EP1897608A1

EP1897608A1 - Mixing device for mixing a liquid product with at least one ingredient

Info

Publication number: EP1897608A1
Application number: EP07115083A
Authority: EP
Inventors: Jan Driessen
Original assignee: Verstegen Holding BV
Current assignee: VERSTEGEN SPICE GROUP B.V.
Priority date: 2006-09-05
Filing date: 2007-08-28
Publication date: 2008-03-12
Anticipated expiration: 2027-08-28
Also published as: ATE517679T1; EP1897608B1; NL1032428C2

Abstract

A mixing device comprises a mixing container (21) with a mixing chamber (20) for receiving a liquid product with at least one ingredient therein. The mixing chamber comprises at least one primary inlet (31) for supply of the product and is provided with mixing means for homogenizing the product in the mixing chamber. The mixing means comprise a mixing apparatus (40) in the mixing chamber with a primary inlet (41) for a main flow of the product at a first flow speed, with a secondary inlet (42) for an auxiliary flow of an auxiliary fluid at a second, significantly higher flow speed, and with a shared outlet (43) for the main flow and the auxiliary flow. Both the primary inlet (41) and the outlet (43) of the mixing apparatus (40) are, at least during operation, in open communication with the mixing chamber (20).

Description

The present invention relates to a mixing device for mixing a liquid product with at least one ingredient, comprising a mixing container with a mixing chamber for receiving the product therein, at least one primary inlet for supply of the product, and with mixing means for homogenizing the product in the mixing chamber.
An existing mixing device of the above described type comprises a stationary mixing container with a mixing chamber for receiving therein a liquid and one or more ingredients. Accommodated in the mixing chamber is a stirring gear which, when energized, sets the product into movement and eventually mixes the ingredients through the liquid to form a homogenous end product. This end product can for instance be a sauce or dressing such as can be used in many types and flavours in, among others, the food processing industry, the kitchen and at table.
A drawback of the existing mixing device is that, when the composition of the product for preparing is changed, an extensive cleaning programme must be followed in order to remove traces of the previously mixed product from the internal parts of the mixing container, and in particular the stirring gear. This is not only necessary from a hygienic viewpoint, but also serves particularly to prevent cross-contamination of products. In addition, some ingredients have a poor interaction with the known mixing device in that the structure of the ingredients is adversely affected by the action of the stirring gear.
The present invention has for its object, among others, to provide a mixing device which obviates these drawbacks in at least significant measure.
In order to achieve the stated object, a mixing device of the type stated in the preamble has the feature according to the invention that the mixing means comprise a mixing apparatus in the mixing chamber with a primary inlet for a main flow of the product at a first flow speed, with a secondary inlet for an auxiliary flow of a foreign auxiliary fluid at a second, significantly higher flow speed, and with a shared outlet for the main flow and the auxiliary flow, that the secondary inlet is coupled to a feed conduit for the auxiliary fluid and that, at least during operation, both the primary inlet and the outlet of the mixing apparatus open into the mixing chamber. A foreign fluid is here understood to mean a product which differs from the product received in the mixing chamber.
Due to the great difference in flow speed of the auxiliary flow relative to the main flow the main flow will be entrained by the auxiliary flow as soon as the two flows come together. This propulsion of the main flow, and the shockwaves occurring here, provides for an agitation of the flowing product, which will thereby mix without moving parts being required for the purpose. The wholly or partially homogenized product appears at the outlet of the mixing apparatus and then re-enters the mixing chamber. From here the product is once again available for a subsequent circulation, until a complete homogenization of the product is achieved.
The possible adverse effect on a structure of ingredients in the product can thus be avoided due to the absence of moving parts acting on the product. Furthermore, the absence of moving parts results in a markedly simpler cleaning step once the product has been prepared, in addition to an increased lifespan and reduced susceptibility to breakdown. In addition, the device according to the invention is found to be significantly more effective and more efficient in practice than the existing device, so that a full homogenization can be realized in a considerably shorter time than has been possible heretofore.
In a preferred embodiment the mixing device according to the invention has the feature that the mixing container comprises on a top side a releasable closure which can be placed in an access opening of the mixing container, that the mixing apparatus is mounted on an outer end of a rigid arm which extends from an opposite outer end of the closure and that the arm comprises a feed conduit for the auxiliary fluid. The product for mixing, or at least a fraction thereof, can thus be admitted via the access opening, after which the mixing apparatus can be carried into the mixing chamber in a single operation while the mixing chamber is closed. In order to also allow feed of product to the mixing vessel during operation while the closure remains in its position, a particular embodiment of the device according to the invention has the feature that the closure is provided with a primary inlet. A further particular embodiment of the mixing device has the feature according to the invention that the closure is provided with at least one venting opening. The at least one venting opening in the closure herein avoids an inadmissible pressure build-up in an otherwise closed mixing vessel, which could otherwise be the particular consequence of feeding the auxiliary fluid to the mixing chamber.
In order to have the exchange of a mixing vessel take place as automatically as possible, a further preferred embodiment of the mixing device according to the invention has the feature that the closure is coupled to a linear drive with which the closure can be carried in a substantially linear movement from a rest position located above the mixing container into a position ready for operation located on the mixing container. A further particular embodiment of a mixing device is more particularly characterized here in that the linear drive comprises a carriage which can travel on a linear guide, and that the closure extends from the carriage. The closure can thus be operated in fully mechanical manner, wherein the mixing apparatus is also admitted into or removed from the mixing chamber.
With a view to a rapid changeover of the mixing device from one product to a subsequent product, a further preferred embodiment of the mixing device has the feature according to the invention that the mixing container comprises a mixing vessel which is removable from the device and exchangeable. After preparation of the product, the exchangeable mixing vessel can thus be readily removed and exchanged for a subsequent similar mixing vessel. An intermediate cleaning step can thus be limited to practically only the mixing apparatus which has been in contact with the product. The danger of cross-contamination can thus be limited to a minimum.
In a further preferred embodiment the mixing device according to the invention is characterized in that the mixing container comprises a product outlet, that a further mixing apparatus is provided comprising a primary inlet for a main flow of the product at a first flow speed, a secondary inlet for an auxiliary flow of an auxiliary fluid at a second, significantly higher flow speed, and comprising a shared outlet for the main flow and the auxiliary flow, that at least during operation the primary inlet of the further mixing apparatus is in open communication with the product outlet of the mixing container and that at least during operation the shared outlet of the further mixing apparatus is in open communication with the primary inlet of the mixing container. The mixing device thus comprises at least two mixing apparatuses, one of which is accommodated in the mixing chamber for the purpose of homogenizing the product therein, and another of which is placed outside the mixing container for the purpose of initiating and maintaining a product flow from the product outlet of the mixing container to a primary inlet thereof.
Such a product circulation outside the mixing container not only enhances homogenization of the product but also provides an additional possibility of adding one or more ingredients to the product via the further mixing apparatus. A further particular embodiment of the mixing device according to the invention is characterized for this purpose in that the further mixing apparatus is provided on an inlet side of the main flow with inlet means for supplying at least one ingredient to the main flow.
In order to drive the product, if desired, in relatively simple and adequate manner out of the further mixing apparatus and the conduits connected thereto, a further particular embodiment of the device according to the invention has the feature that the product outlet of the mixing container is closable, and that the further mixing apparatus is provided on an outlet side with a controllable closing means for closing the outlet of the further mixing apparatus. In order to make possible outflow conduits of the further mixing apparatus free of product, the closing means can be opened on the outlet side while the product outlet of the mixing vessel is closed and the auxiliary flow of the auxiliary fluid is maintained in the further mixing apparatus. The auxiliary flow will thus cause an overpressure in the mixing apparatus which will force the product out of the outflow conduits via the primary inlet in the mixing vessel. By actuating closure or at least closing the closing means on the outlet side while the auxiliary flow of the auxiliary fluid is maintained in the further mixing apparatus and the product outlet of the mixing vessel is opened, a product flow will however be initiated in the opposite direction due to the overpressure in the auxiliary fluid, wherein the product is driven out of the mixing apparatus and possible feed conduits. All in all, the device can then be cleaned relatively efficiently and as little product as possible is lost.
Particularly for use with an exchangeable mixing container a further particular embodiment of the mixing device according to the invention has the feature that a releasable outflow product conduit can be coupled to the product outlet of the mixing container, an outer end of which product outlet is in open communication with an inlet side of the further mixing apparatus. If desired, the outflow conduit can thus be manually or automatically uncoupled from the mixing container in simple manner. When the above described mechanically controllable closure is for instance applied, the mixing container can otherwise also be released relatively simply from the mixing device.
Diverse fluids are per se suitable as auxiliary fluid for the mixing apparatus of the mixing device according to the invention. In order however that the composition of the liquid product is not affected thereby, or hardly so, a further preferred embodiment of the mixing device according to the invention has the feature that the auxiliary fluid comprises a gas under high pressure, in particular with a pressure between 500 and 1500 kPa. At such a pressure the fluid is carried at an exceptionally high to supersonic speed into the mixing apparatus. For this purpose a particular embodiment of the mixing device according to the invention has the feature that the mixing apparatus comprises at least one constriction between the inlet for the auxiliary fluid and a mixing cavity. As a consequence of such a constriction the flow speed of the auxiliary fluid will be accelerated to supersonic values. The shockwaves caused thereby provide an exceptionally effective and efficient mixing of the product with the ingredients added thereto without damaging these ingredients.
In a further preferred embodiment the device has the feature that the auxiliary fluid comprises superheated steam. In addition to an auxiliary fluid for mixing the different components in the product, the superheated steam here also provides a full or partial heating of the product to a desired preparation temperature. Simultaneous sterilization of the product is even a possibility here.
The invention will now be further elucidated with reference to an exemplary embodiment and an associated drawing. In the drawing;

figure 1: shows a front view of an exemplary embodiment of a mixing device according to the invention; and
figure 2: shows a side view of the mixing device of figure 1.

The figures are otherwise purely schematic and not drawn to scale. For the sake of clarity some dimensions in particular may be exaggerated to a greater or lesser extent. Corresponding parts are designated in the figures with the same reference numeral.
The mixing device of figures 1 and 2 is disposed on a flat and stable surface 10 and comprises a mixing container in the form of an exchangeable mixing vessel 21. Situated in the mixing vessel is a mixing chamber 20 with a volume of about 150 litres for the purpose of receiving at least one liquid product therein. In this example use is made of wholly stainless steel mixing vessels 21 for the purpose of durability and for reasons of product hygiene. The invention is however also suitable for other mixing containers and for smaller and larger vessels, as well as for a mixing device on the basis of a fixed mixing container.
A starting point is for instance one or more aqueous or oily basic components of a sauce, dressing, soup or other liquid product mixture of which use is made in the food processing industry or the kitchen. These components are poured into mixing container 21 from above via an opening 23 which is provided for this purpose and which is closable by a removable closure 30. For preparation of an end product this liquid fraction must be mixed, usually at an increased preparation temperature, with further ingredients which are added to the product.
For this purpose the device comprises mixing means in mixing container 21. The mixing means comprise a mixing apparatus 40 having a substantially cylindrical internal mixing cavity 44 with an internal diameter of about 47 mm which is in open communication with a primary inlet 41 for a main flow of the product and with a secondary inlet 42 for an auxiliary flow of an auxiliary fluid. Mixing cavity 44 debouches in a shared outlet 43 for the main and auxiliary flows. Applied in this example as auxiliary fluid is superheated steam which is supplied from a steam conduit 10 provided for this purpose at a pressure in the order of 600-1000 kPa and a flow rate of about 600 kg per hour. Steam conduit 10 comprises a fixed part 11 and a flexible conduit 12 with which the steam conduit is coupled to mixing apparatus 40.
Mixing apparatus 40 internally comprises a system of constrictions (not shown) between steam inlet 42 and mixing cavity 44, whereby the auxiliary fluid is injected at a supersonic speed into the mixing cavity at the above stated pressure and flow rate values. Apparatus 40 herein transports a product flow of a maximum of 55,000 litres per hour, which at the above stated cavity diameter amounts to a maximum flow speed of a maximum of about 8.8 metres per second, this therefore being significantly lower than the flow speed of the auxiliary fluid.
The supersonic inlet of the auxiliary fluid causes a controlled supersonic shockwave which develops further as the wave penetrates further into the product flow. The product flow is herein accelerated and propelled by the auxiliary flow. A mixing zone is thus created from a centre of the cavity, in which an exceptionally efficient transfer of momentum from the auxiliary fluid to the product mixture occurs, whereby an exceptionally effective admixing into the product takes place without moving parts acting on the product. The constituents in the product do not therefore suffer any damage whatsoever as a result of this mixing.
The product flow and the auxiliary flow leave mixing apparatus 40 via the shared outlet 43. Just as the primary inlet 41, outlet 43 of mixing apparatus 40 is in open communication with mixing chamber 20, whereby a product circulation is initiated in mixing chamber 20 which results within a few minutes in full homogenization of the content of mixing vessel 21. Due to the absence of moving parts or the like acting on the product, damage to the product or other adverse effects on the ingredients are avoided. Such a mixing apparatus is for instance described in the international patent application WO 01/94197 , the content of which should be deemed as cited and incorporated herein.
Feed means 50 are provided outside mixing vessel 21 for the purpose of adding dry substances as ingredients. These are specifically ingredients such as salts, sugars, binders, herbs, spices and other aromatic and flavouring substances, but also coarser constituents such as optionally dried, shredded vegetables and fruits, raisins, nuts and the like. These ingredients are pre-mixed with each other in a desired mutual ratio and in a quantity adjusted to the volume of the mixing container, and guided into the system via a feed funnel 51.
In order to mix the thus added constituents with the product, the mixing device of this embodiment comprises close to feed funnel 51 a further mixing apparatus 80 of the same type as mixing apparatus 40 in mixing vessel 21. During operation a primary inlet 81 hereof is in open communication with a product outlet 24 of mixing vessel 21 for the purpose of receiving a product flow therefrom. On an inlet side the feed funnel 51 debouches into this product flow so that the ingredients added via the funnel are taken up directly into the product flow and (pre-) mixed with the liquid fraction of the product by the further mixing apparatus 80.
The further mixing apparatus also comprises a secondary inlet 82 for an auxiliary fluid which is also supplied with superheated steam under high pressure of about 600 kPa. Via a shared outlet 83 of the further mixing apparatus for the auxiliary fluid and the main flow the product flow is guided via a product conduit 60 to the mixing vessel. The product conduit also comprises one or more fixed parts 61 and one or more flexible conduits 62. Via a primary inlet 31 provided for this purpose in closure 30 the product flow is carried into mixing chamber 24 for homogenizing therein by the primary mixing apparatus 40.
In the light of the product flows to be processed, it is possible in respect of the further mixing apparatus 80 to suffice with a processing capacity in the order of a quarter of that of mixing apparatus 40 in mixing chamber 20. This is manifested in the size of the further mixing apparatus which, with an internal diameter of 25 millimetres in respect of mixing cavity 84, has significantly less sizeable dimensions than the first mixing apparatus 40 in mixing chamber 20. The further mixing apparatus 80 is operated at an auxiliary fluid flow rate of about 180 kg per hour and a maximum product flow therein amounts to about 14,000 litres per hour. The flow speed of the main flow amounts in that case to a maximum of about 7.9 metres per second, while the auxiliary fluid is injected supersonically via constrictions provided for this purpose into mixing cavity 84 of mixing apparatus 80.
In order to enable relatively simple and rapid changeover from the one product to another during operation, the mixing device of this embodiment makes use of removable mixing vessels 21 as mixing container. These are open on a top side and can be pre-filled via opening 23 with one or more basic components of the product. These are specifically the liquids which serve as basis for the product, such as for instance food oils and/or water. During operation the opening 23 is closed with the closure which is provided for this purpose and which can be moved from a rest position located above mixing vessel 21, as shown in figure 2, into a position ready for operation on mixing container 21 of figure 1, wherein the top side of the mixing vessel is sealed liquid-tightly.
In order to allow a fully automatic process, the closure is connected to a displaceable carriage 36 which is arranged on a linear guide 35 and which is driven via a belt or chain by an electric motor 37. Closure 30 is also provided with a primary inlet 31 and a thermometer 33 to enable close monitoring of a product temperature during the process. The primary mixing apparatus 40 is also connected to closure 30. Placed for this purpose between mixing apparatus 40 and closure 30 is a rigid arm 32 which positions mixing apparatus 40 at a desired depth in mixing vessel 21. Rigid arm 32 is hollow and also comprises a part of the feed conduit for the auxiliary fluid. On the outer side the closure is provided with the necessary connections 13 for flexible feed conduits for respectively the product and the auxiliary fluid. The mixing apparatus 40, thermometer 33 and primary inlet 31 are brought into position by closing the vessel 21 with closure 30. In order to avoid an inadmissible pressure build-up taking place in mixing vessel 21 during the process as a result of the injection of the auxiliary fluid, closure 30 is provided at different locations with venting openings 35.
On an underside the mixing vessel comprises a product outlet 24 to and from which a flexible product conduit 62 can be coupled and uncoupled in order to respectively incorporate mixing vessel 21 in and release it from the mixing device. Using a free outer end remote from mixing vessel 21 the flexible product conduit 62 is in open communication with a primary inlet 81 of the further mixing apparatus 81. A coupling 63 of the flexible conduit to mixing vessel 21 comprises a closing means (not shown) which prevents product escaping from mixing container 21 after uncoupling of conduit 62.
During normal operation product flows from mixing container 21 via product conduit 62 to the further mixing apparatus 80 and is therein mixed with ingredients which have been added via feed funnel 51. From the further mixing apparatus 80 the product then flows back to mixing vessel 21 via an outflow product conduit 60 with a fixed portion 61 and a flexible portion 62. The outflow product conduit 60 herein debouches in primary inlet 31 of closure 30. This external product circulation is sustained at least until the desired quantity of ingredients has been introduced via funnel 51 into the product. On an inlet side 81 of the further mixing apparatus 80 an automatically controllable closure 85 is arranged, closing of which can be actuated in order to end the product circulation outside mixing container 21. Under the influence of the steam injection in the further mixing apparatus 80 the outflow product conduit 60 will be flushed empty so that as little product residue as possible remains therein. An automatically controllable closure 86 is likewise arranged on an outlet side 83 of the further mixing apparatus 80. After interruption of the steam injection in the further mixing apparatus 80, closing of this closure 86 is actuated and closure 85 on the inlet side is then opened. After resumption of the steam injection the product conduit 62 will now be emptied by spraying, wherein the product is driven via product outlet 24 to mixing container 21.
During the external circulation of the product an internal circulation also takes place in the mixing container by means of the primary mixing apparatus 40. Owing to this combined internal and external product circulation by means of the applied mixing apparatuses 40,80, the mixing device can be utilized in exceptionally versatile and efficient manner. The whole content of mixing vessel 21 can thus be fully homogenized within less than 10 minutes. After the closure 30 has been moved to the rest position, see figure 2, and the product outlet 24 uncoupled, the device is ready for a following mixing container. A cleaning step can meanwhile be performed. For this purpose the device comprises a further container 22 which is filled with a suitable cleaning liquid. The displaceable carriage 36 is able to pivot the guide 35 through a determined angle, wherein closure 30 is carried above this further container 22. After closure 30 has been lowered thereon, mixing apparatus 40 is set into operation, wherein it is flushed clean. The product conduits 61,62 of the mixing device can also be flushed from the further mixing vessel 22. The whole process can be monitored and controlled by an operator at a terminal 90 with display.
Although the invention has been further elucidated above on the basis of only a single exemplary embodiment, it will be apparent that the invention is by no means limited thereto. On the contrary, many variations and embodiments are still possible within the scope of the invention.

Claims

Mixing device for mixing a liquid product with at least one ingredient, comprising a mixing container with a mixing chamber for receiving the product therein, at least one primary inlet for supply of the product, and with mixing means for homogenizing the product in the mixing chamber, characterized in that the mixing means comprise a mixing apparatus in the mixing chamber with a primary inlet for a main flow of the product at a first flow speed, with a secondary inlet for an auxiliary flow of a foreign auxiliary fluid at a second, significantly higher flow speed, and with a shared outlet for the main flow and the auxiliary flow, that the secondary inlet is coupled to a feed conduit for the auxiliary fluid and that, at least during operation, both the primary inlet and the outlet of the mixing apparatus open into the mixing chamber.
Mixing device as claimed in claim 1, characterized in that the mixing container comprises on a top side a releasable closure which can be placed in an access opening of the mixing container, that the mixing apparatus is mounted on an outer end of a rigid arm which extends from an opposite outer end of the closure and that the arm comprises a feed conduit for the auxiliary fluid.
Mixing device as claimed in claim 2, characterized in that the closure is provided with a primary inlet.
Mixing device as claimed in claim 2 or 3, characterized in that the closure is provided with at least one venting opening.
Mixing device as claimed in claim 2, 3 or 4, characterized in that the closure is coupled to a linear drive with which the closure can be carried in a substantially linear movement from a rest position located above the mixing container into a position ready for operation located on the mixing container.
Mixing device as claimed in claim 5, characterized in that the linear drive comprises a carriage which can travel on a linear guide, and that the closure extends from the carriage.
Mixing device as claimed in one or more of the foregoing claims, characterized in that the mixing container comprises a mixing vessel which is removable from the device and exchangeable.
Mixing device as claimed in one or more of the foregoing claims, characterized in that the mixing container comprises a product outlet, that a further mixing apparatus is provided comprising a primary inlet for a main flow of the product at a first flow speed, a secondary inlet for an auxiliary flow of an auxiliary fluid at a second, significantly higher flow speed, and comprising a shared outlet for the main flow and the auxiliary flow, that at least during operation the primary inlet of the further mixing apparatus is in open communication with the product outlet of the mixing container and that at least during operation the shared outlet of the further mixing apparatus is in open communication with the primary inlet of the mixing container.
Mixing device as claimed in claim 8, characterized in that the further mixing apparatus is provided on an inlet side of the main flow with inlet means for supplying at least one ingredient to the main flow.
Mixing device as claimed in claim 8 or 9, characterized in that the product outlet of the mixing container is closable, and that the further mixing apparatus is provided on an outlet side with controllable closing means for closing the outlet of the further mixing apparatus.
Mixing device as claimed in claim 8, 9 or 10, characterized in that a releasable outflow product conduit can be coupled to the product outlet of the mixing container, an outer end of which product outlet is in open communication with an inlet side of the further mixing apparatus.
Mixing device as claimed in one or more of the claims 8-11, characterized in that the mixing apparatus in the mixing container has a higher throughflow capacity than the further mixing apparatus.
Mixing device as claimed in one or more of the foregoing claims, characterized in that the auxiliary fluid comprises a gas under high pressure, in particular with a pressure between 500 and 1500 kPa.
Mixing device as claimed in one or more of the foregoing claims, characterized in that the mixing apparatus comprises at least one constriction between the inlet for the auxiliary fluid and a mixing cavity.
Mixing device as claimed in claim 13, characterized in that the auxiliary fluid comprises superheated steam.