A vacuum mixing tank is a homogenization equipment mainly composed of a water bath heating vacuum mixing tank, a buffer tank, and a tube condenser tank. The tank can withstand certain positive and negative pressures. The vacuum mixing tank body is a three-layer structure, with a heating medium layer between the inner and middle layers, which can be filled with hot water or steam to heat the materials inside the tank. The middle and outer layers are made of high-efficiency insulation materials, which do not affect the ambient temperature. The vacuum mixing tank is made of stainless steel and meets GMP requirements. It has the characteristics of compact structure, smooth and uniform mixing, and low noise. Vacuum mixing tanks are widely used in industries such as pharmaceuticals, food, and fine chemicals as heating and homogenization equipment. Especially suitable for the sol process in the production of soft capsules.
Below, the editor will briefly introduce the types of vacuum mixing tanks, as follows:
1. Magnetic heating mixer: The Corning digital heating mixer comes with an optional external temperature controller (Cat. No. 6795PR), which can also monitor and control the temperature inside the container.
2. Turbine agitator: composed of 2-4 straight or curved blades installed on a horizontal disk (Figure 3). The ratio of the outer diameter, width, and height of the blade is generally 20:5:4, and the circumferential velocity is generally 3-8m/s. Turbine generates highly turbulent radial flow during rotation, suitable for the dispersion of gases and immiscible liquids, as well as liquid-liquid phase reaction processes. The viscosity of the stirred liquid generally does not exceed 25 Pa · s.
3. Paddle mixer: There are two types: flat paddle and inclined paddle. The flat blade agitator consists of two straight blades. The ratio of blade diameter to height is 4-10, and the circumferential velocity is 1.5-3m/s, resulting in a relatively low radial flow velocity. The two blades of the inclined blade agitator (Figure 4) are folded at opposite angles of 45 ° or 60 °, resulting in axial liquid flow. The paddle agitator has a simple structure and is commonly used for mixing low viscosity liquids and dissolving and suspending solid particles.
4. Spiral propeller agitator: composed of 2-3 propeller blades (Figure 2), with a high working speed and a circumferential velocity of 5-15m/s at the outer edge of the blades. The rotary blade agitator mainly causes axial liquid flow and generates a large circulation volume, suitable for stirring low viscosity (<2Pa · s) liquids, emulsions, and suspensions with solid particle content less than 10%. The rotating shaft of the mixer can also be inserted horizontally or diagonally into the groove, and at this time, the circulation loop of the liquid flow is asymmetric, which can increase turbulence and prevent liquid level depression.
5. Anchor mixer: The outer edge shape of the blade should be consistent with the inner wall of the mixing tank (Figure 5), with only a small gap between them, which can remove viscous reaction products attached to the tank wall or solid matter accumulated at the bottom of the tank, and maintain good heat transfer effect. The peripheral velocity of the blade edge is 0.5-1.5m/s, which can be used to stir Newtonian and quasi plastic fluids with viscosity up to 200Pa · s (see viscous fluid flow). However, when stirring high viscosity liquids, there is a large stagnant zone in the liquid layer.
6. Spiral belt agitator: The outer diameter of the spiral belt is equal to the pitch (Figure 6), specifically used for stirring high viscosity liquids (200-500 Pa · s) and quasi plastic fluids, usually operated in laminar flow.
7. Magnetic stirrer: The Corning digital heater comes with a closed loop knob to monitor and adjust the stirring speed. The microprocessor automatically adjusts the motor power to adapt to water quality, viscous solutions, and semi-solid solutions.