Separator of fluids having components with different densities in screw type cyclonic separator

Abstract

The present invention relates to a separator (1) for fluids having at least two components with different densities. According to the invention, the separator (1) comprises a separation chamber (2) with a substantially tubular shape and a variable pitch axial impeller (3) inserted within the separation chamber (2) and rotatable therein. The pitch of the screw (31) increases along the longitudinal axis (X) of the axial impeller (3), which imparts an axial advancement to the fluid (22) along the longitudinal axis (X). The axial rotation of the axial impeller (3) also imparts to the fluid (22) a rotation around the longitudinal axis (X), which is a function of the increase in the pitch of the screw (31) and reaches its maximum value near the axial end (25) of the separation chamber, where, due to the centrifugal effect, the two components (27, 29) of different densities of the fluid (22) separate along a radial direction (R).

Description

[0001] SEPARATOR OF FLUIDS HAVING COMPONENTS WITH DIFFERENT DENSITIES IN SCREW TYPE CYCLONIC SEPARATOR

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to a separator of fluids having components with different densities. In particular, the present invention pertains to a separator of fluids that can be integrated into circuits where fluids circulate, such as hydraulic circuits that include hydraulic machines (hydraulic pumps or hydraulic motors), to separate two distinct components of the fluid, such as two fluid components with different densities such as, for example, in a gas / liquid mixture, the gaseous component from the liquid component.

[0004] STATE OF THE ART

[0005] As is known, a fluid can consist of a mixture of two or more components, which may form two or more distinct phases. A gas / liquid mixture is an example of a two-phase fluid comprising a liquid phase and a gaseous phase. Another example of a two-phase fluid may be a mixture of water and oil, which includes a first liquid phase, water, at least partially immiscible with a second liquid phase, oil.

[0006] For the purposes of the following description, it is understood that a fluid with components of different densities can be a fluid comprising two distinct phases: one liquid and one gaseous, or two liquid phases differing in density, or even two gaseous phases differing in density. A fluid with components of different densities can also be a fluid consisting of a mixture of at least two immiscible fluids, or a mixture of miscible fluids which, at a given temporary moment, are nonetheless distinct from each other, or in any case fluids that, at least in part, are immiscible. A fluid with components of different densities can also be a fluid composed of a mixture of more than two distinct components or phases, such as, for example, a mixture of water, oil, and natural gas, in which two distinct, at least partially immiscible, liquid phases and a third gaseous phase are present.

[0007] In the hydraulic sector, the oil industry, as well as in the chemical, pharmaceutical, and biotechnological industries, there are various situations where it is necessary to separate distinct components or phases of a fluid. For example, in oil extraction plants, oil, water, and natural gas coexist in a single mixture and must be separated from each other.

[0008] Another example concerns the separation of the gaseous phase from the liquid phase in gas / liquid mixtures. As is well known, the performance of hydraulic circuits is severely affected by the presence of gas in the fluid, such as the presence of air in oil. However, gas is almost always present in hydraulic circuits to some extent, with varying degrees of negative consequences. For instance, integrated hydraulic systems that use the same oil for different functions often contain a very high amount of air, both dissolved and free, in the form of bubbles. The presence of air bubbles causes various problems in hydraulic pumps, including noise, phenomena related to cavitation or very similar to cavitation in their effects, efficiency losses, increased pressure fluctuations, oil cracking, reduced compressibility modulus of the fluid, and decreased system stiffness, as well as lower output performance compared to the nominal values.

[0009] Hydraulic motors also face issues similar to those of hydraulic pumps and do not operate efficiently in the presence of air. Additionally, hydraulic valves and distributors in hydraulic circuits containing fluids with air do not function properly.

[0010] Dissolved air in the liquids circulating in hydraulic circuits is also often harmful, and the only way to reduce its presence is to maintain a low air bubble content in the liquid. This limits the dissolution of air into the liquid during its pressurization.

[0011] Currently, various methods exist to separate air, or other gases, from a liquid, particularly oil, which primarily exploit the difference in density between air and the liquid.

[0012] For example, in cyclonic separators, the centrifugal effect is used to separate the liquid component, which is denser and therefore characterized by greater inertia, from the gaseous component, which is less dense and lighter.

[0013] Jet systems are also known, which operate by spraying a high-speed jet of the mixture against a wall. The heavier liquid phase, generally consisting of oil, tends to adhere to the wall, while the gaseous phase is released and separates from the liquid phase.

[0014] Other gas / liquid separation systems combine the two effects described above: centrifugal and jet effects.

[0015] Other systems exploit gravity to separate the heavier liquid phase from the lighter gaseous phase.

[0016] All the known gas / liquid separation systems described above are not without drawbacks, including the fact that they cause an undesirable pressure drop in the circuit in which they are installed and often have unacceptable dimensions.

[0017] In a hydraulic circuit comprising a hydraulic pump, the optimal operating conditions are achieved when gas / liquid separation occurs upstream of the pump, in the suction branch, to prevent the undesirable effects mentioned above. However, if gas / liquid separation systems cause undesirable pressure drops, pumps located downstream of such separation systems will be subject to cavitation, resulting in damage and unwanted noise generation. In this scenario, the use of an auxiliary pump capable of operating on the gas and liquid mixture is often provided. However, this solution introduces additional drawbacks, primarily an increase in the complexity of the hydraulic circuit.

[0018] Filters are also known which, when appropriately placed in hydraulic circuits, exploit coalescence effects to promote the aggregation of gas bubbles, thereby facilitating their separation from the liquid phase. However, this solution also has significant drawbacks, one of which is the requirement that the fluid mixture remains in a state of rest, for example in dedicated tanks, for a sufficiently long period, on the order of minutes or even tens of minutes. Therefore, this solution is not feasible in hydraulic circuits where it is not possible to interrupt the fluid flow for extended periods.

[0019] SUMMARY OF THE INVENTION

[0020] In view of the above, the aim of the present invention is to provide a separator of fluids with components of different densities that overcomes the limitations of the prior art, enabling the effective separation of the components or phases of fluids, and in particular performing such separation in real time and inline.

[0021] As part of this aim, the scope of the present invention is to provide a separator of fluids that prevents pressure drops and additionally imparts a slight head pressure to the fluid passing through it.

[0022] Another scope of the present invention is to provide a separator of fluids with components of different densities, such as gas / liquid mixtures, that also imparts a slight head pressure to the lower-density component, such as the gas, once separated from the mixture, to facilitate its expulsion.

[0023] Another scope of the present invention is to provide a separator of fluids with components of different densities, such as gas / liquid mixtures, that exploits coalescence phenomena to enhance the efficiency of fluid component separation.

[0024] A further scope of the invention is to provide a separator of fluids that can also contribute positively to the overall energy balance within the circuit or system in which it is installed.

[0025] An additional scope of the invention is to provide a separator of fluids capable of ensuring the highest levels of reliability and safety in use.

[0026] Yet another scope of the invention is to provide a separator of fluids that is easy to manufacture, simple, compact, and economically competitive compared to the prior art.

[0027] The above-described aim, as well as the mentioned scopes and others that will become more apparent later, are achieved by a separator of fluids having at least two components with different densities, comprising a separation chamber with a substantially tubular shape extending longitudinally along a longitudinal axis, and an axial impeller housed within said separation chamber, said axial impeller extending longitudinally along said longitudinal axis and being rotatable within said separation chamber about said longitudinal axis. Said separation chamber comprises, at a first axial end, an inlet port for a fluid, and, at a second axial end opposite said first axial end, at least one outlet port for at least a first component of said fluid having a density greater than the density of a second component of said fluid. Said axial impeller comprises a variable pitch screw, wherein the pitch of said screw increases along said longitudinal axis between said first axial end and said second axial end such that the helix angle of said screw also increases between said first and second axial ends. The rotation of said axial impeller imparts an axial advancement of said fluid along said longitudinal axis, and further imparts a rotation to said fluid around said longitudinal axis such that the radial component of the velocity of the fluid, being a function of the increase in the pitch and helix angle of said screw, reaches its maximum value near said second axial end, where the pitch and helix angle of the screw are at their maximum value, and where said first component separates from said second component along a radial direction. At least said first component is conveyed along said radial direction toward said at least one outlet port positioned radially peripherally along said radial direction relative to said separation chamber.

[0028] Preferably, said separation chamber comprises, at said second axial end, an additional port positioned radially centrally with respect to said separation chamber along said radial direction, said additional port being in fluid communication with the internal volume of said separation chamber and configured to allow the passage of said second component of said fluid.

[0029] Preferably, said screw comprises a core, at least at said second axial end, said core being internally hollow to define a cavity for containing said second component of said fluid, said core comprising, on its outer surface at said cavity, a plurality of through openings configured to allow the passage of said second component into and / or out of said cavity, said cavity being in fluid communication with said additional port.

[0030] Preferably, the fluid separator comprises a drive unit connected to said axial impeller and adapted to impart to said axial impeller a rotation about said longitudinal axis, said drive unit comprising a drive shaft coaxial with said axial impeller, internally hollow, and defining an axial conduit in fluid communication with said additional port, configured to place said cavity in fluid communication with said additional port.

[0031] Preferably, said first component of said fluid is conveyed along said radial direction toward said at least one outlet port, while said second component is conveyed along said radial direction toward said additional port.

[0032] Preferably, said first component of said fluid and said second component of said fluid are both conveyed, separated from each other, along said radial direction toward said at least one outlet port, said additional port being configured to allow the entry of an auxiliary fluid into said separation chamber, said auxiliary fluid being compatible with said second component of said fluid. More preferably, said second component is a gaseous component, and said auxiliary fluid comprises air.

[0033] Preferably, said auxiliary fluid enters said fluid separator through said additional port and exits said cavity through said plurality of through openings, interacting with said second component of said fluid to facilitate its separation from said first component of said fluid.

[0034] Other preferable features are provided in the dependent claims.

[0035] LIST OF FIGURES

[0036] Further features and advantages will become more apparent from the exemplary but nonlimiting description of a preferred embodiment of the present invention, illustrated with the aid of the accompanying drawings, in which:

[0037] -Figure 1 is a schematic perspective view of an embodiment of a separator of fluids having components with different densities, according to the invention;

[0038] -Figure 2 is a front sectional view of the separator of fluids, according to the invention;

[0039] -Figure 3 is a simplified, transparent perspective view of the separator of fluids, according to the invention, illustrating in particular the axial impeller;

[0040] -Figure 4 is a front elevation view of the axial impeller of the separator of fluids, according to the invention;

[0041] -Figure 5 is a front sectional view of the axial impeller of Figure 4;

[0042] -Figure 6 is a side view of the separator of fluids shown in Figure 3, illustrating the absolute pressure profiles of the fluid in axial and radial directions;

[0043] -Figure 7 is a front view of a variant of the separator of fluids, according to the invention;

[0044] -Figure 8 is a front sectional view of another embodiment of a separator of fluids having components with different densities, according to the invention;

[0045] -Figures 9 and 10 illustrate two different operating modes of the separator of fluids, according to the invention.

[0046] DETAILED DESCRIPTION OF THE INVENTION

[0047] With particular reference to the figures, the separator of fluids having components with different densities, generally indicated by reference numeral 1, comprises, according to the invention, a separation chamber 2 with a substantially tubular shape extending along a longitudinal axis X, and an axial impeller 3 housed within said separation chamber 2. The axial impeller 3 is referred to as axial because it extends longitudinally along the longitudinal axis X and is rotatable within the separation chamber 2 about the longitudinal axis X.

[0048] The separation chamber 2 comprises, at a first axial end 20, or inlet end, an inlet port 21 for a fluid 22, and, at a second axial end 25, or outlet end, opposite the first axial end 20, at least one outlet port 26 for at least a first component 27 of the fluid 22 having a density greater than the density of a second component 29 of the fluid 22.

[0049] The two components, or phases, 27 and 29 of the fluid 22 have different densities, with the first component 27 having a density greater than that of the second component 29. An example of a fluid 22 can be a gas / liquid mixture, in which the gaseous phase (second component 29) is distinct from the liquid phase (first component 27) due to their differing densities, as well as the fact that they belong to two different states of matter.

[0050] As explained in more detail below, a fluid 22 enters the separator 1 through the inlet port 21 located at the first axial end 20, or inlet end, of the separation chamber 2. Within the separator 1, the two components 27 and 29 of the fluid 22 separate, and at the second axial end 25, at least a first component 27 exits through at least one outlet port 26, separated from the second component 29.

[0051] According to the invention, the impeller 3 comprises a variable pitch screw 31. The pitch of the screw 31 increases along the longitudinal axis X between the first axial end 20 and the second axial end 25. The rotation of the impeller 3 imparts an axial advancement to the fluid 22 along the longitudinal axis X. Additionally, the rotation of the impeller 3 imparts a rotation to the fluid 22 around the longitudinal axis X, which is a function of the increasing pitch of the screw 31 (i.e., the radial velocity component of the fluid 22 increases with the pitch, and thus the helix angle, of the screw 31, as explained further below) and reaches its maximum value near the second axial end 25. At this point, due to the centrifugal effect, the first component 27 separates from the second component 29 along a radial direction R, owing to their different densities. At least the first component 27, having a higher density, is conveyed along the radial direction R toward at least one outlet port 26 positioned radially peripherally along said radial direction R with respect to the separation chamber 2.

[0052] As explained further below, at the second axial end 25, the fluid separator 1 also comprises an additional port 28 arranged in a radially central position with respect to the separation chamber 2 along the aforementioned radial direction R. This additional port 28 is in fluid communication with the internal volume of the separation chamber 2 and is configured to allow the passage of the second component 29 of the fluid 22.

[0053] Preferably, as shown in the accompanying figures, the at least one outlet port 26 is positioned exclusively at said second axial end 25 of the separation chamber 2. Indeed, between the first axial end 20 and the second axial end 25 along the longitudinal axis X, the inner walls 12 of the separation chamber 2 are closed and continuous. In other words, between the first axial end 20 and the second axial end 25, the inner walls 12 of the separation chamber 2 do not include any ports or openings for the passage of the fluid 22.

[0054] Preferably, both the outlet port 26 and the additional port 28 are arranged exclusively at said second axial end 25 of the separation chamber 2.

[0055] Depending on the pressure difference between the suction zone (indicated as P21 in the attached figures), at the first axial end 21 of the separation chamber 2, and the delivery zone at the second axial end 25 of the separation chamber 2, specifically at the radially central position of the separation chamber 2 (indicated as P28 in the attached figures), this additional port 28 can operate in two different ways:

[0056] Mode 1 : if the pressure of the fluid 22 at the radially central position of the second axial end 25 (central delivery zone P28) is higher than the pressure of the fluid 22 at the first axial end 21 (suction zone P21) then the additional port 28 acts as a secondary outlet port specifically for the second component 29 of the fluid 22, while the first component 27 of the fluid 22 exits through the main outlet port 26, or

[0057] Mode 2: if the pressure of the fluid 22 at the radially central position of the second axial end 25 (central delivery zone P28) is lower than the pressure of the fluid 22 at the first axial end 21 (suction zone P21), then the additional port 28 acts as an auxiliary port through which an additional amount of the second component 29 of the fluid 22 is drawn in — an amount not originally present in the fluid 22 entering the separator 1 — and this further promotes the separation of the two components 27 and 29 of the fluid 22, both of which then exit together, though separated, through the main outlet port 26.

[0058] According to mode 1, therefore, the first component 27 of the fluid 22 is conveyed along the radial direction R toward the at least one outlet port 26, while the second component 29 is conveyed along the radial direction R toward the additional port 28 and exits the separator 1 through that additional port 28.

[0059] According to mode 2, the first component 27 of fluid 22 and the second component 29 of fluid 22 separate from each other as described above, but they are both conveyed, separately from each other, along the radial direction R toward the at least one outlet port 26. According to mode 2, the additional port 28 is configured to allow an auxiliary fluid — compatible with the second component 29 of fluid 22 — to enter the separation chamber 2, thereby further promoting the separation of the second component 29 from the first component 27 within the separation chamber 2.

[0060] The auxiliary fluid entering through the additional port 28 may be a fluid of the same nature as the second component 29 of fluid 22, or a fluid capable of interacting with the second component 29 to facilitate its separation from the first component 27 of fluid 22. With reference to Figure 9, by way of example, if the fluid 22 consists of a mixture of oil (first component 27) and air (second component 29) drawn from a reservoir containing the fluid to be treated, and if the pressure of the fluid 22 in the suction zone P21 is lower than the pressure of the fluid 22 in the radially central portion of the delivery zone P28, then the oil component 27 of the fluid 22 will exit through the main outlet port 26, while the air component 29 of the fluid 22 will exit through the additional port 28, thus making that additional port 28 act as a secondary outlet port. As illustrated in Figure 9, the air bubbles present in the fluid tend, by virtue of the centrifugal action of screw 31, to coalesce and separate from the oil before exiting through the additional port 28.

[0061] With reference to Figure 10, if the pressure of fluid 22 in the suction zone P21 is higher than the pressure of fluid 22 in the radially central portion of the delivery zone P28, then additional air (or another suitable fluid) will enter through the additional port 28. Consequently, the additional port 28 acts as an auxiliary port that draws air in and introduces it into fluid 22, further promoting, through coalescence, the separation of the air originally present in fluid 22. Oil (the first component 27) and air (the second component 29) will both exit, though separately, through the main outlet port 26. As illustrated in Figure 10, the air bubbles in the fluid tend, due to the centrifugal action of screw 31, to coalesce with the air bubbles entering from the additional port 28, thereby separating from the oil and ultimately exiting together with it through the outlet port 26.

[0062] The separator 1 can also operate with a fluid 22 containing two or more fluid components, as it can consistently separate the lower-density component 29 from the denser component(s) 27. Specifically, the latter will always exit through the main outlet port 26, while the component 29 may exit — depending on the pressure differences between zones P21 and P28 described above — either through the additional port 28 or through the same main outlet port 26.

[0063] The fluid 22 entering the separation chamber 2 moves in the initial section with an advancing velocity that essentially has only an axial component. As the fluid 22 progresses along the longitudinal axis X, it encounters the crests 32 of the screw 31 which, due to the increasing pitch of the screw 31, also impart a radial component to the advancing velocity of the fluid 22, thereby causing the fluid 22 to rotate around the longitudinal axis X.

[0064] In addition, as fluid 22 progresses along the variable-pitch screw 31, it encounters progressively larger flow cross-sections, thereby reducing its relative velocity with respect to screw 31 and consequently increasing its pressure for well-known fluid dynamic reasons, such as those explained by Bernoulli’s theorem. This rotation reaches its maximum value at the second axial end 25 of the separation chamber 2, where, by centrifugal effect, the second component 29 of fluid 22, being less dense and lighter, separates from the first component 27, which is denser and heavier.

[0065] Indeed, the gradual increase of the pitch of the variable-pitch screw 31 along the longitudinal axis X corresponds to an increase in the helix angle of screw 31. This increasing helix angle imparts a rotation about the longitudinal axis X to the fluid 22, which causes the two components, or phases, of different densities to separate by centrifugal effect. This separation reaches its maximum at the second axial end 25 of the separation chamber 2, where the outlet port 26 is located, and possibly the additional port 28 for the two components 27 and 29 and where, as explained further below and illustrated in the attached figures, the core 33 of the screw 31 is radially perforated.

[0066] Preferably, the variable-pitch screw 31 is a screw with two or more threads 3 Ipl, 31p2, in which contiguous crests 32 of said two or more threads 3 Ipl, 3 lp2 define, together with the inner walls 12 of the separation chamber 2, one or more diverging conduits.

[0067] Preferably, the variable-pitch screw 31 is a two-thread screw or a three-thread screw. Alternatively, the screw 31 may also be a screw with four threads.

[0068] In the example shown in the figures, the screw 31 is a two-thread screw 3 Ipl, 31p2. A diverging conduit is defined between the contiguous crests 32 of the two threads 3 Ipl, 31p2, meaning a conduit that increases its width as the pitch of the screw 31 increases.

[0069] Advantageously, the divergence of the conduits defined by the crests 32 of the screw 31 allows part of the velocity of the fluid 22 to be converted into pressure head.

[0070] Figure 6 schematically illustrates the absolute pressure profile of the fluid 22 within the separation chamber 2 along both the longitudinal axis X and the radial axis R. In this case, the pressure of fluid 22 in the radially central portion of the delivery zone P28 is greater than the pressure of fluid 22 in the suction zone P21 (mode 1), and therefore, the additional port 28 acts as a secondary outlet port for the second component 29 of fluid 22.

[0071] The divergence of the conduits defined by the crests 32, as mentioned, results in a reduction of the axial velocity of fluid 22 along the conduits relative to the axially rotating screw 31, and a corresponding increase in pressure between the first axial end 20 and the second axial end 25. At the same time, the increase in the pitch of the screw 31, and thus the increase in the helix angle, leads to an increase in the rotational velocity of fluid 22 around the longitudinal axis X, generating a centrifugal effect. Due to this centrifugal effect, the pressure of fluid 22 in the radially peripheral zone of the separation chamber 2 is greater than the pressure of fluid 22 in the radially central zone, causing the separation of the first component 27, which is denser, from the second component 29, which is less dense.

[0072] This effect occurs in the presence of a downstream load on the separator 1, and in particular on the outlet port 26, such that a certain flow rate along the impeller 3 corresponds to a certain pressure downstream of the separator 1, similarly to what generally happens in dynamic machines.

[0073] Preferably, the screw 31 includes a core 33. At least at the second axial end 25, the core 33 is internally hollow, defining a cavity 35 for containing the less dense second component or phase 29, which separates from the denser first component or phase 27 due to the centrifugal effect. For example, in the case of a gas / liquid mixture 22, the cavity 35 collects the gaseous component 29, which separates from the liquid component 27 (or, depending on the pressure differences in zones P21 and P28, enters from the additional port 28).

[0074] Preferably, the core 33 includes, on its outer surface at the cavity 35, a plurality of through openings 34 configured to allow the passage of the less dense second component 29 into the cavity 35 (or out of the cavity 35, depending on the pressure differences in zones P21 and P28).

[0075] The cavity 35 is in fluid communication with the additional port 28, so that:

[0076] In the case where the second component 29, due to the centrifugal effect, enters the cavity 35, it is then expelled from the separator 1 through the additional port 28, which acts as a secondary outlet port (mode 1), or

[0077] In the case where an auxiliary fluid compatible with the second component 29 of fluid 22 is drawn into the cavity 35 from outside the separator 1, this auxiliary fluid can flow from the cavity 35 into the internal volume of the separation chamber 2 and interact with the second component 29 of fluid 22, promoting its separation from the first component 27 through coalescence. The two components 27 and 29, separated from each other, are then expelled together through the outlet port 26 (mode 2).

[0078] Advantageously, as mentioned above, the second component 29 of fluid 22, at the second axial end 25 of the separation chamber 2 where centrifugal separation primarily occurs, exhibits a pressure slightly higher than atmospheric pressure or, in any case, higher than the pressure at the inlet of the separator 1. This facilitates the expulsion of the second component 29 from the separator 1.

[0079] An example simulation of the operation of the fluid separator 1 is now described, relating to an axial impeller 3 with an outer diameter of 50 mm rotating at a speed between 5000 and 5500 revolutions per minute. The axial impeller 3 draws fluid 22 through the inlet port 21 from a reservoir maintained at atmospheric pressure (1 bar). In the inlet zone P21, the pressure of fluid 22 is slightly lower than that in the reservoir due to small losses in the connecting pipes between the reservoir and the separator 1. The absolute pressure of fluid 22 at the inlet of the separator 1, specifically at the initial portion of the axial impeller 3 (zone P21), is thus approximately 0.9 bar. The axial impeller 3 in this example is capable of imparting a maximum pressure increase of approximately 0.8 bar to the fluid 22. This means that the maximum absolute pressure of fluid 22 detectable at the outlet port 26 is approximately 1.7 bar (0.9 bar + 0.8 bar). However, the pressure detectable at the outlet port 26 also depends on the downstream load of the separator 1 and the flow rate of fluid 22 in this outlet zone. If the downstream load, for the flow rate that stabilizes under equilibrium conditions (e.g., approximately 120 1 / min according to the described example), results in a pressure drop of 0.25 bar between the outlet port 26 and the return reservoir for the separated fluid 22, and if the pressure in the reservoir is 1 bar absolute, the absolute pressure at the outlet port 26 will be approximately 1.25 bar (1 bar + 0.25 bar). This is lower than the maximum absolute pressure that the axial impeller 3 could provide (i.e., 1.7 bar), at the cost of a decrease in flow rate as the pressure head increases, which could cause the flow rate to drop below 120 1 / min, potentially reaching zero.

[0080] Now, the pressure of fluid 22 near the core 33 of the axial impeller 3, specifically in the P28 zone, logically depends on the pressure of fluid 22 at the outlet port 26, because there is a pressure increase between the P28 zone and the outlet port 26 zone due to the centrifugal (radial) component of the action of the axial impeller 3. For example, if the pressure difference between these two radial zones is approximately 0.4 bar and, as mentioned above, the pressure at the outlet port 26 is about 1.25 bar, then the pressure in the P28 zone is approximately 0.85 bar (1.25 bar - 0.4 bar) (in the absence of fluid flow from the additional port 28). Thus, given the pressure difference, there is a flow from the reservoir of the less dense component 29 of fluid 22 (e.g., air) entering through the additional port 28. However, the flow of less dense fluid coming from the additional port 28 increases the pressure in the P28 zone, bringing it closer to the value detected at the outlet port 26 until equilibrium is achieved.

[0081] Figure 6 illustrates an example of the operation of the axial impeller 3 where the two components 27 and 29, at least partially separated from the fluid 22, both exhibit, at the second axial end 25, absolute pressures greater than the pressure at the inlet of the separator 1. Specifically, in the radially innermost zone at the second axial end 25, the absolute pressure can reach approximately 1.1 bar (a pressure difference of about +0.2 bar compared to the inlet) and increases, still at the second axial end 25, up to 1.5 bar in the radially outermost zone (a pressure difference of about +0.6 bar compared to the inlet). In this case, the second component 29 (air) of the fluid 22 exits the separator 1 through the additional port 28.

[0082] Preferably, the cross-section of the conduit through which the fluid 22 flows, defined between the outer surface of the core 33 of the screw 31, the two contiguous crests 32 of the screw 31, and the inner walls 12 of the separation chamber 2, increases along the direction of the longitudinal axis X. Specifically, considering a so-called "mean helix" curve that develops along this conduit and is equidistant at every point from pairs of opposing walls among the four walls defining the conduit (i.e., equidistant from the outer surface of the core 33 and the inner wall 12 of the separation chamber 2, as well as equidistant from two contiguous crests 32), it is possible to identify, at each point along this mean helix, corresponding to a cross-section of the conduit perpendicular to the axis, the tangent to the mean helix.

[0083] It is then possible to construct four cones, each having its outer surface tangent to a respective inner surface of the walls of the conduit (i.e., the outer surface of the core 33, the contiguous crests 32, and the inner wall 12). For each point on the mean helix, a so-called "wall divergence angle" can be determined for each of the aforementioned four inner wall surfaces of the conduit. This angle is defined as the angle of the generatrix of the cone relative to the axis of the cone located on the tangent to the mean helix. The angle will be positive if the cone has its vertex pointing toward the fluid inlet and diverges, opening in the direction of fluid advancement. Preferably, this "wall divergence angle" is less than 12°, more preferably less than 7°, for at least one of the four walls defining the conduit, even more preferably for a plurality of these walls, or even for all four walls.

[0084] It has been observed that wall divergences in conduits through which fluids flow, greater than 12°, cause undesirable flow separation phenomena, leading to sudden local increases and decreases in pressure. This, in turn, results in turbulence in the flow and sudden, undesirable, localized expansions of the gaseous components of the fluids. Ensuring that the conduit through which fluid 22 flows in the separator 1 has walls that never diverge by more than 12°, and preferably never by more than 7°, significantly reduces the undesirable phenomenon of flow separation.

[0085] The initial portion of the conduits through which the fluid flows may also exhibit a slight reduction in cross-sectional area along the direction of the longitudinal axis X. However, this reduction only affects the initial portion of the conduits, specifically the portion corresponding to the inlet. Preferably, this reduction affects only an initial length of the conduits that is less than 10 times the minimum axial distance between the crests 32, and more preferably less than 5 times the minimum axial distance between the crests 32. For example, in the case of a screw 31 with an outer diameter of 50.0 mm, where the axial distance between the crests 32 at the conduit inlet is 7.5 mm, the length along the longitudinal axis X within which the conduits may exhibit a slight reduction in cross-sectional area is less than 75.0 mm, more preferably less than 37.5 mm, and typically between 15.0 and 20.0 mm.

[0086] Preferably, at the end of the screw 31 located at the first axial end 20 (inlet) of the separation chamber 2, the crests 32 of the screw 31 are oriented in a plane substantially orthogonal to the longitudinal axis X.

[0087] Preferably, at the end of the screw 31 located at the second axial end 25 (outlet) of the separation chamber 2, the crests 32 are oriented in a plane substantially parallel to the longitudinal axis X.

[0088] In other words, the pitch angle, or helix angle, of the screw 31 at the first axial end 20 is preferably between 0° and 20°, more preferably between 4° and 15°, while the pitch angle of the screw 31 at the second axial end 25 is preferably between 60° and 90°, more preferably between 75° and 90°.

[0089] Preferably, in the case of a two-thread screw 31, the pitch angle at the first axial end 20 is between 5° and 12°, while in the case of a three-thread screw, the pitch angle at the first axial end 20 is between 6° and 15°.

[0090] Advantageously, such values of the pitch angle, or helix angle, at the inlet and outlet of the separator 1 facilitate the predominantly axial entry of the fluid 22 into the separation chamber 2 and its flow along the longitudinal axis X with a gradual increase in the rotational or radial velocity component as well.

[0091] Preferably, the pitch of the threads 3 Ipl, 31p2 of the screw 31 increases gradually and continuously between the inlet end 20 and the outlet end 25.

[0092] Essentially, along the length of the screw 31, the crests gradually change their orientation from the inlet end 20 to the outlet end 25, transitioning from a perpendicular configuration to a parallel configuration.

[0093] In particular, the helix angle of the screw 31 varies gradually, between the first end 20 and the second end 25, from a value between 0° and 20°, preferably between 4° and 15°, to a value between 60° and 90°, preferably between 75° and 90°.

[0094] Preferably, as illustrated in particular in Figure 5, the core 33 of the screw 31 has a crosssection with a diameter that varies along the longitudinal axis X. This facilitates the entry of the fluid 22 into the separation chamber 2 and its subsequent flow along the longitudinal axis X.

[0095] Preferably, the diameter of the cross-section of the core 33 near the first axial end 20 is greater than the diameter of the cross-section of the core 33 near the second axial end 25.

[0096] Preferably, the diameter of the core 33 of the screw 31 near the first axial end 20 (inlet) is between 50% and 80% of the average outer diameter of the screw 31, more preferably between 60% and 70%. The portion of the core 33 with an enlarged cross-section is generally indicated in Figure 5 with the reference SI. This configuration facilitates the engagement of the axial impeller 33 with the fluid 22, where the relative tangential velocity of the fluid 22 is higher, and ensures reasonable continuity of the axial advancement velocity of the fluid 22, as the velocity triangles formed by the axial and tangential velocity vectors in the reference frame of the axial impeller 3 undergo negligible variations.

[0097] Preferably, the diameter of the core 33 of the screw 31 near the second axial end 25 (outlet) is between 25% and 50% of the average outer diameter of the screw 31, more preferably between 30% and 45%. The portion of the core 33 with a smaller cross-sectional diameter is generally indicated in Figure 5 with the reference S2.

[0098] As explained further below, the screw 31 may have a constant outer diameter when inserted into a cylindrical separation chamber 2 but may also have a variable outer diameter, for example, when inserted into a separation chamber 2 with a variable cross-section along the longitudinal axis X, such as a separation chamber 2 with at least one frusto-conical portion 80, as in the variant shown in Figure 7. Toward the outlet, it is necessary to separate the components of the fluid 22 with different densities, such that the first component 27, which is denser and heavier, is positioned radially outward, while the second component 29, which is less dense and lighter, is directed toward the center.

[0099] Advantageously, thanks to the enlarged core 33 and to the relatively small pitch angle, or helix angle, at the first axial end 20, the inlet port 21 acts as a dynamic fluid intake, while concentrating this dynamic intake on the outer portion prevents significant variations in dynamic pressure due to radial differences.

[0100] In fact, the fluid 22 reaching the inlet port 21 enters the separator 1 with only a specific axial velocity component. Within the separator 1, however, the fluid 22 encounters the crests 32 of the impeller 3, which define inlet openings moving relative to the fluid 22 at a tangential high speed. The rotation of the impeller 3 about the longitudinal axis X thus creates relative rotation between the fluid 22 and the impeller 3 itself, given that the fluid 22 at the inlet port 21 has no tangential velocity component.

[0101] At the inlet of fluid 22 into the openings defined by the crests 32, the fluid 22 encounters resistance to motion, which inherently generates a local pressure increase due to the stagnation pressure resulting from the difference between the relative velocity of the fluid and the crests and the velocity at which the fluid enters the openings defined by the crests. Furthermore, if the fluid 22 comprises a gaseous phase, the compressibility of the fluid 22 contributes to the pressure increase attributable to the gaseous phase, which further slows the fluid 22. This effect of local pressure increase is particularly advantageous because, typically, at the inlet between the crests 32 of the screw 31, near the leading edge of the separation chamber 2, vortices are generated, which locally reduce the pressure of the fluid 22 and may potentially trigger local cavitation phenomena.

[0102] The effect is even more advantageous when the two-phase fluid 22 includes a gaseous phase 29, as the local pressure decrease would increase the volume of the gaseous fraction 29. However, the configuration of the axial impeller 3, according to the invention, eliminates or significantly reduces this malfunction. Essentially, even at the entrance to the separation chamber 2, the fluid 22 follows orderly, non-turbulent flow lines, which it maintains as it advances along the axial direction X.

[0103] The variations in the diameter of the cross-section of the core 33 are such that, in the initial section of the screw 31, near the first axial end 20 (the inlet), the radial distance between the outer surface of the core 33 and the outermost part of the screw 31 is minimized. This effectively makes the separation of the fluid components 27 and 29 negligible in this section. The separation, instead, takes place in the final section of the screw 31, near and at the second axial end 25 (the outlet), where the radial distance between the outer surface of the core 33 and the outermost part of the screw 31 is maximized. This configuration ensures better guidance of the fluid 22 and more efficient separation, as the separation is concentrated where the lighter second component 29 of the fluid 22 can be extracted, and where the pressure distribution is stabilized, with the only significant gradient being in the radial direction.

[0104] The separation chamber 2, which is substantially tubular in shape, can be substantially cylindrical, as illustrated in Figures 1 to 7. In this case, the axial impeller 3 has an outer diameter of the screw crests 32 of the screw 31 that remains substantially constant along the longitudinal axis X.

[0105] Alternatively, the substantially tubular-shaped separation chamber 2 may include at least one portion with a substantially variable cross-section 80 along the longitudinal axis X, such as a frusto-conical portion, as shown in the variant of Figure 6. In this case, the axial impeller 3 has an outer diameter of its crests 32 that substantially matches the shape of the separation chamber 2, including the shape of its substantially variable cross-section portion 80, specifically the frusto- conical shape.

[0106] Preferably, the portion with a substantially variable cross-section 80 is arranged such that the cross-section with the smaller area is oriented toward the first axial end 20, while the crosssection with the larger area is oriented toward the second axial end 25.

[0107] Preferably, the conicity angle CCC, measured between the generatrix line of the frusto- conical portion and the longitudinal axis XXX, is less than 10°, more preferably less than 5°. This conicity angle CCC is preferably divergent toward the second axial end 25 of the separator 1. The conicity angle CCC may be constant, in which case the portion with a variable cross-section assumes a frusto-conical shape, or it may vary. Advantageously, the fact that the separation chamber 2 includes a portion with a variable cross-section (e.g., frusto-conical) 80 that widens toward the second axial end 25 allows for a further increase in the volume of space available for the fluid 22 between the core 33 and the outer diameter of the crests 32 of the axial impeller 3. This space is where, primarily, the centrifugal separation of the two components 27 and 29 of the fluid 22, with different densities, occurs. In this variant, the radial distance between the outer surface of the core 33 and the outermost part of the screw 31 at the second axial end 25 of the separator 1 is further maximized, both due to the reduction of the diameter of the cross-section of the core 33 and the increase in the external diameter of the screw 31.

[0108] It is also contemplated that the separation chamber 2 may have a portion with a variable cross-section (e.g., frustoconical) 90 that narrows toward the second axial end 25.

[0109] Preferably, the longitudinal length of the axial impeller 3 is between 250% and 800% of the external diameter of the axial impeller 3 itself, more preferably between 400% and 600%. Such a length-to-diameter ratio is unusual, if not unheard of, for axial impellers in hydraulic machines. However, in the case of the impeller 3 of the separator 1, the length of the impeller is determined by the need to gradually convert the velocity components of the fluid 22, as described above, giving the different components 27, 29 of the fluid 22 the necessary time to ensure their efficient and optimal separation.

[0110] A correct length-to-diameter ratio for a specific type of fluid 22 allows for a good balance between the efficiency of the separation and the residence time of the fluid 22 within the separation chamber 2. In any case, the fluid 22 flows through the separation chamber 2 without interruptions, continuously, although it is evident from the figures that the separation effectively occurs in the terminal section of the separation chamber 2.

[0111] Advantageously, the axial impeller 3 can be manufactured using metal die-casting techniques, for example, in an aluminum alloy, or through molding techniques using a polymeric material, such as plastic. In fact, from a technological perspective, the axial impeller 3 has a unique characteristic that makes its production particularly economical: the crests 32 can be designed to be mouldable, allowing the impeller 3 to be manufactured either by metal die-casting (e.g., aluminum alloy) or by molding in an appropriate plastic material mold. This can be achieved, even if requiring the use of radial "sliders" to define the external shape of the screw, typically with 4 or 6 sliders.

[0112] Preferably, the outlet port 26 includes a collection structure 260 for at least the first, denser component 27, which circumferentially surrounds the separation chamber 2. As illustrated in Figures I and 2, this collection structure 260 preferably has a volute-shaped configuration. This design optimizes the collection of the entire first component 27 of the fluid 22, which, due to the centrifugal effect, rotates around the longitudinal axis X and is also pushed radially outward in the direction R toward the exterior of the separation chamber 2, along the entire circumference of the separation chamber 2.

[0113] As illustrated in particular in Figure 2, the fluid separator 1 includes a drive unit 5 connected to the axial impeller 3, designed to impart rotation to the axial impeller 3 about the longitudinal axis X.

[0114] Preferably, the drive unit 5 is at least partially immersed in the fluid 22. Specifically, the drive unit 5 includes a motor 50 housed within an outer casing 51 configured to be filled with the fluid 22 itself. This solution, which involves immersing the motor 50 in the fluid 22, is particularly simple to implement, as it eliminates the need for any seals between the motor 50 and the separation chamber 2.

[0115] Preferably, the separator 1 includes an axial conduit 280 that places the cavity 35 in fluid communication with the additional port 28. This conduit 280 preferably has a cross-section with a diameter compatible with or smaller than the cross-sectional diameter of the core 33 at the location of the cavity 35, as the conduit 280 opens into the cavity 35.

[0116] In the example of the figures, the diameter of the conduit 280 relative to the external diameter of the axial impeller is compatible with the separation of a gas from a fluid. However, for the separation of two liquid components with different densities, also considering the relative percentage of the two liquids, it could be larger, as could, consequently, the minimum diameter of the core.

[0117] Preferably, the motor assembly 5 comprises a drive shaft 53 coaxial with the axial impeller 3. This drive shaft 53 is internally hollow, meaning it has a longitudinal through-hole, and defines an axial conduit 280 in fluid communication with the additional port 28, configured to allow the passage of the second, lighter component 29 of the fluid 22. Specifically, the axial conduit 280, formed within the drive shaft 53, is designed to place the cavity 35 in fluid communication with the additional port 28.

[0118] As illustrated in figure 2, the drive shaft 53, with one of its ends, faces the cavity 35, and with its opposite end, faces the additional port 28. This configuration is advantageous because it does not require rotary seals on the drive shaft 53 and, therefore, does not expose the separator 1 to the risk of fluid leakage due to the failure of one of these rotary seals, also eliminating the friction torque that these seals always entail. Even if the motor were to have seals on the shaft, their failure would not result in any fluid leakage from the separator 1 but would simply lead to the fluid invading the motor’s air gap area.

[0119] Furthermore, as illustrated in figure 2, the separation chamber 2 comprises a central tubular body 200, connected, at the first axial end 20, to an inlet structure 210, and at the second axial end 25, to the collection structure 260.

[0120] Gaskets 201 and 202 are provided for sealing between the central tubular body 200 and, respectively, the inlet structure 210 and the collection structure 260. The collection structure 260 is, in turn, connected to the motor assembly 5, sealed by a gasket 205.

[0121] The external casing 51 of the motor assembly 5 also comprises an external tubular body 54, a flange 55, and a cover 56. The flange 55 is configured to allow the motor assembly 5 to be fixed to the separator 1, and in particular to the collection structure 260.

[0122] Between the cover 56 and the external tubular body 54, an additional gasket 206 is provided for sealing.

[0123] At the interface between the collection structure 260 and the flange 55, the drive shaft 53 is rigidly fixed to the axial impeller 33, for example, by means of a clamp 57, or a keyed connection, or other fixing means.

[0124] The drive shaft 53 is rotatably supported relative to the external casing 51 by a pair of bearings 58 and 59, preferably positioned in the flange 55 and the cover 56, respectively. The axial impeller 33 is rotatably supported at the first, inlet end 20, by means of a bearing 36, preferably positioned in the inlet structure 210. By virtue of the rigid connection between the axial impeller 33 and the drive shaft 53, the axial impeller 33 is also rotatably supported at the second, outlet end 25, by means of the bearings 58, 59. A thrust bearing 37, or another equivalent element for rotatable support of axial thrust, is also provided between the axial impeller 33 and the inlet structure 210.

[0125] As illustrated in figure 2, the sealing gaskets 205 and 206 associated with the motor assembly 5 ensure fluid sealing relative to the external casing 51, while the motor 50, housed within this external casing 51, is preferably in direct contact with the fluid 22, which from the separation chamber 2 can invade the internal volume of the external casing 51, and thus the motor 50. Advantageously, this solution improves the cooling of the motor 50 itself.

[0126] In any case, even if the fluid 22 does not invade the internal volume of the external casing 51, its flow, or at least one of its components, through the drive shaft 53 towards the outlet port 28 contributes to cooling the rotor of the motor 50, which is known to be the most heat-sensitive part, with an effect made more efficient by the fact that the fluid flows at a considerable velocity within the conduit 280.

[0127] Advantageously, in the case where the fluid 22 comprises more than two components or phases, it is possible to use two different separators 1 in series, according to the invention. For example, in the case of a mixture of oil, water, and natural gas, a first separator 1 can be configured to separate the liquid phase of oil and water from the gaseous phase of natural gas, and a second separator 1 can be configured to separate the two liquid phases of oil and water from each other, based on their different densities.

[0128] Figures 1 to 6 refer to a first exemplary embodiment of the fluid separator 1, while figure 7 refers to a variant of this embodiment in which the separation chamber 2 does not have a cylindrical structure.

[0129] Figure 8 relates to a second exemplary embodiment of the separator 1, which, however, lacks the additional port 28 and, in fact, has only a single outlet port 26 in addition to the inlet port 21. In this second embodiment, therefore, the first component 27 and the second component 29 of the fluid 22 exit, separated from each other, solely through the outlet port 26, and no auxiliary fluid, such as air, is introduced.

[0130] In this second embodiment, the core 33 of the screw 31 does not have openings towards cavities that can be invaded by the second component 29 of the fluid 22. The screw 31 is preferably connected to the motor assembly 5 via the drive shaft 53.

[0131] The operation of the fluid separator is clear and evident from the description provided.

[0132] In particular, the fluid separator 1, implemented according to the first embodiment, operates effectively even under varying load conditions at the outlet of the separator itself, being able to operate, depending on the pressure differences that may be present between the suction zone P21 and the central outlet zone P28, in the two modes described above.

[0133] The fluid separator 1 implemented according to the second embodiment, which has a simpler structure to manufacture, is particularly suitable for operation when the load conditions at the outlet are such that the pressure in the central outlet zone P28 is substantially equal to or slightly greater than the pressure in the suction zone P21.

[0134] It has been demonstrated that the separator of fluids with components of different densities, according to the present invention, fulfills the aim and the scopes stated above, as it allows for the efficient separation of the components or phases of a fluid with different densities, such as a gaseous phase from a liquid phase.

[0135] Moreover, the fluid component separator, according to the invention, operates “in-line,” providing separation of the components or phases in real time, i.e., within the time required for the fluid to pass through the separator itself.

[0136] Another advantage of the fluid separator, according to the invention, is that it prevents undesirable pressure drops and even provides the fluid with a slight head, which benefits the operation of the pump located downstream of the separator.

[0137] A further advantage of the fluid separator, according to the invention, is that it can be easily integrated into different types of hydraulic circuits, also due to its characteristic of having an external diameter only slightly larger than that of the possible inlet pipeline for the fluid.

[0138] Yet another advantage of the fluid separator, according to the invention, is that it does not limit itself to providing head only to the liquid component separated from the gaseous component but also provides a slight head to the gaseous component, facilitating its expulsion. Yet another advantage of the fluid separator, according to the invention, is that its most impactful component, the axial impeller, lends itself to particularly economical manufacturing methods such as die-casting or plastic molding.

[0139] Yet another advantage of the fluid separator, according to the invention, is that the electric motor can be reduced in size due to the cooling effect provided by the fluid itself, with which the motor is brought into contact. Indeed, the heat exchange with the liquids that at least partially make up the fluid to be separated is more efficient than that with air or gases in general.

[0140] The separator thus conceived is subject to numerous modifications and variations, all falling within the scope of the inventive concept. Moreover, all details may be replaced with other technically equivalent elements. In practice, the materials used, as long as they are compatible with the specific use, as well as the contingent dimensions and shapes, may be any, depending on the requirements. In particular, the axial impeller is not subject to heavy stresses, so die-cast aluminum alloys or suitable thermoplastic materials can be advantageously used.

Claims

CLAIMS1. A separator (1) of fluids having at least two components with different densities, comprising a separation chamber (2) having a substantially tubular shape extending longitudinally along a longitudinal axis (X) and an axial impeller (3), housed within said separation chamber (2), said axial impeller (3) extending longitudinally along said longitudinal axis (X) and being rotatable within said separation chamber (2) about said longitudinal axis (X), said separation chamber (2) comprising, at a first axial end (20), an inlet port (21) for a fluid (22), and, at a second axial end (25) opposite said first axial end (20), at least an outlet port (26) for at least a first component (27) of said fluid (22) having a density greater than the density of a second component (29) of said fluid (22), said axial impeller (3) comprising a screw (31) having a variable pitch, wherein the pitch of said screw (31) increases along said longitudinal axis (X) between said first axial end (20) and said second axial end (25) so that the helix angle of said screw (31) increases between said first axial end (20) and said second axial end (25), the rotation of said axial impeller (3) imparting an axial advancement of said fluid (22) along said longitudinal axis (X), the rotation of said axial impeller (3) further imparting to said fluid (22) a rotation about said longitudinal axis (X), wherein the radial component of the velocity of said fluid (22), being a function of said increase of said pitch and of said helix angle of said screw (31), reaches its maximum value at said second axial end (25) where said pitch and said helix angle of said screw (31) are at their greatest and where said first component (27) separates from said second component (29) along a radial direction (R), at least said first component (27) being conveyed along said radial direction (R) towards said at least an outlet port (26) arranged in a radially peripheral position along said radial direction (R) relative to said separation chamber (2).

2. A separator (1) of fluids, according to the preceding claim, wherein said variable pitch screw(31) is a two, or more, thread screw (3 Ip 1 , 3 lp2), preferably a two-thread or a three-thread screw.

3. A separator (1) of fluids, according to the preceding claim, wherein the contiguous crests(32) of said two or more threads (3 Ipl, 31p2) define, together with the inner wall (12) of said separation chamber (2), one or more diverging conduits.

4. A separator (1) of fluids, according to one or more of the preceding claims, wherein the helix angle of said screw (31) at said first axial end (20) is between 0° and 20°, preferably between 4° and 15°, and the helix angle of said screw (31) at said second axial end (25) is between 60° and 90°, preferably between 75° and 90°.

5. A separator (1) of fluids, according to claim 4, wherein said helix angle of said screw (31)varies gradually between said first axial end (20) and said second axial end (25).

6. A separator (1) of fluids, according to one or more of the preceding claims, wherein said screw (31) comprises a core (33), the diameter of the cross-section of said core (33) at said first axial end (20) being greater than the diameter of the cross-sectional of said core (33) at said second axial end (25).

7. A separator (1) of fluids, according to one or more of the preceding claims, wherein said screw (31) comprises a core (33), and wherein the diameter of the cross-section of said core (33) at said first axial end (20) is between 50% and 80% of the average outer diameter of said screw (31), preferably between 60% and 70%, and / or the diameter of the cross-section of said core (33) at said second axial end (25) is between 25% and 50% of the average outer diameter of said screw (31), preferably between 30% and 45%.

8. A separator (1) of fluids, according to one or more of the preceding claims, comprising a drive unit (5) connected to said axial impeller (3) and adapted to impart to said axial impeller (3) a rotation about said longitudinal axis (X), said drive unit (5) being configured to be at least partially immersed in said fluid (22).

9. A separator (1) of fluids, according to the preceding claim, wherein said drive unit (5) comprises a motor (50) housed within an outer casing (51) configured to be filled with said fluid (22).

10. A separator (1) of fluids, according to claim 8 or 9, wherein said drive unit (5) comprises a drive shaft (53) which, being immersed in said fluid (22), is devoid of rotary seals.

11. A separator (1) of fluids, according to one or more of the preceding claims, wherein the longitudinal length of said axial impeller (33) is between 250% and 800% of the outer average diameter of said axial impeller (33), preferably between 400% and 600%.

12. A separator (1) of fluids, according to one or more of the preceding claims, wherein said separation chamber (2) having a substantially tubular shape comprises at least one variable cross-sectional portion (80) whose cross-section varies along said longitudinal axis (X).

13. A separator (1) of fluids, according to the preceding claim, wherein said variable cross- sectional portion (80) is defined by a conicity angle (C), constant or variable, measured between the generatrix line of said variable cross-sectional portion (80) and said longitudinal axis (X), which is less than 10°, preferably less than 5°, said conicity angle (C) being preferably divergent towards said second axial end (25).

14. A separator (1) of fluids, according to one or more of the preceding claims, wherein the cross-sectional area of the conduit defined between the outer surface of the core (33) of the screw (31), between the two contiguous crests (32) of the screw (31) and between the innerwall (12) of the separation chamber (2) increases along the direction of the longitudinal axis (X).

15. A separator (1) of fluids, according to the preceding claim, in which, having identified a 'mean helix' curve that develops along said conduit and is equidistant at each of its points from pairs of opposing walls among the four walls defining said conduit, said four opposing walls being respectively defined by:-the outer surface of the core (33) of the screw (31) and the inner wall (12) of the separation chamber (2), and-the two contiguous crests (32) of the screw (31) and having identified four cones, each having its outer surface tangent to a respective inner surface of one of said four walls of said conduit, at each point of said "mean helix" curve, the angle defined as the angle between the generatrix of said cone of said respective wall and the axis of said cone located on the tangent to the mean helix is less than 12°, preferably less than 7°, for at least one of said four walls defining the conduit, preferably for a plurality of said four walls defining the conduit.

16. A separator (1) of fluids, according to one or more of the preceding claims, wherein said separation chamber (2) comprises, at said second axial end (25), an additional port (28) positioned radially centrally with respect to said separation chamber (2) along said radial direction (R), said additional port (28) being in fluid communication with the internal volume of said separation chamber (2) and being configured to allow the passage of said second component (29) of said fluid (22).

17. A separator (1) of fluids, according to claim 16, wherein said screw (31) comprises a core (33), at least at said second axial end (25), said core (33) being internally hollow to define a cavity (35) for containing said second component (29) of said fluid (22), said core (33) comprising, on its outer surface facing said cavity (35), a plurality of through openings (34) configured to allow the passage of said second component (29) into and / or out of said cavity (35), said cavity (35) being in fluid communication with said additional port (28).

18. A separator (1) of fluids, according to claim 17 when dependent on claim 8, wherein said drive unit (5) comprises a drive shaft (53) coaxial with said axial impeller (3), internally hollow, and defining an axial conduit (280) in fluid communication with said additional outlet port (28), configured to place said cavity (35) in fluid communication with said additional port (28).

19. A separator (1) of fluids, according to claim 16, 17, or 18, wherein said first component(27) of said fluid (22) is conveyed along said radial direction (R) towards said at least one outlet port (26), and wherein said second component (29) is conveyed along said radial direction (R) towards said additional port (28).

20. A separator (1) of fluids, according to claim 19 when dependent on claim 17, wherein said second component (29) of said fluid (22) enters said cavity (35) through said plurality of through openings (34) and exits said separator (1) through said additional port (28).

21. A separator (1) of fluids, according to claim 16, 17, or 18, wherein both said first component (27) and said second component (29) of said fluid (22) are conveyed separately along said radial direction (R) towards said at least one outlet port (26), said additional port (28) being configured to allow the entry of an auxiliary fluid into said separation chamber (2), said auxiliary fluid being compatible with said second component (29) of said fluid (22).

22. A separator (1) of fluids, according to claim 21, wherein said second component (29) is a gaseous component and said auxiliary fluid comprises air.

23. A separator (1) of fluids, according to claim 21 or 22 when dependent on claim 17, wherein said auxiliary fluid enters said separator (1) through said additional port (28) and exits said cavity (35) through said plurality of through openings (34), interacting with said second component (29) of said fluid (22) to facilitate its separation from said first component (27) of said fluid (22).

24. A separator (1) of fluids, according to claim 1, wherein said at least one outlet port (26) is positioned exclusively at said second axial end (25) of said separation chamber (2).

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