overheating, which makes it possible to dry thermoablative substances in such a dryer. . FIG. 1 shows the proposed dryer, longitudinal section; FIG. 2 section A-A in FIG. 1. 94 Dryer for wet material contains a vertical samovacuum vortex located, pipe 1. It has a nozzle-lead-2 for the tangential supply of hot gas, a gas path 3 and a slit diffuser 4, with adjustable clearance, and the outer wall 1 of the diffuser serves as a diaphragm 6 having a central opening to which a funnel 7 is connected for introducing moist material with an axial air passage 8. The funnel 7 is installed in the central opening of the diaphragm 6 with a gap 9 for air leaks. Channel 8 is used to supply heated gas, which ensures the spin twisting. To this end, the central opening of the 6th and ka. The 8 eccentric of the relatively longitudinal axis of the vortex coarse one is located 1. The direction of the gas movement is indicated by arrows, and the direction of the movement of the material is indicated by dots. Drying wet gers is dried in a dryer in a drying manner. Drying agent: for example, hot air, under pressure above atmospheric, is fed tangentially through a copper inlet 2 of the vortex self. Vacuum tube 7 of the tube 1. Here a vortex flow forms, which spreads inside the gas path 3 in a spiral and out through the adjustable gap of the diffuser 4. At the same time, due to the occurrence of the vortex effect along the axis of the vortex tube 1, a vacuum zone is formed, and near the walls of the gas path 3 a zone of increased pressure. - The wet material from the funnel 7 enters the thinning zone of the vortex tube 1. Simultaneously with the ETSU, atmospheric air enters the same zone through the annular gap 9 and the heated gas through the axial channel 8. The vortex flow formed by the hot gas entering through the nozzle Input 2 twists the wet material along with atmospheric air and heated gas as it moves to the zone of maximum vacuum. In this case, there is an intense interaction of the oncoming vortex gas flows, and the humid one. material. This interaction is transient in nature and has a positive effect on the process of heat and mass transfer between the gas and the particles of the wet material. The amplitude of oscillation of a part of the wet material can be changed

by means of an adjustable gap 5 of the diffuser 4. In it, the kinetic energy of the vortex flowing out of it is converted into pressure energy, this provides a sharp decrease in pressure and a cooling of the axial gas layers. The eccentric position of the central hole 6 relative to the longitudinal axis of the vortex samovacuum tube 1 with axial marking of the outlet hole of the funnel .70 of channel 8 relative to the axis of the opening of the diaphragm 6 creates a radial unsteady irregularity of the axial flow of gas and wet material, which initiates the development of the auto-oscillation process. This increases the precession amplitude of the axial swirling flow, increases the level of pressure and velocity pulsations in the peripheral vortex, which contributes to the occurrence and generation of sound vibrations. This will also significantly intensify the process of heat and mass transfer inside the vortex samovacuum tube 1, which is a drying chamber.

In addition, near the walls of the path 3, they have an annular zone of increased pressure, which prevents the material from sticking to the walls of the gas path. The lighter dry material is caught in the peripheral layers of the gas and the adjustable gap 5 is carried away, and the heavy (more humid) material remains in the drying volume.

The proposed dryer allows us to significantly intensify the process of drying thermolabile materials, completely eliminating their sticking to the walls of the gas path. Due to the eccentricity of the central aperture of the diaphragm, it is possible to intensify the drying process by 10-15%. Taking into account the increase in the residence time of the particles of wet material in the drying volume, it is possible to further increase the efficiency of the proposed dryer. This dryer is especially economical and expedient when processing small amounts of thermolabile expensive materials.

Claims (4)

1. A dryer containing a self-vacuum ruddy vortex tube with a nozzle inlet of compressed gas, a diaphragm, a central opening, a funnel is connected to KOTopoiviy for suction of the material being dried, and a slot diffuser, characterized in that, in order to intensify heat and mass transfer, the funnel is installed in the diaphragm. an air channel is made for air suction and along the funnel axis, the diffuser being located on the side that extends to the positive nozzle inlet, and the diaphragm serves as the outer wall of the diffuser. 2. Dryer according to claim 1, characterized in that the central opening of the diaphragm is located eccentrically relative to the longitudinal axis of the pipe. Sources of information taken into account in the examination 1. USSR author's certificate number 469867, cl. F 26 B 3/12, 1973. 2. USSR author's certificate number 573685, cl. F 26 B 3/12, 1975. 3. Accepted for Japan No. 42-7OO26, cl. 69 C 3, published. 1972., 4. USSR author's certificate No. 211398, cl. F 26 B 3/10, 1966.