Static mixing element having deflectors and a mixing device

Abstract

The static mixing element in a flow channel (7) has at least two deflectors (30) disposed on mountings (20) at a distance from the channel wall. The deflectors form an angle W of from 10 DEG to 45 DEG to the main flow direction Z. They have different orientations and the projection FZ of the deflectors in the main flow direction amounts to from 5% to 50% of the channel cross-section F. Cross-flows providing very efficient transverse mixing are therefore produced in a simple manner. When dispensing tubes (20, 21) are used as mountings a very effective mixing device is provided.

Description

BACKGROUND OF THE INVENTIONThe invention relates to a static mixing element in a flow channel, the element having at least two deflectors, and to a mixing device having such element. Simple static mixing elements having deflectors are known but their mixing and homegenising abilities are very limited and they always produce a relatively high pressure drop. More elaborate static mixers, for example, comprising crossing subchannels of slats (Sulzer-SMV-mixers) provide very good mixing but are relatively costly to produce. Good mixing is particularly necessary when a small quantity of a fluid is injected by means of an injection system into a main flow of another fluid in a flow channel. When relatively small quantities, for example, of less than 10%, of a gas or a liquid are admixed into the flow of another gas or another liquid, very one mixing paths in the empty tube are necessary to ensure thorough homogeneous mixing. However, conventional mixing devices having complicated adjustab...

AI Technical Summary

Benefits of technology

The invention solves these problems by means of a mixing element having deflectors attached to a mounting at a distance from the channel wall. The deflectors form an angle of between 10.degree. and 45.degree. relative to the main flow direction. A projection of the deflectors in the main flow direction amounts to between 5% and 50% of the channel cross-sectional area. Since deflectors are disposed by means of mountings at a distance from the channel wall, the deflectors are flowed around completely at the front and back with very reduced losses, with the result that efficient deflection and eddying are produced in the direction of the angle W. The provision of a few deflectors with different orientations is a very simple means of producing crossing radial subflows with a reduced pressure drop. Because of the deflectors a relatively large turbulence cone is produced in the main flow and deflected in the direction W1. Simultaneously, the dispensing tube injects the fluid for mixing along its axis at the same piece into the deflected turbulence cone. Immediate intensive mixing of the two fluids is therefore produced and the local deflection in the directions W of the at least two oppositely oriented deflectors produces a cross-flow causing intensive mixing over the whole flow channel cross-section. In all, therefore, the device according to the invention produces intensive mixing of the two fluids in the injection zone and good homogenization over the entire channel cross-section by simple means and with a reduced pressure drop. The projection FZ of the deflectors in the main flow direction can be as little as from 5% to 25% of the channel cross-section and therefore lead to optimal mixing with very reduced complexity and a very reduced pressure drop. The deflectors can be rectangular or triangular or trapezoidal or round or bent or curved or cylindrical and even perforate, they can be staggered relatively to one another and, in a substantially uniform distribution, can cover the complete channel cross-section. At least two consecutive mixing elements of this kind can form a mixer arrangement, the elements possibly having deflectors which are offset or turned relatively to one another. A mixing element can be followed by an aftermixing section or path which further enhances mixing.

Problems solved by technology

Simple static mixing elements having deflectors are known but their mixing and homegenising abilities are very limited and they always produce a relatively high pressure drop.

More elaborate static mixers, for example, comprising crossing subchannels of slats (Sulzer-SMV-mixers) provide very good mixing but are relatively costly to produce.

However, conventional mixing devices having complicated adjustable injection systems cannot provide thorough mixing over a wide range of loads and more particularly at very low volume flow relationships.

Also, this thorough mixing must be achieved over short paths and with a low pressure drop and known mixing devices cannot provide these two features.

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