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Kenics HEV Bulletin

Kenics HEV Bulletin
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The patented Kenics High Efficiency HEV Static Mixer gives you pressure drops drastically lower than any other static mixer available today and can be applied to any turbulent flow mixing problem regardless of line size or shape. Typical applications for the HEV include all low viscosity liquid-liquid blending problems, as well as gas-gas mixing. It is offered in unlimited sizes and mixes in the shortest possible pipe length for applications having space restrictions. HEV Technology University studies of turbulence led to the understanding of fluid flow phenomena that made the development of the HEV Static Mixer possible. Years of research have gone into defining the patented element geometry parameters to maximize conversion to fluid energy into efficient mixing. The length, width, and attack angle of the HEV mixing elements have been optimized for mixing performance while limiting pressure drop. To create mixing action the mixing element must impart momentum to the fluid stream. The level to which this momentum is converted to effective mixing versus wasted turbulence determines the mixer efficiency. Because the HEV is configured to promote a “natural” mixing pattern, the redirection of the flow stream results in virtually no loss of pumping energy. The benefit you gain is minimum pressure loss and significant energy savings compared to static mixers using more disruptive-type mixing elements. The HEV mixing element consists of special patented trapezoidal tabs mounted at an acute angle relative to the downstream surface of the mixer housing. As the process stream strikes the base of the tab, it is deflected up the angled incline creating a pressure gradient between the upstream and downstream surfaces of the tab. This pressure differential causes the fluid to flow around the opposite sides of the tab generating alternating tip vortices having their axes of rotation oriented in the direction of the main fluid flow. The alternating rotations of the tip vortices induce vigorous cross-stream mixing which results in rapid uniformity of the process components. Full-scale mixing tests have confirmed the performance of the HEV and have resulted in highly accurate equations for predicting uniformity levels. These equations evaluate various parameters such as side-stream ratio and injection techniques that are influential to the process performance of the mixer. Control of these parameters allows the HEV to be applied with complete certainty. Uniformity Criteria Comprehensive testing of the HEV mixer using tracer injection techniques has quantified its mixing performance. Multipoint sampling probes were utilized to generate stream uniformity data. Statistical analysis applied to this data resulted in the equations that predict mix quality as a function of the inlet and outlet coefficient of variation (CoVo and COV, respectively). By knowing the inlet stream conditions any desired level of uniformity can be achieved by adjusting the design of the HEV. Typical Mixing Performance of HEV CoV/(CoV)o Coefficient of Variation mixer exit o = Standard Deviation x = Mean Concentration of added component (maximum .50) Coefficient of Variation at mixer entrance Volume fraction added Reynolds Number

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Process Performance You can adapt the HEV Static Mixer to most turbulent flow applications without having to upgrade pump capacity. Another great advantage is its ability to be used effectively in non-circular ducts. The extremely low pressure drop and high mixing efficiency make the HEV ideal for low pressure gas phase blending situations or applications with severe space restriction. The model HEV Static Mixer produces complete stream uniformity through controlled vortex action generated by its unique mixing elements. The patented element geometry takes advantage of the naturally...

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