SYSTEM FOR FILTRATION OF AN AEROSOL BY MEANS OF MULTIPLE SEPARATORS BY CYCLONE EFFECT AND FILTRATION PROCESS

Abstract

AEROSOL FILTRATION SYSTEM USING A MULTIPLE CYCLONE SEPARATORS AND FILTRATION METHOD. A filtration system (1) for an atmosphere laden with oil droplets comprises a feed channel and a plurality of cyclone separators (5). The feed channel (4) is connected to a container holding the oil-droplet-laden atmosphere. Each cyclone separator (5) has an inlet (5a) opening into the feed channel (4). Several cyclone separators (5) of the plurality of cyclone separators (5) and their respective inlets (5a) are arranged consecutively along the feed channel (4) and on the same side of the feed channel (4). Two consecutive inlets of two cyclone separators (5) of the plurality of cyclone separators (5) on the same side of the feed channel (4) are arranged at different heights and / or have different cross-sections.Figure for the abridged version: figure 1.

Description

Title of the invention: SYSTEM FOR FILTRATION OF AN AEROSOL BY MEANS OF A MULTIPLE SEPARATORS BY CYCLONE EFFECT AND METHOD OF FILTRATION technical field

[0001] The invention relates to a filtration system and a filtration method. State of the art

[0002] In many technical fields, it is known to inject oil to facilitate a cutting, engraving, cooling, or surface treatment operation. The injected oil is often in the form of droplets that saturate the atmosphere of the cutting, engraving, cooling, or surface treatment equipment. These oil-laden atmospheres are called oil mists.

[0003] It is particularly advantageous to recover oil for reuse and / or recycling, thereby maintaining a healthy atmosphere. Therefore, it is beneficial to filter the atmosphere laden with oil droplets to separate the gaseous and liquid components. The oil mist is transferred to a filtration device configured to separate the carrier gas from the oil droplets.

[0004] It is known that filtration systems perform filtration by cyclone effect. Separation by cyclone effect allows for the separation of the carrier gas and the oil droplets without using one or more filters that become clogged and therefore require regular cleaning.

[0005] The separation efficiency depends on the centrifugal acceleration experienced by the droplets, the number of revolutions in the cyclone, their density, and their size. Therefore, it is advantageous to find a cyclone configuration that is best suited to the oil droplets.

[0006] In general, filtration efficiency is greater when velocities are high or the number of cyclones is high. An optimum must therefore be found between manufacturing complexity and energy consumption. Description of the invention

[0007] An object of the invention is to provide a filtration system which has a better ratio between energy consumption and compactness while maintaining the provision of good separation between the particles and the gaseous medium of the aerosol.

[0008] These drawbacks are addressed by means of a filtration system which includes.

[0009] - a power supply channel having a first end intended to be connected to a supply unit configured to supply an aerosol to be treated; - a plurality of cyclone separators, each cyclone separator having an inlet opening into the feed channel.

[0010] Several cyclone separators from the plurality of cyclone separators and their respective inlets are arranged consecutively along the feed channel and on the same side of the feed channel. Two consecutive inlets of two cyclone separators from the plurality of cyclone separators on the same side of the feed channel are arranged at different heights and / or have different cross-sections.

[0011] According to one aspect of the invention, the feed channel is obstructed or reduced by a plurality of flow diverters, each flow diverter being configured to divert a portion of a flow from the atmosphere laden with oil droplets towards one of the corresponding cyclone separators.

[0012] Preferably, the feed channel is connected to N cyclone separators and in which each flow diverter diverts 1 / N from the initial section of the feed channel to a corresponding cyclone separator and reduces the section of the feed channel by a value equal to 1 / N for the cyclone separators to follow according to the direction of advancement of the aerosol flow.

[0013] Advantageously, the filtration system consists of only two parts, a first part defining the lower part of the cyclone separators, the lower part of the feed channel and possibly the flow separators where applicable, the second part forming a hood closing the feed channel and closing the cyclone separators.

[0014] The invention also relates to a filtration process that is efficient and simple to use.

[0015] This result is to be achieved by means of a filtration process for an aerosol comprising particles and a gaseous medium comprising the following steps:

[0016] - provide a filtration system according to any one of the pre-configurations previous; - supply the filtration system with an aerosol; - to recover the particles exiting the separators by cyclone effect.

[0017] Preferably, the aerosol is an oil mist and oil is recovered at the outlet of the separators by cyclone effect. Description of the drawings

[0018] Other advantages and features will become clearer from the following description of particular embodiments and implementations of the invention given by way of non-limiting examples and shown in the accompanying drawings, in which:

[0019] [Fig-1]: [Fig.1] schematically illustrates a cross-sectional view of a system of filtration according to a first embodiment;

[0020] [Fig.2]: [Fig.2] schematically illustrates one side of the filtration system according to the first embodiment in the direction of the inlet of the supply channel; [Fig.3]: [Fig.3] schematically illustrates a section of the feed channel inlet;

[0021] [Fig.4]: [Fig.4] schematically illustrates a section of the feed channel between the first separators and the second separators by cyclone effect;

[0022] [Fig.5]: [Fig.5] schematically illustrates a section of the feed channel between the second separators and the third separators by cyclone effect;

[0023] [Fig.6]: [Fig.6] schematically illustrates a section of the feed channel between the third separators and the fourth separators by cyclone effect. Detailed description

[0024] The filtration system is a filtration system 1 for an aerosol. The aerosol is formed by a collection of particles in a solid or liquid state that are suspended in a gaseous medium. For example, the filtration system is a filtration system for an atmosphere laden with oil droplets. The filtration system is configured to separate the oil present in the atmosphere in the form of droplets from the carrier gas, which may be air. The carrier gas supports the oil droplets. The filtration system is configured to facilitate the recovery of the particles, and more specifically, the oil.

[0025] The particles are discharged through a first outlet 2. The carrier gas is discharged through another outlet 3 and can also be partially discharged through the first outlet. Advantageously, the particles are discharged through a lower outlet while the carrier gas is discharged through an upper outlet to take advantage of the density difference between these two components. The lower outlet is at a lower altitude than the upper outlet.

[0026] The filtration system 1 includes a feed channel 4 having a first end intended to be connected to a supply device configured to provide an aerosol to be treated, which is, for example, the source of an atmosphere laden with oil droplets. The feed channel 4 receives a mixture containing a carrier gas and particles, for example, droplets. If the aerosol is an oil mist, the latter can be supplied from equipment using oil and forming the mist. of oil. Alternatively, the aerosol is supplied by a reservoir receiving the atmosphere to be treated. The arrow shown in [Fig. 1] represents the direction of flow of an oil mist in the feed channel 4. The aerosol is set in motion by means of a ventilation system, for example, a fan. Depending on the configuration, the ventilation system is positioned upstream and / or downstream of the filtration system 1 so that the aerosol enters the filtration system 1 at a certain velocity.

[0027] The feed channel 4 is connected to a plurality of cyclone separators 5. A cyclone separator 5 has an inlet 5a receiving the mixture to be separated and two distinct outlets. Each cyclone separator 5 has a first outlet 2 for recovering the aerosol particles, preferably the oil, and a second outlet 3 for recovering the carrier gas free of oil or with an oil content lower than the oil content at the inlet 5a. The cyclone separator 5 uses the effect of gravity to separate the particles and the carrier gas.

[0028] The inlet 5a of each cyclone separator 5 is connected to the feed channel 4 so that each cyclone separator 5 receives a fraction of the flow from the atmosphere to be treated. The cyclone separators 5 are not connected in series but in parallel. The cyclone separators 5 receive the same or substantially the same atmosphere to be treated at their inlets 5a.

[0029] A cyclone separator 5 is a separator comprising an inlet 5a that engages in a cone or a structure substantially cone-shaped. In the illustrated embodiment, the upper part of the cyclone separator 5 has a circular cross-section, while the lower part has a conical, and more specifically frustoconical, cross-section. The lower end of the cyclone separator 5 is open to form the outlet 2 for oil extraction. The upper part of the cyclone separator 5 is covered by a hood 6 that defines a through-opening. The through-opening forms the outlet 3 for the carrier gas, which has a low oil content. Preferably, the cyclone separators are identical.

[0030] To increase the efficiency of the separation between the carrier gas and the particles, particularly oil, it is advantageous to have a cyclone separator 5 with a small diameter. The smaller the diameter, the greater the centrifugal effect for a given velocity of the atmosphere to be treated in the feed channel 4. It is therefore beneficial to reduce the cross-section of the conical part to increase the gas flow velocity and thus better separate the oil.

[0031] However, the smaller the diameter of the cyclone separator 5, the smaller the volume of gas processed. Therefore, there is an advantage to feeding several cyclone separators 5 connected in parallel in order to increase the quantity of carrier gas treated for a given time.

[0032] To facilitate the feeding of the cyclone separators 5, it is advantageous to mount the cyclone separators 5 consecutively along the feed channel 4. The inlets 5a of the cyclone separators 5 are arranged consecutively along the feed channel 4. It is also advantageous to have a straight or slightly curved feed channel 4 to limit the pressure drop along the feed channel 4. The feed channel 4 is divided into multiple portions, each of which feeds a cyclone separator 5.

[0033] Preferably, the filtration system 1 has an even number of cyclone separators 5. The cyclone separators 5 are distributed symmetrically with respect to the longitudinal direction of the feed channel 4 so as not to disturb the flow of the particle-laden atmosphere. It is advantageous to draw two identical portions of the carrier gas flow symmetrically with respect to the median longitudinal plane of the feed channel 4 in order to avoid disturbing the flow and to facilitate obtaining a controlled flow in the cyclone separator 5. In other words, the same amount of flow is drawn from the right and left sides of the feed channel 4.

[0034] To create a compact filtration system, it is advantageous to offset the cyclone separators 5 transversely with respect to the feed channel 4, i.e., along the width of the feed channel 4. The separators are arranged in a staggered pattern. In this way, with the same length of feed channel 4, it is possible to connect more cyclone separators 5 without significantly increasing the width of the filtration system.

[0035] Advantageously, two consecutive inlets 5a of two cyclone separators 5 of the plurality of cyclone separators 5 on the same side of the feed channel 4 are arranged consecutively and at different heights. The two inlets 5a are located at different levels. For example, the first inlet 5a is at a lower level of the feed channel 4 and the second inlet 5a is at a higher level of the feed channel 4. The offset of the inlets 5a along the height of the feed channel 4 improves the capture of the carrier gas flow by limiting disturbances to the flow for the other inlets that follow. The height is measured in a vertical direction.

[0036] A plurality of flow diverters 7 are present which divert the carrier gas flow towards the separator inlets by cyclone effect 5. Depending on the configuration, the diverters are installed in the feed channel 4 or they are formed by the side wall 4a of the feed channel. In the embodiment illustrated in [Fig. 1], the diverters are formed by the side wall 4a of the feed channel 4. The flow diverters 7 obstruct or reduce the active cross-section of the feed channel 4 to divert a part of the flow towards the cyclone separator 5 to feed and reduce the section of the feed channel 4 for the cyclone separators 5 to follow along the longitudinal direction of the feed channel 4.

[0037] Preferably, the flow separators 7 define a curved wall so as to shift the direction of the carrier gas flow between the feed channel 4 and the cyclone separator 5 so that the carrier gas which flows in the longitudinal direction flows tangentially in the cyclone separator 5. This allows for a more efficient separation.

[0038] In an advantageous embodiment, the filtration system 1 has a first number of cyclone separators 5, for example N cyclone separators 5, arranged on one side of the feed channel 4. The inlets 5a of the cyclone separators 5 are distributed vertically over the first number of stages, i.e., N stages. In other words, the N inlets 5a define N different stages for capturing the carrier gas flow. The carrier gas flow is diverted in each of the cyclone separators 5 by means of said first number of flow diverters 7, i.e., N flow diverters 7. The N flow diverters 7 are arranged consecutively along the longitudinal axis of the feed channel, and the N flow diverters reduce the cross-section of the feed channel by a value equal to 1 / N.Each flow diverter feeds a cyclone separator 5 with a gas flow representing 1 / N of the initial flow that fills the feed channel. Preferably, each flow diverter 7 obstructs or reduces the cross-section of the feed channel 4 by a value equal to 1 / N for the remainder of the feed channel. In other words, the active cross-section of the feed channel 4 decreases each time a portion of the carrier gas flow is diverted to a cyclone separator 5.

[0039] Each input 5a has a height h which corresponds to H / N with H the initial height of the feed channel 4.

[0040] Figure 2 shows the distribution of the different flow diverters 7 in the feed channel 4. The eight flow diverters 7 corresponding to the eight cyclone separators 5 have a total diverter area which is equal to the initial area of ​​the feed channel 4. The series of flow diverters 7 extend from the side walls towards the center of the feed channel 4. In a series, the flow diverters are arranged one above the other.

[0041] Figure 3 shows a section of the inlet of the feed channel 4, which defines the value of the initial section of the feed channel 4. Figure 4 shows a cross-sectional view of the feed channel at the start-up of the first two flow diverters intended to feed the first two cyclone separators 5. Figure 5 shows a cross-sectional view of the feed channel at the start-up of the second two flow diverters intended to feed the second two cyclone separators 5. cyclone 5. The feed channel was reduced in cross-section by the first two flow separators.

[0042] In another embodiment, the filtration system 1 has a first number of cyclone separators 5, for example N cyclone separators, arranged on one side of the feed channel 4. The number of cyclone separators 5 is an even number. The inlets of the cyclone separators 5 are distributed over a second number of stages corresponding to half the first number, i.e., N / 2 stages. The carrier gas flow is deflected in each of the cyclone separators 5 by means of said first number of flow deflectors 7, i.e., N flow deflectors 7. The N flow deflectors 7 are arranged consecutively along the longitudinal axis of the feed channel 4, and the N flow deflectors reduce the active cross-section of the feed channel 4 by a value equal to 1 / N.Each flow diverter 7 feeds a cyclone separator 5 with a gas flow that represents 1 / N of the initial flow that fills the feed channel 4.

[0043] The N flow diverters 7 are divided into two series of a second number of flow diverters 7, i.e., N / 2. Each series extends from one end to the other along the height of the feed channel 4. Each of the two series of flow diverters 7 defines N / 2 stages. The cross-section of the feed channel 4 is divided into two equal portions along its height, i.e., along a direction parallel to the central axis. Advantageously, each inlet series captures a section of the initial flow from one side wall of the feed channel to the opposite side wall.

[0044] Figure 1 illustrates a filtration system configuration 1 with eight cyclone separators 5. Only the four cyclone separators on the left side are shown. The four inlets 5a are arranged in two sets of two inlets 5a. Figure 2 illustrates a view of the various flow diverters 7 in the feed channel 4. The eight flow diverters 7 occupy a cross-section equal to the cross-section of the feed channel 4 to divert all the flow towards the cyclone separators 5.

[0045] In another embodiment, the filtration system 1 has a first number of cyclone separators 5, for example N cyclone separators 5, arranged on one side of the feed channel 2. The inlets of the cyclone separators 5 are distributed into n series of inlets with n series of flow diverters 7. Each of the n series of inlets has N / n inlets with N / n flow diverters 7.

[0046] Each flow diverter 7 feeds a cyclone separator 5 with a gas flow representing 1 / N of the initial flow filling the feed channel 4. Each series of flow diverters 7 occupies 1 / n of the cross-section of the feed channel 4 relative to the initial cross-section of the feed channel 4. The carrier gas flow is diverted into each of the cyclone separators 5 by means of said first number of flow diverters 7, i.e., N flow diverters 7. The N flow diverters are Arranged consecutively along the longitudinal axis of the feed channel 4, the N flow diverters 7 reduce the cross-section of the feed channel 4 by a value equal to 1 / N. The operation is identical to that of the previous embodiment.

[0047] In a particular embodiment, the filtration system has 2N cyclone separators. The 2N cyclone separators are divided into N cyclone separators on the right side of the feed channel 4 and N separators on the left side of the feed channel 4. Depending on the configuration, the N inlets 5a and the N flow separators are distributed in n series, with n a non-zero integer, for example 1, 2 or 3. N is also a non-zero integer.

[0048] In a particular embodiment, the different cyclone effect separators 5 all have the same deflection section value.

[0049] Such a configuration makes it possible to optimize the cross-section of the feed channel to supply each of the cyclone effect separators 5.

[0050] Preferably, the deflection section defined by a flow diverter 7 has a height h which is greater than the width, preferably the height h is at least twice greater than the width.

[0051] In order to obtain a height greater than the width of the deflection section, it is advantageous to choose the number of cyclone separator series 5 and the number of cyclone separators 5 in each series. In the embodiment illustrated in [Fig. 1], the filtration system 1 has eight cyclone separators with four cyclone separators on each side of the feed channel. Such a configuration allows for a cross-section close to a square, which is preferable for feeding the cyclone separators 5. Depending on the constraints imposed, the number of separators to be used and their distribution define the cross-section of the feed channel 4, or the cross-section of the feed channel defines the number of cyclone separators 5 to be used.

[0052] In a particularly advantageous embodiment, the filtration system 1 is formed by only two parts made of polymer material, which can be produced by injection molding. The first part defines the feed channel 4, as well as the cyclone separators 5 and the flow diverters 7, if applicable. The second part forms the hood 6 with the outlet 3 for the carrier gas. It is then particularly economical to form an efficient separation system 1 for separating air and oil from an oil mist.

[0053] The filtration of an oil mist and more generally of an aerosol is carried out by injecting the mist at the inlet of the feed channel 4. The oil mist stream is divided into a plurality of elementary streams which each feed a cyclone separator 5. Each cyclone separator 5 carries out the filtration to extract the oil which exits through a dedicated outlet.

[0054] The multiple cyclone separators 5 are mounted in parallel and are compactly integrated into the filtration system, which makes it possible to form a small yet highly efficient filtration system.

[0055] Although the embodiment examples describe the separation of an oil mist, the separation system can be used to separate the particles of an aerosol, the aerosol being able to contain particles in solid state and / or particles in liquid state.

Claims

Demands

1. A filtration system (1) for an aerosol carrying a carrier gas and particles comprising: - a feed channel (4) having a first end intended to be connected to a supplying element configured to supply the aerosol; - a plurality of cyclone separators (5), each cyclone separator (5) having an inlet (5a) opening into the feed channel (4); wherein several cyclone separators (5) of the plurality of cyclone separators (5) and their respective inlets (5a) are arranged consecutively along the feed channel (4) and on the same side of the feed channel (4) and wherein two consecutive inlets of two cyclone separators (5) of the plurality of cyclone separators (5) on the same side of the feed channel (4) are arranged at different heights.

2. Filtration system (1) according to claim 1 wherein the feed channel (4) is obstructed or reduced by a plurality of flow diverters (7), each flow diverter (7) being configured to divert a portion of an oil droplet-laden atmosphere stream towards one of the corresponding cyclone separators (5).

3. Filtration system (1) according to the preceding claim wherein the feed channel (4) is connected to N cyclone separators and wherein each flow diverter (7) diverts 1 / N from the initial section of the feed channel (4) to a corresponding cyclone separator and reduces the feed channel section by a value equal to 1 / N for the cyclone separators to follow in the direction of advancement of the aerosol flow.

4. System according to any one of the preceding claims consisting of only two parts, a first part defining the lower part of the cyclone separators (5), the lower part of the feed channel (4) and optionally the flow separators (7) if applicable, the second part forming a hood closing the feed channel (4) and closing the cyclone separators (5).

5. A system according to any one of the preceding claims, wherein the two consecutive inlets of two cyclone separators (5) on the same side of the feed channel (4) have different sections.

6. Filtration method comprising the following steps: - providing a filtration system according to any one of the preceding claims; - supplying the filtration system with an aerosol; - recovering particles at the outlet of the separators by cyclone effect (5).

7. A filtration method according to the preceding claim in which the aerosol is an oil mist and oil is recovered at the outlet of the separators by cyclone effect (5).

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