Title of Invention

METHOD AND DEVICE FOR DISSOLVING

Abstract

The invention relates to a dissolving device comprising, arranged vertically, a feed conduit (1) for the pulverulent material, a liquid feed nozzle (3) arranged concentrically with respect to the said conduit and comprising a plurality of uniformly distributed openings, a mixing tube (4) a reception column (5) comprising a deflecting plate (7) concentric with the mixing tube, an air extraction tube (8) arranged under the said plate and a tube (9) for extracting the solution. Fig. I

Full Text

Method and device for dissolving The invention relates to a method for continuously dissolving a pulverulent material in a liquid, and to the device for implementing this method. In factories it is important to provide dissolving systems, for example for dissolving milk powders, because if it is desired to prepare a mixture of powders having a composition which is constant over time, it is first necessary to dissolve this mixture of powders in the desired proportion and then to spray-dry the mixture. Filling in liquid form may also be envisaged. There are already systems for dissolving pulverulent material. Patent US 3,816,427 (corresponding Indian patent No. 138229) relates to a method and to a device for continuous dissolving, including a powder supply channel and a liquid spray nozzle. The problem with this device is that it does not avoid the formation of dust, that it does not guarantee that all the powder is properly wetted and that it can therefore lead to clogging phenomena because of the formation of lumps. Patent DE 2,650,631 also relates to a dissolving device including a channel for supplying the powder and a liquid spray nozzle. The drawback of this system, and of the previous system, is that, when the powder is supplied, it feeds a large quantity of air which should preferably be removed to avoid an excessive increase in the volume of the solution obtained. The object of the present invention is to develop a dissolving method in which the formation of dust during dissolving is minimized, in which the formation of lumps is avoided and good wettability is therefore guaranteed for the powder which is processed, and in which the increases in volume of the solution obtained are avoided. The invention relates to a method for continuously dissolving a pulverulent material in a liquid, in which the pulverulent material is sprayed radially under pressure with the liquid, mixing and dissolving are allowed to take place, the residual air is extracted and the solution is collected. It is important for the liquid supply to go inwards, because this allows uniform wetting of the powder and consequently avoids any risk of lumps being formed and therefore of the system being blocked. The pulverulent material which is processed may be of any type. Examples which may be considered are fat-free, skimmed and full-cream milk powder, casein powder. soya powder, whey powder and any type of flour, for example soya flour. As already mentioned above, a mixture of powders is, in particular, dissolved, for example a mixture of skimmed milk powder, whey protein powder and casein powder. Another benefit of the method according to the invention is that the procedure is continuous and guarantees a constant dry material content throughout production. The dry material content is not critical and depends above all on the viscosity of the final solution: the solution must remain pumpable. For example, the dry material content may vary between 10 and 65% depending on the type of powder. For casein powder, a dry material content of at most 15% must be reached, and the value is at most 60% for whey powder. In general, dissolving takes place in a time of the order of one second. When the powder enters the dissolving device, there is always a certain quantity of air which also enters. According to the invention, it is important to remove as much as possible of the air which is present: the residual air is therefore extracted. This also has the effect of minimizing the present of foam. The solution is then collected for its subsequent use, namely concentration and spray or other drying. In order to dissolve the powder properly, it is also important for the liquid to be supplied under pressure. The liquid is normally water, but could also be milk. The liquid pressure is between 1 and 10 bar, preferably 2 to 4 bar. The temperature at which the liquid is injected is not critical. The operation is normally carried out at a temperature of between 10 and 90° C, preferably between 30 and 40'C. In order to dissolve the powder properly, the pulverulent material and water must be introduced in a constant ratio. The invention also related to the device for implementing the method described above. This device comprises, arranged vertically, a feed conduit for the pulverulent material, a liquid feed nozzle arranged concentrically with respect to the said conduit and comprising a plurality of uniformly distributed opening, a mixing tube, a reception column comprising a deflecting plate concentric with the mixing tube, an air extraction tube arranged under the said plate and a tube for extracting the solution. The great advantage of the device according to the invention is that it makes it possible to work continuously without risk of causing blockages by the formation of lumps, ll is possible to operate for up to one week before cleaning. The liquid is supplied through a nozzle which includes opening around the powder supply column. These uniformly distributed holes must be small enough, on the one hand, to allow proper suction of the said powder and proper wetting. These holes are inclined so that the water goes towards the centre of the powder column. A second row of opening is arranged beside this first row, also making it possible to supply liquid. The function of this second row of opening is to allow the mixing lube to be washed, so as to ensure reliably that the powder will not remain adhering to the walls. The number of opening in this second row is smaller than that in the first row. The dimension of these second opening is the same. These opening are directed more towards the walls of the mixing tube. Ihe feed to the two rows is the same and is therefore at the same pressure. For the first row of openings, between 50 and 100 opening are provided. The second row includes about half as many openings. The size of the openings is not critical, is tailored to the water flow rate and should make it possible to ensure a pressure of between 1 and 10 bar. The working water flow rate is usually between 1000 and 10,000 1 hour. In order to create a good turbulent effect, and consequently effective and quick wetting of the powder, liquid distribution chicanes are provided in the mixing tube. These chicanes are not critical in terms of their shape and their number. The reception column includes a deflection plate so as to move the product in solution away from the centers, thus releasing the air suction tube arranged below. In a firs! embodiment, the bottom of the reception column includes a tube for extracting the solution. This tube is bent, so as to create a liquid level in the reception column, which isolates the said column from the outside, on the one hand preventing the foam from leaving and allowing good degassing by the air suction tube. The air is thus extracted without resorting to any auxiliary pump. The solution flows progressively from the extraction tube and falls into the main container, from which it is fed using a pump to the site where it is used, namely concentrating, spray drying or liquid filling. In a second embodiment, the tube for extracting the solution is connected directly to a pump which We claim: 1. Method for continuously dissloving a pulverulent material in a liquid. in which the pulverulent material is sprayed radially under a pressure between 1 and 10 bar, with the liquid a) a temperature of between 10 and 90 ° C mixing and dissolving are allowed to take place. The residual air is separated and the solution is collected. 2. Method according to Claim t, in which the liquid is water or milk. 3. Device for implementing the method according to one of claims 1 to 2, comprising, arranged vertically, a feed conduit for the pulverulent material, a liquid feed nozzle arranged concentrically with respect to the said conduit and comprising a plurality of uniformly distributed opening, a mixing tube, a reception column comprising a deflecting plate concentric with the mixing tube, an air extracting tube arranged under the said plate and a tube for extracting the solution. 4. Device according to Claim 3, in which the liquid feed nozzle comprises a second row of openings, arranged beside the first, the number of openings in this second row being smaller than (hat In the first. 5. Device according to Claim 4. In which the number of openings in the liquid feed nozzle of the first row is between 50 and 100. 6. Device according to one of Claims 3 to 5, in which the tube for extracting the solution is bent. 7. Device according to one of Claims 3 to 5, in which the tube for extracting the solution is connected directly to a pump with automatic level maintenance. 8. Device according to Claim 3, in which the mixing tube includes liquid distribution chicanes, 9. Device according to one of Claims 3 to 8, in which the air extraction tube has a serrated opening. 10. Method for continuously dissolving a pulverulent material in a liquid, substantially as hereinabove described and illustrated with reference to the accompanying drawings.

Documents:

0548-mas-97 abstract-duplicate.pdf

0548-mas-97 abstract.jpg

0548-mas-97 abstract.pdf

0548-mas-97 claims-duplicate.pdf

0548-mas-97 claims.pdf

0548-mas-97 correspondence-others.pdf

0548-mas-97 correspondence-po.pdf

0548-mas-97 description (complete)-duplicate.pdf

0548-mas-97 description (complete).pdf

0548-mas-97 drawings.pdf

0548-mas-97 form-1.pdf

0548-mas-97 form-13.pdf

0548-mas-97 form-26.pdf

0548-mas-97 form-4.pdf