General Signal Corporation

Spx Corporation

Corning Glass Works

Ronald J Weetman

Richard A Howk

Keith T McDermott

Richard Howk

Gary Hodenius

John T Brown

Marlin D Schutte

Meryle D Adler

Thomas A Post

Horst P Engelbrecht

Jonathan C Everdyke

Frederick W Kehr, Iii

Chandler K Coyle

Thomas A Taylor

Walter C Webster

Robert G Folmar

Jerry A Carpenter

Roger N Voss

Craig B Bahr

The present invention provides an improved aeration impeller for use in a mixing assembly having an axis of rotation. The aeration impeller includes a hub and a first and second blades that are connected to the hub. Each blade has a first portion positioned at an angle to the axis of rotation and a second portion positioned at an angle to the first portion. The first portion of each blade has an opening that at least partially extends the width of the first portion.

Aeration apparatus and method

A radial disc impeller for use with a liquid or liquid suspension mixing assembly, having an axis of rotation. The radial disc has a hub and at least one disc extending radially away from the axis of rotation. The disc is connected to the hub at first axial location. The disc impeller includes a first blade connected to the disc. The first blade has an extension that extends radially away from the axis of rotation. The disc impeller also includes a second blade connected to the disc. The second blade has an extension that extends radially away from the axis of rotation.

Radial disc impeller apparatus and method

A more efficient process and method for dispersing gas or other fluids into a liquid which may have solid suspension. More particularly, the process includes maximizing the transfer of oxygen by an impeller by selecting a Froude Number value and/or Surface Power Density value and analyzing these two relative to the desired Standard Aeration Efficiency value desired for the impeller.

Mass transfer method

The present invention provides an improved surface aeration impeller for use in a mixing assembly. The improved surface aeration impeller includes a hub and a first blade that is connected to the hub. The blade has a substantially straight first portion and a substantially curved second portion. The impeller also has a second blade connected to the hub that has a substantially straight first portion and a substantially curved second portion.

The present invention provides an apparatus and method for mass transfer of gas or other fluids into a liquid and/or liquid suspension. The present invention is preferably used in conjunction with waste treatment processes and/or fermentation processes that are commonly carried out in a mixing vessel. In such an arrangement, the mass transfer process is utilized to contact air to liquid in a mixing vessel or aeration basin.

An improved mixing apparatus and method for dispersing gas or other fluids into a liquid which may have solid suspension. The improved mixing apparatus includes a mixing vessel having at least one side wall and a bottom wall. The apparatus also has upper and/or lower reflectors attached to the side wall, positioned at an angle to the side wall. The apparatus may additionally include a shaft with a first impeller having a first diameter attached thereto and a second impeller having a second diameter attached thereto. The first impeller and second impeller are positioned a distance apart.

Mixing vessel apparatus and method

An axial flow mixer impeller which is high in efficiency in terms of flow is made more effective, when used in a sparging system for dispersion and for mass transfer of a liquid phase or a gaseous phase into a liquid which is being mixed or agitated, by forming a shear field which breaks the phase being dispersed into fine bubbles which are dispersed by the impeller. This is accomplished without a major effect on the high flow efficiency of the axial flow impeller. To this end a structure which forms a Venturi is located on the side or sides of the blade where the phase (bubbles of fluid of different density or viscosity which are to be mixed or dispersed by the impeller) occurs, in the high velocity region near the tip of the blade. This Venturi creates a high shear field which breaks up the bubbles and disperses them as fine bubbles as they leave the impeller. The structure may be provided by a pair of proplets in the vicinity of the tip end of the blade which form a wedge shaped flow path therebetween. The structure may also be provided by an overlying blade or blade segment which has a blade angle different from the angle of the main blade so as also to provide a wedge shaped flow path which creates the shear field which shears the phase being dispersed into fine bubbles. These fine bubbles facilitate mass transfer, for example for aeration, when the gas contains oxygen.

Fluid mixing impellers with shear generating venturi

An axial flow mixing impeller system for efficient mass transfer by control of size of the bubbles of the fluid which is being dispersed, especially gases and liquids with viscosities greater than the liquid into which dispersion occurs, is obtained by creating passageways through the impeller blades for flow between the suction and pressure sides of the blades which disrupts the flow over the suction sides of the blades thereby reducing the tendency for bubbles to grow or coalesce into large bubbles which instead of being dispersed, rise to the surface without effective mass transfer to the liquid which is pumped by the impeller. The blades of the impeller may be slotted inwardly from the tips thereof to provide the passageways or may be formed from segments, gaps between which provide the flow passageways. The segmented blades have the advantage of enabling systems of large diameter impellers, of size approaching the diameter of the tanks or in closed tanks where access is by way of a manway smaller than the impeller blade dimensions, to be assembled within the tank, either upon initial installation or for replacement or retrofit. If the system is not used for gas or liquid dispersion, the segments may be in edge-to-edge abutment. Gas-to-liquid dispersion may also be improved by sparging below the impeller at the bottom of the tank and between the impellers in the tank, as with sparge rings of diameter less than the diameter of the impellers enabling gas supply at different pressures commensurate with the depth of the sparge rings, sufficient to overcome the head at the depth of the sparge ring.

Mixing impeller system having blades with slots extending essentially all the way between tip and hub ends thereof which facilitate mass transfer

Mixer apparatus having an impeller on a shaft, which circulates a body of liquid the surface of which can clear the impeller, especially when the liquid is in a tank, and the tank is drained, is protected against excessive by use of a flexural member, which may be in the form of radially opposed pairs of resilient plates, which extend from the shaft and are attached thereto by a collar. As the liquid surface drops below the impeller, the members present surfaces to the liquid in the tank on which forces are opposing the oscillation are developed by interaction of the surfaces with the liquid in the tank. Restoring forces on the shaft due to the flexing of the resilient plates also reduce the shaft oscillation. The stiffness of the plates is selected to optimize the restoring forces for the mixing apparatus which is stabilized.

Apparatus for stabilizing a mixer which circulates liquid against

A mixing process may be carried out in a tank of a certain diameter. The process may also be constrained to the use of an impeller of certain diameter in order to obtain the flow pattern desired to carry out the process. The power consumption of the system which may be expressed in terms of flow per unit (Q/P) is optimized for the impeller diameter to tank diameter (D/T) constraint by utilizing an axial flow blade, preferably having camber and a tip chord angle at the tip and an angle near the attachment to the shaft (the hub) which rotates the impeller, where the tip chord angle and the twist the difference between the blade angle (between the chord and a plane perpendicular to the axis of rotation of the shaft between the tip and hub) are varied in opposite senses; for example, increasing the tip chord angle to provide a more D/T for a more optimum Q/P to which the process is constrained and then reducing the twist to maintain the power efficiency at the higher tip chord angle. The freedom to increase the tip chord angle and reduce the twist provides flexibility enabling the use of a limited number, say three, of hubs, thereby reducing the cost of the impeller system. The efficiency of the impeller is further increased by reducing tip vortices using slots in the tip which have an effect on the flow pattern similar to the effect of proplets but at reduced cost of fabrication. Where additional turbulence is required so as to establish shear forces in the fluid or fluid suspension being mixed, the blade segments which define the slots may be twisted at angles different from the tip chord angle. These twisted segments increase turbulence and shear the material being mixed.

Mixing impellers and impeller systems for mixing and blending liquids

A rotatably driveable enhanced-flow impeller system has a radial flow impeller with a first impeller face disposed proximate the bottom of the tank and proximate or extending into an inlet port for liquids in the tank bottom. The radial flow impeller has a plurality of blades with radially outermost blade tips terminating along a blade terminating circle. The blades and inlet port are contoured to reduce shear stress on the liquids. Disposed adjacent a second opposing face of the radial flow impeller is a radial flow extension plate which preferably extends radially outwardly along the second face by a radial distance beyond the blade terminating circle. The radial flow extension plate may be fixedly attached to the second impeller face. The enhanced-flow impeller system can be used advantageously to form efficiently and with enhanced effectiveness a liquid - liquid dispersion as droplets of at least one liquid in at least one other immiscible liquid and to distribute the dispersion uniformly through the tank volume during a dispersion residence time in the tank, while avoiding, because of minimization of shear stress on the liquids, the formation of fine (smaller) of droplets of one of the liquids that do no readily separate from the other liquid upon settling.

Impeller system for mixing and enhanced-flow pumping of liquids

In order to extend the life of mixing impellers which circulate materials, and particularly which suspend solids, in the form of particles which erode the blades of the impellers and place a practical limit on impeller speed and/or angle of attack due to increased erosion at high flow velocity (erosion being a function of the cube of the velocity), the blades are constructed from blades into an airfoil configuration which does not limit the thickness of the plates and thereby allows the use of thick plates having extended life. An erosion resistant layer is located at least over the leading edge region of the blade and the shape of the blade reduces velocity of flow over the leading edge; the camber of the blade being maximized midway between the leading and trailing edge. The suction surface of the blade in the region subject to erosion is continuous thereby avoiding discontinuities which form vortices which enhance erosion. Fins, which may be at the tip on the suction side of the blade from midway between the leading and trailing edges to the trailing edge reduces tip vortices thereby further extending blade life in erosion-producing environments.

Erosion resistant mixing impeller

Impellers and impeller systems are described which enable liquids and liquid suspensions to be mixed and blended where the size of the impeller and the viscosity of the liquid may require operation in the turbulent and laminar flow regimes, as well as in the transitional flow regime therebetween. The impellers have a plurality of fluidfoil blades and have camber and twist. The angle at the tip of two diametrically disposed blades of a four blade impeller may have a different blade angle at the tip than the other pair of blades. A pair of impellers may be used. These impellers may be of different diameter and disposed in close proximity so that they are in dependent relationship (preferably spaced apart by less than the diameter of the larger impeller). The impellers and impeller systems provide axial flow over a large range of viscosities of the liquid or liquid suspension being mixed or blended, minimizing radial flow patterns and reducing the time required for blending while maintaining efficiency of operation.

Impellers and impeller systems are described which enable liquids and liquid suspensions to be mixed and blended where the size of the impeller and the viscosity of the liquid may require operation in the turbulent and laminar flow regimes, as well as in the transitional flow regime therebetween. The impellers have a plurality of fluidfoil blades and have camber and twist. The geometric pitch or blade angle increases from the tip of the blade towards their axis of rotation in a manner to provide an over pitched condition so that the pitch ratio of the blades at 40% of the blade radius from the axis is greater than the pitch ratio at the tip. The blades are preferably smoothly tapered and increased in width from the tip towards the axis. The impeller blades are mounted on a hub connected to a drive shaft. The blades may decrease in width where they connect to the hub. The pitch angle at the tip is in the range of 18.degree. to 30.degree. (preferably about 20.degree.). The angle at the tip of two diametrically disposed blades of a four blade impeller may have a different blade angle at the tip than the other pair of blades. A pair of impellers may be used.

A method of injection molding a thermoplastic material around a two-piece insert having a rotational axis through which a bore passes is disclosed. The insert is formed from two pieces which are axially spaced to define an annular gate through which the injected thermoplastic material passes radially outward. This technique is particularly useful for forming mixing impellers, because it orients fibers contained within the thermoplastic material in a radially outward direction within the impeller's blades to provide increased strength. The insert also allows improved performance for injection molding parts by reducing their cross-sectional thickness to optimal values. The insert also allows machining the bore without harming the injected plastic material.

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Rochester, NY, United States of America

Ronald J Weetman