FR2480135A1 - FLUID MIXER HAVING A SINGLE-SIDED WAVY LAYER STACK - Google Patents

Abstract

MIXER FOR FLUIDS WITH A SINGLE-SIDED CORRUGATED LAYER STACK. THE MEDIA (GAS, LIQUIDS) TO BE TREATED FROM THE DUCTS 20, 22 ARE INTRODUCED SEPARATELY INTO AN INLET SURFACE (A OR B, RESPECTIVELY) OF THE MIXER 10. THEY MOVE THERE IN SEPARATE CHANNELS, FORMED BY THE WAVES, TO ARRIVE AND DISTRIBUTE UNIFORMLY ON THE EXIT SIDE C. AN EQUALITY OF TEMPERATURES OR CONCENTRATIONS IN THE MIXTURE DISCHARGED IN THE OUTLET DUCT 24 IS THUS OBTAINED.

Description

The present invention relates to an apparatus for mixing media

  flowing fluids, such as gases or liquids, into which fluid media are introduced

  separately and from which they come out mixing.

  In many industrial fields it is necessary to mix flowing fluid media, such as gases and / or liquids, for example to equalize temperatures, degrees of concentration, etc., and this is as well as in the chemical industries, a known practice is to use static mixers to standardize the concentrations of the various media. In ventilation systems in which a heating coil, for example, is supplied with external cold air and recirculating hot air, a static mixer may be used to mix the airflows or currents before they enter the battery.

  heating and thereby achieve temperature equalization

  erature intended to prevent unequal charge of the battery and also a breakdown or breakage thereof as a result of a

freezing or icing.

  The most common type of mixer for the aforementioned purposes consists of an apparatus in which the media to be mixed are introduced separately, the mixing operation taking place within the apparatus itself. Mixers

  of this type have the disadvantage of generating a fall of

  relatively large pressure drop or loss in the apparatus and at the same time the volume of the mixer itself must be large if the media are to be sufficiently well mixed

before leaving the device.

  Another method, used for example in a burner

  their consists in carrying out the mixing of the media as they leave the body of the burner, the mixture being obtained by a turbulence caused in the media by various

  means, for example using baffles arranged helically

  inside the burner body. However,

  ception of such devices is complicated and so they are

  expensive to manufacture, especially in large series.

  The main object of the present invention is to provide a simple and inexpensive mixer in which the media are effectively and intimately mixed, while the pressure drop in the apparatus remains light and the

  volume of the mixer itself is low.

  According to its main characteristics, the mixer -5 according to the invention comprises at least two channel systems

  open and separated, each starting from a surface of

  respectively, move towards a common outlet and discharge face of the mixer and form an angle relative to each other such that the media flowing from the two or more input faces are distributed in such a manner that essentially uniform on the surface of the exit face. The mixer comprises at least two layers of single-sided corrugated units, each unit having a flat sheet and a corrugated sheet arranged to be in contact with each other. The single-sided corrugated units are arranged so that the corrugations of the sheets

  waved lines form a fixed and constant angle between them in

  adjacent areas. When viewed in plan, the mixer has a triangular shape

  gular. Two of the sides of the triangle form the faces of

  The third side forms the outlet or discharge face of the mixer body. In order to be able to receive different flow rates or volumes of alintentation currents, the triangular mixer pathways may comprise corrugations of different heights from the faces that have been approached. Similarly, the short sides of the triangular mixer may have different lengths to correspond to different flow rates or volumes of feed streams. Throttling devices may be arranged in the triangular mixer at the corners connecting the common outlet side to equalize or

  to balance the flow of media in the body of the

  geur. The throttling devices may be in the form of blades covering a determined number of channel orifices on the inlet surfaces of the mixer, the area covered by the blades increasing as the aforementioned corners of the mixer are approached. Throttling devices may also be in the form of perforated plates disposed on the mixer inlet surfaces and which are progressively

  less perforated as we approach the aforementioned corners.

  The inlet faces of the mixer may be connected to pressure compensation devices, arranged upstream of the mixer, having linear and parallel channels and having a shape such that in combination with the mixer channels, channels are formed. or passages producing essentially the same pressure drop or pressure drop, regardless of the position of these passages relative to the mixer. To equalize the flow rate in the output zone of the mixer, it may comprise several channel systems having the same length in each layer. To avoid excessive flow or flow velocity near the outer edges or surfaces of the mixer, the channels in these

  zones and delivering to one of the environments may

  a smaller section and, for example, a lower height than the other channels of the mixer. To avoid a

  acceleration of the media in the device, it may

  carry a system of conical channels presenting, for the passage of a medium, a section of increasing size in the direction of flow. The mixer may comprise devices, mounted upstream of its inlet faces, in order to regulate the relative amounts of media to enter the mixer. To allow to vary

  the proportion of two media to be mixed to at least a third

  In the middle, two mixer modules of the invention can be connected in series, one of which can be displaced relative to the other over a distance equivalent to the width of at least

a tracking channel.

  Embodiments of the mixer constructed in accordance with the principles of the invention will now be described in more detail, by way of non-limiting examples, in

  view of the attached drawings in which:

  Figure 1 shows schematically in perspective a mixer constructed according to the principles of the invention and mounted in a pipe; Figure 2 is a plan view of the apparatus of Figure 1;

  FIG. 3 is a plan view, similar to FIG.

  Figure 2, but showing another variant;

  FIG. 4 is a perspective view of a mixing

  geur comprising a throttling device for regulating the flow through the apparatus;

  FIG. 5 is a plan view of a mixer comprising

  a device for compensating the pressure of the fluids;

  Figure 6 shows a modified version of a

  similar to that shown in Figure 5; Figures 7a to 7c show a modified embodiment of a mixer having splines or channels of equal lengths; Figures 8a and 8b show an apparatus for

mix three media.

  Fig. 9 is a plan view of a sheet comprising

  both conical corrugations and for a mixer

  truit according to the principles of the invention; Figures 10 and 11 show a section of the sheet

  with conical corrugations, along the lines X-X and XI-XI,

  respectively, deo1a Figure 9; Fig. 12 is a plan view of a mixer made of sheets of the type shown in Fig. 9; FIG. 13 shows in perspective a mixer equipped with a device for regulating the respective flow rates of the media to be mixed; and

  Figures 14a and 14b show mixers des-

  to regulate the relative proportions of three

media to mix.

  The embodiment of the mixer 10, designed according to the principles of the invention and shown in FIGS. 1 and 2, comprises a number of basic elements consisting of a corrugated sheet 12 bearing against a flat sheet 14 to form a single-sided corrugated element ". Other basic elements or single-faced corrugated elements 12,14 are

  placed alternately so as to form between

  12,14 adjacent, a certain angle and for example

  to form a right angle as shown in Figure 1.

  The linear channels formed by the corrugations of the corrugated layers will thus extend alternately in two directions, perpendicular to each other, over the entire thickness of the body of the mixer 10, as indicated by the arrows 16 and 18. 1 and 2. The basic elements of the mixer preferably have a triangular shape in cross section, as best seen in FIG. 2. The short sides of such a triangle are perpendicular to the undulations of the wavy layers. This results in two continuous linear channel systems. The channels of each system depart from their separate input, A and B, to pass through the mixer, the channels of one system remaining separate from those of the other, and reach the discharge side C of the apparatus where their lights or exits are spread over a

  common surface, the outputs of each system being regularly

  distributed on the discharge side of the mixer.

  In the embodiment illustrated in FIGS. 1 and 2, two separate supply ducts 20, 22 are connected to the inlets A and B of the mixer 10 to allow two currents of the media to be mixed to enter, while a third conduit 24 is intended to convey, to remove them from the device, the mixed media. The flow direction of the media is schematically represented by large arrows in the figures. The mixer 10 can be used to mix all the flowing fluid media,

  like liquids, gases, etc., but for the sake of simplicity

  cited, the following description will refer to the mixture of

  separate air currents in order, for example, to equalize the

  temperature in ventilation circuits.

  The two air currents 16, 18, shown in FIG. 1 as borrowing the two channel systems of the mixer 10, when they reach the common discharge face along the long side of the triangular mixer, will mix when they leave the apparatus 10, as indicated

  by the arrows 16,18 in Figure 2. Since, as

  When the channel outlets are uniformly distributed over the entire discharge surface of the mixer 10, both laterally and vertically, it is clear that the large number of narrow channels will produce an effective mixing effect and pushed media, such as drafts, so that each of these media, such as drafts, will be evenly distributed over the entire surface or

discharge or outlet area.

  The body of the mixer 10 comprises alternately

  corrugated layers 12 and plates 14 bearing one on the other.

  A material suitable for producing the relatively thin layers thus formed is a plastic material, a mineral fiber such as certain glass fibers, a metallic material such as aluminum, stainless steel, etc., or other material. similar in the environment in which the mixer 10 is intended to operate. The height chosen for the corrugations must be relatively large so as to produce by friction only a small loss of pressure or load. A suitable method to build

  the mixer 10 is to stack one on top of the other

  single-sided corrugated, rectangular or square,

  until the desired thickness for the body of the

  the elements being united by gluing, welding or

  analogous operation, after which we obtain the triangular form

  desired by dividing by a diagonal the square or rectangular body, so as to obtain at least two triangular mixers. Of course, one can also design a mixer body whose shape deviates from the pure triangle having three linear sides> and can produce

  triangular or other shapes by separating

  each of the single-sided corrugated layers whose

mixer body is constituted.

  In the embodiment shown in Fig. 3, the mixer 10a is mounted in two supply conduits 26,28 of different width. The mixer no longer has an isosceles triangle shape; but each of its short sides has a different length, so as to

  match the different widths of the ducts.

  It can be seen from FIGS. 2 and 3 that the length of the linear channels starting from the inlet A or B to go towards the outlet C varies, depending on whether the channel in question starts at the angle of the mixer 1Q, the neighbor of the top of the right angle or is getting closer to one of the vertices of the base of the

  triangle. This difference in length may result in some

  There is a slight variation in the pressure drop in various parts of the mixer 10, 10a, which in turn can cause some unbalance in the mixed air flow coming out of the C side.

discharge of the mixer.

  The invention proposes several ways of solving this problem. As illustrated on the left-hand side of FIG. 4, blades 30, 32, 34 may be attached to mixer 10, near a corner of its base, and cover some of the openings in the channels on the B input side. way, the current

  penetrating air near the corners near the base of the

  In this case, where the channels are the shortest, it will be throttled and the air passing through the mixer body will be balanced. The same amount of air will thus come out of the mixer uniformly distributed over the discharge surface C. As illustrated in FIG. 4, the blade 34 located closest to the corner of the base of the mixer 10 is wider than

  the blades 32 and 30 further away from this corner, and an

  The proper width and position of the blades will make it possible to balance the rest of the air fairly effectively.

through the mixer 10.

  A throttling of the air stream at the corners of the base of the mixer 10 can also be obtained using perforated plates having a greater or lesser proportion of

  holes, as shown on the right-hand side of Figure 4.

  It can be seen from the figure that the plate 36 has fewer holes than the plate 38, which is closer to the middle of the mixer 10, that is to say covers longer channels, while the channels located even closer to the

  mixing center 10 remain entirely devoid of

  nes of strangulation. Perforated plates 36,38 allow adjustment and balancing with a high degree of accuracy

  the flow of air passing through the mixer 10.

  Another way of equalizing the currents flowing through the mixer is to equip it with a pressure compensation device, as shown in FIGS. 6 and 6. The pressure compensation device 40, illustrated in FIG. 5, is manufactured in the same material as the body of the mixer 10 and consists of layers of single-sided corrugated elements stacked one on the other, the corrugated layers being preferably all parallel. The device therefore comprises linear channels starting from the small side D of the device 40, parallel to the other small side E, toward the third side or base F diagonally in contact with one of the input sides of the mixer 10, this which allows the channels of the device 40 to communicate with those of the mixer 10. It is appropriate to choose the height of the undulations and the length 1 of the device-side 40, so as to ensure that the pressure drop in the medium will be approximately the same. amplitude, because the medium borrowing the longest channels of the device 40 will pass through the shortest channels of the mixer 10 and vice versa. The devices illustrated in FIG. 5 may, like the mixer 10, be produced from a square or rectangular body divided diagonally. FIG. 6 illustrates an example of a case in which the adaptation of the device 40a ', 40a "to the pressure drop occurring in the mixer 10a has led

  to give this device an irregular shape with long

  1 ', 1 "different from the edges of this device 40a', 40a".

  The pressure compensation devices 40, 40a ', 40a', illustrated in FIGS. 5 and 6, produce a uniform distribution of the flow to each channel of the 10,10a mixers and can therefore be used in

  high requirements for a precise mix, however,

  as the version using blades 30,32,34 or

  36,38 throttling, as shown in Figure 4,

  is best used when requests for uniformity

half of the mixture are moderate.

  Another way of equalizing the flow through, the discharge surface of the mixer is to design

  this one so that its channels have the same length.

  An embodiment of this nature is shown in Figures 7a, 7b and 7c. It shows that the mixer lOb

  is mounted in the usual manner in the two conduits 20,22 trans-

  carrying the media to be mixed and that the conduit 24 carries

  mixed media and allows them to move away from the

  geur in. circulating in the direction of the arrows drawn in Figure 7a. The mixer 10b shown in FIG. 7a therefore comprises parallel linear channels 44, starting from the inlet faces of the mixer 10b adjacent to the ducts 20, 22 to move, parallel to the respective external wall of the mixer 10b, towards the exit surface. and discharge in the conduit 24. Like the mixers described in the previous paragraphs, the mixer 10b consists of layers of single-sided corrugated elements. These layers communicate

  alternatively with each of the ducts 20 and 22, respec-

  and the medium coming from one or the other of these conduits can only borrow one channel out of two of the mixer, when one looks at it vertically. The admission to the intermediate layer must therefore be closed as illustrated in FIG. 7b. The shutter 46 can be made during manufacture as a result of an appropriate design of the corrugated elements or by welding or gluing a

  separate band on the element already set up.

  In this embodiment as in the preceding forms, it is clear that the mixer can be constructed so as to be able to fit in the circular section conduits, and in this case, the shape of the device in section will be circular, as shown in Figure 7c for the

mixer 10c.

  The mixer can of course also be constructed so as to be able to mix three or more media,

  as shown in the case of the illustrative embodiment

  in FIGS. 8a and 8b. The mixer 1Qd of FIG. 5a is connected not only to the ducts 20 and 22, but also to an intermediate duct 48. The mixer 10d of FIG. 8a therefore comprises at least three layers of stacked single-sided corrugated elements, the middle layer starting from the conduit 48 to reach the outlet conduit 24 having a rectangular sectional shape and having parallel channels

  on its long sides, while layers starting from

  20 and 22, respectively, to reach the common outlet conduit 24 have parallel channels at the oblique sides of the mixer. Since the medium from each of the inlet ducts 20, 22, 48 can only take one of the three layers leading to the common outlet duct 24, the entry of the two intermediate layers must be closed, as shown in FIG. in FIG. 8b, in the same way as that described with reference to FIGS. 7a and 7b. The mixers 1b, 10c, 10d shown in FIGS. 7a, 7b, 7c and 8a, 8b, thus consist of single-sided corrugated sheet layers stacked one on top of the other, all

  corrugated layers for conveying a medium preferably forming

  a certain angle with all the other layers.

  A medium passing through the mixer will thus be intimately mixed with the other media at the outlet leading to the common conduit 24. It is therefore important to correctly adjust the flow of the media in each of the conduits. If the first and last corrugated layers have the same height of corrugations as the others, the flow through these layers will be excessive and mixing will not be uniform on each of these sides of the mixer. A convenient way of

  to combat this effect is to reduce the height of

  the first and last corrugated elements or corrugated layers, giving them a height which is preferably equal to or slightly less than half of the normal corrugation height as illustrated in FIGS. 7b and 8b

  layer 50, the height of which can be compared

  with the ripples of the layers or channels

intermediaries 44.

  In the mixer embodiments illustrated in FIGS. 7a, 7b, 7c, Sa and Sb, the flow velocity of the media in the outlet duct 24, immediately downstream of the mixer, is greater than the flow velocity in the mixer. the ducts 20, 22, 48 upstream of the mixer. In the embodiment of the mixer 10b, illustrated in FIG. 7a, for example, the flow velocity of the media in the

  24 output is proportional to the sum of the vi-

  the two media in the feed ducts 20,22,

  which is a disadvantage in many cases.

  One way of eliminating this disadvantage is to give the corrugations an increasing height and / or to widen the distance between the peaks of the corrugations from the inlet to the outlet of the mixer or, alternatively,

  increasing distance between the undulations, but

  constant height of undulations, always in

  to the exit. Wavy leaves of this kind can

  can be produced between more or less conical rolls, which can produce corrugated sheets with weights of increasing height and an alugent distance.

  between the peaks of the undulations. By moving in a

  venable one of the conical rollers of realization corrugations

  compared to the other, it is also possible to produce

  corrugated sheets having a constant height of

  tions, but with an increasing interval between

  tions themselves; Another way of making such sheets is, once, a sheet produced between corrugated and conical rolls and when this sheet has corrugations of increasing height and distance.

  from one wave to another, to continue the process of

  by pressing the sheets to reduce the height of the corrugations to the desired value. FIGS. 9 to 11 show an example of a conical corrugated sheet 52 whose peaks or ridges are, as measured at D 'and D "in FIGS. 10 and 11 respectively, closer to one end of the sheet 52 than at the other end, while the height H of the corrugations remains the same, the end of the sheet 52 where the crests are the closest is thus mounted in one of the ducts, 20 or 22, feeding media to be mixed, and the end where the peaks are the most spaced apart is mounted in the discharge conduit 24, as shown in FIG. 12, which shows an embodiment of a mixer 10e consisting of layers 52 of elements corrugated single-sided corrugated, of the type shown

in Figure 9.

  Devices, illustrated in FIG. 13, can be mounted in the feed ducts 20, 22 upstream of the mixer 10 to regulate the relative proportions of the

  two media to mix. In the embodiment

  13, these devices take the form of movable plates 54 in which are cut slots or buttonholes 56 whose shape is equivalent to that of the inlet of each layer of the mixer 10. Since we can do more or less coincide the slots 56 with the channels

  44 of the mixer 10, it is possible to regulate the

  relative media from the corresponding inlet ducts 20, 22 for mixing, as is apparent from FIG. 13. This regulator may also take the form of a throttling device or a similar device of the invention. type used for mixing gases, or it may be of a similar design to the control valves used

for liquids.

  Another way to regulate relative proportions

  media to be mixed is to connect two

  lob, of the type shown for example in Figure 7a, and to make one of the mixers mobile relative to the other,

  as shown in Figure 14a, where we see that the

  Upper geur 10 'is movable relative to the lower lob "mixture.

  An arrangement of this kind is suitable, for example, for mixing three media and when it is desirable to be able to vary the relative proportions of two media to mix

  to a third. The mobile mixer must be capable of

  placed in a direction perpendicular to the plane of the channels or

  single-sided corrugated layers. In one of the two posi-

  of this mixer 10b ', shown in FIG. 14a, the channels are open or unobstructed and

  allow the millet Mil from the food conduit 20

  to flow into the mixer connected in series. The media M1 and M13 from the ducts 20 and 22 are thus mixed, the latter leading directly to the fixed lower mixer 10b ", providing the communication at its output with the common discharge duct 24. When the upper mixer 10b 'is moved by a movement which occurs in a vertical direction relative to this mixer 10b ', that is to say perpendicular to the plane of Figure 14a, as indicated by the double arrow in Figure 14b, the channels are closing more and more. in the middle M1 from the conduit 20 and open more and more to the M12 medium from the conduit 48, which means that a mixture of the M1, M2 and M3 media from each of the conduits 20, 48 and 22, respectively,

  will occur when the mixer 10b 'is placed in its position.

  intermediary The mobile mixer 10b 'thus operates in accordance with the same principles as the movable perforated plates 54 illustrated in FIG. 13, except that in addition to closing the supply from one of the conduits or 48, the mobile mixer lob' FIGS. 14a and 14b also open the medium supply from the other conduit 48 or 20. When the mobile mixer lob 'is placed in its other extreme position, the channels are fully open to the medium M2 from the conduit 48, but closed to Ml medium from the conduit 20, which means that there is then a mixture of media M2 and M3 from

  ducts 48 and 22 respectively. In the form of reali-

  According to the invention, medium M3 conveyed via line 22 is always part of the resulting mixture discharged into line 24, and the proportions of M1 and M2 medium added thereto from lines 20 and 48 respectively.

  may vary between 0 and 100% o (of the sum Ml + M2).

  It follows from the above that the invention proposes a mixer in which the pressure drop is significantly lower than that existing in the previous mixers,

  and whose footprint is much less than that of

  previous generations. Likewise, less material is required to construct the proposed mixer and, in addition, the material used may be thin, since the various layers of the mixer provide a mutual support effect. A protective casing (not shown) may surround the mixer to improve the convenience of handling, and fixing brackets 42, shown in the figures, may

  serve to facilitate assembly of the mixer in the ducts.

  For the equalization of temperatures, the mixer proposed by the present invention behaves remarkably well for mixing two media at different temperatures. The mixer of the invention is also extremely useful in continuous chemical processes involving a mixing or reaction step. A mixture is completed very quickly, at the stage or mixing stage, by the apparatus proposed here. Effective mixing shortens the diffusion path of the reactants, and the reaction as a whole is accelerated, thereby increasing production per unit of time. In the case of instant reactions at the reaction stages, the rate at which mixing can be achieved is fundamental to the flow of the products. The intimate and fast mixture obtained

  in the apparatus of the invention allows a high level of

  continuous duction, while requiring only a small volume for the reaction (s). In rapid reactions, the mixing and the reaction itself occur simultaneously by causing a rise or fall in the temperature

  The efficiency of the mixture achieved by the apparatus of the invention

  guarantee the existence of a uniform temperature in

  environments without temperature zones below or above

above the required value.

  It goes without saying that without departing from the scope of the invention,

  many changes can be made to the mix

  described and represented. Thus, it is clear that the mixer 10, 10a need not be oriented

  as shown in the figures, but it can be

  with the single-sided corrugated layers

  hold or in any other position in relation to the

  horizontal plane. Similarly, it is of course not indis-

  thought that the angle formed by the channels of

  adjacent single-sided lines be a right angle. This angle

  may vary depending on the shape of the mixer. It is natural-

  It is also conceivable to use the blender to mix

  more than two media and in this case the device may

  a number of input faces from which linear channels are

  uniform discharge on the face of a common output side.

  In addition, because of the pressure drop available and the variations that occur in the flow, etc. it may be advantageous if the ripple height of the channels directed in one direction is greater than that of the channels

  directed in another or the other direction.

Claims (15)

  1. Mixer for mixing fluid media, such as gases or liquids or both, in flow, in   which these media are introduced separately and from which they   In mixing, this mixer (10, 10a, 10b, 10c, 11d, 10e) is characterized in that it comprises at least two separate channel systems each starting from a respective input surface (A, B). to move towards and exit into a common output face (C) by forming a given angle with each other so that the media flowing from the two or more input faces (A, B ) are distributed substantially uniformly over the surface the exit face (C).   2. Mixer according to claim 1, characterized in that it comprises at least two layers with single-sided corrugations, that is to say layers formed of a corrugated sheet (12) and a flat sheet (14). ), placed in contact with one the other.   Mixer according to Claim 2, characterized in that the single-sided corrugated layers are arranged in such a way that the undulations of the corrugated sheets (12) form   with each other a determined angle in adjacent layers. Centes.   4. Mixer according to any one of the claims   1 to 3, characterized in that it has a triangular shape in planar section, two sides of this triangle forming the inlet faces (A, B) and the third side (C) forming the   outlet or discharge side of the mixer body.   Mixer according to Claim 4, characterized in that the channels of the triangular shaped apparatus (la) have corrugations of different heights from the input faces (A and B) in order to be able to process currents   feeders formed by different volumes or flow rates.   6. Mixer according to claim 4, characterized in that the short sides of the triangular mixer (10a) are of different length to allow the treatment   supply currents of different volumes or flows.   7. Triangular mixer (10, la) according to one   of claims 4 to 6, characterized in that   has throttles (30,32,34; 36,38) mounted on the input faces near the corners of the triangle corresponding to the base thereof and the common discharge face to equalize or balance the flow of   media in the mixer body.   8. Mixer according to claim 7, characterized in that the throttling devices have the shape of blades (30,32,34) covering a predetermined number of channel openings on the surfaces (A, B) of the inlet of this mixer, and in that the surface covered by the blades (30,32,34)   increases when you get closer to the corners of the cor- responding to its base.   Mixer according to Claim 7, characterized in that the throttling devices have the form of perforated plates (36, 38) arranged on the inlet surfaces.   (A, B) of the mixer (10) and that these plates are pro-   gressively less perforated as we get closer to   corners of the triangle corresponding to the base or face of age of this one.   Mixer according to any one of the claims   4 to 6, characterized in that at the inlet faces (A, B) of the mixer (10, 10a) there are connected pressure equalization devices (40, 40a, 40a) with channels.   linear and parallel, the shape of each of these   such that in combination with the canals of the   they ensure the formation of passages or pathways producing essentially the same pressure drop   whatever the position of these passages in the mixer.   11. Mixer according to any one of the claims   1 to 10, characterized in that it comprises several channel systems arranged so that these channels (44) have the same length in each layer of the mixer (10b, 10c, 10d)   12. Mixer according to any one of the claims   1 to 11, characterized in that the channels (50) of the mixer (10b, 10c, 10d) located near the two outer surfaces provide for the passage of a medium a smaller section, and have   example a lower height> than the central channels (44).   Mixer according to any one of the claims   1 to 12, characterized in that it comprises a system (52) of conical channels providing for the passage of a medium an increasing section in the direction of flow of this medium in the blender (10th).   Mixer according to any one of the claims   1 to 13, characterized in that it comprises   54,56), mounted upstream of the inlet faces (A, B) of this mixer (10) to regulate the relative amounts of   media penetrating into this mixer.   Mixer according to any one of the claims   1 to 14, characterized in that it comprises at least two modules (lob ', lob ") connected in series and one of which (lob') is movable, with respect to the other (lOb"), on a distance   equivalent to the width of at least one channel, so as to   see vary the relative proportion of two media   (Ml, M2) to mix with at least a third medium (M3).