Mixing, Homogenizing And Emulsifying Apparatus

Abstract

An apparatus for mixing, homogenizing and emulsifying liquid and liquid/solid mixtures comprises a plurality of individual chambers connected in series. Each chamber has the shape of a double frustum and adjacent chambers are connected to each other by supply and discharge channels which enter the individual chambers tangentially.

Description

BACKGROUND OF THE INVENTION

The invention relates to an apparatus, for mixing, homogenizing and emulsifying liquid and liquid/solid mixtures, of the type comprising a plurality of individual chambers arranged in series in the flow direction which are connected with one another by supply and discharge channels.

A large number of apparatus are known for mixing, homogenizing and emulsifying media having a liquid to pasty consistency. In particular for emulsifying so-called high pressure homogenizing machines are widely used. These machines generally function in such a manner that a coarse dispersion prepared in a separate installation and consisting of the ingredients to be mixed is brought to an elevated pressure, e.g., 400 kp/cm.sup.2 with the aid of a volumetrically operating pump.

Immediately thereafter the dispersion is released again through one or more narrow slot-like cross sections. If for example a water/oil mixture is subjected to such a treatment then a more or less stable emulsion is obtained. The grease and water particles are so deformed during this process that they are divided up into a plurality of small globules.

The smaller the particle size and the narrower the distribution spectrum the more stable the emulsion.

Homogenizing machines of the type described only operate with adequate homogenizing action at pressures in the range of approximately 50 and above kp/cm.sup.2. As the energy used in obtaining the necessary pressures cannot be recovered the running costs of such machines are unnecessarily high. Therefore numerous other designs have been developed which operate according to most varied methods. The homogenizing takes place hereby at pressures up to about 10 kp/cm.sup.2. Due to the smaller pressures the energy requirements of such machines are correspondingly lower. However the homogenizing action which in these designs is also substantially dependent on the pressure gradient level is reduced. Thus such machines can generally only be used for problems which are relatively easy to solve. They are not suitable for difficult tasks.

SUMMARY OF THE INVENTION

An object of the invention is therefore to obviate, or at least reduce, the described disadvantages particularly the too high power consumption, the costly and inefficient medium or high pressure pumps and the coarse dispersion plant.

This problem is solved with an apparatus of the type indicated hereinbefore according to the invention in that the individual chambers are formed in the shape of a double frustum and connecting channels are provided which enter and leave the individual chambers tangentially in such a way that in the flow direction adjacent individual chambers are alternately connected in the area of their largest cross section and then in the area of their smallest cross section.

As a result of this construction there is a multiple dividing and recombining of the flow of the material to be mixed of alternating composition and the homogeneity or efficiency of mixing of the flow of material to be mixed increases progressively with the number of separation and/or recombining actions whereby consequently the physical effect is utilised that both in a vortex source and in the vortex sump considerable flow distortions occur, i.e., secondary flows are formed which can lead to a partial mutual displacement of the particles of the material to be mixed.

As comminutable solid particles on passing through the apparatus particularly at the edges of the mouth of the connecting channels can undergo comminution, it is advantageous in view of this to so design the apparatus that the connecting pipes which enter or leave the chambers tangentially are successively smaller in their cross sectional dimensions in the flow direction.

Some substance mixtures e.g., emulsions reveal a strong increase in their consistency during treatment. For such cases it is therefore advantageous to successively widen the connecting pipes between the individual chambers of the apparatus in the flow direction.

A development of the apparatus whereby each chamber is so arranged relative to the following chamber that its largest or smallest cross section is located in the plane of the smallest or largest cross section of the previous chamber leads advantageously to a very compact possibility of arranging the individual chambers and therefore to a very compact construction of the apparatus which similarly can advantageously be so developed that the series-connected individual chambers are arranged approximately in a circular formation.

In order to obtain maximum flows it is possible whilst retaining the same solution principle to so advantageously develop the apparatus that the individual chambers comprise a plurality of superimposed and interconnected frustums.

The apparatus according to the invention is also very advantageous from a constructional and manufacturing viewpoint because it can be so developed that the centrifugal chamber comprises a housing consisting of individual plates arranged between end plates whereby in the frustum-shaped cavities and connecting channels are cut into the stacked individual plates, and which also leads to the possibility of accommodating this housing in a further housing whereby the space formed between the housings is provided with feed and discharge pipes for a cooling or heating medium, whereby according to the treatment requirements of the ingredients to be mixed an appropriate temperature control of the complete apparatus can take place. Cross sectionally frustum-shaped divisions of the mixing chamber are already known from U.S. Pat. No. 2,391,110, but in that case it is a cylindrical container which is axially traversed over its complete cross section whereby in said container conical plates are stacked and the plates are completely perforated on their surfaces. The geometry of the centrifugal chambers selected in the mixer according to the invention is a purely functional shape physically pre-determined by the desired flow pattern -- vortex source/vortex sump. The same applies for the tangential connecting channels. As opposed to this in the mixer according to U.S. Pat. No. 2,391,110 there is no necessity for having the perforated bodies in other than a plate-shaped geometry, because the flow is always axially directed and no improvement of the mixing effect can be expected from other external shapes of said perforated bodies. In the object of U.S. Pat. No. 2,391,110 in front of and behind each perforated body the same physical processes take place, i.e., a repetition of equivalent effects. However in the case of the object of this application the number of branching paths for the material for mixing increases with an increasing number of individual chambers according to a mathematical interrelationship. Thus in principle the object of the U.S. Patent relates to a parallel and series connection of a particular number of perforated bodies which are traversed by the product to be mixed, producing at their outlet cross sections a free non-directed turbulence which is associated with high pressure losses and heat generation. Much the same happens with the object of U.S. Pat. No. 3,417,967 where the product to be mixed flows through series and parallel connected perforated bodies. Once again free non-directed turbulence occurs which is linked with high energy losses and heat generation. Here again the loss factor is at an estimate at least a tenth power higher than in the mixer according to the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention, reference will now be made, by way of example, to the accompanying drawings, in which:

FIG. 1 shows a section through an apparatus in accordance with the invention;

FIG. 2 is a plan view of the apparatus shown in FIG. 1;

FIG. 3 is a section through another embodiment of an apparatus in accordance with the invention;

FIG. 4 is a section through a further embodiment of an apparatus in accordance with the invention;

FIG. 5 shows schematically one arrangement of the individual chambers of an apparatus in accordance with the invention;

FIG. 6 shows schematically a further arrangement of the individual chambers; and

FIG. 7 shows partly in section and partly in elevation an arrangement of an apparatus within a thermostatically controlled housing.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings, reference numeral 1 identifies individual chambers which are connected together by connecting pipes 2. Each chamber 1 comprises two or more frustums 5 having a larger end 3 and a smaller end 4. Disposed at either end of the chambers 1 are plates 6. Between the plates 6 are individual plates 7 into which are cut the frustums 5 as halves of the individual chambers and the connecting pipes 2. Plates 6 and 7 assembled together in a stack and correspondingly held together form the apparatus housing 8 or 8' (FIGS. 5 and 6) to which via supply openings or pipes 13 the material for mixing is supplied under pressure and whereby after traversing the individual chambers 1 it leaves the same again via the discharge opening or discharge pipe 14.

In FIGS. 1 and 2 the individual chambers 1 are series connected in such a way that the material for mixing initially flows into the chamber 1 in the area of its smallest cross section and leaves the same again in the area of largest cross section 3, and in the area of largest cross section passes into the next chamber 1 which it then leaves in the area of smallest cross section etc. FIG. 2 shows clearly the course of the connecting pipe.

The embodiment of FIG. 3 differs from that according to FIG. 1 in that the individual chambers 1 are to a certain degree nested in each other i.e., the largest or smallest cross sections 3, 4 of adjacent chambers are located in common planes.

This leads to the operational difference that the mixture flow passes from a large cross section via the relevant connecting pipe into a small cross section.

According to FIG. 4 the chambers are also to a certain extent multi-staged whereby however all partial areas of one chamber are directly connected.

As is shown by the flow arrows in this figure there is a greater fanning out of the total flow and the total throughput is obviously greater than in the embodiments of FIGS. 1 and 3.

Apart from these variants of the chamber design and arrangement it is naturally also possible to change the chambers as regards their formation.

Unlike in the arrangement according to FIGS. 1 to 4 the chambers according to FIG. 5 are arranged approximately in two circles parallel to the supply and discharge openings 13, 14 whereas according to FIG. 6 all are series connected in one approximately circular formation.

As indicated the apparatus with its individual chambers is advantageously so constructed that the apparatus housing 8 or 8' is made from individual plates 7 wherein are cut the chamber halves and connecting pipes whereafter the correspondingly worked individual plates are stacked and held together so as to be precisely aligned with the end plates 6.

The arrangement of such a shousing 8 within the thermostatically controlled housing 9 provided with supply and discharge pipes 11, 12 to the inner chamber 10 is shown in FIG. 7.

In addition to the indicated advantages this apparatus also provides the advantages of a minimum expenditure for sealing and good cleaning possibilities.

Claims

What is claimed is:

1. In apparatus, for mixing, homogenizing and emulsifying liquid and liquid/solid mixtures, of the type comprising a plurality of individual chambers series connected in the flow direction connected to one another via supply and discharge channels, the improvement comprising forming the individual chambers in the shape of a double frustum and providing connecting channels which enter and leave the individual chambers tangentially in such a way that in the flow direction adjacent individual chambers are alternately connected in the area of their largest cross section and then in the area of their smallest cross section.

2. Apparatus according to claim 1, wherein the individual chambers comprise frustums arranged with their smallest cross sections towards one another.

3. Apparatus according to claim 1 wherein the connecting pipes of the chambers in the flow direction consecutively have smaller cross sections.

4. Apparatus according to claim 1, wherein the connecting pipes of the chambers in the flow direction consecutively have larger cross sections.

5. Apparatus according to claim 1, wherein the individual chambers comprise a plurality of superimposed and interconnected frustums.

6. Apparatus according to claim 5, wherein the series connected individual chambers are arranged approximately in a circular formation, wherein said housing consists of individual plates arranged between end plates whereby the frustum shaped halves of the chamber and connecting pipes are cut into the stacked individual plates, and wherein the housing is placed in a further housing whereby the space formed between the housings is provided with supply and discharge pipes for a cooling or heating medium.

7. Apparatus according to claim 1, wherein the series connected individual chambers are arranged approximately in a circular formation.

8. Apparatus according to claim 1, comprising a housing consisting of individual plates arranged between end plates whereby the frustum shaped halves of the chamber and connecting pipes are cut into the stacked individual plates.

9. Apparatus according to claim 8, wherein the housing is placed in a further housing whereby the space formed between the housings is provided with supply and discharge pipes for a cooling or heating medium.

10. In apparatus, for mixing, homogenizing and emulsifying liquid and liquid/solid mixtures, of the type comprising a plurality of individual chambers series connected in the flow direction connected to one another via supply and discharge channels, the improvement comprising forming the individual chambers in the shape of a double frustum and providing connecting channels which enter and leave the individual chambers tangentially in such a way that in the flow direction adjacent individual chambers are alternately connected by means of the area of their smallest cross section being in communication with the area of their largest cross section.

11. In apparatus, for mixing, homogenizing and emulsifying liquid and liquid/solid mixtures, of the type comprising a plurality of individual chambers series connected in the flow direction connected to one another via supply and discharge channels, the improvement comprising forming the individual chambers in the shape of a double frustum and providing connecting channels which enter and leave the individual chambers tangentially in such a way that in the flow direction adjacent individual chambers are alternately connected by means of the area of their largest cross section being in communication with the area of their smallest cross section.