CA1059985A - Flow tube mixer with wall mounted nozzles - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

Method and apparatus for mixing a stream of highly viscous fluid material by means of impinging jets of high pressure fluid is disclosed.
The stream is divided into a plurality of substreams by impingement of a plurality of jets of high pressure fluid at predetermined points along the stream. A predetermined rotational flow pattern in a first direction is imparted to alternate substreams by tangentially impinging jets of high pressure fluid and a predetermined rotational flow pattern in the opposite direction is imparted to the remaining substreams also by tangential impingement of jets of high pressure fluid.

Description

~0599BS
BACKGROllND OF THE INVE~TION
Field of t~e Invention The present invention relates to mixing techniques and devices. More particularly, the present invention relates to a method and apparatus for mixing a highly viscous fluid mass by altering the flow pattern of a viscous fluid stream so as to generate interfacial surfaces in the fluid mass.
The Prior Art The thorough mixing of extremely viscous material has been a problem of considerable commercial concern. One approach to mixing viscous materials involves transporting a viscous fluid mass through a conduit containing baffles or other ob-structions which serve to split the stream of fluid materials flowing through the conduit, effectively spreading the stream out and creating a large surface area, and then combining the streams again in an overlapped type of relationship so as to provide relatively efficient mixing without turbulence and in-dependent of the flow rate of the reacting stream. Typical of such devices are those described in U.S. Patent 3,239,197 of James E. Tollar issued 8 March 1966 and U.S. Patent 3,664,638 of Kenneth M. Grout and Richard D. Devellin issued 23 May 1972, for example. Among the deficiencies of the type of mixing de-vices just mentioned are the relatively large pressure drops associated with extensive internal baffles and the difficulty of cleaning such devices particularly when the fluid mass is a highly reactive material such as a thermoset resin which rapidly sets and cures into a solid mass.
SUMMARY OF THE INVENTION
In its simplest sense, the present invention pro-vides a method for mixing a stream of fluid mass, particu-larly a viscous fluid mass, by dividing the stream of fluid mass into a plurality of substreams, imparting a predeter-

-2-~-~..e 1 ~hrnFd rotational flow pattern in a first direction to alter-2 nate substreams and imparting a predetermined rotational

3 flow pattern opposite in direction to said first direction

4 to the remaining substreams.
In a preferred embodiment of the present invention, 6 a hi~hly viscous fluid is mixed by establishing a stréam of 7 fluid mass. This stream is divided into a plurality of sub-8 streams by subjecting said stream of fluid mass to the 9 impingement of a plurality of jets of high pressure fluid, preferably a gas, at predetermined points along the stream 11 of fluid mass. A predetenmined rotational flow is imparted 12 in a first direction to alternate substreams, for example, 13 substream 1, 3, 5, 7, etc. by subjecting these alternate 14 substreams to a tangentially impinging jet of the high pressure fluid. The remaining substreams, for example, 16 substream 2, 4, 6, 8, etc. are rotated in a predetenmined 17 flow opposite in direction to the first rotational direction 18 by the tangential impingement of a jet of the high pressure 19 fluid. ~
In another embodiment of the present invention, 21 a static mixer is provided for mixing very viscous and even .
22 rapidly reacting materials. The mixing device consists of 23 an elongated tube or conduit through which the reactant 24 materials are forced. Based at predetermined locations along the elongated tube are a plurality of means for intro-26 ducing a jet of a high pressure fluid, preferably a gas, at 27 substantially rLght angles to the longitudinal axis of the '28- -5tub~so as to divide a stream of reactant materials into a 29 plurality of substreams. Also spaced at predetermined loca-tio~s^ along the elongated tube or conduit are a plurality of 31 means for introducing jets of the same or different high pres-32 surel fluid substantially tangential~to the--inner surface of the 1 elongated tube or condui~. Preferably the elongated tube or 2 conduit has a circular cross-section. Also, preferably the 3 means for introducing jets of high pressure fluid are spaced 4 at substantially equal distance along the ëlongated tube.
Preferably, each means for introducing a jet of high pressure 6 fluid is based at right angles with respect to the next 7 successive means for introducing a jet of high pressure 8 fluid.
9 In a particularly preferred embodiment of the pre-sent invention, a stream of highly viscous material is forced 11 through a conduit or pipe. This stream is divided into a 12 plurality of substreams by means of the impingement of a jet 13 of hlgh pressure fluid, such as air, which is introduced 14 through a nozzle means located at substantially right angles to the longitudinal axis of the pipe at a plurality of loca-16 tions along the periphery of the pipe. The alternating sub-17 streams are given a rotational motion in a first direction 18 by introducing a high pressure fluid, such as air, tangential 19 to the inner periphery of the pipe. The remaining substreams are given a rotational motion opposite to the first direc-21 tion by the introduction of a high pressure fluid, such as 22 air, tangential to the inner periphery of the pipe by a 23 plurality of nozzle means located along the periphery of the 24 pipe.
The broad outline of the method and apparatus of 26 the invention will be more clearly understood from the de-27 tailed description which follows, taken with the accompany-28 ing drawings.

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Figure 1 is a perspective and isometric view of a 31 simple form of device according to the present invention.
- 32 ~ - Figure 2 is an enlarged partial view, partly in ~05~985 section, diagrammatically show~ng the fluid flow in the device of Figure 1._ Figure 3 is a cross-sectional along lines 3-3 of Figure 1 partly cut away and partly showing the directional motion of the impinging fluid streams.
Figure 4 which appears on the first sheet of drawings, is a side elevation of a nozzle used for introducing a high pressure fluid tangential to the inner surface of the device according to the present invention.
Figure 5, which appears on the first sheet of drawings, is a side elevation of a nozzle used for dividing the stream of fluid mass into substreams in accordance with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
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A particularly desirable application of the present invention is in rapidly mixing extremely viscous reactive materials such as a foamable liquid resin composition, parti-cularly a foamable resin composition containing reinforcing fibers, solid fillers and the like. Thus, the present inven-tion will be described with reference to this particular desir-able application. It should be understood, however, that the invention is not intended to be limited strictly to the specific embodiments shown and described herein but may be modified ex-tensively while still within the spirit of the present invention.
In preparing a fiber-reinforced plastic foam it is ~ necessary to introduce resin precursors premised with fiber-; glass and other reinforcing material into the mixer simul-taneously with a catalyst (if desired), blowing agents and other ingredients desired. These reactant materials must be mixed thoroughly and rapidly since within a very short period of time they will begin to react. Accordingly, they ~ _5_ must be quickly placed in a mold immediately after mixing so the foaming process may occur therein. Thus, -5a 10~9985 1 referring to the drawings and particularly to Figure 1, a 2 mixer embodying the invention is indicated generally at 12.
3 A stream of viscous material of the type mentioned above is 4 shown as line 10 entering opening 15. Precisely predeter-mined quantities of viscous materials can be supplied to the 6 mixing device 12 by means of precision volumetric control 7 pumps and the like (not shown).
8 In any event, the viscous stream of material 9 enters the first passageway at 15 and is caused to flow through the elongated tube or conduit 11 of mixer 12 by a 11 ram or plunger of a pumping device, for example.
-12 As can be seen in Figure 1, the mixing device is 13 an elongated tube or conduit 11 which has a first end 14 and 14 a second end 16. In a preferred embodiment of the present invention the mixer 12 is provided with a mounting flange 16 17 for operatively connecting the inlet end of the mixer 17 to a metering and pumping system. ThUSJ as is shown, 18 entrance passages 18 and 19 are provided for the flow of 19 liquid reactants from meters and pumps ~not shown) into the principle flow passage of mixer 12 through opening lS at 21 first end 14. Thus, flange 17 provides a convenient mount-22 ing means for mounting the mixer and a suitable entrance 23 support system having a corresponding flange such as flange 24 20.
As can be seen, the mixer 12 is also provided with 26 a second flange 21 at second end 16 for cooperatively mount-27 ing with any desired distribution system. ThUSJ elbow 22 is 28 mounted on a flange 23 and when operatively connected with 29 mixer 12, the thoroughly mixed stream o material exiting the mixer at second énd 16 can be dischargedJ for example, 31 downwardiy onto a suitable mold (not shown).
32 At various intervals along the length of mixer 12 . .

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1 are a series of mounting blocks 24 for supporting the mlxer 2 in a suitable position. Other mounting means, of course, 3 can be employed.
4 Spaced along the conduit or elongated tube 11 which forms the central mixing chamber 12 of the present 6 invention are a plurality of nozzle means for introducing 7 a high pressure fluid into the reactor substantially radi-8 ally so as to divide a stream of material flowing through 9 the mixer into a plurality of substreams. These dividing means are shown as nozzles Bl, Dl, B2 and D2 in Figure 1.
11 As can be seen in Figure 3, it is preferred that each 12 dividing nozzle be substantially at 180 with respect to 13 the next dividing nozzle. Thus, Dl is on the opposite side 14 of the tubular body portion 11 of mixer 12 than Bl, but spaced further along the longitudinal axis.
16 Further in accordance with the preferred embodi-17 ment of the present invention as shown in Figure 5, the 18 dividing nozzles or jet fit~ings such as Bl are inclined 19 generally at an angle, ~, of about 10 with respect to the radius of the tubular body portion so as to deliver a jet 21 of high pressure fluid that has both a forward component 22 as well as a radial component, for the purposes hereinafter 23 discussed.
24 Returning again to Figure 1, it can be seen that the plurality of means for introducing a high pressure fluid 26 tangential to the periphery of the main tubular section of 27 mixer 12 is provided. These fluid stream rotating nozzles 28 are designated as Al, Cl, A2 and C2 in the figure. As can 29 be seen particularly with regard to Figure 3, these nozzles, Al and Cl for example, are arranged on opposite sides of the 31 main tubular body portion of mixer 12. Thus, as can be seen 32 in Figure 2, these nozzle fittlngs also are inclined at an ~r_. . .

~OS998S
1 angle, ~, of about 10 with respect to the radius of the 2 main tubular section so as to impart a high pressure rota-3 tion fluid stream having both a forward component and a 4 tangentiat component thereby rotating a substream in a clockwise or counterclockwise fashion. Indeed, thé tangen-6 tial component is so arranged that alternating nozzles will 7 have a first tangential entry direction and the remaining 8 will have a second tangential direction opposite from said 9 first tangential direction.
In Figure 3, lines 1, 2, 3 and 4, diagrammatically 11 depict the general directional movement of the high pressure - 12 fluid introduced via each respective nozzle. Thus, the high 13 pressure fluid introduced via fluid stream divider nozzles 14 Bl and Dl enters generally radially as is indicated by lines 1 and 2 respectively. The high pressure fluid introduced 16 via the tangential nozzles Al and Cl have opposite rotation-17 al directions shown by lines 3 and 4 respectively. Thus, 18 the rotational direction of fluid entering via Cl is clock-19 wise whereas the rotational direction of fluid entering via Al is counterclockwise. This clockwise, counterclockwise 21 rotational direction is also shown in Figure 2.
22 The number of nozzles for dividing a main stream 23 and the number of nozzles to provide substreams and the 24 number of nozzles for rotating the various substreams may be varied to give the desired performance for any specific 26 viscous liquid mixing problem. As should be appreciated, 27 the apparatus a1~so may be constructed from any of a wide 28e vari`ety of materiàls~r~nclud~ng~metal and the like, the choice 29 of materials being predicated upon the particular conditions which will be encountered in the situation for which ~he 31 apparatus is designed.
32 ~ ~ As is shown in the drawings, and in particul*r inr ~ ~

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- lOS9985 1 Figures 4 and 5, the var~ous nozzle means include threaded 2 inserts for suitably connecting the nozzle means to a source 3 oi! high pressure fluid. Thus, threads 32 permit easily 4 connecting a source of high pressure fluid to the mixer.
Also threads 33 permit easy removal of the insert portion 6 for cleaning, if necessary, of the radially directing 7 opening 31 of Bl and the tangential opening 35 of Al.
8 Generally, in the practice of the present inven-9 tion the high pressure fluid employed will be a gaseous material such as air or nitrogen; however, the fluid mater-11 ial introtuced under high pressure may also be one of the 12 components of the main fluid stream to be mixed.
13 The operation of all or any of the previously 14 illustrated embodiments of the present invention and the method thereof is substantially achieved as follows:
16 (a) A stream of relatively viscous material is 17 established by introducing the material to be mixed at first 18 end 14 of the mixer 12. For example, polyurethane resin 19 precursor with fiberglass is metered and introduced through passageway 18 and catalyst and blowing agent is metered and 21 introduced via passage 19 thereby establishing stream 10 22 for a transversed flow through .the tubular conduit 11 of 23 mixer 12.
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24 (b) The main stream thus established is divided into a plurality of substreams by the high pressure fluids 26 introduced at spaced predetermined positions along the 27 longitudinal axis of the mainlstream and subs~antially 28 radial thereto, for éxample-,~v~a Bl, Dl, :~2 and D2-29 (c) The substreams are then rotated in a prede-termined flow pattern by the h~igh pressure fluid introduced 31 tangentially at spaced predetermined positions along the 32 ..1~ng.itudinal axis of the main-s~tream, or example, vi~..~..e...~.. ..

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lossass 1 Al, Cl, A2 and D2. It should be noted that alternate sub-2 streams have imparted to them a first predetermined rota-3 tional flow pattern in a first direction which is opposite - 4 to the predetermined rotational flow pattern imparted to the remaining substreams. Thus, for example, a plurality of 6 substreams will be given a clockwise rotational motion while 7 alternate substreams will be given counterclockwise rota-8 tional motion.
9 The net effect of dividing the stream of viscous material into substreams and rotating the various substreams 11 in opposite directions is to continually divide and recom-12 bine the substreams so that complete mixing is achieved.
13 Thus, the viscous material is forced to flow through a 14 serpentine path without being in contact with dams or baffles or other such internal arrangements. Thus, in the 16 case of forming a foamable resin composition of the type 17 which will typically foam and begin to set within about 30 18 seconds after the foam components begin to come into con-19 tact with each other, the device of the present invention offers considerable advantage in regard to cleaning the 21 mLxer fter each use.

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Claims (6)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PRIVILEGE OR PROPERTY IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A method for mixing a viscous fluid mass comprising:
establishing a stream of fluid mass containing components to be mixed;
subjecting said stream of fluid mass to the impingement of a plurality of jets of high pressure fluid at predetermined points along the stream of fluid mass thereby dividing said stream of fluid mass into a plurality of substreams;
subjecting alternate substreams to a tangentially impinging Jet of high pressure fluid thereby imparting a predetermined rotational flow pattern in a first direction to said alternate substreams; and, subjecting the remaining substreams to a countertangentially impinging jet of high pressure fluid thereby imparting a predetermined rotational flow pattern opposite in direction to said first direction to the remaining substreams whereby interfacial surfaces are generated and recombined thereby mixing said components of said viscous fluid mass.

2. The method of claim 1 wherein said high pressure fluid is a gas, which is not reactive with the components being mixed.

3. The method of claim 2 wherein the high pressure fluid is a component to be mixed with the main stream.

4. A static mixer for mixing viscous material comprising:
an elongated tube having a first end and a second end for transversal therethrough toward said second end by a stream of viscous material to be mixed;
a plurality of successive first nozzle means being spaced at predetermined locations along said elongated tube, said nozzle means having a substantially radially directed entry port inclined in a forwardly direction toward said second end of said elongated tube at an angle of about 10° with respect to the radius of said elongated tube for introducing jets of high pressure fluid substantially radially to the longitudinal axis of said elongated tube and in a forwardly direction, each succeeding first nozzle means being located on opposite sides of the elongated tube from the preceding first nozzle means;
a plurality of successive second nozzle means being spaced at predetermined locations along said elongated tube, alternate members of said second nozzle means having a substantially tangentially directed entry port and inclined in a forwardly direction toward said second end of said elongated tube at an angle of about 10° with respect to the tangent to a radius of said elongated tube for introducing jets of high pressure fluid in a first substantially tangential and forward direction, and the remainder of said second nozzle means having a substantially counter tangentially directed entry port and inclined in a forwardly direction toward said second end of said elongated tube at an angle of about 10° with respect to the tangent to a radius of said elongated tube for introducing jets of high pressure fluid in second substantially tangential and forward direction, each succeeding second nozzle means being located along the elongated tube at a point which is between two successive first nozzle means.

5. An apparatus for mixing a fluid mass comprising:
an elongated tube having a first end and a second end whereby the material to be mixed is introduced into said first end, transverses said tube and exits at said second end;
a plurality of successive first nozzles located at predeter-mined intervals along said elongated tube having a substantially radially directed conduit for introducing a high pressure fluid whereby a stream of viscous material travelling from said first end to said second end will be divided into a plurality of substreams when subjected to the impinge-ment of high pressure fluid from said first nozzles, each succeeding first nozzle means being located on opposite sides of the elongated tube from the preceding first nozzle means;
a plurality of successive second nozzles having substantially tangentially directed conduits for delivering a high pressure fluid substantially tangential to the inner surface of said conduit, each one of said second nozzles being located between two of said first nozzles along said tube and alternate second nozzles having conduits which are in opposite tangential relationship to that of the preceding nozzle, whereby the plurality of substreams will be given rotational motion when subject to the impingement of high pressure fluid from said second nozzles and whereby the rotational motion imparted to each successive substream will be in opposite direction to the next sub-stream each of said second nozzles being located on opposite sides of the elongated tube from the preceding second nozzle.

6. The apparatus of claim 5 wherein the conduits of the first nozzles are inclined in a forwardly direction toward the second end of the elongated tube at an angle of about 10° with respect to the radius of said elongated tube and the conduits of the second nozzles are inclined toward the second end of the elongated tube at an angle of about 10° with respect to the tangent to a radius whereby said substreams when subjected to the impingement of high pressure fluid have a forward motion also imparted thereto.