EP1897608B1

EP1897608B1 - Mixing device for mixing a liquid product with at least one ingredient

Info

Publication number: EP1897608B1
Application number: EP07115083A
Authority: EP
Inventors: Jan Driessen
Original assignee: VERSTEGEN SPICE GROUP BV
Current assignee: Verstegen Spice Group BV
Priority date: 2006-09-05
Filing date: 2007-08-28
Publication date: 2011-07-27
Anticipated expiration: 2027-08-28
Also published as: EP1897608A1; ATE517679T1; 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 food product mixing station for mixing a liquid food product with at least one added ingredient, comprising a mixing vessel, having a mixing chamber, which is provided with at least one primary inlet for supply of the liquid product; and with mixing means which, at least during operation, reside in the mixing chamber for homogenizing the liquid product and said at least one added ingredient.
An existing mixing station of the type described in the opening paragraph consists of 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.
Document GB-A-2 072 030 discloses a food product mixing station in accordance with the preamble of claim 1.
A drawback of the existing mixing station 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 station in that the structure of the ingredients is adversely affected by the action of the stirring gear.
European patent application EP 818.235 discloses a mixing station for mixing dry materials, herbs and spices in which such cross-contamination is counteracted in that the filling, mixing and discharge of the products concerned is performed into and from one and the same mixing vessel which travels through the plant. The products are mixed with each other, primarily, by turning over the mixing vessel several times.
The present invention has for its object, among others, to provide a mixing device station which obviates these drawbacks in at least significant measure.
In order to achieve the stated object, a mixing station of the type as mentioned in the opening paragraph is characterized in that the mixing means comprise a mixing device with a primary inlet which is open communication with the mixing chamber to receive a main flow of the product at a first flow speed, with a secondary inlet which is coupled to a feed conduit for a foreign auxiliary fluid to receive an auxiliary flow of asaid foreign auxiliary fluid at a second, higher flow speed; and with a common outlet, shared by the main flow and the auxiliary which opens into the mixing chamber, and in that the mixing vessel is removable from the mixing station to be exchangeable. 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 device 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 life span 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.
With a view to a rapid transition in the mixing station from one product to a subsequent product, the mixing container comprises a mixing vessel which is removable from the device to be 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 device which has been in contact with the product. The danger of cross-contamination can thus be limited to a minimum.
It is noted that the application of a stationary mixing device is known per se from for instance EP 1.445.014 , USP 2.577.797 and WO 00/71235 for use in a storage tank for mineral oil products or waste water, respectively, in order to continuously maintain movement and disturbance of the contained product in order to inhibit the settlements of solid or semi-solid components.
French patent application FR 2.120.292 describes a mixing station for photographic solutions in which a first fluid is contained in a storage tank and is continuously recirculated to be mixed with a second fluid added externally to the re-circulating flow.
In a preferred embodiment the mixing station according to the invention is characterized in that the mixing vessel comprises on a top side a resealable closure for an access opening to the mixing chamber, that the mixing device is mounted on an distal end of a rigid arm which extends at a proximal end from the closure and that the arm comprises the 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 device 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 device according to the invention has is characterized in that the closure is provided with a primary inlet.
A further particular embodiment of the mixing station 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 station according to the invention is characterized in that the closure is coupled to a linear drive by which the closure can be carried in a substantially linear movement from a rest position located above the mixing vessel into a position ready for operation located on the mixing vessel. A further particular embodiment of a mixing station is more particularly characterized here in that the linear drive comprises a carriage traveling 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 device is also admitted into or removed from the mixing chamber.
In a further preferred embodiment the mixing station according to the invention is characterized in that the mixing vessel comprises a product outlet, that a further mixing device 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 device is in open communication with the product outlet of the mixing vessel and that at least during operation the shared outlet of the further mixing device is in open communication with the primary inlet of the mixing vessel. The mixing station thus comprises at least two mixing devices, 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 vessel for the purpose of initiating and maintaining a product flow from the product outlet of the mixing vessel to a primary inlet thereof.
Such a product circulation outside the mixing vessel 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 device. A further particular embodiment of the mixing station according to the invention is characterized for this purpose in that the further mixing device is provided on an inlet side of the main flow with inlet means for adding said 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 device and the conduits connected thereto, a further particular embodiment of the device according to the invention is characterized in that the product outlet of the mixing vessel is closable, and that the further mixing device is provided on an outlet side with a controllable closing means for closing the outlet of the further mixing device. In order to make possible discharge conduits of the further mixing device 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 device. The auxiliary flow will thus cause an overpressure in the mixing device which will force the product out of the discharge 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 device 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 device 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 vessel a further particular embodiment of the mixing station according to the invention is characterized in that a releasable discharge conduit is connectable to the product outlet of the mixing vessel, an outer end of which product outlet is in open communication with an inlet side of the further mixing device. If desired, the discharge conduit can thus be manually or automatically uncoupled from the mixing vessel in simple manner. When the above described mechanically controllable closure is for instance applied, the mixing vessel can otherwise also be released relatively simply from the mixing station.
Diverse fluids are per se suitable as auxiliary fluid for the mixing device of the mixing station 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 station according to the invention is characterized in 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 device. For this purpose a particular embodiment of the mixing station according to the invention has the feature is characterized in that the mixing device 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 is characterized in that said conduit is a conduit for carrying superheated steam during operation. 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 station according to the invention; and
figure 2: shows a side view of the mixing station 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 station of figures 1 and 2 is disposed on a flat and stable surface 10 and comprises 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,
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 vessel 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 vessel 21. The mixing means comprise a mixing device 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 device 40.
Mixing device 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. device 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 device 40 via the shared outlet 43. Just as the primary inlet 41, outlet 43 of mixing device 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 device is for instance described in the international patent application WO 01/94197 .
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 vessel, and guided into the system via a feed funnel 51.
In order to mix the thus added constituents with the product, the mixing station of this embodiment comprises close to feed funnel 51 a further mixing device 80 of the same type as mixing device 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 device 80.
The further mixing device 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 device 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 device 40.
In the light of the product flows to be processed, it is possible in respect of the further mixing device 80 to suffice with a processing capacity in the order of a quarter of that of mixing device 40 in mixing chamber 20. This is manifested in the size of the further mixing device which, with an internal diameter of 25 millimetres in respect of mixing cavity 84, has significantly less sizeable dimensions than the first mixing device 40 in mixing chamber 20. The further mixing device 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 device 80.
In order to enable relatively simple and rapid changeover from the one product to another during operation, the mixing station of this embodiment makes use of removable mixing vessels 21 as mixing vessel. 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 vessel 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 device 40 is also connected to closure 30. Placed for this purpose between mixing device 40 and closure 30 is a rigid arm 32 which positions mixing device 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 device 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 354.
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 station. 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 device 81. A coupling 63 of the flexible conduit to mixing vessel 21 comprises a closing means (not shown) which prevents product escaping from mixing vessel 21 after uncoupling of conduit 62.
During normal operation product flows from mixing vessel 21 via product conduit 62 to the further mixing device 80 and is therein mixed with ingredients which have been added via feed funnel 51. From the further mixing device 80 the product then flows back to mixing vessel 21 via an discharge product conduit 60 with a fixed portion 61 and a flexible portion 62. The discharge 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 device 80 an automatically controllable closure 85 is arranged, closing of which can be actuated in order to end the product circulation outside mixing container vessel 21. Under the influence of the steam injection in the further mixing device 80 the discharge 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 device 80. After interruption of the steam injection in the further mixing device 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 vessel 21.
During the external circulation of the product an internal circulation also takes place in the mixing vessel by means of the primary mixing device 40. Owing to this combined internal and external product circulation by means of the applied mixing devices 40,80, the mixing station 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 vessel. A cleaning step can meanwhile be performed. For this purpose the device comprises a further vessel 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 vessel 22. After closure 30 has been lowered thereon, mixing device 40 is set into operation, wherein it is flushed clean. The product conduits 61,62 of the mixing station 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 as defined in the claims.

Claims

MFood product mixing station for mixing a liquid food product with at least one added ingredient, comprising a mixing vessel (21) having a mixing chamber, (20) which is provided with at least one primary inlet (23,31) for supply of the liquid product; and with mixing means which, at least during operation, reside in the mixing chamber (20) for homogenizing the liquid product and said at least one added ingredient,
characterized in that the mixing means comprise a mixing
device (40) with a primary inlet (41) which is open communication with the mixing chamber (20) to receive a main flow of the product at a first flow speed, with a secondary inlet (42) which is coupled to a feed conduit (10,11,12,32) for a foreign auxiliary fluid to receive an auxiliary flow of a said foreign auxiliary fluid at a second, higher flow speed; and with a common outlet (43), shared by the main flow and the auxiliary flow;
which opens into the mixing chamber, and in that the mixing vessel is removable from the mixing station to be exchangeable.
Mixing station as claimed in claim 1, characterized in that the mixing vessel (21) comprises on a top side a resealable closure (30) for an access opening (23) to the mixing chamber (20), that the mixing device is mounted on an distal end of a rigid arm (32) which extends at a proximal end from the closure and that the arm comprises the feed conduit for the auxiliary fluid.
Mixing station as claimed in claim 2, characterized in that the closure is provided with a primary inlet (31).
Mixing station as claimed in claim 2 or 3, characterized in that the closure is provided with at least one venting opening (34).
Mixing station as claimed in claim 2, 3 or 4, characterized in that the closure (30) is coupled to a linear drive (35,36) by which the closure can be carried in a substantially linear movement from a rest position located above the mixing vessel (21) into an operative position, closing the mixing vessel.
Mixing station as claimed in claim 5, characterized in that the linear drive comprises a carriage (36) traveling on a linear guide (35), and that the closure extends from the carriage.
Mixing station as claimed in one or more of the preceding claims, characterized in that the mixing vessel comprises a product outlet (24), that a further mixing device (80) is provided comprising a primary inlet (81) for a main flow of the product at a first flow speed, a secondary inlet (82) for an auxiliary flow of an auxiliary fluid at a second, significantly higher flow speed, and comprising a shared outlet (83) for the main flow and the auxiliary flow, that at least during operation the primary inlet (81) of the further mixing device is in open communication with the product outlet (24) of the mixing vessel (21) and that at least during operation the shared outlet (83) of the further mixing device is in open communication with the primary inlet (31) of the mixing vessel.
Mixing station as claimed in claim 7, characterized in that the further mixing device (80) is provided on an inlet side of the main flow with inlet means (51) for adding said at least one ingredient to the main flow.
Mixing station as claimed in claim 7 or 8, characterized in that the product outlet (24) of the mixing vessel (21) is closable, and that the further mixing device (80) is provided on an outlet side with controllable closing means (86) for closing the outlet (83) of the further mixing device.
Mixing station as claimed in claim 7, 8 or 9, characterized in that a discharge conduit (62) is releasably connectable to the product outlet (24) of the mixing , vessel, having an opposite end which is in open communication with an inlet (81) of the further mixing device (80).
Mixing station as claimed in one or more of the claims 7-10, characterized in that the mixing device (40) in the mixing vessel has a higher throughput capacity than the further mixing device (80).
Mixing station as claimed in one or more of the preceding claims, characterized in that the auxiliary inlet of said mixing device is coupled to a conduit for feeding a gas under high pressure, in particular a pressure between 500 and 1500 kPa, during operation.
Mixing station as claimed in one or more of the preceding claims, characterized in that the mixing device comprises at least one constriction between the inlet for the auxiliary fluid and a mixing cavity.
Mixing station as claimed in claim 12, characterized in that said conduit is a conduit which carries superheated steam during operation.