Fluid treatment system and method

Abstract

A fluid treatment system (1), such as a turbo emulsifier, comprises a tank (2) for containing a static fluid mass. The rotating shaft (3) is rotated by a motor (4). The cavitation impeller (5) is mounted to the rotating shaft (3) inside the compartment (21) of the tank (2) so as to be submerged in the fluid mass. The impeller (5) has a pair of walls (51), a gap (53) defined by inner surfaces (54) of the walls (51), and blades (56) arranged in the gap (53).

Description

Technical Field

[0001] The present invention relates to the field of fluid processing, more particularly to the field of turboemulsification. Background Art

[0002] A turbo emulsifier is a machine used to process fluids, for example in the field of cosmetic production. The fluid to be processed includes a main component in liquid form, and one or more secondary components in the form of solid particles suspended in the main component, and / or a gas dispersed in the mixture.

[0003] Treatment aims to even out the distribution of solid particles and gases in the liquid and to reduce their size.

[0004] Known examples of turbo emulsifiers include a tank for processing fluids in batches. Thus, while processing is ongoing, there is no flow of fluid in either the input or output of the tank. A propeller is mounted on a shaft, both of which are rotated by a motor to stir the fluid, thereby obtaining an emulsifying effect.

[0005] WO 2020075039 discloses a system for treating different types of fluids, in particular a cavitation reactor, which provides a continuous flow of the fluid to be treated in and out of a stator compartment. The rotor is similar to the rotor of a closed impeller centrifugal pump, but without a suction opening, which induces cavitation in the flowing fluid.

[0006] FR 1580389 discloses a water purifier without cavitation function, in which an impeller is fixed to a rotating shaft. The upper wall of the impeller has a central opening, which communicates with the inner side of the rotating shaft so as to suck air from above and introduce bubbles into the water.

[0007] US2015320053 and US2012275260 disclose examples of agitators with perforated impellers without cavitation functionality. Summary of the invention

[0008] The object of the present invention is to increase the efficiency of batch fluid processing, for example for use as a turbo emulsifier.

[0009] The applicant has noticed that the efficiency of the cavitation reactor of WO 2020075039 in treating fluids is higher than that of conventional turbo emulsifiers. However, the cavitation reactor structure of WO 2020075039 is not designed for batch operation.

[0010] The applicant then surprisingly noticed that the single impeller of the reactor of WO 2020075039 could be added to or replaced by a propeller of a turboemulsifier, without necessarily providing a stator in which the fluid to be treated flows continuously.

[0011] Hence, the stated objects are achieved by a fluid treatment system or method according to any one of the appended claims.

[0012] The system comprises a tank having a compartment shaped to contain a predetermined mass of static fluid. Thus, during the treatment process, there is no fluid flowing in the input or output of the tank. Similar to the cavitating impeller of WO 2020075039, the cavitating impeller is mounted on a rotating shaft so as to be immersed in the fluid mass.

[0013] By driving a cavitating impeller, cavitation phenomena can be obtained inside the tank, which has the beneficial effect of reducing the particle size in the fluid mass, wherein a convective stirring motion can also be developed.

[0014] Although there is no stator in which the fluid flows, the intensity of cavitation can be promoted and increased by one or more of the following means:

[0015] - Increase the rotation speed of the cavitation impeller,

[0016] - increase the pressure of the fluid in the location of the cavitation impeller,

[0017] - making the blades in the cavitating impeller curved so that they rotate in a rotational orientation such that the concave side of the blade precedes the convex side, and

[0018] - Properly design the radius of the cavitating impeller and the width of the internal gap.

[0019] In some embodiments, to increase the pressure of the fluid, the cavitating impeller may be positioned at a greater depth, or a second impeller of a pumping type may be provided, for example, configured to press the fluid from the top downward in the direction of the underlying cavitating impeller.

[0020] Those skilled in the art will be able to recognize other features and advantages of the present invention from the following detailed description of exemplary embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to better understand the following detailed description, some embodiments of the present invention are illustrated in the accompanying drawings, in which:

[0022] - Figure 1 Schematically shows a cross-sectional view of a fluid treatment system according to an embodiment of the present invention,

[0023] - Figure 2 schematically shows a cross-sectional view of a fluid treatment system according to an alternative embodiment of the present invention,

[0024] - Figure 3 Schematically shows Figure 1 and Figure 2 A cross-sectional view of the cavitation impeller of the system, and

[0025] - Figure 4 Schematically shows Figure 1 and Figure 2 A cross-sectional view of the pumping impeller of the system. DETAILED DESCRIPTION

[0026] A fluid treatment system is indicated by number 1. System 1 is a system for mechanical fluid treatment, in particular a system for emulsifying a fluid, preferably a turbo emulsifier,

[0027] The system 1 comprises a tank 2 having a compartment 21 shaped to contain a predetermined amount of static fluid mass.

[0028] In a preferred embodiment, the can 2 has a bottom wall 22 and at least one side wall 23, for example a substantially cylindrical side wall 23 extending above the bottom wall 22. The bottom wall 22 and the side wall 23 at least partially delimit the compartment 21.

[0029] In the present invention, the terms "above" and "below" are intended to refer to the normal use position of the tank 2, whereby the weight of the fluid mass presses downwards on the bottom wall 22 from the top if there is a fluid mass in the tank 2.

[0030] The fluid mass in tank 2 is indicated as static, in contrast to the case of fluids flowing continuously in input and output from compartments of different types. However, other motions of the static fluid mass are permitted, such as convection motion, wave motion or other agitation motion.

[0031] It should be noted that when a fluid mass is present in the tank 2 in a predetermined amount, the fluid mass has a free surface 100 spaced apart from the bottom wall 22 by a predetermined height H. At least during use, the tank 2 lacks open channels that are in fluid communication with the compartment 21 below the level of the free surface 100 of the fluid mass (i.e., below the predetermined height H).

[0032] In more detail, in an embodiment, the bottom wall 22 and the side wall 23 of the tank 2 completely lack openings and therefore have no passages connected thereto. In this case, the tank 2 may have an upper opening 24 for entering the compartment 21 so as to fill and empty the fluid of the compartment 21 before and after treatment. In still more detail, the tank 2 may have a top wall 25 connected to at least one side wall 23, and the upper opening 24 may be formed by the top wall 25. Alternatively, the tank 2 may lack a top wall 25, and the top opening 24 may be defined by at least one side wall 23.

[0033] In an alternative embodiment, the tank 2 has one or more channels (not shown) in fluid communication with the compartment 21 below the level of the free surface 100 of the fluid mass. Thus, the bottom wall 22 and / or at least one side wall 23 has one or more access openings to the compartment 21 below this level. These channels and openings can be opened before and after treatment to fill and empty the fluid compartment 21 or for other purposes. However, the tank 2 includes a closure element (not shown) for each of these channels so that during treatment, each channel is closed and the flow of fluid in the input or output of the tank 2 is prevented.

[0034] In the presence of such a passage, the can 2 may or may not have a top wall 25 and / or a top opening 24 , and the top opening 24 may or may not be closed by a lid 27 in use.

[0035] The system 1 then comprises a rotation axis 3 which extends mainly along a longitudinal axis AA.

[0036] In a known manner, the rotation shaft 3 may be directly or indirectly connected to the tank 2 and is configured to rotate about the longitudinal axis AA relative to the tank 2. Furthermore, the rotation shaft 3 is at least partially arranged inside the compartment 21 of the tank 2 to be at least partially immersed in the fluid mass.

[0037] The system 1 comprises a motor 4, for example an electric motor, connected to the rotating shaft 3 and configured to rotate the rotating shaft 3 relative to the tank 2. Preferably, the motor 4 is located outside the compartment 21.

[0038] In an embodiment, the rotating shaft 3 is rotatably connected to the bottom wall 22 and protrudes from the bottom wall 22 toward the inner side of the compartment 21. For example, the rotating shaft 3 may extend through a sealed bearing device 26 positioned in the bottom wall 22.

[0039] In another embodiment, the rotating shaft 3 at least partially extends through the upper opening 24 of the tank 2. In this case, the rotating shaft 3 is not necessarily supported by the tank 2, but is supported by any supporting structure that can be selected by a person skilled in the art.

[0040] In another embodiment, the rotating shaft 3 includes a portion located inside the compartment 21, a portion located outside the compartment 21 fixed to a portion of the motor 4, and a magnetic joint connecting the inner and outer portions together through the wall of the tank 2.

[0041] However, the invention can also be implemented with other different possible positionings of the shaft 3 and also allows for a shaft 3 with a non-vertical orientation.

[0042] The system 1 comprises a first impeller 5, also known as a cavitation impeller, mounted to a rotating shaft 3. Thus, when the shaft 3 rotates, the first impeller 5 is configured to rotate with the shaft 3 relative to the tank 2 about a longitudinal axis AA.

[0043] The first impeller 5 has at least one pair of walls 51 spaced from each other in the direction of the longitudinal axis AA. Each wall 51 is surrounded by a peripheral free edge 52 spaced from the longitudinal axis AA in the radial direction. Each wall 51 may be substantially planar or funnel-shaped.

[0044] The first impeller 5 has at least one gap 53 between two consecutive walls 51. If there are more than two walls 51, there may be more gaps 53, but for the sake of simplicity only a single gap 53 will be referenced below.

[0045] In more detail, each wall 51 has an inner face 54 facing the gap 53 and transverse to the direction of the longitudinal axis AA and an outer face 55 opposite the inner face 54. The inner faces 54 of consecutive walls 51 face each other and delimit the gap 53 in the direction of the longitudinal axis AA.

[0046] The gap 53 is accessible by passing between the peripheral edges 52 of the walls 51. Instead, each wall 51 of the first impeller 5 lacks an open access opening to the gap 53. Therefore, the fluid cannot enter the gap 53 through the openings formed by the walls 51.

[0047] In more detail, each wall 51 may lack an opening entirely, or may be provided with one or more openings which, in use, are closed by respective closing elements.

[0048] The impeller 5 has a plurality of blades 56 arranged in the gap 53. The blades 56 extend between a central portion of the impeller 5 close to the longitudinal axis AA and a peripheral portion of the impeller 5. The blades 56 divide the gap 53 into compartments which are distributed circumferentially around the longitudinal axis AA and each compartment extends between the central portion and the peripheral portion of the impeller 5.

[0049] In a preferred embodiment, each blade 56 has a concave surface and a convex surface opposite the concave surface. In addition, the motor 4 is configured to rotate the shaft 3 in a rotational direction so that the concave surface precedes the convex surface. This rotational orientation promotes cavitation and therefore allows cavitation to be obtained at a lower rotational speed and / or a lower fluid pressure.

[0050] In another embodiment, the direction of rotation is still permitted so that the convex surface precedes the concave surface.Also alternatively, the blades 56 may extend substantially straight radially away from the longitudinal axis AA and thus may lack a concave or convex surface.

[0051] The first impeller 5 is arranged inside the compartment 21 of the tank 2 so as to be immersed in the fluid mass when there is a fluid mass in the tank 2. In particular, the first impeller 5 is arranged below the level of the free surface 100, ie positioned below the above-mentioned predetermined height.

[0052] It should be noted that the first impeller 5 immersed in the fluid is subjected to the pressure of the fluid. When the shaft 3 stops, the fluid pressure at the first impeller 5 presents a predetermined reference value. The reference value of the pressure is determined by the depth of the first impeller 5 relative to the free surface 100 and the air pressure conditions above the free surface 100.

[0053] In an embodiment, for example, when the upper opening 24 is included, the air above the free surface 100 is at atmospheric pressure. Therefore, the reference value is greater than one atmosphere in terms of absolute pressure, ie, greater than zero in terms of relative pressure.

[0054] In another embodiment, the tank 2 is configured to be hermetically closed, and the system 1 may include a pressurizing or depressurizing device (of a known type, not shown) configured to increase or decrease the gas pressure above the free surface 100 relative to atmospheric pressure. This will also affect the reference pressure value on the first impeller 5. In many known applications, the system 1 is vacuum operated so that air is not introduced into the fluid.

[0055] When the shaft 3 rotates, the pressure of the fluid mass may change at least partially relative to the reference value. In particular, the rotation of the first impeller 5 determines a decrease in the pressure inside the gap 53, which promotes cavitation. On the contrary, in an embodiment, even when the shaft 3 rotates, the pressure outside the gap 53 increases or remains substantially equal to the reference value.

[0056] In another embodiment, in order to influence the pressure value, the system 1 comprises a second impeller 6 different from the first impeller 5. The second impeller 6 is arranged inside the compartment 21 of the tank 2 so as to be immersed in the fluid mass when the fluid mass is present in the tank 2.

[0057] exist Figure 1 In the embodiment, two impellers 5, 6 are mounted to the same rotating shaft 3. Figure 2 In the embodiment, the second impeller 6 is mounted on its own rotating shaft 31 which is driven by its own motor 41 and which is different from those on which the first impeller 5 is mounted.

[0058] Preferably, the second impeller 6 is a pumping impeller, which, when rotating, is configured to move the fluid, preferably to induce convective motion in the fluid mass.

[0059] In a preferred embodiment, the second impeller 6 is a closed centrifugal impeller. In this case, similar to the first impeller 5, the second impeller 6 has two walls 61, which are spaced apart in the direction of the longitudinal axis AA and are surrounded by a peripheral free edge 62. There is a gap 63 between the walls 61, which is defined by the inner faces of the walls 61. The blades 64 are arranged in the gap 63. However, unlike the first impeller 5, one of the walls 61 of the second impeller 6 has a central suction opening 65.

[0060] However, other types of pumping impellers known to the person skilled in the art may also be allowed as second impeller 6. Furthermore, the possibility of several pumping impellers 6 and / or several cavitation impellers 5 in the same system 5 is allowed.

[0061] When rotating, the second impeller 6 is configured to move the fluid mass so as to generate an increased pressure value of the fluid mass at the first impeller 5, in particular outside the first impeller 5. The increased pressure value is greater relative to the base pressure value.

[0062] To this end, in a preferred embodiment, the second impeller 6 is positioned higher than the first impeller 5 and, when rotating, is configured to press at least part of the fluid mass downwardly.

[0063] It should be noted that the motor 4 is configured to rotate the rotating shaft 3 at a predetermined speed so that the first impeller 5 induces cavitation in the fluid mass at a predetermined pressure to which the first impeller 5 is subjected, also taking into account the pressure optionally developed by the second impeller 6 .

[0064] In more detail, with fixed geometry of the first impeller 5, and in particular with fixed shapes and dimensions of the blades 56 and also of the wall 51 and of the gap 53, and with fixed pressure outside the first impeller 5, there is a limit value of the rotational speed in order to determine the triggering of cavitation. The rotational speed set by the motor 4 is therefore at least equal to this limit value.

[0065] It will be appreciated from the above that the speed limit can be reduced if the pressure outside the first impeller 5 is increased, for example by means of the second impeller 6, or by increasing the depth of the first impeller 5, or by pressurizing the tank 2. Furthermore, the speed limit can be reduced by making the blades 56 curved and rotating them so that the concave surface precedes the convex surface.

[0066] Reducing the limiting speed means that the same cavitation effect can be achieved at a lower speed of the shaft 3 and therefore with lower energy consumption, or that at the same speed of the shaft 3 the cavitation effect can be intensified.

[0067] In addition to or as an alternative to the pumping effect, the second impeller 6 may be configured to mechanically process the fluid by shear stress lamination.Lamination and pumping effects may be achieved by the same stage of the second impeller 6 or by separate stages.

[0068] From the description so far, the method of using the system 1 in a fluid treatment process is obvious. In particular, it is necessary to fill the compartment 21 of the tank 2 with a static mass of the fluid to be treated so as to flood the first impeller 5 and, if included, the second impeller 6.

[0069] The motor is then driven to overcome the limiting speed so that the first impeller 5 induces cavitation phenomena in the fluid mass. Finally, the fluid mass that has been thus treated is removed from the tank 2.

[0070] During fluid processing, ie as long as the shaft 3 is rotating above the limiting speed, there is no need to inject and / or remove fluid from the tank 2.

[0071] Obviously, a person skilled in the art will be able to make numerous modifications to the variants set out above, without thereby renouncing the scope of protection defined by the attached claims.

Claims

1. A fluid treatment system (1), comprising: a tank (2) having a compartment (21) shaped to contain a predetermined mass of static fluid up to a predetermined height (H) from a bottom wall (22) of the tank (2), - an axis of rotation (3) located at least partially inside the compartment (21) of the tank (2), the axis of rotation (3) extending mainly along a longitudinal axis (AA), a motor (4) configured to rotate the rotation shaft (3) relative to the tank (2), - a first impeller (5) mounted to the rotating shaft (3) inside the compartment (21) of the tank (2) below the predetermined height (H), Wherein, the first impeller (5) has: a pair of walls (51), each wall (51) being surrounded by a peripheral edge (52) spaced apart from said longitudinal axis (AA), each wall (51) having an internal face (54) oriented transversely to the direction of said longitudinal axis (AA), said internal faces (54) of the two walls (51) facing each other, - a gap (53) defined by said inner face (54) of said wall (51), - a plurality of blades (56) arranged in said gap (53), Characterized in that each wall (51) of the first impeller (5) lacks an open access opening to the gap (53).

2. The system (1) according to claim 1, wherein: The tank (2) lacks an open passage in fluid communication with the compartment (21) below the predetermined height (H).

3. The system (1) according to claim 1 or 2, comprising a second impeller (6), preferably mounted to the rotating shaft (3), placed inside the compartment (21) of the tank (2) below the predetermined height (H), in, The second impeller (6) is a pumping impeller which, when rotating and when a fluid mass is present in the compartment (21), is configured to generate an increased pressure value of the fluid mass at the first impeller (5), which is greater relative to a baseline pressure value of the fluid mass at the first impeller (5) when the second impeller (6) is stopped.

4. The system (1) according to claim 3, wherein: The second impeller (6) is positioned higher than the first impeller (5) and, when rotating and when a fluid mass is present in the compartment (21), the second impeller is configured to press downwards at least a portion of the fluid mass.

5. The system (1) according to any one of claims 1 to 4, wherein: The rotating shaft (3) is rotatably connected to the bottom wall (22) of the compartment (21), and protrudes from the bottom wall (22) toward the inner side of the compartment (21).

6. The system (1) according to any one of claims 1 to 5, wherein: - the tank (2) has an upper opening (24) for access to the compartment (21), and - The rotation axis (3) extends at least partially through the upper opening (24).

7. The system (1) according to any one of claims 1 to 6, wherein: - the blades (56) of the impeller extend substantially straight in a radial direction away from the longitudinal axis (AA), or - the blades (56) of the impeller each have a concave surface and a convex surface, and the motor (4) is configured to rotate the rotation shaft (3) so that the concave surface precedes the convex surface, or, - The blades (56) of the impeller each have a concave surface and a convex surface, and the motor (4) is configured to rotate the rotating shaft (3) so that the convex surface precedes the concave surface.

8. A process for treating a fluid by means of a system (1) according to any one of claims 1 to 7, comprising, in order: - filling said compartment (21) of said tank (2) with a static mass of the fluid to be treated, - driving the motor (4) so ​​that the first impeller (5) induces cavitation phenomena in the fluid mass, - Removing said fluid mass from said tank (2).

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