Abstract:
Methods and apparatuses for processing product components. The methods include directing a first jet of fluid along a first path and directing a second jet of fluid along a second path to cause interaction between the jets that forms a stream oriented essentially opposite to one of the jet paths.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to processing product components. 
     Product components can be intermixed to produce a wide variety of products having different physical characteristics. For example, a colloidal system may be a stable system comprising two immiscible substance phases with one phase dispersed as small droplets or particles in the other phase. Colloids may be classified according to the original phases of their constituents. For example, a solid dispersed in a liquid may be a dispersion. A semisolid colloidal system may be a gel. An emulsion may include one liquid dispersed in another. 
     For simplicity, we will call the dispersed phase “oil” and the continuous phase “water”, although the actual product components may vary widely. Additional components may be included in a product such as emulsifying agents, known as emulsifiers or surfactants, that can stabilize emulsions and facilitate their formation by surrounding the oil phase droplets and separating them from the water phase. 
     As is described in U.S. Pat. No. 5,720,551, incorporated in its entirety, high pressure homogenizers are often used to intermix product components using shear, impact, and cavitation forces in a small zone. To prevent rapid wear to a high pressure homogenizer caused by different materials (e.g., relatively large solids), product components may be preprocessed by equipment such as ball mills and roll mills to reduce the size of such materials. 
     SUMMARY OF THE INVENTION 
     In general, in one aspect, a method of processing product components includes directing a first jet of fluid along a first path and directing a second jet of fluid along a second path. The paths are oriented to cause interaction between the jets that form a stream oriented essentially opposite to one of the jet paths. 
     Embodiments may include one or more of the following features. The first and second paths may oriented in essentially opposite directions. May be adjacent to one of the jets (e.g., a cylindrical stream surrounding one of the jets). The jets of fluid may be from a common fluid source. The jets may have identical or different jet characteristics. For example, the jets may have different velocities, for example, by ejecting the two jets at jet orifices of two different diameters. 
     In general, in another aspect, a method of processing product components includes directing a first jet of fluid from a common fluid source along a first path, directing a second jet of fluid from the common fluid source along a second path. The paths are oriented essentially opposite one another to cause interaction between the jets that forms a cylindrical stream surrounding one of the jets. 
     In general, in another aspect, a method of processing product components includes directing a first jet of fluid along a first path, directing a second jet of fluid along a second path, and causing sheer and cavitation in a third fluid by positioning the third fluid between the jets. 
     Embodiments may include one or more of the following features. The third fluid may include solids (e.g., powders, granules, and slurries). A gas may be used to position the third liquid. 
     In general, in another aspect, a method of processing product components includes directing a first jet of fluid formed from a common fluid source along a first path and directing a second jet of fluid formed from the common fluid source along a second path essentially opposite to the first path. The jets have different velocities and cause sheer and cavitation in a third fluid positioned between the jets. The jets form a stream oriented opposite one of the paths. 
     In general, in another embodiment, an apparatus for processing product components includes two nozzles configured to deliver jets of fluid along two different paths, and an elongated chamber that contains an interaction region in which the two paths meet. The chamber is configured to form a stream of fluid from the two jets that follows a path that has essentially the opposite direction from one of the paths of one of the jets. 
     Embodiments may include one or more of the following features. The apparatus may also include an outlet port configured to emit the stream. The nozzles may be aligned essentially opposite one another. The apparatus may also include an inlet port configured for receiving a second fluid. The inlet port may be aligned to position the second fluid such that the jets cause sheer and cavitation in the second fluid. The apparatus may also include a port that may be configured to be either an inlet port or an outlet port. 
     The chamber may include one or more reactors which may have different characteristics (e.g., inner diameter, contour, and composition). Seals may be positioned between the reactors. The seals may have different seal characteristics (e.g., inner diameter). 
     In general, in another aspect, an apparatus for processing product components includes two nozzles, aligned essentially opposite one another, configured to deliver respective jets of fluid along two different paths. The apparatus also includes an elongated chamber containing an interaction region in which the two paths meets. The chamber includes reactors and seals and is configured to form a stream of fluid from the two jets essentially the opposite direction from one of the paths of one of the jets. The apparatus further includes an outlet port configured to emit the stream. 
     Advantages of the invention may include one or more of the following. Very small liquid droplets or solid particles may be produced in the course of combining product components (e.g., emulsifying, mixing, blending, suspending, dispersing, de-agglomerating, or reducing the size of solid and/or liquid materials). Nearly uniform sub-micron or nano-size droplets or particles are produced. A broad range of product components may be used while maximizing their effectiveness by introducing them separately into the double-jet cell. Fine emulsions may be produced using fast reacting components by adding each component separately and by controlling the locations of their interaction. Control of temperature before and during product formation allows multiple cavitation stages without damaging heat sensitive components, by enabling injection of components at different temperatures and by injecting compressed air or liquid nitrogen prior to the final formation step. The effects of cavitation on the liquid stream are maximized while minimizing the wear effects on the surrounding solid surfaces, by controlling orifice geometry, materials selection, surfaces, pressure and temperature. A sufficient turbulence is achieved to prevent agglomeration before the surfactants can fully react with the newly formed droplets. Agglomeration after treatment is minimized by rapid cooling, by injecting compressed air or nitrogen, and/or by rapid heat exchange, while the emulsion is subjected to sufficient turbulence to overcome the oil droplets&#39; attractive forces and maintaining sufficient pressure to prevent the water from vaporizing. 
     Scale-up procedures from small laboratory scale devices to large production scale systems is made simpler because process parameters can be carefully controlled. The invention is applicable to colloids, emulsions, microemulsions, dispersions, liposomes, and cell rupture. A wide variety of immiscible liquids may be used in a wide range of ratios. Smaller amounts of (in some cases no) emulsifiers are required. The reproducibility of the process is improved. A wide variety of products may produced for diverse uses such as food, beverages, pharmaceuticals, paints, inks, toners, fuels, magnetic media, and cosmetics. The apparatus is easy to assemble, disassemble, clean, and maintain. The process may be used with fluids of high viscosity, high solid content, and fluids which are abrasive and corrosive. 
     The emulsification effect continues long enough for surfactants to react with newly formed oil droplets. Multiple stages of cavitation assure complete use of the surfactant with virtually no waste in the form of micelles. Multiple ports along the process stream may be used for cooling by injecting components at lower temperature. VOC (volatile organic compounds) may be replaced with hot water to produce the same end products. The water will be heated under high pressure to well above the melting point of the polymer or resin. The solid polymer or resins will be injected in its solid state, to be melted and pulverized by the hot water jet. The provision of multiple ports eliminates the problematic introduction of large solid particles into the high pressure pumps, and requires only standard industrial pumps. The invention also enables particle size reduction of extremely hard materials (e.g., ceramic and carbide powders). 
    
    
     Other advantages of the invention will become apparent in view of the following description, including the figures, and the claims. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIGS. 1 through 3 are block diagrams of emulsification systems. 
     FIG. 4 is a cross-sectional view of a double-jet cell assembly. 
     FIG. 5 is an enlarged cross-sectional view of an orifice of the double-jet cell assembly. 
     FIGS. 6 and 7 are schematic cross-sectional diagrams, not to scale, of fluid flow in an absorption cell. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In FIG. 1, product components are supplied from sources  110 ,  112 , and  114  into a pre-mixing system  116 . For simplicity, only three types of components are shown by way of example: water, oil, and emulsifier; but a wide variety of other components, or more than three components, could be used depending on the product to be made. The pre-mixing system  116  is of a suitable kind (e.g. propeller mixer, colloid mill, homogenizer, etc.) for the type of product. After pre-mixing, the components are fed into a feed tank  118 . In some cases, the pre-mixing may be performed inside feed tank  118 . The pre-mixed product from tank  118  then flows through line  120  and valve  122  by means of transfer pump  124  to a high pressure process pump  128 . Transfer pump  124  may be any type of pump normally used for the product, provided it can generate the required feed pressure for proper operation of the high pressure process pump. Pressure indicator  126  is provided to monitor feed pressure to pump  128 . The high pressure process pump  128  is typically a positive displacement pump, e.g., a triplex or intensifier pump. From process pump  128  the product flows at high pressure through line  130  into coil  132  where pressure fluctuations generated by the action of pump  128  are regulated by expansion and contraction of coil tubing. It may be desirable or necessary to heat or cool the feed stock. Heating system  148  may circulate hot fluid in shell  154  via lines  150  and  152 , or cooling system  156  may be used. The heating medium may be hot oil or steam with the appropriate means to control the temperature and flow of the hot fluid such that the desired product temperature is attained upon exiting coil  132 . The product exits coil  132  through line  134 , where pressure indicator  136  and temperature indicator  138  monitor these parameters. Line  134  splits into lines  134 A and  134 B to lead the product into double-jet cell  140  from both ends, such that each of the two nozzles in cell  140  is supplied with product at high pressure, for example a pressure of 15,000 psi. 
     Processing of the product components, e.g., to form a colloid system, takes place in double-jet cell  140  where the feed stock is forced through two jet generating orifices and through an absorption cell wherein the jets are forced to flow in close proximity and in essentially opposite directions, thereby causing the jets&#39; kinetic energy to be absorbed by the fluid streams. In each of the treatment stages (there may be one or more), intense forces of shear, impact, and/or cavitation break down the oil phase into extremely small and highly uniform droplets, and allow sufficient time for an emulsifier to interact with these small oil droplets to stabilize the emulsion. Before exiting the absorption cell, the processed product is forced to flow in close proximity to one of the jets which impels some of the processed product back into the absorption cell, thereby effecting repeated cycles of processing. 
     Immediately following the emulsification process the product flows through line  159  which may be a coil or other structure to effect rapid cooling. Cooling system  156  may circulate cold fluid in bath or shell  155  via lines  157  and  158 . The cooling fluid may be water or other fluids with the appropriate means to control the temperature and flow of the coolant such that the desired cooling rate and product temperature is attained. The product exits the cooler through line  142  where metering valve  144  and pressure indicator  145  are provided to control and monitor back-pressure during cooling and ensure that the hot emulsion remains in a liquid state while being cooled, thereby maintaining the emulsion integrity and stability. Finally, the finished product is collected in tank  146 . 
     In the system illustrated in FIG. 2, one or more product components are supplied from supply  110  into feed tank  118 , while other components are supplied from sources  112  and  114  directly into double-jet cell  140 . For simplicity and by way of example, water is fed into H.P. pump  128  while oil and emulsifier are fed directly into cell  140 ; but a wide variety of other components could be used depending on the product to be made. Water may be the continuous phase or the discontinuous phase depending on its ratio to oil. Typically, components that would be fed directly into cell  140  are materials that could not flow through the H.P. pump  128  and/or through the orifice inside cell  140  because they are too viscous and/or abrasive (e.g., resins, polymers, Alumina ceramic powder). Some components may be mixed together to reduce the number of separate feed lines, or there may be as many feed lines as product components. 
     Water from tank  118  flows through line  120  and valve  122 , by means of transfer pump  124  to the H.P. pump  128 . Elements  128  through  138  and  148  through  158  have similar functions to the same numbered elements of the system of FIG.  1 . 
     Oil and emulsifier, each representing a possibly unlimited number and variety of components which may be introduced separately, flow from sources  112  and  114  into double-jet cell  140  through lines  162  and  164 , each line having a pressure indicator  170  and  172  and a temperature indicator  174  and  176 , by means of metering pumps  166  and  168 . Metering pumps  166  and  168  are suitable for the type of product pumped (e.g. sanitary cream, injectable suspension, abrasive slurry) and the required flow and pressure ranges. For example, in small scale systems peristaltic pumps are used, while in production system and/or for high pressure injection, diaphragm or gear pumps are used. 
     Inside double-jet cell  140  the water is forced through two orifices creating two water jets. Other product components, as exemplified by the oil and emulsifier, are injected into double-jet cell  140 . The interaction between the extremely high velocity water jet at one end of double-jet cell  140  and the stagnant components from lines  162  and  164  subjects the product to a series of treatment stages. In each stage intense forces of shear, impact, and/or cavitation break down the oil and emulsifier to extremely small and highly uniform droplets, and allows sufficient time for the emulsifier to interact with the oil droplets. After the interaction between the water jet at one end of double-jet cell  140  and the components from lines  162  and  164 , the processed mixture meets the second water jet of the other end of double-jet cell  140 . The second water jet generates additional forces of shear, impact, and/or cavitation to further reduce the size of oil droplets and increase their uniformity. The second water jet also carries some of the processed product back into the absorption cell thereby effecting repeated cycles of processing. Immediately following the emulsification process, the emulsion is cooled and then exits the double-jet cell  140  and is collected, all in a manner similar to the one used in the system of FIG.  1 . 
     In the system illustrated in FIG. 3, a product&#39;s liquid phase is supplied from supply  210  into feed tank  118 , while a solid phase is supplied from source  212  into feed tank  200 . Compressed gas source  214  may be used to facilitate solids flow and/or to effect cooling inside double-jet cell  140 . 
     Liquid from tank  118  flows through line  120  and valve  122  by means of transfer pump  124  to the high pressure process pump  128 . Elements  128  through  138  and  148  through  158  have similar functions to the same numbered elements of the system in FIG.  1 . 
     Solids, representing a possibly unlimited number and variety of materials in various states (dry powders, granules, slurries, etc.), may be introduced separately through line  264  by means of transfer pump  268  into feed tank  200 . Transfer pump  268  may be selected for the type and state of the solids. For example, dry powders may be fed with a screw pump while granules or slurries may be fed with a diaphragm pump. The solids may be melted if necessary in feed tank  200  by means of heating system  148  and lines  150  and  152 . Such heating may be required for melting materials such as resins or polymers. Solids from tank  200  flow through line  201  and valve  202  by means of metering pump  203  into double-jet cell  140 . Metering pump  203  is suitable for the type of solids pumped and the required flow and pressure ranges. For solids that should be introduced in dry powder form, compressed gas  214  is supplied. Compressed gas (such as air or Nitrogen) from source  214  flows through line  262  and is regulated by regulator  270 . Gas flow into the feed tank discharge line  201  facilitates and regulates the flow of powder into double-jet cell  140 . 
     Inside double-jet cell  140  the liquid phase is forced through two dissimilar orifices, creating two dissimilar jets. The orifices are dissimilar in such a way to create a vacuum in one end of the cell and positive pressure in the other end. For example, one orifice is made larger then the other. The jet from the larger orifice creates a vacuum before entering the absorption cell and creates positive pressure at the other end of the absorption cell. The solid phase is injected into double-jet cell  140  at a point where the liquid jet has generated the vacuum. 
     The interaction between the extremely high velocity liquid jet at one end of double-jet cell  140  and the stagnant solids line  201  subjects the product to a series of treatment stages. In each stage intense forces of shear, impact, and/or cavitation break down the solids to extremely small and highly uniform particles (or droplets if in melted form), and allows sufficient time for the emulsifier to interact with the solids particles and/or droplets. After the interaction between the first liquid jet at one end of double-jet cell  140  and the solids from line  201 , the processed mixture meets the second liquid jet from the other end of double-jet cell  140 . The second liquid jet generates additional intense forces of shear, impact, and/or cavitation to further reduce the size of solid particles/droplets and increase their uniformity. The second liquid jet also carries some of the processed product back into the absorption cell, thereby effecting repeated cycles of processing. Immediately following this process, the processed product is cooled, exits the double-jet cell  140 , and is collected, all in a manner similar to the one used in the system of FIG.  1 . Alternatively, compressed gas through line  271  may be fed into double-jet cell  140  to effect rapid cooling. The decompression of the gas inside cell  140  is coupled with rapid cooling of the gas and thus of the product. 
     As seen in FIG. 4, the double-jet cell  140  is constructed using a series of pieces. In the example of a basic double-jet cell in FIG. 4 there are two (identical) inlet fittings  10 , two bodies  11 , retainer  12 , and coupling  16 . In one end of each inlet fitting  10 , a standard high pressure port  20  is provided, for example ⅜″ H/P (e.g. Autoclave Engineers #F375C). The other end of each inlet fitting  10  makes a pressure containing metal-to-metal seal with a nozzle  13 . Referring also to FIG. 5, sealing surface  40  of nozzle  13  fits into sealing surface  41  of inlet fitting  10 , while sealing surface  42  of nozzle  13  fits into sealing surface  43  in body  11 , making pressure containing metal-to-metal sealing between members  10 ,  13  and  11  upon fastening inlet fitting  10  into body  11 . Nozzle  13  is press-fitted with a ceramic insert  2  which contains orifice  23 . An absorption cell  17  is constructed using a series of reactors  14  and seals  15  held within a lumen of retainer  12  and the ends of the bodies  11 . Reactors  14  are made of an abrasion resistant material such as ceramic or stainless steel depending on product abrasiveness and the reactor lumen inner diameter (e.g. 0.02 inch to 0.12 inch). Seals  15  are made of plastic unless the process requires elevated temperature, in which case other materials such as stainless steel may be used. Upon fastening simultaneously bodies  11  at the two ends of double-jet cell  140 , the series of reactors  14  and seals  15  form a pressure containing absorption cell. Ports  27  and  28  are standard ¼″ M/P (e.g. Autoclave Engineers #F250). The function of ports  27  and  28  varies depending on the system configuration (FIGS.  1  through  3 ). 
     In the type of system shown in FIG. 1, port  27  functions as the discharge port of double-jet cell  140  while port  28  is plugged. Pre-mixed components are fed into the double-jet cell through ports  20  at both ends of the double-jet cell, flow through round openings  21  (e.g. ⅛″ dia. hole), and flow through round openings  22  (e.g. {fraction (1/16)}″ dia. hole). The product liquid is then forced by high pressure through orifice  23 . The diameter of orifice  23  determines the maximum attainable pressure for any given flow rate. For example, a 0.015 in. dia. hole will enable 10,000 psi with a flow rate of 1 liter/min. of water. More viscous fluids require an orifice opening as large as 0.032 in. dia. to attain the same pressure and flow rate, while smaller systems with pump capacity under 1 liter/min. require an orifice as small as 0.005 in dia. to attain 10,000 psi. The high velocity jet is ejected from orifice  23  into opening  24  (e.g. {fraction (1/16)}″ dia. hole) in nozzle  13  and then into opening  25  (e.g. {fraction (3/32)}″ dia. hole) in body  11 . Opening  25  in body  11  communicates with round opening  26  (e.g. {fraction (3/32)}″ dia.) in body  11 . Processing of the product begins in orifices  23  at both ends of the double-jet cell, where the product is accelerated to a velocity exceeding 500 ft/sec. upon entering orifices  23 . This sudden acceleration which occurs simultaneously with a severe pressure drop causes cavitation in the orifice. Cavitation, as well as shear due to the extremely high differential velocity in the orifice, cause break down of the discontinuous phase droplets or particles. 
     Referring now to FIG. 6, coherent jet stream  50  formed in orifice  23  is maintained essentially unchanged as it flows through openings  24 ,  25  and  35  in one end of double-jet cell  140  while coherent jet  51  is maintained essentially unchanged as it flows through openings  36 ,  29  and  31  in the other end of cell  140 . Jet  50  enters the absorption cell through opening  27 , while jet  51  enters the other end of the absorption cell through opening  31 . The two jet streams  50  and  51  impact each other in cavity  32  and form a coherent flow stream  53 . The coherent flow pattern is formed and flows in the direction of exit cavity  32 . Stream  53  exits cavity  32  through opening  35  and ejects into opening  25 . Finally, the processed product  54  exits dual-jet cell  140  through opening  26  and opening  35 . 
     The absorption cell geometry may be easily varied to intensify or curtail the forces of shear, impact and/or cavitation that act on the product. Jet velocity is determined by the size and shape of orifices  23  and by the pressure setting of the H.P pump  128 . The velocity of coherent stream  53  is determined by the inner diameter of reactors  14 . Coherent stream  53  may flow in laminar or turbulent flow patterns, depending on the inner diameter of seals  15 . When seals  15  have the same inner diameters as reactors  14  (not shown), stream  53  will be laminar. When seals  15  have larger inner diameters than reactors  14  (shown), stream  53  will be turbulent. Large reactor inner diameters with laminar flow may be used to effect a more gentle process for products sensitive to shear or cavitation. Smaller reactor inner diameters with turbulent flow may be used to effect intense shear, repeated stages of cavitation, and impact through repeated interaction. The process may be made gradual or with several stages of increasing or decreasing process intensity by assembling various sizes of reactors  14  and seals  15 . Process duration may be easily determined by the number of reactors  15 . Retainer  12  is made with male and female threads of the same size. This enables connecting one, two, or three retainers (not shown) in a single dual-jet cell assembly which in turn enables use of different numbers of reactors (e.g., one to twenty). 
     In the type of system shown in FIG. 2, port  27  functions as inlet port for the oil phase, while port  28  functions as the discharge port of double-jet cell  140 . Water phase is fed into the double-jet cell  140  through ports  20  at both ends of cell  140  and is forced by high pressure through orifices  23  in a manner similar to the one used in the system of FIG.  4 . 
     Referring now to FIG. 7, in the system shown in FIG. 2, jet stream  50  is maintained essentially unchanged as it flows through openings  24  in one end of the double-jet cell while jet  51  is maintained essentially unchanged as it flows through openings  28  in the other end of the double-jet cell. Jet  50  is made more intense than jet  51  by using a larger orifice to generate jet  50  than to generate jet  51 . Since both ends of double-jet cell  140  are subjected to the same pressure, the flow rate through the larger orifice is higher then through the smaller orifice. The two jet streams  50  and  51  impact each other in cavity  32  and form a coherent flow stream  53 . Because jet  50  is more intense than jet  51 , coherent stream  53  exits the double-jet cell through opening  30  and port  28 . Because jet  50  flows uninterrupted and at a very high velocity through opening  25 , vacuum develops in opening  25 . The vacuum facilitates flow of oil through port  27  and opening  26 . 
     The process begins when the high velocity jet  50  meets the much lower velocity stream  56  of oil. The high differential velocity between jet  50  and stream  56  generates intense shear forces. Depending on local temperature, relative velocity and vapor pressure of the two phases, cavitation may be effected in opening  25  due to hydraulic separation. The process continues in cavity  32  where the impact between the two jets and the interaction between coherent stream  53  and jet  51  effect intense and controllable mixing in a manner similar to the one used in the system of FIG.  6 . 
     Stream  53  exits cavity  32  through opening  31  and ejects into opening  29 . Finally, the processed product  55  exits dual-jet cell  140  through opening  30  and port  28 . 
     In the type of system shown in FIG. 3, port  27  functions as an inlet port for the solids phase, while port  28  functions as the discharge port of double-jet cell  140 . The liquid phase is fed into the double-jet cell  140  through ports  20  at both ends of the double-jet cell  140  and is forced by high pressure through orifice  23  in a manner similar to the one used in the system of FIG.  4 . The liquid phase may be the continuous or discontinuous phase depending on the relative flow rates of solids and liquid. Processing in the double-jet cell  140  is in a manner similar to the one used in the system of FIG.  7 . The ability to introduce components directly into the double-jet cell, bypassing the H.P pump and orifices, enables processing of extremely viscous and/or abrasive materials. This feature is particularly useful for replacing a common use of VOC. The interaction between two high velocity jets  50  and  51 , and the repeated interaction between the coherent stream  53  and jet  51 , enable particle size reduction of extremely hard materials such as ceramic and carbide powders. 
     Other embodiments are within the scope of the following claims.