Static Mixers

Static mixers can be applied to a wide range of process operations, including dosing, dispersion, laminar flow heat exchange and emulsion formation. They offer many key benefits for combining liquids, gases and powders and they are tried, tested and trusted in many different industries. Mixing action is achieved by the continuous splitting, extension and transportation of the components. Motionless mixers use a series of precisely configured mixing elements to process the components. Differences in concentration, temperature and velocity are equalized over the flow cross-section. For further information go toprinciples of operation.Mixers are supplied as simple plain ended pipe sections, flanged with multiple injectors and sampling points, fitted in bends, or in square or rectangular section for ducts and open channels. They are manufactured in a wide range of materials, including carbon steel, stainless steel, exotic alloys, GRP, uPVC, cPVC, PTFE, etc.

The elements are made in various designs to suit different applications, and are available fitted into a range of housings, from high pressure to open-channel, making them ideal for all kind of industrial environments. The elements are fixed or removable and the necessary number of mixing elements for a specific application depends on the required homogeneity and on the volume flow ratio of the components.

Mixer elements

The homogeneity requirement differs according to the particular mixing task and should specified by the final user in terms of variation coefficient CoV. Usually a CoV between 0.01 and 0.05 is a reasonable target for most applications. The lower the value of CoV the better the mixture quality.

• Static mixers deliver a high level of mixing efficiency, therefore the consumption of dosed chemicals and formation of byproducts can be dramatically reduced.

• They eliminate the need for tanks, agitators, moving parts and direct motive power and they allows to gain highly efficient mixing with low energy consumption.

• 混合是有效extr所需的能量acted as pressure drop from the fluid flow through the elements. Mixers are invariably installed in existing systems without reducing the capacity of existing pumps.

• The installation is very easy, no special skills are required other than normal engineering skills.

• Mixers have no moving parts and are virtually maintenance free.

• Static Mixers are available in all standard pipe sizes and, in the case of open channel designs, are available in any size with no upper limit.

• Each Static Mixer is carefully designed to meet the specific requirements of each application.

Principles of operation

In case of two miscible liquids in laminar flow, the main mechanism in a static mixer is flow division. The elements are helical or pseudo-helical and are arranged in a series of alternating left and right hand 180 twists. The elements split the fluids entering in two streams and than rotate them through 180 degrees. The elements are in series in the mixer. As the number of streams or layers increases, the layer thickness decreases. Typically, 12 to 24 elements are required to provide a complete mix.

In case of two miscible liquids in a turbulent flow, the main mechanism is radial mixing: fluids are constantly moved from the pipe centre to the pipe walls and the fluid change direction with each succeeding element. To achieve a fully homogeneous mix in a turbulent flow 1.5 to 4 elements are sufficient.

In case of two immiscible liquids in a turbulent flow, the radial mixing mechanism reduces radial differences in velocity and in droplet sizes. This raises the surface area of contact between phases, improving the mixing. The disperser length necessary depends on the required contact time. For mass transfer processes in which equilibrium is quickly established, a length of 5 diameters is generally sufficient.

Drawing ofStatiflo pipe mixer Series 100/150

Types and Applications

Static mixers are installed in thousand of process plants worldwide, providing the highest standard of mixing efficiency, reliability and economy.

The main applications are in the following fields:

Water andwastewatertreatment:

• Coagulationprocesses, e.g. forphosphorous removal from waste water

• Chemical dosing

• Representative sampling

• Aerationof drinking water

• PH control

• Disinfectionofdrinking water, e.g. chlorination and dechlorination

• Diluting flocculants and mixing with water, wastewater orsludge

• Ozoneinjection and mixing

• Desalinationof seawaterReverse Osmosis Systems

Oil, gas and petrochemical industries

• Measurement of water content of crude oil in pipelines

• Desalting crude oil with water

• Diluting ployacrylamide for enhanced recovery

• Mixing additives into gasoline or fuel oil

• Adjusting the viscosity of heavy fuel oil with gas oil

Continuous process industry:

• Plastics, fibres

• PH control

• Resins, adhesives, epoxies

• Colours, hardeners

• Detergents

Foodand pharmaceutical

• Mixing CO₂into fruit juices, wine or coffee extract

• Mixing milk wit acids

• Diluting molasses with water

• Diluting concentrates and mixing flavourings

Pulp and paper:

• Acid and caustic dilution

• PH control

• Blending

• Low consistency bleaching

Lenntech can help you to design the mixer that best suits your application. Do not hesitate tocontact usfor a direct technical and commercial offer.

See also our web page onventuri principle and applications.

Source:www.statiflo.net