DEVICE AND METHOD FOR SEPARATING LIQUID FROM A GAS AND COMPRESSOR DEVICE PROVIDED WITH SUCH A DEVICE

Abstract

Device for separating liquid from a gas, wherein the device (11) comprises two liquid separators (12a, 12b) arranged in series, wherein the liquid separators (12a, 12b) are configured to allow a gas stream from an outlet (14a) of the first liquid separator (12a) to an inlet (13b) of the second liquid separator (12b), characterized in that means (18) are provided for creating radial standing waves in the gas stream.

Claims

1. A device for separating liquid from a gas, wherein the device (11) comprises two liquid separators (12a, 12b) arranged in series, wherein the liquid separators (12a, 12b) are configured to allow a gas stream from an outlet (14a) of the first liquid separator (12a) to an inlet (13b) of the second liquid separator (12b), wherein means (18) are provided for creating radial standing waves in the gas stream.

2. The device according to claim 1, wherein the means are configured to create ultrasonic radial standing waves in the gas stream.

3. The device according to, wherein the means (18) are or comprise one or more piezo actuators (19) and/or solenoids.

4. The device according to one, wherein the outlet (14a) of the first liquid separator (12a) is connected to the inlet (13b) of the second liquid separator (12b) by means of a connecting element (15).

5. The device according to claim 4, wherein the means (18) are mounted on the aforementioned connecting element (15).

6. The device according to claim 4, wherein the means (18) are mounted in the aforementioned connecting element (15).

7. The device according to claim 4, wherein the connecting element (15) is a pipe.

8. The device according to claim 1, wherein the device (11) is provided with more than two liquid separators (12a, 12b), all of which are arranged in series, wherein for every connecting element (15) between two successive liquid separators (12a, 12b) means (18) are provided which are configured to generate radial standing waves in the connecting element (15).

9. The device according to claim 1, wherein the second liquid separator (12b) is a cyclone separator.

10. A compressor device provided with a liquid-injected compressor element with an outlet for a gas stream of compressed gas and with a device for separating liquid from the compressed gas, wherein the device (11) comprises two liquid separators (12a, 12b) arranged in series, wherein the liquid separators (12a, 12b) are configured to allow the gas stream from an outlet (14a) of the first liquid separator (12a) to an inlet (13b) of the second liquid separator (12b), wherein means (18) are provided to create radial standing waves in the gas stream, between the first and second liquid separator (12a, 12b).

11. The compressor device according to claim 10, wherein the means (18) are or comprise one or more piezo actuators (19) and/or electromagnets.

12. A method for separating liquid from a gas, wherein the method comprises: passing the gas through two liquid separators (12a, 12b) placed in series; and generating radial standing waves in the gas, after passing through the first liquid separator (12a).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] With a view to better demonstrating the characteristics of the invention, a number of preferred variants of a device and method according to the invention for separating a liquid from a gas are described below, as example without any restrictive character, with reference to the accompanying drawings wherein:

[0036] FIG. 1 schematically depicts a compressor device provided with a device based on the invention for separating liquid from a gas;

[0037] FIG. 2 depicts the cross-section according to line II-II in FIG. 1;

[0038] FIG. 3 depicts the cross-section according to line III-III in FIG. 1;

[0039] FIG. 4 depicts a variant of FIG. 3;

[0040] FIG. 5 depicts a variant of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

[0041] The compressor device 1 schematically shown in FIG. 1 comprises a compressor element 2, which in this case is an oil-injected screw compressor element 2. It is also possible to inject a liquid other than oil, e.g. water, or to use another type of compressor element 2 that is not of the screw type.

[0042] As is known art, compressor element 2 comprises a housing 3 containing, in this example, two collaborating screw rotors 4a, 4b, which are rotatably provided through bearings 5.

[0043] Housing 3 is provided with an inlet 6 for sucking in gas, e.g. air, and an outlet 7 for compressed gas.

[0044] Compressor unit 1 is further provided with a drive 8, e.g. an electric motor, which is coupled to the shaft 9 of one of the screw rotors 4a to drive it. Obviously, any type of drive may be used.

[0045] The second screw rotor 4b will typically be driven by the first screw rotor 4a.

[0046] The figure also schematically provides a number of injection points 10 for oil. Obviously, these injection points 10 are depicted for illustrative purposes only and do not constitute any limitation for the invention. It is not ruled out either, according to the invention, that a liquid other than oil may be injected.

[0047] Typically, there will be an injection of oil in the housing 3 for cooling, lubricating and sealing the screw rotors 4a, 4b, and possibly at the location of the bearings 5.

[0048] The outlet 7 of the compressor element 2 is connected to a device 11 according to the invention.

[0049] This device mainly comprises two liquid separators 12a, 12b, arranged in series.

[0050] The outlet 7 of the compressor element 2 is connected to an inlet 13a of the first liquid separator 12a.

[0051] An outlet 14a of the first liquid separator 12a is connected to an inlet 13b of the second liquid separator 12b by means of a connecting element 15. The connection element 15 allows a gas stream from the outlet 14a of the first liquid separator 12a to the inlet 13b of the second liquid separator 12b.

[0052] In this case the connecting element 15 is a pipe with a circular cross-section. However, the invention is not limited to this and the pipe could also have a different cross-section.

[0053] Outlet 14b of the second liquid separator 12b can in turn be connected to, for example, a compressed air network to which several users of compressed air are connected.

[0054] In the embodiment depicted, the second liquid separator 12b is a so-called cyclone separator and this second liquid separator 12b comprises a housing 16b, wherein one end 17b of the pipe at the outlet 14b extends over a certain distance into the housing 16b. This end 17b is also known as the ‘vortex finder’. The aforementioned certain distance should preferably be approximately equal to the diameter of the aforementioned pipe.

[0055] In this case both the first and second liquid separator 4a, 4b, are cyclone separators.

[0056] Although, in the depicted example, the device 11 comprises only two liquid separators 12a, 12b, it is not ruled out that the device 11 is provided with more than two liquid separators 12a, 12b, all of which are placed in series.

[0057] According to the invention, means 18 to create radial standing waves are provided in the pipe. In other words, the means 18 will generate standing waves in gas contained in the pipe or in the gas stream flowing through the pipe.

[0058] These radial standing waves are preferably ultrasonic radial standing waves, so that in this case they will not generate any disturbing audible noise.

[0059] Obviously, it is not ruled out that standing waves are generated with a lower frequency.

[0060] The aforementioned means 18 may be realized in different ways.

[0061] In this case, the aforementioned means comprise a number, in this case four, piezo actuators 19.

[0062] It is not ruled out that there may be fewer or more than four such piezo actuators 19.

[0063] Instead of piezo actuators 19, the means 18 may also comprise one or more electromagnets.

[0064] As appears from FIG. 2, the means 18 in the depicted example are mounted on the aforementioned pipe.

[0065] In this case it has been ensured that they are mounted symmetrically on the pipe.

[0066] In case more than two liquid separators 12a, 12b, are placed in series, for each pipe between two consecutive liquid separators 12a, 12b, means 18 will be provided to generate radial standing waves in the pipe.

[0067] The device 11 is also provided with a control unit 20 to control the aforementioned means 18. In this case this can be the control of, e.g., the frequency of the generated radial standing waves.

[0068] The operation of compressor device 1 is very simple and as follows.

[0069] During operation, the drive 8 will rotate the screw rotor 4a and via the synchronization gears the other screw rotor 4b will also be driven with it.

[0070] As a result of the rotation of both screw rotors 4a, 4b, it will be possible to compress gas in the common known way.

[0071] During operation, a liquid, e.g. oil, will also be injected into the compressor element 2 for cooling, lubrication and sealing.

[0072] As a result, oil in the form of drops will be present in the compressed gas which leaves the compressor element 2 through the outlet 7.

[0073] The compressed gas is sent to the inlet 13a of the first liquid separator 12a, where a first separation will take place.

[0074] The gas that will leave the first liquid separator 12a will still contain a certain amount of oil in the form of small drops.

[0075] Then the gas will flow through the pipe to the inlet 13b of the second liquid separator 12b.

[0076] In this pipe, radial standing waves will be generated in the gas by means of the piezo actuators 19.

[0077] As a result, the small drops will move towards the location of the nodes of the radial standing waves, as shown schematically in FIGS. 2 and 3.

[0078] As a result, a kind of cylinder will be formed by the drops stretching out in the longitudinal direction of the pipe.

[0079] This way, the small drops have an increased chance to collide with each other, so they will fuse into larger drops.

[0080] In other words: due to the increased chance of collision with each other while passing through the pipe, the drops will reach an equilibrium more quickly, i.e. over a shorter period of time or a shorter passage distance through the pipe, similar to the situation when the gas would be transported through a pipe of several meters long.

[0081] The control unit 20 will regulate the frequency of the radial standing waves, so that the optimal distribution of the drops size will be obtained.

[0082] The gas with the large drops will reach the inlet 13b of the second liquid separator 12b, while this second liquid separator 12b will be able to separate the liquid from the gas with a similar or almost similar efficiency as during the passage of the gas through the first liquid separator 12a.

[0083] There will be hardly any or no more liquid left in the gas that leaves the second liquid separator 12b through the outlet 14b.

[0084] Typically, when passing through the first liquid separator 12a, if this relates to a cyclone separator, at least 99.9% of the liquid present will be separated. In other words, an efficiency of at least 99.9% is achieved. This means that no more than 0.1% of the total liquid quantity remains in the gas.

[0085] When passing through the second liquid separator 12b, an efficiency of 99.9% will again be achieved. This means 99.9% of the remaining liquid will be removed so that a total of 0.0001% of the total liquid quantity remains in the gas.

[0086] This very pure gas can then be fed into the consumer network.

[0087] FIG. 4 shows a variant of FIG. 3, wherein in this case the aforementioned means 18 are not placed along the outside of the pipe, but the aforementioned means 18 are mounted in the pipe, that is: in the interior of the pipe.

[0088] In the pipe a conduit 21 is provided, wherein the means 18 are provided on this conduit 21. These means 18 will excite the conduit 21 in order to generate standing waves in the gas stream through the pipe.

[0089] This embodiment has the advantage that the means 18 are shielded or protected by the pipe.

[0090] In addition, the operation is analogous to the embodiment described above.

[0091] FIG. 5 shows a variant of FIG. 1, wherein in this case the connection between the two consecutive liquid separators 12a, 12b is realized in a different way.

[0092] In the aforementioned embodiments the liquid separators 12a, 12b, were configured to allow a gas stream from the outlet 14a of the first liquid separator 12a to the inlet 13b of the second liquid separator 12b with the aid of a connecting element 15 which connects the aforementioned outlet 14a to the inlet 13b.

[0093] In this embodiment there is no connecting element 15, but the liquid separators 12a, 12b, are provided in a housing 22 with an inlet 23 for gas to be purified and an outlet 24 for purified gas.

[0094] The inlet 23 is connected to the inlet 13a of the first liquid separator 12a via a pipe 25. The outlet 14a of the liquid separator 12a enters a first section 26a of housing 22.

[0095] The first section 26a is separated from a second section 26b through means 18 to create radial standing waves in the gas stream.

[0096] The second section 26b is separated from a third section 26c by means of the second liquid separator 12b, which connects with its inlet 13b to the second section 26b and connects with its outlet 14b to the third section 26c.

[0097] This third section 26c is in direct connection with the exhaust 24 of the housing 22.

[0098] The gas to be purified enters the first liquid separator 12a through the inlet 23 and the pipe 25, where a first separation will take place.

[0099] The gas will then enter the first section 26a, after which it must pass through the means 18 to enter the second section 26b.

[0100] When passing through the means 18, the remaining drops will fuse to form larger drops.

[0101] When the gas stream has entered the second part 26b, it will have to pass through the second liquid separator 12b, where a second separation will take place, before it can enter the third section 26c and leave the housing 22 through the outlet 24.

[0102] Obviously, the aforementioned means 18 in this embodiment can be implemented in various ways.

[0103] Although in the depicted example both the first and second liquid separators are cyclone separators, this is not necessary for the invention. The first liquid separator may also be another type of liquid separator, which does a (rough) pre-separation. The second liquid separator may also be another type of liquid separator, which does a (fine) liquid separation. In that case, the second liquid separator is preferably, but not necessarily a filter.

[0104] The present invention is by no means limited to the embodiments described as examples and shown in the figures, but a similar device and method according to the invention for separating a liquid from a gas according to the various variants can be realized without going beyond the scope of the invention.