Tang Lian Chemistry


Selection of glass-lined stirrer

(1) anchor (frame) agitator role of glass-lined store, frame agitator belongs to the same type of agitator, can only be considered as a frame is the wrong type of enhancement.

This type of agitator is adapted to the mixing of high-viscosity materials, the container can make the overall material stirring and less dead space. The main function of the agitator on the fluid is shear, due to the mixing anchor, frame diameter, wrong, frame outside near the inner wall of the container, rotating similar to the role of the wall, can thin the inner wall of the container of the liquid laminar boundary layer, is conducive to improving the effect of the jacket heat transfer.

This type of stirrer is generally designed for low-speed stirring, speed ≤ 80t/min, the liquid in the laminar flow state, belongs to the mild type of stirring. Used in the coarse crystallization process, is conducive to grain growth, improve the yield of crystals in the next process of filtration. At the same time it is suitable for heat transfer operations, to a certain extent, to improve the material and the container wall between the heat coefficient (α2), the liquid-liquid dispersion operation, the choice of this type of stirrer is more appropriate.

(2) The role of impeller type (three blades after the shock type) agitator  

Glass-lined standard called impeller stirrer (international commonly known as the three-blade after the swept type). Characterized by: simple structure, strong output performance, small power consumption, wide range of adaptability, to ensure the overall circulation of the fluid container (also known as the volume of the ring), is the current low viscosity material is more suitable for the agitator type.

The agitator is to make the fluid in the blade to promote, produce circumferential movement, and make the fluid in the shear effect of the time piece, promote the refinement of bubbles and droplets, mixing, expanding the contact surface, speed up the heat transfer, mass transfer process.

When rotating, the head of the blade will produce centrifugal force on the liquid, put the liquid to the container wall, form upward and downward circulation liquid flow, and improve the heat coefficient α2 between the liquid and the jacket wall.

Impeller mixer, when the speed of 130r/mim, the circulation is larger and consumes less unit power, a wide range of adaptability, mainly used in non-Newtonian fluid mixing (i.e., the medium in the operation process of viscosity changes in the fluid).           

Impeller mixer with appropriate folding plate, suitable for mixing, thermal conductivity, polymerization, emulsification, gas absorption and suspension and other process operations, can be less power to achieve effective stirring effect, in the reaction, the viscosity of the material will rise faster, and the increase in the stirring power is relatively small, therefore, the mixing of the polymerization is suitable for viscosity rise occasions. The mixing of the liquid in the container to produce up and down circulation is particularly significant, so that it is mixed uniformly, and the unit of power emission is large, so that the liquid has a larger volume of the circulation rate and the 耑 flow intensity, suitable for the requirements of strong turbulent mixing occasions.

In short, glass-lined impeller stirrer for homogeneous mixing, solid-liquid suspension, gas-liquid mixing, non-homogeneous dispersion and other operations have a better effect, which is characterized by: the formation of a larger volume of circulation, there is a certain degree of shear effect of the strong type of stirring pieces.

(3) the role of paddle stirrer  

Sugar glass standard paddle stirrer for the two blocks of straight or folded blade, the number of paddles for 4, is a radial mixing, straight blade of the liquid in the container to form a radial flow effect, if it is a folded blade, will make the liquid in the container to form a radial flow is mainly accompanied by the effect of axial flow.

Stirrer speed is generally 80r/min and 125r/min, belongs to the slow speed stirring, paddle stirring mainly on the liquid in the container to produce a large shear. If equipped with the appropriate baffle, will obtain a certain degree of liquid upward and downward discharge effect. However, the stirring liquid convective external poor, generally applicable to low-viscosity materials dispersion crystallization operation.

(4) the role of axial stirrer

The type of glass-lined stirrer is not included in the glass product standards, in recent years, the user has increased significantly. Due to the development of chemical medicine, the user of the stirrer stirring effect and energy saving is very important. This type of stirrer is characterized by the liquid volume circulation rate in the container, the unit volume of the material section of the power consumption is small, is currently a new type of glass-lined products in the stirrer.

The stirrer is mainly used for solid particles suspended, solid dissolution, gas dispersion in the liquid and gas is absorbed by the liquid, not mutually dissolved liquid mixing, liquid emulsification, suspension polymerization, liquid mixing and other processes, especially for solid-liquid suspension operation, power consumption is small.

Axial stirrer stirring liquid flow is a large volume cycle, with a uniform distribution and mild shear function. Paddle pumping ability is stronger, can produce uniform axial liquid flow, can be faster in addition to the container of two or more kinds of material concentration and temperature inhomogeneity, in order to quickly achieve the purpose of uniformity.


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