Emulsification device for continuously producing emulsions and/or dispersions

Abstract

The invention relates to an emulsification device for continuously producing emulsions, nano-emulsions, and/or dispersions having a liquid crystalline structure, comprising a) at least one mixing system, b) at least one drive for the stirring element, and c) at least one delivery unit for each component or each component mixture.

Claims

1. An emulsifying device for continuous production of emulsions and/or dispersions comprising a) at least one mixing apparatus comprising a rotationally symmetric chamber sealed airtight on all sides, at least one inlet line for introduction of free-flowing components, at least one outlet line for discharge of the mixed free-flowing components, a stirrer unit which ensures laminar flow and comprises stirrer elements secured on a stirrer shaft, the axis of rotation of which runs along the axis of symmetry of the chamber and the stirrer shaft of which is guided on at least one side, wherein the at least one inlet line is arranged upstream of or below the at least one outlet line, wherein the ratio between the distance between inlet and outlet lines and the diameter of the chamber is 2:1, wherein the ratio between the distance between inlet and outlet lines and the length of the stirrer arms of the stirrer elements is 3:1-50:1, and wherein the ratio of the diameter of the stirrer shaft, based on the internal diameter of the chamber, is 0.25 to 0.75 times the internal diameter of the chamber, such that the components introduced into the mixing apparatus via the at least one inlet line are stirred and continuously transported by means of a turbulent mixing area on the inlet side, in which the components are mixed turbulently by the shear forces exerted by the stirrer elements, a downstream percolating mixing area in which the components are mixed further and the turbulent flow decreases, a laminar mixing area on the outlet side, in which a lyotropic, liquid-crystalline phase is established in the mixture of the components, in the direction of the outlet line, b) at least one drive for the stirrer unit and c) at least one conveying device per component or per component mixture.

2. The emulsifying device as claimed in claim 1, characterized in that the chamber has the shape of a hollow cylinder, of a frustocone, of a funnel, of a frustodome, or a shape composed of these geometric shapes, the diameter of the chamber remaining constant or decreasing from the inlet line to the outlet line and the stirrer unit being adapted correspondingly to the shape of the chamber.

3. The emulsifying device as claimed in claim 1, characterized in that the ratio between the diameter of the chamber and the distance between inlet and outlet lines is in the range from 1:50 to 1:2.

4. The emulsifying device as claimed in claim 1, characterized in that the ratio of the diameter of the stirrer shaft to the diameter of the chamber is 0.3 to 0.7.

5. The emulsifying device as claimed in claim 1, characterized in that at least one constituent of the stirrer elements is arranged in parallel and spaced apart from the inner wall of the chamber.

6. The emulsifying device as claimed in claim 1, characterized in that the stirrer unit is a full-blade or part-blade stirrer or a full-wire stirrer or a part-wire stirrer, or a combination of these.

7. The emulsifying device as claimed in claim 1, characterized in that the chamber has at least one baffle which promotes a laminar flow.

8. The emulsifying device as claimed in claim 1, characterized in that the at least one mixing apparatus has a plurality of rotationally symmetric chambers connected in series.

9. The emulsifying device as claimed in claim 1, characterized in that the mixing apparatus as the first mixing apparatus has at least one further mixing apparatus connected downstream, a lyotropic and liquid-crystalline phase being present in the mixture of the components downstream of the first mixing apparatus, and the viscosity of the mixture in the at least one further mixing apparatus downstream being equal to or less than the viscosity downstream of the first mixing apparatus.

10. The emulsifying device as claimed in claim 1, characterized in that at least one flow sensor is arranged in at least one of the lines.

11. The emulsifying device as claimed in claim 1, characterized in that at least one device for temperature control is coupled to at least one of the lines, such that the components, component mixtures and/or emulsions or dispersions are coolable or heatable.

12. The emulsifying device as claimed in claim 1, characterized in that the drive, the conveying device and a sensor, and the device for temperature control are connected to a control device for the monitoring and control of the mixing apparatuses, the supply and removal of the components, component mixtures, or emulsions or dispersions, the control device controlling the system such that the viscosity of the mixture obtained in the first mixing apparatus is always greater than or equal to the viscosity in the downstream mixing apparatus(es) and a laminar flow of the mixed components is ensured.

13. The emulsifying device as claimed in claim 12, characterized in that the control device is or can be connected to a remote maintenance module and/or a formula management module.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) The invention is illustrated more closely with the aid of the following figures and working examples, without restricting it. These show

(2) FIG. 1 Emulsifying device containing a mixing apparatus

(3) FIG. 2 Various mixing apparatus geometries

(4) FIG. 3 Various stirrer units

(5) FIG. 4 Emulsifying device containing a mixing apparatus with a further supply line in the percolating area

(6) FIG. 5 Emulsifying device containing two mixing apparatuses

(7) FIG. 6 Emulsifying device containing two mixing apparatuses and a heat exchanger

(8) FIG. 7 System scheme

(9) FIG. 8 Energy diagram

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(10) FIG. 1 shows in sectional representation an emulsifying device containing a mixing apparatus 1 having a rotationally symmetric chamber 2 sealed on all sides in the form of a hollow cylinder. Into the chamber projects baffles 16, and a stirrer shaft 10, on which are arranged the stirrer wires 11, as shown in FIG. 3D. The stirrer shaft 10 is driven by the motor 12 and guided by the bearings and seals 8. Furthermore, the stirrer shaft 10 is additionally guided in the bearing 9 in the bottom part of the chamber 2. The chamber 2 has inlet lines 5 or 6 in the lower part for the air-free supply of the components A and B to be emulsified. In the upper part of the chamber 2 is arranged the outlet line 7. Inlet and outlet lines are likewise temperature controlled and have corresponding supply pumps (not shown in FIG. 1).

(11) The ratio between the distance between inlet lines 5 and 6 and outlet line 7 and the diameter of the chamber 2 is approximately 3.5.

(12) The ratio between the distance between inlet lines 5 and 6 and outlet line 7 and the length of the stirrer arms of the wire stirrers is approximately 15:1.

(13) The chamber 2 is surrounded by a thermostat jacket 3, which in combination with the thermostat 4 allows temperature control of the mix. On account of the greater distance between inlet and outlet compared to the chamber diameter, the mix can be heated in a controlled manner such that the energy input caused by the stirrer does not destabilize the mix.

(14) The emulsifying device according to FIG. 1 can be utilized as follows, for example, for the dilution of 100 kg per hour of sodium lauryl ether sulfate (SLES):

(15) By means of the pump of phase A, 41.4 kg per hour of 70% SLES is led continuously via the inlet line 5 and by means of the pump of phase B 58.6 kg per hour of water is led continuously via the inlet line 6 into the mixing apparatus 1 and mixed at 3000 revolutions per min.

(16) The mixing apparatus 1 is sealed on all sides and is operated with exclusion of air. The components A and B to be mixed are introduced into the chamber 2 of the mixing apparatus 1 as flowable streams, mixed by means of the stirrer unit 10 containing the stirrer wires 11 until the mixed components reach the outlet line 7 and are led off such that no air penetrates into the chamber 2 of the mixing apparatus 1.

(17) On putting the mixing apparatus into operation, the air contained therein is completely displaced within a short time by the entering components A and B, whereby the application of a vacuum is advantageously unnecessary.

(18) The mixed components A and B pass through the chamber 2 of the mixing apparatus 1 gradually beginning from the inlet 5, 6 to the outlet 7. The components A and B introduced into the chamber 2 via the inlet lines 5, 6 firstly migrate through an inlet-side turbulent mixing area, in which they are turbulently mixed by the shear forces exerted by the stirrer wires 11. In a percolating mixing area connected above it, the components are mixed further, the turbulent flow decreasing and the viscosity increasing until a lyotropic, lamellar liquid-crystalline phase establishes in an outlet-side laminar mixing area. The temperature of the mixture is kept constant by means of the thermostat jacket 3.

(19) 28% strength SLES is obtained at the exit of the stirring stage.

(20) FIG. 4 shows in sectional representation a single-stage emulsifying device, which is constructed and dimensioned analogously to FIG. 1, but has a further inlet line 13 for a component C. Inlet and outlet lines are temperature-controlled and are operatively connected to pumps (not shown in FIG. 4).

(21) The emulsifying device according to FIG. 4 can be utilized as follows for the production of a simple O/W spray.

(22) Component A: aqueous emulsifier phase

(23) Component B: oil phase

(24) Component C: water phase

(25) Component A is continuously introduced air-free at 8.1 kg per hour via the inlet line 5 and component B at 22.5 kg per hour via the inlet line 6 into chamber 2 of the mixing apparatus 1 and mixed at approximately 3000 revolutions per min. The components A and B are mixed by means of the stirrer unit 10 with the stirrer wires 11. After the mixture has passed through approximately 60% of the chamber length, the component C is metered into the mixing chamber at 69.4 kg per hour via the inlet line 13 and mixed until the mixed components reach the outlet line 7. On putting into operation the mixing apparatus 1, the air contained therein is completely displaced by the entering components within a short time, whereby the application of a vacuum is advantageously unnecessary.

(26) The mixed components A and B pass through the mixing apparatus 1 gradually beginning from the inlet 5, 6 to the outlet 7. The components A and B introduced via the inlet lines 5, 6 into the chamber 2 firstly pass through an inlet-side turbulent mixing area, in which they are mixed turbulently by the shear forces exerted by the stirrer wires 11. In a percolating mixing area connected above it, the components A and B are further mixed, the turbulent flow decreasing and the viscosity increasing until a lyotropic, liquid-crystalline phase establishes in an outlet-side laminar mixing area and in which the component C is supplied via the inlet line 13. The temperature of the mixture is kept constant by means of the thermostat jacket 3.

(27) FIG. 5 shows in sectional representation an emulsifying device containing two mixing apparatuses 1 and 1.

(28) The emulsifying device according to FIG. 5 is distinguished in that it consists of two mixing apparatuses 1 and 1 connected in series, the outlet line 7 of the first mixing apparatus 1 being connected with the inlet line of the following mixing apparatus 1. Each mixing apparatus 1 and 1 has a thermostat jacket 3 or 3 and can be individually temperature controlled, if desired, by means of the thermostat 4 or 4. Stirrer elements are wire stirrers fixed to the stirrer shaft according to the representation of FIG. 3 D.

(29) The ratio between the distance between inlet lines 5 and 6 and outlet line 7 and the diameter of the chamber 2 of the mixing apparatus 1 is approximately 2.0.

(30) The ratio between the distance between inlet lines 5 and 6 and outlet line 7 and the length of the stirrer arms of the wire stirrers is 8:1.

(31) Chamber 2 of the mixing apparatus 1 corresponds in construction and dimensioning to the chamber 2 of the mixing apparatus 1.

(32) The mixing apparatuses 1 and 1 are equipped with sensors for viscosity, pressure and temperature (not shown here). The mixing apparatuses 1 and 1 are sealed on all sides.

(33) The emulsifying device according to FIG. 5 can be utilized as follows for the production of a simple OW emulsion (120 kg per hour).

(34) Component A: emulsifier with additional base for neutralization of the thickener

(35) Component B: oil phase

(36) Component C: water phase with thickener

(37) Component A is continuously introduced at 5.65 kg per hour via the inlet line 5 and component B at 21.93 kg per hour via the inlet line 6 into chamber 2 of the mixing apparatus 1 and mixed at approximately 3000 revolutions per min. The components A and B are mixed by means of the stirrer unit 10 with the stirrer wires 11 until the mixed components reach the outlet line 7 and are led off into the chamber 2 of the mixing apparatus 1 such that no air penetrates into the chamber 2 of the mixing apparatus 1. On putting into operation the mixing apparatus 1 and 1, the air contained therein is completely displaced by the entering components within a short time, whereby the application of a vacuum is advantageously unnecessary.

(38) The mixed components A and B pass through the mixing apparatus 1 gradually beginning from the inlet 5, 6 to the outlet 7. The components A and B introduced via the inlet lines 5, 6 into the chamber 2 firstly pass through an inlet-side turbulent mixing area, in which they are mixed turbulently by the shear forces exerted by the stirrer wires 11. In a percolating mixing area connected above it, the components A and B are further mixed, the turbulent flow decreasing and the viscosity increasing until a lyotropic, lamellar liquid-crystalline phase establishes in an outlet-side laminar mixing area. The temperature of the mixture is kept constant by means of the thermostat jacket 3.

(39) Phase C is introduced into the chamber 2 at 72.42 kg per hour together with the highly viscous mixture of the components A and B via the inlet line 13. By means of stirrer unit 10 and stirrer wires 11, the components are mixed until they reach the outlet line 7 and are led off such that no air penetrates into the chamber 2.

(40) In the chamber 2, the highly viscous mixture of the components A and B is diluted with the water phase of the component C to give a flowable emulsion having a particle size of 400 nm and a viscosity of 15 000 m Pas. The thickener there serves for emulsion stabilization and influences the skin sensation positively.

(41) FIG. 6 shows in sectional representation an emulsifying device containing two mixing apparatuses 1 and 1 and an intermediately connected plate heat exchanger 15. The emulsifying device according to FIG. 6 is constructed and dimensioned analogously to the emulsifying device according to FIG. 5. The additional inlet line 13 for the component C and the plate heat exchanger 15 in the outlet line 7 to the inlet into chamber 2 is different.

(42) The emulsifying device according to FIG. 6 can be used as follows for the production of a pearlescent agent (100 kg per hour).

(43) TABLE-US-00001 Vessel Component Component temperature Throughput A SLES room 22 kg per temperature hour (RT) B glycol 70 C. 24 kg per distearate hour C water, RT 21 kg per betaine (co- hour surfactant) D water and RT 33 kg per preservative hour Temperature strand phase A: RT Temperature strand phase B: 80 C. Temperature strand phase C: RT Temperature strand phase D: RT Temperature stirring stage 1 65 C. Temperature stirring stage 5 C. 2: Temperature heat 40 C. exchanger: Stirring stage 1: 3000 rpm Stirring stage 2: 3000 rpm

(44) Component A is introduced at 22 kg per hour and at room temperature continuously via the inlet line 5 and component B is introduced at 24 kg per hour at a temperature of 80 C. via the inlet line 6 into the chamber 2 of the mixing apparatus 1 and mixed at approximately 3000 revolutions per min. The inlet line 6 is temperature controlled such that component B is heated and is led into the chamber 2 at a temperature of 80 C.

(45) When the components A and B mixed by means of the stirrer unit 10 with the stirrer wires 11 reach the area of the inlet line 13, the component C is fed into the mixture at 21 kg per hour and a temperature of 65 C. via the inlet line 13. The thermostat jacket 3 of the chamber 2 is temperature controlled at 65 C. by means of the thermostat 4 such that the components A, B and C are mixed at 65 C.

(46) After feeding in component C, the mixture passes over to a percolating area until it reaches a lyotropic, liquid-crystalline state in the area of the outlet line 7.

(47) Before the lyotropic, liquid-crystalline mixture removed via outlet line 7 is supplied to the chamber 2, this mixture is cooled to 40 C. by means of the plate heat exchanger 15 connected in the line 7. This is necessary, since the liquid-crystalline precursor, which is prepared in the mixing apparatus 1, is temperature-sensitive. The liquid-crystalline precursor is then diluted with the phase D in the second mixing apparatus 1 with counter cooling by the heating/cooling jacket at a temperature of 5 C. The product quality can only be achieved by maintaining this temperature profile. If dilution with the cold phase D was carried out above 40 C., the quality requirements on the product could not be fulfilled. If the product is cooled too deeply before diluting, a product is likewise obtained that does not meet the quality demands. This is owed to the fact that the liquid-crystalline precursor assumes different liquid-crystalline structures depending on the temperature, from which different end states are achieved on dilution.

(48) In FIG. 7, a scheme of a complete emulsifying system for the production of a shampoo is shown. The emulsifying system comprises 3 mixing apparatuses 1, 1 and 1, storage containers A to D for the components A to D to be mixed, connecting lines for the supply of the components A to D to the appropriate mixing apparatuses with associated pumps E, E, E, E and valves, connecting lines for the removal of components, thermostats 4, 4 and 4 for the temperature control of the mixing apparatuses 1, 1 and 1, a control device (not shown in FIG. 7), which monitors and regulates all process stages, a display device (not shown in FIG. 7) with an operating part for the visualization and input of process variables.

(49) The connecting lines between the mixing apparatuses 1 and 1 and also 1 and 1 are equipped with temperature sensors T for the temperature control of the mixing chambers.

(50) The mixing apparatuses and connecting lines have sensors for product and process control (not shown in FIG. 7).

(51) Furthermore, the outlet lines of the individual mixing apparatuses can have further sensors, which, for example, make possible continuous particle size measurement, directly or in a bypass, a temperature measurement, a pressure measurement or the like.

(52) The system according to FIG. 7 is explained with the aid of an emulsifying example for the production of a shampoo.

(53) The following components are stored in the storage tanks: component A: sodium laureth sulfate (SLES) 70% component B: water, preservative, co-surfactant component C: pearlescent agent component D: water, salt, colorants

(54) The three mixing apparatuses 1, 1, 1 which are in each case equipped with a thermostat jacket and have their own heating/cooling circuit form the core constituents. In the mixing apparatus 1, a highly viscous gel phase is produced from the individual components (component A, component B, component C). The mixing apparatus 1 serves for the subsequent stirring of the gel phase which then led to the mixing apparatus 1, to be diluted there with component D.

(55) Component A, component B and component C are aspirated using eccentric spiral pumps E, E and E and supplied to the first mixing apparatus 1 in the ratio 1:3.71:0.36. The component D is supplied to the mixing apparatus 1 using the pump E in the ratio 2.21 based on component A. The pumps were selected such that they supply a uniform, non-pulsing component flow. Each pump must supply a minimal stable supply stream that is sufficient for a total production amount of 100 kg to 300 kg per hour. Eccentric spiral pumps are very highly suitable in the scheme shown, since they are uncritical with regard to changing viscosities.

(56) On account of the fact that in the system shown schematically in FIG. 7, no flow meters for the individual product streams are present, advantageously a pump is to be chosen which has a linear transport characteristic line. Thus changing transport rates can be calculated simply. In systems with flow meters (volume or mass), nonlinear pumps such as, for example, gear wheel pumps can also be employed without problem.

(57) The pumps E are designed for a counter pressure of up to 5 bar. By means of the exits component A to component D, the transport amount of the respective pump can be determined simply at a set speed of rotation. The determination of the transport amount at 100 rpm offers itself here. The corresponding transport stream is captured and weighed in a previously tared vessel for the period of 1 min. This process is repeated three times and the mean value is formed from all three transport streams. The transport stream of the pump thus averaged can then be converted by means of the three set to the desired transport stream needed for the recipe.

(58) Using the speeds thus determined, the pumps and the motors of the stirrer units are now started. The pumps transport only the required amounts of the individual components to the mixing apparatuses in order to obtain the final product. By means of the built-in pressure sensors P, the resulting pressure can be controlled, and in the case of overpressure in the pipeline or the mixing apparatuses the control can react accordingly and emit a warning, stop the system, or take similar countermeasures. By means of the temperature sensors integrated into the outlet lines of the individual mixing apparatuses, the product temperature can be determined and utilized for controlling the temperature control equipment of the double jacket or otherwise processed in the control or a peripheral apparatus.

(59) In the production of the shampoo, the total efficiency of the complete system was measured as a function of total flow.

(60) The total power consumption was measured at a throughput of 100 kg/hour, 150 kg/hour, 200 kg/hour, 250 kg/hour, 300 kg/hour and 400 kg/hour. The measurements determined were plotted in an XY graph (FIG. 8).

(61) Conditions:

(62) Emulsifying system having 3 mixing chambers

(63) Chamber diameter: 50 mm

(64) Stirring tool: part-wire stirrer

(65) Measured values:

(66) TABLE-US-00002 Energy consumption Throughput [kg/h] [kW] 100 1.08 150 1.13 200 1.17 250 1.26 300 1.25 400 1.28

(67) If the values are extrapolated with the aid of a statistics program, even with a throughput of 10 000 kg/h a total energy requirement of 2 kW is not exceeded.