I don’t tell ordinary people about these things about the blender.

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When fluid flows in pipelines, there are three states: laminar flow, transitional flow, and turbulent flow. These three flow states also exist in mixing equipment, and one of the main parameters that determines these states is the viscosity of the fluid (referring to the fluid's resistance to flow. Therefore, we will use a stirrer in the mixing equipment. 1 Principle and flow pattern principle: When the agitator rotates, it transfers mechanical energy to the fluid, forming a high-turbulence and sufficient mixing zone near the agitator, and generates a high-speed jet to push the liquid to circulate in the mixing container. Flow pattern The flow pattern is closely related to the stirring effect and stirring power. The improvement of agitators and the development of new agitators often start from the flow pattern. Three basic flow patterns of the top-mounted center-mounted vertical cylinder of the mixer: Radial flow, axial flow and tangential flow. The flow direction of radial flow fluid is perpendicular to the stirring axis and flows along the radial direction. When it encounters the wall of the container, it is divided into two streams of fluid flowing upward and downward respectively, and then returns to the blade end without passing through the blade, forming two circular flows, one up and one down. The flow direction of the axial flow fluid is parallel to the stirring axis. The fluid is pushed by the paddles, causing the fluid to flow downward. When it encounters the bottom of the container, it turns upward to form an up and down circulation flow. The flow direction of the tangential flow fluid is parallel to the stirring axis. The fluid is pushed by the paddles, causing the fluid to flow downward. When it encounters the bottom of the container, it turns upward to form an up and down circulation flow. 2 How the mixer is installed in the container 3 Classification of the mixer 1 Propeller mixer The propeller mixer is a widely used axial flow type high-performance mixer with discharge performance and low shear force. It is a convection circulation state at low speed and a turbulent flow state at high speed. The larger blade inclination angle and blade twist allow the agitator to achieve a higher flow field in transitional flow or even turbulent flow, and its liquid drainage capacity is 30% higher than that of traditional propeller agitators. Suitable for low viscosity mixing, dissolution, solid suspension, heat transfer, reaction mass transfer, extraction, and crystallization operations. 2 Turbine agitator Turbine agitator (also known as turbine impeller) is a widely used agitator. It can effectively complete almost all mixing operations and can handle fluids with a wide range of viscosity. It consists of 2 to 4 straight or curved blades installed on a horizontal disk. The speed of the turbine agitator is relatively high, 300~600r/min. The main advantage of the turbine mixer is that when the energy consumption is not large, the mixing efficiency is high, and the mixing produces strong radial flow. It has a large shear force and can disperse fluid microclusters very finely. It is suitable for mixing low to medium viscosity fluids, liquid-liquid dispersion, liquid-solid suspension, and promoting good heat transfer, mass transfer and chemical reactions. 3-paddle mixer The paddle mixer has the simplest structure. The blades are made of flat steel and are welded or fixed on the hub with bolts. The number of blades is 2, 3 or 4. The blade forms can be divided into straight blades and folded blades. That is, according to the shape characteristics of the blades, they can be divided into flat paddle mixers and inclined paddle mixers. The flat paddle mixer produces radial force, while the inclined paddle mixer produces axial force. The paddle mixer is suitable for mixing low-viscosity liquids, suspensions and dissolved liquids. application: 1. In the liquid-liquid system, it is used to prevent separation and make the temperature of the tank uniform. In the solid-liquid system, it is mostly used to prevent solid settlement. 2. Mainly used for fluid circulation. Because under the same displacement, the folding blade type consumes less power and has lower operating costs than the straight blade type, so axial flow blades are used more often. 3. It is also used for stirring high-viscosity fluids to promote the exchange of fluids up and down. It can replace the expensive spiral belt impeller and achieve good results. 4 Anchor-type mixer The anchor-type mixer has a simple structure and is suitable for mixing fluids with a viscosity below 100Pa·s. When the fluid viscosity is between 10 and 100Pa·s, a horizontal blade can be added in the middle of the anchor paddle, which is a frame-type mixer, to increase mixing in the container. Special frame anchor stirrer This type of stirrer is a slow-speed stirrer, which is often used in processes such as mixing medium and high viscosity liquids, heat transfer reactions, etc. 1. The anchor frame type (MKS) can obtain large shear force along the wall when rotating at low speed, which can prevent settlement and wall adhesion. The bottom shape fits the oval tank and the bottom bearing in the middle. 2. Anchor belt type (MDS) is a combination of ribbon and frame type, which combines the functions of ribbon and frame agitators. 3. Square frame type (FKS) and square grid type (FSS) are simple in shape and easy to make. The performance is the same as that of the frame type. They are more suitable for mixing and dissolving with medium viscosity. 4. Plate and frame type (BKS) is a high-efficiency mixing impeller with a wide viscosity range. The impeller has a simple structure. The projected area of ​​the impeller on the longitudinal section of the mixing tank accounts for a large proportion of the longitudinal section area of ​​the tank. It has high mixing efficiency and large shear force, and is suitable for solid-liquid suspension, liquid-liquid dispersion, and gas-liquid mass transfer and heat transfer operations where gas is sucked from the liquid surface. 5 Ribbon mixer The blades of the ribbon mixer are in the shape of ribbons. The number of ribbons is two to three, which are installed on the screw in the center of the mixer. The pitch of the ribbon mixer determines the outer diameter of the ribbon. Ribbon mixers usually operate in a laminar flow state and are suitable for mixing high-viscosity liquids and pseudo-plastic fluids. 6. Frequency conversion double-layer mixer. Frequency conversion double-layer mixer. The base, support rod and motor of the frequency conversion mixer are fixed into one body using patented technology. Patented chuck, no looseness, no swing, no falling off, safe and reliable. Chrome-plated struts, thick at the bottom and thin at the top, have strong rigidity and reasonable structure. It has the advantages of easy movement and light weight. It is suitable for all kinds of small containers. 7 Side-entry mixer The side-entry mixer installs the stirring device on the side wall of the equipment cylinder. The agitator on the mixer usually adopts axial flow type, mostly push-type mixer. It can obtain the highest mixing effect under the same power consumption. The power consumption is only 1/3 to 2/3 of the top stirring, and the cost is only 1/4 to 1/3 of the top stirring. The rotation speed can be between 200~750r/min. It is widely used for desulfurization, denitrification and mixing of various large storage tanks or tanks. Especially when one or more side-entry mixers are used to work together in large storage tanks or tanks, good mixing effects can be obtained with low energy consumption. 4. Mixer selection 1. Select according to the purpose of stirring. Recommended form of baffle conditions for mixing. Mixing of miscible liquids in flow state and chemical reactions therein. Baffleless three-blade hinged turbine, six-blade hinged open turbine, paddle type, disc turbine. Turbulent flow (low viscosity fluid). Three-blade hinged turbine with guide tube, six-blade hinged open turbine, pusher type with or without guide tube. Paddle type, screw type, frame type, ribbon type, anchor type laminar flow (high viscosity fluid). Solid-liquid phase dispersion, dissolution and chemical reaction in it, with or without baffles, paddle type, six-blade hinged open turbine turbulent flow (low viscosity fluid) with guide tube, three-blade hinged turbine, six-blade hinged open turbine, pusher type with or without guide tube, ribbon type, screw type, anchor type laminar flow (high viscosity fluid) Liquid-liquid phase dispersion (mutually miscible liquids) and in which mass transfer and chemical reactions are enhanced, there are baffled three-blade hinged turbines, six-blade hinged open turbines, paddles, disc turbines, propelled turbulence (low viscosity fluids) Liquid-liquid phase dispersion (immiscible liquids) and in which mass transfer and chemical reactions are enhanced, there are baffled disc turbines, six-blade hinged open turbines turbulent flow (low viscosity fluids) Three-blade hinged blade turbine with reflector, three-blade hinged blade turbine with guide tube, six-blade hinged blade open turbine, propeller type with or without guide tube, ribbon type, screw type, anchor type laminar flow (high viscosity fluid) gas-liquid phase dispersion and enhanced mass transfer and chemical reaction in it, baffle disc turbine, closed turbine turbulent flow (low viscosity fluid) Three-blade hinged blade turbine with reflector, three-blade hinged blade turbine with guide tube, six-blade hinged blade open turbine, propeller type with guide tube, screw type laminar flow (high viscosity fluid), anchor type without guide tube, ribbon type 2. Select the propeller mixer according to the mixer type and applicable conditions - used for mixing low-viscosity fluids, with strong circulation capacity and low power consumption, and can be applied to large-volume mixing containers. Turbine mixer - has a wide range of applications and is suitable for various mixing operations, but the fluid viscosity should not exceed 50 Pa·s. Paddle mixer - has a simple structure and is widely used in mixing small-volume fluids. However, it has insufficient circulation capacity for mixing large-volume fluids. Anchor type, screw type, ribbon type - suitable for mixing high-viscosity fluids 3. Select the mixer according to different processes. The main control factors of the mixing process are the mixer type mixing (low viscosity homogeneous liquid) circulating flow push type, turbine type. When the requirements are not high, paddle type mixing (high viscosity liquid) ① Circulating flow ② Low speed turbine type, anchor type, frame type, spiral type Belt type, paddle type with baffle type dispersion (heterogeneous liquid) ① Droplet size ② Circulating flow turbine type solution reaction (mutual solution system) ① Turbulence intensity ② Circulating flow turbine type, propelling type, paddle type solid suspension ① Circulating flow ② Turbulence intensity is determined by the size, content and density of the solid particles. Paddle type, propelling type or turbine type solid dissolution ① Shearing effect ② Circulating flow turbine type, propelling type, paddle type gas absorption ① Shearing effect ② Circulating flow ③ High speed turbine crystallization ① Circulating flow ② Shearing effect ③ Low speed using turbine type, paddle type or paddle type deformation heat transfer according to control factors ① Circulation Flow rate ② High flow rate on the heat transfer surface Paddle type, push type, turbine type 5 Measures to improve the mixing effect 1. Install baffles Installing baffles can not only increase the turbulence of the liquid, but also change the tangential flow into axial and radial flow to prevent the swirling phenomenon. After the baffle is installed, the concave phenomenon of the liquid level basically disappears, and the liquid flow in the kettle forms turbulent flow, which significantly improves the mixing effect. 2. Eccentrically installed agitator The eccentric or eccentric and tilted installation of the agitator can not only destroy the symmetry of the circulation path and effectively suppress the swirling phenomenon, but also increase the turbulence of the liquid to improve the mixing effect. 3. Set up the guide tube. The guide tube is a cylindrical body. Its function is to make the liquid discharged from the blade form an axial circulation flow inside and outside the guide tube. The guide tube can limit the flow path of the liquid in the kettle, forcing the liquid in the kettle to pass through the strong mixing zone in the guide tube, which not only improves the circulation flow and mixing effect, but also helps eliminate short circuits and flow dead zones.