WO2010063918A1

WO2010063918A1 - Method and equipment for manufacturing deep-frozen beads

Info

Publication number: WO2010063918A1
Application number: PCT/FR2009/052250
Authority: WO
Inventors: Cémal OZTAS; Moez Tammar
Original assignee: L'air Liquide Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude
Priority date: 2008-12-04
Filing date: 2009-11-23
Publication date: 2010-06-10
Also published as: FR2939499A1; EP2373936A1; FR2939499B1

Abstract

The present invention relates to a method for manufacturing solid particles from a liquid or semi-liquid composition (1) using a device for totally or partially deep-freezing a material, the deep-freezing device being of the type where the material is placed, in a treatment tank (10), in contact with a refrigerating surface that results from the use of a vibrating carrier and a cryogenic liquid film placed on said carrier, and where the excess cryogenic liquid leaves the device along with the materials and is separated from the materials by a separation system (7) located outside the device, the thus-retrieved cryogenic liquid (7) being collected then pumped by a pump (8) so as to be reused in the equipment. The invention is characterized in that the following measures are implemented: - the equipment comprises at least one chute (6), comprising a conduit structure on all or part of the length thereof; - the equipment comprises a system (2) for producing and depositing drops of said composition into each of said conduits; - the equipment comprises a system for supplying cryogenic liquid to each of said conduits; - the system for producing drops is positioned in the immediate vicinity of the system for supplying cryogenic liquid so as to allow each drop that is produced by the system for producing drops to encounter the stream of cryogenic liquid produced by one of the openings in said system for supplying cryogenic liquid, and also to allow each drop to be carried by said stream to the conduit, that corresponds to the stream, and to the cryogenic film flowing thereon.

Description

METHOD AND INSTALLATION FOR MANUFACTURING FROZEN BALLS

The present invention relates to the field of processes and installations for the cryogenic treatment of products, in particular food, pharmaceutical or cosmetic products, the targeted processes being in particular the so-called processes of "spheronization" i.e of manufacture of solid particles (it is often said

"Pellets" in this industry), from a liquid or semi-liquid composition, especially in food applications (such as ice cream particles) or ferments, including lactic, or for example beads used in manufacturing cosmetic products.

The following documents illustrate the very abundant and sometimes ancient literature which has been devoted to this question: EP-919 279, US-4,655,047, GB-2,092,880, or US-4,982,577.

The existing solutions are for some insufficient to produce very regular particles and in the desired diameter range (for example 3 to 6 mm), or on the contrary are very powerful but much too expensive or very complex, which discourages some producing sites ( for example 200 to 300000 euros, which is considered exorbitant by some producers).

The present invention then seeks to propose a new solution for the production of such particles, which is simple, which allows both to meet the technical specifications posed while being of moderate cost, or even allowing adapt easily and inexpensively to existing equipment.

The freezing of such products is usually done in freezing tunnels where cold is obtained by mechanical means. These products that one seeks to freeze are often sticky and adhere to the carpet of the tunnel of freezing on which they are conveyed, thus posing a problem of maintenance and hygiene.

In addition, these products can be very compact and easily dislocated, thereby losing the shape they want to be given during their handling.

The Applicant has proposed in EP-A-505 222 a new concept of a process for freezing food products, according to which the product is brought into contact with a cooling surface, which results from the use of a vibrating support and a liquefied gas, the cooling surface consisting of a liquefied gas film disposed on the support.

According to this prior method, the products, even very sticky, do not adhere to the support, this despite a film thickness which can be very low, it is estimated in fact that in all likelihood the product thus treated floats on the surface of the film. gas liquefied by a phenomenon of calefaction, and turns regularly in this film, thus obviating any risk of adhesion on the support.

Typically, this system works as follows: a large quantity of liquid nitrogen is injected into the tank, which is, for example, in a slightly rising slope configuration. The overflow of liquid comes out of the device with the products. The nitrogen is then separated from the products by a grid located at the device outlet. The nitrogen thus recovered is recycled: it is collected in a reserve and then pumped back into the treatment tank.

The nitrogen level is traditionally kept substantially constant in the reserve by a valve controlled by a probe which measures the level of liquid nitrogen.

Thus the nitrogen circulates in semi-closed circuit, it leaves the circuit only by evaporation in contact with the products, this nitrogen outlet is permanently compensated by the supply of the reserve. The products make only one passage in the tank.

It should be emphasized that this prior system has many advantages among which: - The level of liquid nitrogen is stable;

- The treatment of the products is regular;

- The intensity of treatment can be adjusted by changing the slope of the tray;

- The duration of the treatment can be adjusted by modifying the amplitude of the vibrations;

- The principle is simple, easy to implement and easy to adjust;

- The strong injection of nitrogen into the tank (injection rate = pump flow) makes it possible to obtain a very effective treatment of the products.

The present invention relates to an installation for manufacturing solid particles, from a liquid or semi-liquid composition, implementing a spheronization device (bead formation), then a step of freezing total or partial products.

The present invention is based on the implementation of three steps:

the dosage and the formation of drops of product,

spheronization of the drops of products to give them a substantially rigorous shape of beads,

- Freezing total or partial balls.

The essential elements constituting the present invention can be summarized in the following.

The dosage or the formation of drops of product can be achieved by a standard device (peristaltic pumps, injectors controlled by PLCs, or other), to generate substantially identical drops, well calibrated, and preferably with a system of adjustment of the injection timing to satisfy the requested production rate.

Once emitted and formed, the drops fall on a slide through an injection system, toboggan having all or part of its length several channels (the slide can be for example formed of a corrugated plate in the form of multiple successive V as it will be better visualized in the context of the appended figures). The installation also comprises a system (preferably a percolator type) for supplying cryogenic liquid, by gravity, from each of the channels, the dosing / production system of the product drops being positioned in the immediate vicinity of the percolator to allow each drop produced meets the jet of cryogenic liquid produced by one of the orifices of the cryogen supply system (for example a percolator) and is driven by this jet to the corresponding channel and the cryogenic film circulating therein.

Adjusting the inclination of the slide makes it possible to adjust the speed of advance of the drops (beads) and the residence or spheronization time, also based on the diameter of the openings of the percolator (flow of cryogenic liquid).

The height of the cryogenic liquid in the different channels is also adjustable by the diameter of the orifices, the flow rate of the cryogenic liquid pump and the inclination of the slide. At the exit of the slide, the balls fall into the trough of a treatment tank, thus coming into contact with a cooling surface that results from the use of a vibrating support and a film of a cryogenic liquid disposed on said support, and where the overflow of cryogenic liquid leaves the apparatus with the products and is separated from the products by a separator system located at the device outlet, the cryogenic liquid thus recovered being collected and then pumped by a pump to go back -power the percolator or other system of supply of the installation in cryogenic liquid.

The present invention thus relates to an installation for manufacturing solid particles, from a liquid or semi-liquid composition, implementing a device for freezing total or partial product, of the type where it puts in contact the produced in a treatment tank with a cooling surface which results from the use of a vibrating support and a film of a cryogenic liquid disposed on said support, and where the overflow of cryogenic liquid leaves the device with the products and is separated from the products by a separating system located at the device outlet, the cryogenic liquid thus recovered being collected then pumped by a pump to be reused in the installation, characterized by the implementation of the following measures:

- The installation comprises at least one slide, having over all or part of its length a channel structure; the installation comprises a system for producing and depositing drops of said composition in each of said channels;

the installation comprises a cryogenic liquid supply system of each of said channels,

the drop production system being positioned in the immediate vicinity of the cryogenic liquid supply system, in order to allow each drop produced by the drop production system to meet the jet of cryogenic liquid produced by one of the orifices of said system of droplets; supply of cryogenic liquid and is driven by this jet to the channel corresponding thereto and the cryogenic film circulating therein; the particles at the outlet of a slide falling into the vibrating support treatment tank;

and said cryogenic liquid collected and then pumped is re-directed to said cryogenic liquid supply system of the slide.

According to one of the embodiments of the invention, there are several toboggan systems in parallel and superimposed thereby in particular to increase the production rate. It is also conceivable that the cold gases or lower slides advantageously serve to cool the slide above and thus to avoid problems of deformation of the plates.

The experiments carried out successfully by the Applicant have in fact made it possible to demonstrate that, thanks to the configuration adopted, it is possible to achieve the desired objectives, for example small balls of 3-6 mm in diameter with excellent regularity and which are frozen individually without bonding, this with equipment at extremely advantageous cost compared to equipment available on the market. Other features and advantages will emerge from the following description, given solely by way of example and with reference to the appended drawings, in which:

- Figure 1 is a schematic view of a vibrating support freezing installation according to the prior art;

FIG. 2 is a general schematic view of an installation according to the invention;

FIG. 3 is an illustration of one embodiment of the invention implementing several superimposed toboggans for increasing the production rate;

FIG. 4 is a schematic and partial representation of an embodiment of the system for producing (depositing) balls of the product, in which hot nitrogen gas, preferably in the form of a laminar flow, circulates in coaxial pipes. to the product injection lines.

In Figure 1, there is shown a schematic view of a vibrating support freezing installation according to the prior art as illustrated by EP-A-505222 mentioned above in the present description.

This schematic view shows the tank 21 (whose vibration means have not been shown here for the sake of clarity), supplied with products 22 to be frozen, and liquid nitrogen via the inlet means 24.

The tray is for this embodiment in an upward slope situation.

The overflow of cryogenic liquid comes out of the unit with the products. The nitrogen is then separated from the products by a grid system 25. As can be seen in the figure, the nitrogen thus recovered is recycled (loop 23) in the following manner: the nitrogen is collected in a reserve (20). ) and then pumped by a piston pump and thus returns to the treatment tank (return line 26).

The level of nitrogen is kept substantially constant in the reserve by a valve 27 controlled by a probe 28 which measures the level of liquid nitrogen.

In summary : - The nitrogen circulates in semi-closed circuit: it leaves the circuit only by evaporation in contact with the products. This loss of nitrogen is permanently compensated by the supply of fresh cryogenic liquid to the reserve (29).

- The products only make one pass in the tank.

FIG. 2 is a schematic overall view of an installation according to the invention:

- The slide 6 consists of channels extending in the direction of progression of the products and in the opposite direction of the direction of progression of the cryogenic liquid in the trough with vibrating support 10;

- The percolator 4 is located near the slide it supplies cryogenic liquid, by gravity, in each of the channels through orifices preferably positioned above the middle of each channel;

the system 2 for dosing and producing drops of product is positioned in the immediate vicinity of the percolator, downstream, in order to allow each drop produced to meet the jet of cryogenic liquid produced by one of the orifices of the percolator and be driven by this jet to the corresponding channel and the cryogenic film circulating there.

- At the outlet of the slide 6, the balls fall into the trough of a treatment tank 10, thus coming into contact with a cooling surface that results from the use of a vibrating support and a film or bath d a cryogenic liquid disposed on said support, and where the overflow of cryogenic liquid leaves the apparatus with the products and is separated from the products by a separating system (gate 7) situated at the device outlet, the cryogenic liquid thus recovered being collected and pumped (8) by a pump to re-feed the percolator (4).

It is noted in the figure that the percolator 4 consists of two zones: the first zone is designed to receive the liquid nitrogen from the pump 8 while the second zone is designed to avoid the eddy and have a liquid nitrogen " calm "(franc).

The bottom of the second zone is pierced with as many orifices as channels to be fed on the toboggan. FIG. 3 illustrates a possible and advantageous embodiment of the invention, using a superposition of several slides to increase the production rate, which makes it possible to have a variable and extensible production rate machine.

FIG. 4 shows, in a schematic and partial representation, an advantageous embodiment of the system for producing (depositing) beads of the product in the channels, where hot nitrogen gas (but other gases can be envisaged it will have been understood), preferably in the form of a laminar flow, circulates in coaxial pipes to the injection pipes of the product.

This production / injection system, where the output of product balls is in a certain way protected by a sleeve (sweep) of hot gas, avoids the phenomena of plugging of the orifices, clogging of the orifices which is essentially due to the low temperature of the bath of liquid nitrogen located below and the rise of cold gases from the evaporation of liquid nitrogen during the injection of the drops.

According to one of the embodiments of the invention, the production / injection system consists of:

• a set of pipes in a heat-insulated enclosure for the injection (removal) of the product

• if necessary a heating resistor on the lower part and around the injection ports of a nitrogen gas injection chamber in the preferred form of a laminar flow that flows in coaxial pipes to the injection lines (removal) of the product. During the injection of the product, this laminar flow prevents the rise of cold gases and also allows the inerting of the product during injection. The nitrogen gas injection chamber is located for example in the upper part of the injection system.

Claims

1. An installation for manufacturing solid particles from a liquid or semi-liquid composition, implementing a device for freezing all or part of a product, of the type in which the product is brought into contact with a product. treatment tank with a cooling surface which results from the use of a vibrating support and a film of a cryogenic liquid disposed on said support, and where the overflow of cryogenic liquid leaves the device with the products and is separated products by a separator system located at the device outlet, the cryogenic liquid thus recovered being collected and pumped by a pump to be reused in the installation, characterized by the implementation of the following measures:

- The installation comprises at least one slide (6), having over all or part of its length a channel structure; the installation comprises a system (2) for producing and depositing drops of said composition in each of said channels;

the installation comprises a system for supplying cryogenic liquid, of each of said channels,

and said cryogenic liquid collected and then pumped is directed to said cryogenic liquid supply system.

2. Installation according to claim 1 characterized in that said cryogenic liquid supply system is a percolator cryogenic liquid supply, by gravity, each of the channels through orifices positioned substantially above the middle of each channel .

3. Installation according to claim 1 or 2 characterized in that the system for producing and depositing drops comprises a set of pipes for depositing drops of product in each of said channels, and comprises a set of pipes coaxial with the delivery lines of the product, coaxial pipes able to receive a flow of gas, preferably of the laminar type, thus forming around the beads produced a sweep gas sleeve, thus able to avoid clogging phenomena of the orifices of the product removal pipes.