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Publication numberUS3861652 A
Publication typeGrant
Publication dateJan 21, 1975
Filing dateNov 15, 1972
Priority dateNov 15, 1972
Also published asCA991632A1
Publication numberUS 3861652 A, US 3861652A, US-A-3861652, US3861652 A, US3861652A
InventorsRichard Allen Clark, John William Coryell
Original AssigneeDu Pont
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Mixing device
US 3861652 A
The use of a screen structure between groups of static mixing elements located in a conduit through which tow or more liquids flow increases mixing efficiency.
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Description  (OCR text may contain errors)

United States Patent I [191 Clark et al.

[ 1 Jan. 21, 1975 MIXING DEVICE Inventors: Richard Allen Clark; John William Coryell, both of Waynesboro, Va.

Assignee: E. I. du Pont de Nemours and C0.,

Wilmington, Del.

Filed: Nov. 15, 1972 Appl. No.: 306,921

US. Cl. 259/4 Int. Cl B011 15/02 Field of Search 259/4, 18, 36, 60; 138/38 References Cited UNITED STATES PATENTS 11/1966 Armeniades 259/4 8/1967 Katzer 259/4 3,635,444 1/l972 Potter 259/4 3,664,638 5/1972 Grout H 259/4 3,704,006 11/1972 Grout 4. 259/4 Primary Examiner-Robert W. Jenkins [57] ABSTRACT The use of a screen structure between groups of static mixing elements locatedin a conduit through which tow or more liquids flow increases mixing efficiency.

2 Claims, 2 Drawing Figures Patented Jan. 21, 1975 3,861,652

MIXING DEVICE BACKGROUND OF THE INVENTION This invention relates to a device for mixing two or more liquids of highly differing viscosities. In particular, the invention is concerned with an improvement on a mixer having no moving parts.

Armeniades et al., in U.S. Pat. No. 3,286,992 disclose a mixer that consists of a hollow tube or pipe containing a series of curved dividing elements that provide repeated division and recombination of the materials to be mixed as they flow through the tube. The chief mechanisms for accomplishing mixing in such a device are flow division and radial mixing. Flow inversion and backmixing contribute to a lesser extent. Where miscible liquid systems are being combined, diffusion across the flow strata in the mixer enhances mixing somewhat. However, for an all-liquid system in which the constituents possess widely differing viscosities, mixing performance is determined almost exclusively by the amount of flow division attained. In such systems in which the viscosity ratio of the liquids is 1,000 or higher, globules or islands of the high viscosity component tend to form after passing the first few curved dividing elements of the mixer. These discrete particles then pass the remaining elements essentially unchanged. This problem is aggravated in those systems in which the low viscosity component is in volumetric excess.

Attempts to overcome this problem by increasing the number of dividing elements often result in a prohibitively large pressure drop through the mixer. The problem of excessive pressure drop through such mixers is recognized by Grout et al., U.S. Pat. No. 3,664,638.

SUMMARY OF THE INVENTION It has been found that the problem of undissolved high viscosity inhomogeneities in such systems may be overcome by the use of one or more fine mesh screens or other foraminous structures placed between sets of Armeniades et al. mixer elements. The use of a screen between the mixer elements greatly increases the mixing efficiency. Thus, fewer mixer elements are needed and a lower pressure drop results.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a partially sectioned view of one embodiment of the invention, showing a screen section be tween mixing sections;

FIG. 2 is a partial perspective view partly in section of the screen section of FIG. 1.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT In the drawing, a hollow cylindrical tube of uniform cross section consists of a premixing section 12, an initial mixing section 13, a screen section 14 and a final mixing section 15. Low viscosity liquid A is fed directly into premixing section 12 and high viscosity liquid B is introduced through flow distributor 16 having several orifices 17. From delivery end 18 of the tube issues a homogeneous mixture of A and B. Within the initial mixing section 13 and final mixing section of tube 10 are sets of curved elements 20, 21, 22, etc., and 30, 29, etc., respectively. As more fully described in the aforementioned Armeniades et al. patent, the downstream edge of each of the elements 20, 21 29, 30,

are positioned at a substantial angle to the upstream edge of the next adjacent one. The elements are preferably physically connected, eg. by welding or brazing at their contact point 33. Two cylindrical screens 34 having solid end plates 36 are mounted in the end walls 35 of screen section 14.

The screens placed between sets of the curved mixer elements are positioned in such a way that the liquid stream is required to pass through the meshes of the screens. The screens may be planar, cylindrical or of any desired shape. If planar, they are conveniently positioned transversely in the hollow tube between sets of the mixing elements. If cylindrical, they may be positioned, for example, as shown in the drawing. ln general, a screen having a mesh opening approximately. equal to the maximum particle size of the undissolved high viscosity globules gives satisfactory results. In such a case, the screen does not serve as a filter since the averageparticle size is smaller than the mesh opening, However, the invention will operate satisfactorily even if the average particle size is not smaller than the mesh opening. Usually screens of I00 mesh or finerwill be effective and are preferred.

In an example, a mixer consisting of a set of 35 Armeniades et al. elements followed by two ZOO-mesh cy-- lindrical screens followed in turn by a set of 21 elements produced complete mixing in the following system: 4 parts of a high viscosity liquid (440 poises) and 6 parts of a low viscosity solvent (1 centipoise) at 30C.

The viscosity ratio was 44,000/1. Good'mixing was indicated by no'discernible globules of the high viscosity component in the effluent and no buildup on the screens. Similar results were obtained in a two component liquid system having a viscosity ratio of approximately 150,000/l.

In the operation of the embodiment illustrated in the drawing, it is preferred that the coaxially oriented flow distributor l6 and the initial mixing section 13 be disposed within 10 of a vertical position, most preferably, absolutely vertical. Flow direction, either up or down, has not been found to make a significant difference in efficiency of mixing.

The concept of using fine mesh screens between sets of Armeniades et'al. mixer elements for the purpose of dividing or dispersing the higher viscosity component is applicable to any liquid system. It is especially beneficial in those cases where precise drop size is a critical objective or in those instances where an excessive number of mixer elements would otherwise be required to achieve the desired degree of mixing and/or in'obtaining homogeneous mixing with minimum pressure drop.

Although the invention has been described using two spaced groups of elements or mixing sections l3, 15 of the same diameter, more than two mixing sections as well as mixing sections of differing diameters may be used with a screen section incorporated between at least two of the mixing sections.

What is claimed is:

1. In a device for mixing a plurality of flowing liquids including a hollow cylindrical tube and a plurality of curved mixing elements positioned in said tube. the improvement comprising: said elements being formed in spaced groups and a cylindrical shaped screen positioned between at least two spaced groups of elements, said screen having a diameter less than the diameter of the conduit, said screen being connected to the walls of the conduit at one end and being closed at the other groups of elements, said second screen being the same end. as the first screen and having its closed end adjacent 2. The device as defined in claim 1, including a secthe closed end of the first screen. ond cylindrical shaped screen positioned between said

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3286992 *Nov 29, 1965Nov 22, 1966Little Inc AMixing device
US3338560 *Apr 15, 1965Aug 29, 1967Dow Chemical CoMixing apparatus
US3635444 *Sep 8, 1970Jan 18, 1972AmvitStatic mixer
US3664638 *Feb 24, 1970May 23, 1972Kenics CorpMixing device
US3704006 *Jan 25, 1971Nov 28, 1972Kenics CorpDispersion producing method
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Citing PatentFiling datePublication dateApplicantTitle
US3999592 *Apr 21, 1975Dec 28, 1976The Quaker Oats CompanyApparatus and method for manufacturing cores and molds with static mixer stage
US4068830 *Jan 4, 1974Jan 17, 1978E. I. Du Pont De Nemours And CompanyMixing method and system
US4109318 *Apr 15, 1977Aug 22, 1978General Signal CorporationFluid injection and sampling device for an in-line blender
US4123178 *Mar 21, 1977Oct 31, 1978General Signal CorporationIn-line blender
US4270576 *Jun 19, 1979Jun 2, 1981Masahiro TakedaSelf-contained fluid jet-mixing apparatus and method therefor
US4408038 *Mar 29, 1982Oct 4, 1983E. I. Du Pont De Nemours & Co.Countercurrent injection of coagulant under high pressure atomization
US4548509 *Oct 5, 1984Oct 22, 1985Clif Mock CompanyIn a fluid sampling device
US5053202 *Aug 2, 1990Oct 1, 1991Olin CorporationStatic mixer configuration
US5104233 *Jun 1, 1990Apr 14, 1992Hisao KojimaMixing element with a tapered porous body
US5785424 *Dec 22, 1995Jul 28, 1998Kansai Chemical Engineering Co. Ltd.Agitator blade having agitators with open first and second ends and inner fabrics therein
US6074613 *Feb 26, 1998Jun 13, 2000Bohdan Automation, Inc.Elongated tubular, thin walled body; filter; projection pattern; threads
US6279611 *May 10, 1999Aug 28, 2001Hideto UematsuApparatus for generating microbubbles while mixing an additive fluid with a mainstream liquid
US6405759Aug 5, 1997Jun 18, 2002Owens Corning Composites SprlApparatus for the continuous preparation of glass fiber sizing compositions
US6488402 *Mar 30, 2001Dec 3, 2002Komax Systems, Inc.Steam injector and tank mixer
US7857247Aug 14, 2006Dec 28, 2010Brian SulaimanMilling system
US7946753 *Aug 23, 2010May 24, 2011Dow Global Technologies LlcRotatable mixing device and dynamic mixing method
US8360630 *Jan 31, 2007Jan 29, 2013Stamixco Technology AgMixing element for a static mixer and process for producing such a mixing element
US8512740Mar 26, 2008Aug 20, 2013Baxter International Inc.Fibrin foam and process for making
US8641661Jan 4, 2011Feb 4, 2014Baxter International Inc.Mixing system, kit and mixer adapter
US8648209 *Dec 28, 2006Feb 11, 2014Joseph P. LastellaLoop reactor for making biodiesel fuel
US8753670Mar 26, 2008Jun 17, 2014Baxter International Inc.Fibrin foam and process
US20120134232 *Jan 31, 2007May 31, 2012Stamixco Technology AgMixing Element for a static mixer and process for producing such a mixing element
EP0814854A1 *Jan 16, 1996Jan 7, 1998JOHNSON & JOHNSON CORPORATIONOn-line drug delivery system in extracorporeal therapy
EP0914861A2 *Aug 3, 1998May 12, 1999N.V. Owens-Corning S.A.Apparatus for the continuous preparation of glass fiber sizing compositions
EP2213245A1 *Jan 17, 2007Aug 4, 2010Baxter International Inc.Device, system and method for mixing
WO1992014541A1 *Feb 20, 1992Sep 3, 1992Dena TechnologyMixing and homogenising apparatus
WO1999000180A1 *Jun 9, 1998Jan 7, 1999Robbins & MyersMulti-component static mixer and method of operation
WO2005016501A1 *Aug 11, 2004Feb 24, 2005Daniel P BrownMulti-component fluid dispensing device with mixing enhancement
WO2007084919A1 *Jan 17, 2007Jul 26, 2007Baxter IntDevice, system and method for mixing
WO2011025725A1Aug 23, 2010Mar 3, 2011Dow Global Technologies Inc.Mixing device and dynamic mixing method
U.S. Classification366/336
International ClassificationB01F5/06
Cooperative ClassificationB01F5/0612, B01F5/0694, B01F5/0682
European ClassificationB01F5/06F4F2, B01F5/06F, B01F5/06B3B4