Chemical mixer- Purpose
Mixing materials evenly, enhancing heat and mass transfer, stirring equipment is an indispensable device.
Mainly used for mixing homogeneous substances, including liquid-liquid dispersion, gas-liquid dispersion, solid-liquid dispersion; crystal; Strengthen heat transfer, etc.

Chemical mixer—Blade selection

Paddle stirrer

The structure is simple, and the blades are made of flat steel, welded or fixed to the hub with bolts. The number of blades is 2, 3 or 4, and the blade form can be divided into two types: straight blade and folded blade.

The rotational speed of a paddle mixer is generally between 20 and 100 r/min, with a high viscosity of 20 Pa · s. Cannot be used for gas-liquid dispersion operations aimed at maintaining gas and achieving refinement.

Chemical mixer- Application

In liquid-liquid systems, it is used to prevent separation and make the temperature of the tank uniform, while in solid-liquid systems, it is mostly used to prevent solid settling.

The circulation of fluids, due to the lower power consumption and operating costs of the folded blade type compared to the flat blade type at the same displacement, results in the use of more axial flow blades.

Stirring high viscosity fluids promotes up and down exchange of fluids, replacing expensive helical impellers and achieving good results.

propeller agitators

Propulsion mixers (also known as marine thrusters) are commonly used in low viscosity fluids.

The standard propeller mixer has three blades with a pitch equal to the propeller diameter d. It has a smaller diameter, d/D=1/4～1/3， The blade tip velocity is generally 7-10 m/s, with a maximum of 15 m/s.

During stirring, the fluid is sucked in from above the blade and discharged in a cylindrical spiral shape from below. The fluid reaches the bottom of the container and then returns along the wall to above the blade, forming an axial flow. The turbulence level of the fluid during stirring is not high, the circulation volume is large, the structure is simple, and the manufacturing is convenient. Good cycling performance, minimal shear effect, belonging to the cycling type agitator.

In situations with low viscosity and high flow rate, using smaller stirring power can achieve better stirring effect. Mainly used for liquid-liquid mixing, achieving uniform temperature, and preventing sediment settling in low concentration solid-liquid systems.

turbine agitator

Turbine agitator (also known as turbine impeller) is a widely used agitator that can effectively complete almost all mixing operations and handle fluids with a wide viscosity range.
Turbine agitator has a large shear force, which can disperse fluid micro clusters very finely, suitable for mixing, liquid-liquid dispersion, liquid-solid suspension of low to medium viscosity fluids, as well as promoting good heat and mass transfer and chemical reactions.

anchor stirrer

The structure is simple. Suitable for stirring fluids with viscosity below 100Pa · s. When the fluid viscosity is between 10-100Pa · s, a transverse blade can be added in the middle of the anchor blade, which is a frame stirrer, to increase mixing in the middle of the container.

The mixing effect of anchor or frame propeller blades is not ideal and is only suitable for situations where mixing requirements are not too high.

Due to the higher flow velocity near the container wall compared to other agitators, anchor agitators are commonly used for heat transfer and crystallization operations, as they can achieve a larger surface heat transfer coefficient.

Commonly used for stirring high concentration slurries and settling slurries. When stirring fluids with a viscosity greater than 100 Pa · s, spiral or screw type should be used.

Tank size
When the volume is constant, the larger the aspect ratio, the larger the surface area, which is more conducive to heat transfer; And at this time, the closer the heat transfer surface is to the center of the tank, the greater the temperature gradient of the material, which is conducive to the heat transfer effect. Therefore, from the perspective of jacket heat transfer alone, it is generally desirable to have a larger aspect ratio.

packing seal