Agitating – Having specified feed means – Liquid injector within mixing chamber
Patent
1998-08-18
2000-12-05
Soohoo, Tony G.
Agitating
Having specified feed means
Liquid injector within mixing chamber
3661761, B01F 1502, B01F 504
Patent
active
061557102
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a method of producing emulsions used in the food industry, manufacturing of drugs and cosmetics, etc. and to a device implementing the method.
BACKGROUND ART
Techniques in which a biphasic system for which a separated state is thermodynamically stable, such as that composed of a water phase and an organic phase, is emulsified to obtain a semi-stable emulsion have been conventionally known. For general emulsification methods, as described in "Science of Emulsions" (Asakura-shoten, 1971), methods using a mixer, a colloid mill, a homogenizer, etc. and a method of dispersion with a sound wave are known.
These general methods mentioned above have such a disadvantage that diameters of dispersed phase particles in a continuous phase distribute over a wide range.
Then, a method using filtration through a membrane comprising polycarbonate (Biochemica et Biophysica Acta, 557 (1979), North-Holland Biochemical Press); a method using repeated filtrations through a PTFE (polytetrafluoroethylene) membrane (Proceedings of the 26th Autumn Meeting of the Society of Chemical Engineers, Japan, 1993); and a method of manufacturing homogenous emulsions by sending a dispersed phase into a continuous phase through a porous glass membrane with uniform pores (Japanese Patent Application Laid-Open No. 2-95433) have been proposed.
As a method of producing emulsions using a nozzle or a porous plate, a laminar-flow dripping method (KAGAKU K OGAKU vol. 21, No. 4, 1957) is also known.
Among the conventional modified methods mentioned above, the method using filtration through a membrane comprising polycarbonate and the method using repeated filtrations through a PTFE membrane cannot manufacture emulsions of particles larger than membrane pores theoretically or cannot separate particles smaller than membrane pores. These methods are therefore especially unsuitable for producing emulsions of large particles.
In the method using a porous glass membrane with uniform pores, as shown in a graph in FIG. 11, when an average diameter of membrane pores is small, particle diameters distribute in a narrow range and thus homogenous emulsions can be obtained. When an average diameter of membrane pores is increased, however, particle diameters distribute over a wide range so that homogenous emulsions cannot be obtained.
In addition, in the laminar-flow dripping method, particle sizes become 1,000 .mu. or more and distribute over a wide range so that homogenous emulsions cannot be obtained.
DISCLOSURE OF THE INVENTION
The present invention aims at solving the above-mentioned problems of prior art and intends to provide a method and a device for efficiently producing homogenous emulsions without broadening a distribution of particle diameters.
In order to achieve this object, according to the method for producing emulsions of the present invention, a pressurized dispersed phase is forced to be sent into a continuous phase through a large number of microchannels with a predetermined width formed on a base, etc.
In the device for producing emulsions of the present invention, a base on which a supply port for a dispersed phase is formed is provided, a gap to which the dispersed phase is supplied is formed between the base and a plate placed opposing the base, a boundary section between the dispersed phase and a continuous phase is formed on a side opposing the plate of the base, a large number of microchannels with a predetermined width are formed in the boundary section, and the dispersed phase is brought into contact with the continuous phase via the microchannel.
The plate opposing the base may be a transparent plate. It enables direct optical observation of channel moving of a dispersed phase and a condition of contact between the dispersed phase and the continuous phase, thereby enabling control of production of emulsions.
The boundary section, in which a large number of microchannels are formed, is provided so as to surround the supply port for the dispersed phase so that emulsions can be produce
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Biochimica et Biophysica Acta, 557 (1979) 9-23, Elsevier/North-Holland Biomedical Press, Preparation of Liposomes of Defined Size Distribution by Extrusion Through Polcarbonate Membranes, Olsen et al.
Proceedings of the 28th Autumn Meeting, Chemical Engineering Institute of Japan (1993), Membrane-Emulsifying Process Using a PTFE Membrane and Emulsion Characteristics, Biological Production Department of Hiroshima University, Japan, Kan-ichi Suzuki et al.
Effect of Surfactant on Production of Monodispersed O/W Emulsion in Membrane Emulsification, Nakashima et al., Ind. Res. Inst. of Miyazaki Prefecture, Miyazaki-shi 800, Jun. 19, 1993.
Preparationof Monodispersed O/W Emulsion by Glass Membrane, Nakashima et al. Ind.Res. Inst. of Miyazaki Prefecture, Miyazaki-shi 880, Jun. 19, 1993.
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Kawakatsu Takahiro
Kikuchi Yuji
Nakajima Mitsutoshi
Japan, as represented by Director of National Food Research Inst
Soohoo Tony G.
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