RU209701U1 - Mixer - Google Patents

Abstract

The utility model relates to a mixer for simultaneous mixing of Newtonian and structured homogeneous liquids and emulsions at macro and micro levels and can be used, for example, in the chemical, petrochemical, pharmacological, food industries. The mixer comprises a housing, a central high-speed agitator mounted on the drive shaft, a low-speed agitator and a fluid coupling with a driven half-coupling in the form of a cylindrical branch pipe fixed on the blades of the low-speed agitator. Moreover, the cylindrical branch pipe in the upper and lower parts is connected to the drive shaft by means of rolling bearings. The technical result of the proposed design of the mixer is to increase productivity. 1 ill.

Description

The utility model relates to the design of mixers for the simultaneous mixing of Newtonian and structured homogeneous liquids and emulsions at macro and micro levels and can be used in chemical, petrochemical, pharmacological, food and environmental processes for mixing liquid and gas-liquid waste during their recycling.

A known apparatus for mixing emulsions - the Mensing extractor, consisting of an outer cylinder body, axisymmetrically mounted on the body, and an inner cylinder, mounted on the deckhouses, supplying the secondary solvent and the source product to the blades of the high-speed mixer, mounted on the drive shaft, mounted on the housing cover [Strank F. Stirring and apparatus with agitators. - M. Chemistry, 1975, p. 322].

The reasons hindering the achievement of the desired technical result include insufficient productivity due to mixing only at the macro level, which reduces the mass transfer surface during extraction and the number of drops.

A known apparatus for improving large volumes of liquid and organizing its directed flow (with a large ratio of height to diameter of the apparatus), consisting of a housing, a shaft, a propeller and a diffuser. The diffuser is a short cylindrical or conical glass, inside which a stirrer is placed (Kasatkin A.G. Processes and apparatuses of chemical technology, Edition 8, revised. - M.: Chemistry, 1971, p. 209).

The reasons hindering the achievement of the desired technical result include the rigid fastening of the diffuser to the walls of the housing, which leads to the occurrence of stagnant zones near the side walls and bottom of the housing, reduces the intensity and efficiency of mixing near the fixed walls and the bottom of the housing, as well as outside the stationary diffuser itself, especially when mixing structured high-viscosity and non-Newtonian liquids, and the operation of the stirrer contributes to mixing mainly at the macrolevel, which reduces the rate of heat and mass transfer processes and leads to a decrease in productivity.

Known mixer design, selected for the prototype, containing a housing, a central high-speed mixer mounted on the drive shaft, a low-speed mixer equipped with a float made in the form of a torus, rigidly fixed in its upper part, and installed coaxially with the housing, and a fluid coupling, the driven coupling half of which is fixed on the blades of a low-speed agitator, made in the form of a cylindrical pipe and installed axisymmetrically with the shaft, and the leading half-coupling, having the shape of a cylinder rigidly fixed to the shaft (Utility Model Patent RF No. 109010, B01F 7/16, 2011).

The reasons hindering the achievement of the desired technical result include mixing mainly at the macro level, which reduces the number of drops and their surface, and therefore reduces the intensity of the formation of a homogeneous homogenized liquid phase, the number and surface of microdroplets and, as a result, leads to low productivity.

The technical result of the proposed design of the mixer is to increase productivity.

The stated technical result is achieved by the fact that in a mixer containing a housing, a central high-speed agitator mounted on a drive shaft, a low-speed agitator and a hydraulic coupling with a driven half-coupling in the form of a cylindrical pipe mounted on the blades of a low-speed mixer, the cylindrical pipe in the upper and lower parts is connected to drive shaft through rolling bearings.

The connection of the cylindrical branch pipe in the upper and lower parts with the drive shaft by rolling bearings ensures the flow of liquid phases of the emulsion or gas-liquid phases of heterogeneous systems circulating inside the cylindrical branch pipe, due to the pumping effect, is additionally intensively mixed at the micro level in the rolling bearing separators during their rotation. This reduces the size of the heterogeneous phase (droplets or gas bubbles), increases their number and heat and mass transfer surface, which contributes to productivity growth.

In FIG. 1 shows the proposed mixer design in section.

The mixer includes a housing 1 with a cover 2 (the motor is not shown in the drawing) connected to the shaft 3, on which a high-speed propeller mixer 4 is installed, which acts as a driving coupling half. Axially symmetrically with the propeller mixer 4, a transverse blade 5 of a frame (for example, anchor) mixer 6 is installed, to which a cylindrical pipe 7 is attached. the lower parts are connected to the shaft 3 by rolling bearings 8. In the cover 2, a branch pipe 9 is installed for introducing mixed liquids, and in the housing 1, a branch pipe 10 is installed in its lower part to drain liquids mixed at macro- and microlevels from the housing 1.

The mixer works as follows. The original liquid for mixing is supplied through the branch pipe 9 in the housing 1, and the mixed liquid is discharged from the housing 1 through the branch pipe 10. The drive is turned on, the shaft 3 with a high-speed propeller mixer 4 begins to rotate, creating a mixing zone in the central part of the housing 1. Torque transmitted from the shaft 3 to the frame (anchor) low-speed mixer 6 through the cylindrical pipe 7 and the transverse blade 5, creates a mixing zone in the peripheral (side and bottom) parts of the body 1, that is, the frame (anchor) low-speed mixer 6 creates mixing at the macro level, and the propeller high-speed mixer 4 creates mixing at the macro and partially micro level as in the prototype. Rolling bearings 8 serve to intensify the micro level of mixing. They work as follows. The high-speed propeller agitator 4 creates a pumping effect during rotation, which forms flows of agitated liquid in a cylindrical pipe 7, directed from bottom to top (shown in the figure by arrows). These macroflows of liquid, falling into the rotating cages of rolling bearings, are crushed by them into small drops (gas bubbles), forming a microdispersed phase with a large heat and mass transfer surface, leading to the intensification of these processes, and hence an increase in productivity.

Example. Comparison of the efficiency of micromixing in the mixer of the proposed design and in the prototype [Strank F. Mixing and apparatus with mixers. - M. Chemistry, 1975, p. 322].

Given: The number of revolutions of the high-speed agitator shaft: n=100 rpm.

Then the angular velocity of rotation:

The inner diameter of the rotating cage of the ball bearing (roller bearing) d _in \u003d 200 mm, and the diameter of the inner track in which the balls (rollers) rotate D _in \u003d 216 mm (δ \u003d 8 mm) with a diameter of balls (rollers) d \u003d 16 mm, then linear the speed of rotation of the balls (rollers) [Anuryev V.I. Handbook of the designer of the machine builder: in 3 volumes - 9th ed., Revised. and additional ./ ed. I.N. Rigid. - M.: Mashinostroenie, 2006. - 928 p.]:

With a gap between balls (rollers) separated by separators equal to:

z=6 mm=0.006 m.

Average velocity gradient:

The first factor, equal to 2, takes into account the opposite direction of the vectors υ of adjacent balls (rollers).

Compare the obtained average velocity gradient between the balls (rollers) of the rotation bearing with the average velocity gradient in an apparatus with a propeller stirrer and a diffuser (cylinder sleeve), that is, with the velocity gradient in the prototype.

The inner diameter of the diffuser, in which the outer race of the bearing is mounted:

d _n \u003d D _in + d + 2⋅δ \u003d 0.216 + 16 + 2 ⋅ 8 \u003d 0.248 m.

With the diameter of the apparatus D _a = 0.6u and the span of the propeller mixer blades d _m = 0.2 ⋅ D _a = 0.2 ⋅ 0.6 = 0.12 m.

In the gap between the wall of the cylindrical pipe and the edge of the blade of a high-speed propeller mixer rotating at an angular velocity ω=10.46 s ^-1 , the linear velocity of the mixer blades

Then the average velocity gradient in the prototype is:

where

Thus, the average velocity gradient in the separator between the balls (rollers) in the proposed design is greater than the average velocity gradient in the prototype:

Accordingly, micromixing of macroflows of the stirred liquid in the separator between the balls (rollers) of the rolling bearing occurs 32.3 times more intensively than in the annular gap between the wall of the cylindrical pipe and the blades of the propeller mixer in the patent selected for the prototype.

For non-Newtonian fluids, an increase in the velocity gradient leads to a decrease in the effective viscosity, which means that it contributes to even greater thinning and micromixing.

Thus, the connection of the cylindrical branch pipe 7 in its upper and lower parts with rolling bearings 8 with the drive shaft 3 provides micromixing of the agitated liquids in the rotating separators of these rolling bearings 8 while filtering the agitated liquid through the separators pumped inside the cylindrical branch pipe 7 from the bottom up due to the pumping effect high-speed propeller agitator 4.

This leads to an increase in the volume of mixing at the micro level, the intensification of the micromixing process itself, and generally contributes to an increase in productivity.

Claims (1)

A mixer comprising a housing, a central high-speed agitator mounted on a drive shaft, a low-speed agitator and a hydraulic coupling with a driven half-coupling in the form of a cylindrical pipe mounted on the blades of the low-speed agitator, characterized in that the cylindrical pipe in the upper and lower parts is connected to the drive shaft by means of rolling bearings .

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