EP0526416A2

EP0526416A2 - Dissolver apparatus

Info

Publication number: EP0526416A2
Application number: EP92830352A
Authority: EP
Inventors: Silvano Marin
Original assignee: AGRISTRADE Srl
Current assignee: AGRISTRADE Srl
Priority date: 1991-07-11
Filing date: 1992-07-03
Publication date: 1993-02-03
Also published as: ITBZ910022A1; ITBZ910022A0; IT1253330B; EP0526416A3

Abstract

The invention relates to a dissolver apparatus of the type constituted by a mixing tub (1) and by at least two feeding devices of the solute and of the solvent and also by a recycling device (2) of the solution (7); inside the mixing tub mixing means are arranged into which are conveyed the solvent and the solute; the said mixing means (3) is constituted by a multiple basket (9) into which a series of first nozzles (5) and second nozzles (6) are inserted, which feed the solvent into the multiple basket (9); the said multiple basket (9) is constituted by a series of vertical baffles (10) positioned concentrically with the aim of forming, internally to the basket (9), a labyrinthine course.

Description

The invention relates to a dissolver apparatus. This kind of apparatus is commonly used in the chemical field and is more specifically used for the preparation of liquid solutions or mixtures.
At present, in accordance with a first type of prior art dissolver apparatus, it is usual to prepare solutions using only ordinary diffusion. The dissolver apparatuses which employ only this principle for solution preparation are normally constituted by cylindrical recipients having a flat or concave bottom into which the solid, that is the solute, is loaded discontinuously, while the liquid, that is the solvent, is made to flow in continuously from below.
The performance of this type of dissolver apparatus is strictly connected to the parameters influencing the dissolution velocity, that is the form and the size of the solute particles and the size and the shape of the dissolver apparatus. The productive capacity of a dissolver apparatus thus made is directly proportional to the contact surface between solvent and solute; thus, to reach optimal performance level, this first type of apparatus is normally constituted by large recipients with a capacity of up to 1000 cubic metres.
If on the one hand an ordinary-diffusion dissolver apparatus is a very simple device, on the other hand its performance is conditioned by its size.
A further disadvantage is its discontinuous function.
The prior art also teaches a second type of dissolver apparatus, wherein solutions are prepared using a turbulent diffusion process.
Such dissolver apparatuses are substantially constituted like the above-mentioned ordinary dissolver apparatus, but are equipped with internal appropriate mechanical paddles to agitate the solution.
A disadvantage of the above systems is their discontinuous functioning and the presence of mechanical organs which require maintenance.
An essential aim of the present invention is thus that of obviating the above-described drawbacks manifested in the discontinuous ordinary dissolver apparatus and the discontinuous turbulent-diffusion apparatus by providing a dissolver apparatus which, depending on the loading mechanism, can be either continuous or discontinuous, with an elevated productive capacity and which is smaller with respect to the above-described dissolver apparatus given a similar productive capacity.
Further aims of the present invention are also:

a) making use of water jet mixers instead of mechanical agitators;
b) reducing to a minimum the use of mechanical devices equipped with kinematic parts and thus subject to wear;
c) obtaining, thanks to recycling mechanisms, saturated and homogeneous solutions.

These and other aims besides are all attained by the dissolver apparatus according to the present invention, which is of the type constituted by a mixing tub and by at least two feeding devices of at least one liquid part and at least one solid part as well as a recycling device, and which is characterised by the fact that inside the mixing tub mixing means are arranged into which are conveyed respectively, the solid part constituting the solute, through an aperture, and the liquid part constituting the solution, by means of a series of first and second nozzles, the liquid part being the solvent, and also characterised by the fact that the resulting solution formed within the mixing means, which is equipped with an overflow, flows through this last and is conveyed into the mixing tub.
Further characteristics and advantages of the dissolver apparatus according to the invention will better emerge from the detailed description that follows, of a preferred embodiment illustrated in the accompanying diagrams purely in the form of a non-limiting example, and in which:

Figure 1 shows a vertical section of the dissolver apparatus according to the invention;
Figure 2 shows the feeding circuit of the first and second feeding devices;
Figure 3 shows the body of the first feeding device.

With reference to the accompanying drawings, the dissolver apparatus according to the invention is formed by a tub 1 equipped with a recycling device 2.
A box 15 is inserted into the tub 1, supported on uprights 20.
Mixing means 3 are housed inside the said box 15 and are fixed to the cover 21 of the tub 1; the said mixing means 3 being constituted of a multiple basket 9 formed by vertical baffles 10 arranged concentrically.
The vertical baffles 10 form a labyrinthine course, commonly referred to as a "chicane filter", equipped with an overflow 8 and a filter 14. At the centre of the multiple basket 9 first nozzles 5 are inserted, which first nozzles 5 are of preferably tubular shape and are equipped centrally with holes 12 and, at the free end, with a spout 13 of preferably arched shape, while second nozzles 6 can be positioned between the baffles 10.
The positioning and the connecting of the first nozzles 5 and the second nozzles 6 to the recycling device 2 is schematically represented in figure 2.
The superior part of the multiple basket 9 is equipped with an ingress aperture 4 for the solid material.
Beneath the tub 1, at the level of the conical aperture 16 of the box 15, a sump 17 is housed, which is connected to the recycling device 2 fed by a pump 18.
Internally to the tub 1 and connected to the recycling device 2 are housed a third type of nozzle 19.
The functioning of the invention is as follows:
The solid part, that is the solute, is brought into the central part of the basket 9, where it is bombarded with jets exiting from the lateral holes 12 and the spout 13 of the first nozzles 5. Thus begins the turbulent dissolving process of the solute.
The solution 7 formed, in which solid not-yet dissolved particles are suspended, follows the course imposed by the baffles 10, between which the second nozzles 6 are inserted, which second nozzles 6 impose a second turbulent movement, and furthermore prevent any eventual sedimentation at the base of the basket 9 between the interspaces.
The solution, overflowing from the basket 9, returns to the tub 1, while eventual solid parts still present in the solution, passing from the filter 14 positioned along the overflow 8, are intercepted by the box 15 and thus conveyed towards the sump 17 and by action of the recycling device 2 are redeposited in the basket 9 whence the cycle recommences.
Once the loading of the solute is finished, the solution 7 formed is kept in agitation by a third type of nozzle 19 connected also to the recycling device 2 fed by the pump 18.
Naturally the dissolver apparatus according to the invention can be equipped with all the prior art devices and components according to the technical conditions. For this reason the electric command organs are not described herein, nor the dosing organs, the extraction organs and so on.

Claims

A dissolver apparatus of the type consituted by a mixing tub (1) and by at least two feeding devices of at least one liquid part and at least one solid part as well as a recycling device (2), and which is characterised by the fact that inside the mixing tub (1) mixing means (3) are arranged into which are conveyed respectively, the solid part constituting the solute, through an aperture (4), and the liquid part constituting the solution, by means of a series of first and second nozzles (5 and 6), the liquid part being the solvent, and also characterised by the fact that the resulting solution (7) formed within the mixing means (3), which is equipped with an overflow (8), flows through the said overflow (8) and is conveyed into the mixing tub (1).
A dissolver apparatus as in claim 1, characterised by the fact that the said mixing means (3) is constituted by a multiple basket (9) in which the said first nozzles (5) and the said second nozzles (6) are inserted.
A dissolver apparatus as in claim 2, characterised by the fact that the said multiple basket (9) is constituted by a series of vertical baffles (10) arranged concentrically and forming a labyrinthine course.
A dissolver apparatus according to claims 1 and 2, characterised by the fact that the said first nozzles (5) are inserted inthe central part of the said basket (9).
A dissolver apparatus as in claims 2 and 3, characterised by the fact that the said second nozzles (6) are inserted in the interspaces (11) between the said baffles (10), forming the said labyrinth.
A dissolver apparatus according to claims 2, 4 and 5, characterised by the fact that the said first nozzles (5) are constituted in their central parts by a body of preferably cylindrical shape equipped with lateral holes (12) and, at their free end, by a spout (13) which spout (13) characteristics dictate the shape of the resulting jet.
A dissolver apparatus according to claim 1, characterised by the fact that the said overflow (8) is equipped with a filter (14).
A dissolver apparatus according to claims 1, 2, 3 and 7 characterised by the fact that the said multiple basket (9) is inserted in a box (15) which is in its turn inserted in the said tub (1), terminating in an funnel-type or conical aperture (16), aimed at conveying towards the sump (17) any eventual parts of solute which have remained undissolved after having passed through the filter (14).
A dissolver apparatus according to claims 1 and 8, characterised by the fact that the said funnel-type or conical aperture (16) is at the level of the said sump (17) constituting the ingress point of the said recycling device (2).
A dissolver apparatus as in claims 1, 2, 8 and 9, characterised by the fact that the said recycling device (2) is constituted by at least one pump 18, by the said first nozzles (5) and the said second nozzles (6) and by at least a third type of nozzle (19) arranged between the said tub (1) and the said box (15).