The present invention relates to the field of designing and manufacturing thermal exchange systems for the thermal treatment of fluids, and especially the field of plate exchangers for the treatment of heterogeneous fluids.

The invention relates more particularly to a homogenisation device of an inlet flow of said fluid in such a plate exchanger.

In the above field, it has been noted by users of thermal exchangers with welded plates that the treatment of certain fluids, especially heterogeneous fluids such as gas-liquid mixtures or liquid-solid mixtures, produces very low yields and above all rapid and premature wearing of bundles of plates of the exchanger, causing production stoppages for repairing or replacing the exchangers frequently, and therefore considerable extra production costs.

These phenomena, particularly encountered in the field of hydrometallurgy for cooling mineral muds, have been explored by the applicant in an effort to understand the causes. Studies undertaken have consequently shown that the phenomena of wear and poor resulting yields were essentially due to poor distribution of the fluid veins to be treated at the level of the admission chamber of the exchangers, with especially, in the case of treating viscous and/or heterogeneous products, concentrations of materials localised on the inlet surface of the bundle of plates of the exchanger, causing considerable losses of charges as well as the early wear of the bundle in these localised zones. It should also be noted that the angle of incidence of the fluid veins in a direction perpendicular to the inlet of the exchange chambers covers a fundamental importance as to the rapid development of local eroded zones able to rapidly reach large dimensions.

The aim of the present invention is to resolve these problems associated with poor distribution of a fluid at the inlet of a plate exchanger within the scope especially of treatment of heterogeneous fluids, this poor distribution of the fluid itself being able to be generated by poor arrangement of the piping and/or of the nozzle of the admission elements upstream of the bundle.

Another aim of the invention consists in procuring a solution to the abovementioned problems which is economical and simple to carry out and to use.

Another aim of the invention consists in procuring a solution to the abovementioned problems which does not need any or very few modifications on the existing plate exchangers.

The different aims of the invention are achieved hence to a homogenisation device of a material flow, in particular of fluid veins, at the inlet of a plate exchanger, said device being designed and adapted to be arranged in the admission chamber of said plate exchanger, and this substantially against the bundle of plates of said exchanger. This device is composed of a plate, of sufficient thickness to resist the pressure of the material flow, constituted with orifices, preferably circular, distributed uniformly over the entire surface of said plate and generating uniform and parallel distribution of the fluid veins on the inlet surface of the bundle of the plate exchanger.

Such a homogenisation device has the advantage, when introduced into the admission chamber of a plate exchanger, of re-accelerating, re-mixing, distributing and guiding the fluid veins towards the bundle of the plate exchanger. By introduction of the device of the invention at the inlet of a plate exchanger, the angles of attack of the fluid veins to the right of the inlet of the bundle of the exchanger are therefore reduced to a minimum.

Thus, the fluid passing through the perforations of the device exhibits a uniform and parallel flow rate on exiting said perforations and therefore at the inlet of the bundle of plates of the exchanger.

In addition, the fluid to be treated no longer risks being concentrated at a few places of the surface of the bundle nor impacting the latter violently, but is distributed uniformly over the entire section due to carefully placed perforations in the homogenisation device.

Initial assays conducted thus showed a reduction in losses of charges and phenomena of wear at the level of the bundles of plates when the device of the invention is introduced into the admission chamber of an exchanger.

According to a first preferred characteristic of the device of the invention, the total area of the orifices represents between 35% and 45% of the total surface of the perforated plate, and, preferably, substantially 40%.

In addition, in keeping with another preferred characteristic of the invention, the diameter of the orifices of the perforated plate is between 20 and 30 mm, preferably substantially equal to 25 mm.

Still according to the invention, it is also advantageous that the orifices are arranged on the surface of the plate according to a triangular pitch.

In a preferred embodiment, the perforated plate of the device of the invention is constituted by metal and formed from material or fixed on a reinforcing and chocking frame in the inlet frame of the admission chamber of a plate exchanger.

The perforated metallic plate of the device of the invention is preferably reinforced on a dorsal face by stiffeners positioned symmetrically relative at least to one median transversal plane of the device. In this embodiment, the reinforcing frame and the stiffeners fixed on the perforated plate are preferably still formed from the same moulded or forged metallic piece, and constituted for example by steel. By way of variant, stiffeners and reinforcing frame can also be made from mecano-welded sheet metal.

Various other characteristics will emerge from the following description in reference to the attached drawings which show, by way of non-limiting examples, a preferred embodiment of the device of the invention and in which:

FIG. 1 illustrates in perspective the homogenisation device of the present invention;

FIG. 2 illustrates a rear view of the device of FIG. 1;

FIG. 3 illustrates a section view according to the axis III-III in FIG. 2;

FIG. 4 illustrates a plate exchanger with an exploded view of the homogenisation device of the invention of FIG. 1 in the admission chamber of said exchanger;

FIG. 5 is a view similar to FIG. 4 with the homogenisation device of the invention in use position in the admission chamber of the plate exchanger;

FIG. 6 is a similar view in FIGS. 4 and 5 on which the exchanger is closed in configuration of use with the admission and extraction chambers of the exchanger in communication with inlet and outlet nozzles of the exchanger.

The present invention proposes a homogenisation device of a flow of a fluid in the admission chamber of an exchanger with a welded plate.

Such a homogenisation device 1 is illustrated in detail in FIGS. 1 to 3 and is designed to be integrated into the admission chamber 2 of a plate exchanger 3, as illustrated in FIGS. 4 to 6. A plate exchanger such as illustrated in FIGS. 4 to 6 is well known from the state of the art and its specific structure will not be described in detail hereinbelow.

The homogenisation device 1 of the present invention consists in a sort of grille perforated with orifices 5, preferably circular, and distributed uniformly over the entire surface of the grille 1.

Said grille is constituted advantageously of a metallic plate 6 in which the orifices 5 are pierced, said orifices 5 terminating on either side of the metallic plate on a first face 6a, called frontal face, and on a second face 6b, called dorsal face.

This metallic plate 6 is solid with a peripheral reinforcing frame 7, also metallic and attached on the non perforated sides of the plate 6 by welding, or else, if needed, formed from material with said plate, for example during moulding and/or forging of said plate prior to the perforations 5 being made in the latter.

As a complement to the reinforcing frame 7, the grille 1 also comprises stiffeners 9, at least two, placed against the dorsal face 6b of the plate 6, symmetrically relative to a median plane Pm and solid with the reinforcing frame 7 at the level of their ends. The function of these stiffeners 9, like the reinforcing frame 7 of the grille 1, is to reinforce the perforated metallic plate 6 to prevent deformation of the latter under the pressure created by a fluid F within the scope of the use of the device 1 of the invention in a plate exchanger 3, as will be described hereinbelow.

The orifices 5 or perforations of the grille 1 preferably have a diameter between 20 and 30 mm, and preferably substantially equal to 25 mm, and are formed and distributed uniformly on the surface of the plate 6 according to a triangular pitch, the total surface of the perforations 5 representing according to the invention around 40% of the total surface of the metallic plate 6 of the device 1.

The dimensions and thicknesses of the plate 6, of the reinforcing frame 7 and of the stiffeners 9 of the homogenisation device 1 of the invention, are selected and adapted to correspond, in part to the dimensions of the admission chamber 2 of a plate exchanger 3 wherein it is designed to be integrated as illustrated in FIGS. 4 to 6, but also to be capable of resisting the pressure of a fluid to be treated propelled into the admission chamber 2 by a pump, even if all the orifices 5 of the homogenisation device 1 are blocked.

As illustrated in FIGS. 4 to 6, the homogenisation flow device 1 is designed to be inserted into the admission chamber 2 of a plate exchanger 3 at the level of the inlet of the bundle of plates 4 of the exchanger, in the frame 8 of the admission chamber delimiting the inlet surface S_e of the bundle 4. The device 1 now lodged in the frame 8 of the admission chamber of the exchanger allows homogenisation of a fluid flow F to be treated admitted under pressure to the admission chamber 2 via an inlet nozzle Te of the exchanger.

As illustrated in the figures, the reinforcing frame 7 can be fitted with notches 10 provided on each of its sides to cooperate with chocking skids 11 formed to attach to the frame 8 of the admission chamber so as to correctly wedge the homogenisation device 1 against the inlet surface S_e of the bundle 4 of the exchanger, such that the homogenisation device 1 fully covers this inlet surface S_e.

The device 1 is placed in the frame 8 such that the frontal face 6a of the plate 6 is the first found by the fluid F admitted to the admission chamber 2, the dorsal face 6b of the device 1 facing the inlet surface S_e of the bundle 4 of the exchanger. Therefore, the reinforcing frame 7 and the stiffeners 9 of the device 1 can fulfil their function of reinforcement and stiffening of the plate 6, which is subjected to the pressure of the fluid admitted to the admission chamber 2 to pass through the plate exchanger 3, this pressure currently able to be between 5 and 20 bars.

Once it is put in place such as described previously in the admission chamber of a plate exchanger 3, the homogenisation device 1 of the invention, due to its orifices 5, placed uniformly and homogeneously over the entire surface of the plate 6, forces the fluid F, whether it is homogeneous or heterogeneous, to be mixed then to be passed via the orifices 5, to continue its route towards the bundle 4 of the exchanger, to pass through the latter and be cooled or heated.

The orifices 5 of the device 1 allows homogeneous distribution of the fluid treated over the entire surface of the plate 6 of the device 1 and therefore over the entire inlet surface S_e of the bundle 4 of the exchanger, which reduces load losses in the inlet nozzle of the exchanger, homogenises and redirects the fluid flow passing through the orifices 5, towards the bundle of the exchanger.

Respecting the dimensional criteria of the orifices 5 and of their cumulative surface on the plate 6 covers a specific importance within the scope of the invention; in fact, below the values specified hereinabove, the diameter of the orifices 5 is reduced excessively, causing charge losses of the fluid treated in the exchanger, whereas beyond these values more homogenisation effects of the fluid in the admission chamber of the exchanger are obtained. The same applies to the cumulative surface of the orifices 5 relative to the total surface of the plate 6.

The homogenisation device of the invention thus produces an improvement in the yield of the exchanger 3, at the same time as a reduction in wear phenomena at the inlet of the bundle of plates 4 of the exchanger, due previously to the localised concentrations of materials in certain zones of the bundle of the inlet surface S_e of the bundle.

The homogenisation device 1 of the invention thus enables an improvement in the performance of known plate exchangers, especially within the scope of applications to the treatment of heterogeneous fluids such as liquid/gas or liquid/solid mixtures such as mineral muds or others which to date caused considerable wear to the plate exchangers.

The invention is not limited to the examples described and illustrated since various modifications can be made without departing from its scope.