Patent Application
20060050608
One of the most promising courses for further technological development in chemical, pharmaceutical, cosmetic, refining, food products, and many other areas relates to the production of emulsions and dispersions having the smallest possible particle sizes with the maximum size uniformity. Moreover, during the creation of new products and formulations, the challenge often involves the production of two, three, or more complex components in disperse systems containing particle sizes at the submicron level. Given the ever-increasing requirements placed on the quality of dispersing, traditional methods of dispersion that have been used for decades in technological processes have reached their limits. Attempts to overcome these limits using these traditional technologies are often not effective, and at times not possible.
Hydrodynamic cavitation is widely known as a method used to obtain free disperse systems, particularly lyosols, diluted suspensions, and emulsions. Such free disperse systems are fluidic systems wherein dispersed phase particles have no contacts, participate in random beat motion, and freely move by gravity. Such dispersion and emulsification effects are accomplished within the fluid flow due to cavitation effects produced by a change in geometry of the fluid flow.
Hydrodynamic cavitation is the formation of cavities and cavitation bubbles filled with a vapor-gas mixture inside the fluid flow or at the boundary of the baffle body resulting from a local pressure drop in the fluid. If during the process of movement of the fluid the pressure at some point decreases to a magnitude under which the fluid reaches a boiling point for this pressure, then a great number of vapor-filled cavities and bubbles are formed. Insofar as the vapor-filled bubbles and cavities move together with the fluid flow, these bubbles and cavities may move into an elevated pressure zone. Where these bubbles and cavities enter a zone having increased pressure, vapor condensation takes place withing the cavities and bubbles, almost instantaneously, causing the cavities and bubbles to collapse, creating very large pressure impulses. The magnitude of the pressure impulses within the collapsing cavities and bubbles may reach 150,000 psi. The result of these high-pressure implosions is the formation of shock waves that emanate from the point of each collapsed bubble. Such high-impact loads result in the breakup of any medium found near the collapsing bubbles.
A dispersion process takes place when, during cavitation, the collapse of a cavitation bubble near the boundary of the phase separation of a solid particle suspended in a liquid results in the breakup of the suspension particle. An emulsification and homogenization process takes place when, during cavitation, the collapse of a cavitation bubble near the boundary of the phase separation of a liquid suspended or mixed with another liquid results in the breakup of drops of the disperse phase. Thus, the use of kinetic energy from collapsing cavitation bubbles and cavities, produced by hydrodynamic means, can be used for various mixing, emulsifying, homogenizing, and dispersing processes.
It will be appreciated that the illustrated boundaries of elements (e.g., boxes or groups of boxes) in the figures represent one example of the boundaries. One of ordinary skill in the art will appreciate that one element may be designed as multiple elements or that multiple elements may be designed as one element. An element shown as an internal component of another element may be implemented as an external component and vice versa.
Further, in the accompanying drawings and description that follow, like parts are indicated throughout the drawings and description with the same reference numerals, respectively. The figures are not drawn to scale and the proportions of certain parts have been exaggerated for convenience of illustration.
Illustrated in
In one embodiment, the device 10 can include a flow-through channel or chamber 15 having a centerline CL. The device 10 can also include an inlet 20 configured to introduce a fluid into the device 10 along a path represented by arrow A and an outlet 25 configured to permit the fluid to exit the device 10 along a path represented by arrow B.
In one embodiment, the flow-through chamber 15 can include an upstream portion 30 that is defined by a wall 35 having an inner surface 40 and a downstream portion 45 that is defined by a wall 50 having an inner surface 55. The upstream portion 30 of the flow-through chamber 15 can have, for example, a circular cross-section. Similarly, the downstream portion 45 of the flow-through chamber 15 can have a circular cross-section. Obviously, it will be appreciated that the cross-sections of the upstream and downstream portions 30, 45 of the flow-through chamber 15 can take the form of other geometric shapes, including without limitation square, rectangular, hexagonal, octagonal or any other shape. Moreover, it will be appreciated that the cross-sections of the upstream and downstream portions 30, 45 of the flow-through chamber 15 can be different from each other or the same.
In one embodiment, the diameter or major dimension of the upstream portion 30 of the flow-through chamber 15 is less than the diameter or major dimension of the downstream portion 45 of the flow-through chamber 15. The differences in diameter or major dimension between the upstream portion 30 of the flow-through chamber 15 and the downstream portion 45 of the flow-through chamber 15 can assist in the process of selectively generating one or more cavitation stages in the fluid. For example, the fluid can be subjected to one or more hydrodynamic cavitation stages in the upstream portion 30 of the flow-through chamber 15, but not in the downstream portion 45 of the flow-through chamber 15, which will be discussed in further detail below.
With further reference to
In one embodiment, the baffles 60a-d can be disposed in the flow-through chamber 15. For example, all of the baffles 60a-d can be initially disposed in the downstream portion of the flow-through chamber 15 as shown in
To vary the degree and character of the cavitation fields generated downstream from each baffle, the baffles 60a-d can be embodied in a variety of different shapes and configurations. For example, the baffles 60a-d can be conically shaped where the baffles 60a-d each include a conically-shaped surface 70a-d, respectively, that extends to a cylindrically-shaped surface 75a-d, respectively. The baffles 60a-d can be oriented such that the conically-shaped portions 70a-d, respectively, confront the fluid flow. It will be appreciated that the baffles 60a-d can be embodied in other shapes and configurations such as the ones disclosed in
As discussed above, each baffle 60a-d is configured to generate a hydrodynamic cavitation field downstream therefrom when a baffle is selectively moved into the upstream portion 30 of the flow-through chamber 15. Accordingly, when one or more baffles 60a-d are moved into the upstream portion 30 of the flow-through chamber 15, the fluid passing through the device 10 can be subjected to a selected number of cavitation stages depending on the number of baffles moved into the upstream portion 30 of the flow-through chamber 15. In general, the number of baffles moved into the upstream portion 30 of the flow-through chamber 15 corresponds to the number of cavitation stages that the fluid is subjected to. In this manner, the device 10 can be dynamically configurable in multiple states in order to subject the fluid to a selected number of cavitation stages.
Illustrated in
In one embodiment, the size of the local constriction 80a is sufficient enough to increase the velocity of the fluid flow to a minimum velocity necessary to achieve hydrodynamic cavitation, the minimum velocity being dictated by the physical properties of the fluid being processed. For example, the size of the local constriction 80a, or any local constriction of fluid flow discussed herein, can be set in such a manner so that the cross-section area of the local constriction 80a would be at most about 0.6 times the diameter or major diameter of the cross-section of the flow-through chamber 15. On average, and for most hydrodynamic fluids, the minimum velocity can be about 16 m/sec (52.5 ft/sec) and greater.
In this first state, the fluid is subjected to a single stage of cavitation because the first baffle 60a is the only baffle positioned in the upstream portion 30 of the flow-through chamber 15. The remaining baffles (i.e., second, third, and fourth baffles 60b-d) are positioned in the downstream portion 45 of the flow-through chamber 15, which provides gaps 85b-d defined between the inner surface 55 of the downstream wall 50 and the cylindrically-shaped surfaces 75b-d of the baffles 60b-d, respectively. The size of gaps 85b-d are sufficiently large enough so as to not materially affect the flow of the fluid. In other words, the gaps 85b-d are sufficiently large enough so that hydrodynamic cavitation is not generated downstream from each baffle positioned in the downstream portion 45 of the flow-through chamber 15.
Illustrated in
In this second state, the fluid is subjected to two stages of hydrodynamic cavitation because the first and second baffles 60a-b are positioned in the upstream portion 30 of the flow-through chamber 15. The remaining baffles (i.e., third and fourth baffles 60c-d) are positioned in the downstream portion 45 of the flow-through chamber 15, which provides gaps 85c-d defined between the inner surface 55 of the downstream wall 50 and the cylindrically-shaped surfaces 75c-d of the baffles 60c-d, respectively. The size of the gaps 85c-d are sufficiently large enough so as to not materially affect the flow of the fluid. In other words, the gaps 85c-d are sufficiently large enough so that hydrodynamic cavitation is not generated downstream from each baffle positioned in the downstream portion 45 of the flow-through chamber 15.
Illustrated in
In this third state, the fluid is subjected to three stages of hydrodynamic cavitation because the first, second, and third baffles 60a-c are positioned in the upstream portion 30 of the flow-through chamber 15. The remaining baffle (i.e., fourth baffle 60d) is positioned in the downstream portion 45 of the flow-through chamber 15, which provides the gap 85d defined between the inner surface 55 of the downstream wall 50 and the cylindrically-shaped surfaces 75d of the baffle 60d. The size of the gap 85d is sufficiently large enough so that hydrodynamic cavitation is not generated downstream from the fourth baffle 60d positioned in the downstream portion 45 of the flow-through chamber 15.
In the same manner, the fluid can be subjected to four stages of hydrodynamic cavitation by positioning all four baffles 60a-d in the upstream portion 30 of the flow-through chamber 15. It will be appreciated that since any number of baffles can be used to implement the device 10, a corresponding number of hydrodynamic cavitation stages can be generated by the device 10.
It will be appreciated that if the flow-through chamber 15 has a circular cross-section and the first baffle 60a has cylindrically-shaped portion 75a, then the local constriction 80a of fluid flow can be characterized as an annular orifice. It will also be appreciated that if the cross-section of the flow-through chamber 15 is any geometric shape other than circular, then the local constriction of flow may not be annular in shape. Likewise, if a baffle is not circular in cross-section, then the corresponding local constriction of flow may not be annular in shape.
To selectively move the one or more baffles 60a-d into the upstream portion of the flow-through chamber 15, the shaft 65 is slidably mounted in the device 10 to permit axial movement of the baffles 60a-d between the upstream portion 30 and the downstream portion 45 of the flow-through chamber 15. In one embodiment, the shaft 65 can be manually adjusted and locked into position by any locking means known in the art such as a threaded nut or collar (not shown). In an alternative embodiment, the shaft 65 can be coupled to an actuation mechanism (not shown), such as a motor, to adjust the axial position of the baffles 60a-d in the flow-through chamber 15. It will be appreciated that other suitable electromechanical actuation mechanisms can be used such as a belt driven linear actuator, linear slide, rack and pinion assembly, and linear servomotor. It will also be appreciated that other types of actuation mechanisms can be used such as slides that are powered hydraulically, pneumatically, or electromagnetically.
Illustrated in
With reference to
While the present invention has been illustrated by the description of embodiments thereof, and while the embodiments have been described in considerable detail, it is not the intention of the applicants to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the invention, in its broader aspects, is not limited to the specific details, the representative apparatus, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of the applicant's general inventive concept.
