Silver son Emulsifier and liquid liquid mixing
Silver son emulsifier is used for mixing or homogenizing coarse particles in the emulsion and suspension to the fine form of reduced particles. Its capacity ranges from Imp up to 12 liters, and its ability to mix in-line with flow rates is up to 201t/min.
Principle
Silver son emulsifier works on the principle of shearing forces and turbulence produced by the high-speed rotors. The fluid passes through fine spaces formed by closely placed perforated metal sheets under the influence of turbulence. The material circulates through the head by the suction produced in the inlet at the head bottom. As the material circulates, the dispersed fluid rapidly breaks down into smaller globules.
Construction
Silverson emulsifier consist of long supporting columns connected to a motor providing support to the head. It has a centrally located shaft with one end connected to the motor and the other end connected to the head. Turbine blades are present in the head. These blades are surrounded by a mesh enclosed by a cover having openings.
Working
The head of Silver son emulsifier is placed in the vessel (containing immiscible fluid or coarse emulsion) in such a way that it gets completely immersed in the fluid. On Electric starting the motor, the central rotating shaft motor rotates the head at a very high speed, which further rotates the turbine blades at the same speed; thus, creating a pressure difference. As a result, fluid in the center of the base is sucked into the head and subjected to intense mixing action. The silverson mixer homogenizers contents of the head are forcefully expelled through the mesh and onto the cover by the centrifugal Stand forces. A fine emulsion is obtained through the openings of the outer cover. This intake and expulsion of mixture set up such an Emulsifying circulation pattern that the bigger line mixers globules rapidly breakdown into smaller ones.
Use
It is used for mixing creams. ointments, sauces, flavoring emulsions, and pharmaceutical suspensions of globule or droplet size ranging from 2-5B.
Merits
Silver son emulsifier has the following merits:
1) It is available in different sizes, thus making handling of liquids ranging from a few milliliters to several thousand liters possible.
2) It is a batch process; but it can also be used for continuous operation by incorporating it into a pipeline through which the immiscible liquids flow.
3) It yields emulsions in the range of 0.5-5g.
4) Its high shear action rapidly disperses gums, alginates, CMC, Carbopol’s, etc., forming an agglomerate-free solution in a short time.
5) It can disintegrate matter of animal, vegetable, mineral, or synthetic origin.
6) It rapidly yields a homogeneous product when liquids of similar or greatly varying viscosities are being blended.
7) Its mixing action reduces the process time and also reduces the mixing time by up to 90%.
8) Its versatility makes it capable of performing a wide range of mixing applications.
Demerits
Silver son emulsifier has the following demerits:
1) Clogging of mesh pores may occur.
2) It consumes high operating power.
3) It requires high shear force.
Mostly liquid-liquid and sometimes liquid-solid mixing processes are carried out using a propeller or a turbine in a tank. In liquid-liquid mixing, the liquid system contains any one of the following liquids:
1) Liquids with or without non-viscous solids, e.g., light oils.
2) Liquids with or without viscous and pourable solids, e.g., heavy oils and paints.
3) Liquids with solids forming stiff pastes, e.g., oil-bound distempers.
The agitated vessel in which an agitator is fixed in a vertical tank is the normal form of equipment. The diameter of the impeller is one-third of the diameter of the tank, and the height of the vessel is 1.5 to 2 times the diameter.
It is important to note that mixing and agitation are not the same. Mixing of two or more phases of different liquids into and over one another for random dispersal is called mixing; whereas the induced circular motion of the material within a tank or vessel is called agitation.
Types of Liquid-Liquid Mixing
Liquid mixing may be divided into the following two sub-groups:
1) Mixing of liquids and liquids:
i) Mixing of two miscible liquids, and
ii) Mixing of two immiscible liquids.
2) Mixing of liquids and solids:
i) Mixing of liquids and soluble solids, and
ii) Mixing of liquids and insoluble solids.
The mixing types listed above are discussed below:
1) Mixing of Two Miscible Liquids (Homogeneous Mixtures, e.g., Solutions): This type of mixing easily takes place through diffusion. Electric stirrer might be needed if liquids have unlike viscosities or they are not readily miscible, otherwise simple stirring or shaking is sufficient. In both the liquids of mixture, turbulence might occur occasionally.
2) Mixing of Two Immiscible Liquids (Heterogeneous Mixtures, e.g., Emulsions): Transfer of a dissolved material from one fluid to another is affected by this type of mixing; for example, for emulsion preparation, for Pr0moting a chemical reaction after component transfer, or to allow heat transfer from one liquid to another laboratory mixers occurs when penicillin is extracted in acidic form into amyl nitrate (an organic solvent) from aqueous solution. emulsifier ion is generally formed by mixing two immiscible liquids together the Presence of an emulsifying agent. A stable emulsion can be obtained by carrying out mixing continuously and efficiently; otherwise, the compose of mixture will separate.
3) Mixing of Liquids and Soluble Solids (Homogeneous mixtures, e.g., Solutions): In this type of mixing, soluble solids are solubilized in an appropriate solvent through stirring. A solution is formed by solubilizing the soluble solid via physical alteration
4) Mixing of Liquids and Insoluble Solids (Heterogeneous Mixtures, e.g., Suspensions): By mixing insoluble solids with a liquid, an Unstable suspension is obtained whose español português ingredients separate out on standing for some time. A stable suspension can be obtained with the use of a suspending agent. Mortar and pestle are used for making suspensions on a small scale.
Mechanism of Liquids Mixing
The mechanism involved in the mixing of liquids can be described under four classes. Generally, more than one mechanism is practically involved in the mixing process:
1) Molecular Diffusion: The prime mechanism involved in the mixing of molecules is diffusion due to their thermal motion. When diffusion and the laminar flow are combined together, the sharp discontinuities formed at the interface between the two fluid layers tend to reduce due to the effect of molecular diffusion. If this is allowed to take place for a longer time period, complete mixing can be achieved. This whole process can be quantitatively expressed in terms 日 本 語 of Fick 's law of diffusion:
dm/dt = — DA dc/dx
Where, dm/dt = Rate of transport of mass across an interface of area A, which is directly proportional to the concentration gradient across the interface (dc/dx).
Diffusion coefficient (D) which is a function of variables like fluid viscosity and size of the diffusing molecules, governs the rate of intermingling. The difference in the concentration at the original boundary is a decreasing function of time approaching zero as the process of mixing approaches
2) Bulk Transport: It involves to the movement of a large amount of material to be mixed from one position to another in the system. To achieve efficient mixing of the bulk material, simple circulation in a mixer is not sufficient; therefore, different of the material are rearranged and transformed from one location to another to be mixed properly. This can be achieved with the help of revolving blades, paddles, or other devices fixed inside the mixer to facilitate the movement of adjacent volume of the fluid in various directions, thus, shuffling the whole system in three directions.
3) Turbulent Mixing: The turbulent flow of liquid means random fluctuation of the fluid velocity in the system at any given point; thus, resulting in the phenomenon of turbulent mixing. At any given point, the fluid velocity can be defined as the vector sum of its components in the x, Y, and z directions. With the effect of turbulence, the directional components fluctuate randomly along their individual mean values, similar to that of the velocity(اللغة العربية).
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