ELEMENT, DEVICE AND METHOD FOR COMPRESSION OF A GAS TO BE COMPRESSED HAVING A LOW TEMPERATURE

Abstract

An element for compression of a gas to be compressed having a low temperature of ?40? C. or lower, which element (1) is provided with a housing (2) containing at least one rotor (3) which is mounted rotatably with its shaft (5) with respect to the housing (2) and with an inlet (6) for the gas to be compressed and an outlet (7) for compressed gas, characterized in that the element (1) is provided with a heating means for an end (9a) of the shaft (5) of the rotor (3) located closest to the inlet (6).

Claims

1. Element for compression of a gas to be compressed having a low temperature of ?40? C. or lower, which element (1) is provided with a housing (2) containing at least one rotor (3) which is mounted rotatably around its shaft (5) with respect to the housing (2) and with an inlet (6) for the gas to be compressed and an outlet (7) for compressed gas, characterized in that the element (1) is provided with a heating means for an end (9a) of the shaft (5) of the rotor (3) located closest to the inlet (6).

2. The element according to claim 1, characterized in that a temperature of the gas to be compressed at low temperature has a temperature of maximally ?60? C., and preferably of maximally ?100? C.

3. The element according to claim 1, characterized in that the heating means comprises a first injection circuit (8) for injecting a heating medium at a temperature higher than the low temperature to said end (9a) of the shaft (5) of the rotor (3).

4. The element according to claim 3, characterized in that the first injection circuit (8) is provided with a nozzle (12) located at the aforementioned end (9a) of the shaft (5), which nozzle (12) sprays the heating medium directly onto the aforementioned end (9a).

5. The element according to claim 3, characterized in that the rotor (3) is mounted rotatably with respect to the housing (2) by means of bearings (4) and that the element (1) is provided with a second injection circuit (14) for injecting heating medium at a temperature higher than the low temperature to the bearings (4).

6. The element according to claim 5, characterized in that a first duct (10) of the second injection circuit (14) with a first feed point (11) for heating medium into the element (1) is positioned in a first part of the housing (2) which, according to an axial direction of the shaft (5), is located at a side of the housing (2) where the inlet (6) is positioned.

7. The element according to claim 5, characterized in that a second duct (16) of the second injection circuit (14) with a second feed point (15) for heating medium into the element (1) is positioned in a second part of the housing (2) which, according to an axial direction of the shaft (5), is located at a side of the housing (2) where the outlet (7) is positioned.

8. The element according to claim 6 characterized in that the first feed point (11) and the second feed point (15) are interconnected by means of a connecting duct (18) for heating medium in the housing (2).

9. The element according to claim 5, characterized in that the second injection circuit (14) is connected to, is part of, is integrated into or forms a single unit with the first injection circuit (8).

10. The element according to claim 5, characterized in that the nozzle (12) is configured to be able to also spray heating medium on the bearings (4).

11. The element according to claim 10, characterized in that the nozzle (12) is provided with at least two nozzle openings (13a, 13b).

12. The element according to claim 1, characterized in that the element (1) is a screw compressor element with at least one helical rotor, preferably two helical rotors.

13. The element according to claim 12, characterized in that the element (1) is an oil-free screw compressor element.

14. A device for compression of a gas to be compressed having a low temperature of ?40? C. or lower, characterized in that the device is provided with at least one element (1) according to claim 1.

15. A method for compression of a gas to be compressed having a low temperature of ?40? C. or lower by means of an element, which element (1) is provided with a housing (2) containing at least one rotor (3) which is mounted rotatably around its shaft (5) with respect to the housing (2) and with an inlet (6) for the gas to be compressed and an outlet (7) for compressed gas, characterized in that an end (9a) of the shaft (5) of the rotor (3) located closest to the inlet (6) is heated.

16. The method according to claim 15, characterized in that the gas to be compressed at low temperature has a temperature of maximally ?60? C., and preferably of maximally ?100? C.

17. The method according to claim 15, characterized in that a heating medium is injected to said end (9a), whereby the heating medium has a temperature higher than the gas to be compressed.

18. The method according to claim 17, characterized in that the rotor (3) is rotatably mounted with respect to the housing (2) by means of bearings (4) and that the heating medium is also injected to the bearings (4).

19. The method according to claim 17, characterized in that the heating medium is a lubricating liquid, preferably oil.

20. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0065] With a view to better demonstrate the characteristics of the invention, as example without any restrictive character, a number of preferred embodiments of an element for compressing a gas to be compressed having a low temperature according to the invention and a device provided with such an element are described here below, with reference to the accompanying drawings, wherein:

[0066] FIG. 1 shows schematically and in perspective an element according to the invention for use in a device according to the invention;

[0067] FIG. 2 shows a view according to arrow F2 in FIG. 1;

[0068] FIG. 3 shows a cross-section according to line III-III in FIG. 1;

[0069] FIG. 4 shows schematically and in perspective a view according to arrow F4 in FIG. 1, but with partial cut away of the housing.

DETAILED DESCRIPTION

[0070] The element 1 according to the invention shown in the figures for use in a device according to the invention, is in this case a screw compressor element.

[0071] The element 1 comprises a housing 2 containing therein at least one rotor 3, in this case two helical rotors.

[0072] The screw compressor element is in this case an oil-free screw compressor element, i.e. no oil is injected into a compression chamber in the housing 2 of the element 1 for lubrication and/or sealing of the helical rotors.

[0073] The helical rotors are arranged rotatably with their shafts 5 with respect to this housing 2 by means of bearings 4.

[0074] The housing 2 also comprises an inlet 6 for gas to be compressed having a low temperature and an outlet 7 for the compressed gas.

[0075] According to the invention, the temperature of the gas to be compressed at low temperature is ?40? C. or lower and preferably, but not necessary for the invention, ?60? C. or lower, and more preferably ?100? C. or lower.

[0076] Obviously, as a consequence of the compression, the compressed gas will have a higher temperature than the gas to be compressed before compression. Depending on the process, this temperature may higher than ?100? C., ?60? C. or ?40? C.

[0077] According to the invention, the element 1 is provided with a first injection circuit 8 for the injection of a heating medium at a higher temperature than the low temperature to the end 9a of the shaft 5 of the rotor 3 located closest to the inlet 6. This is shown in FIG. 3.

[0078] It is important to note that this first injection circuit 8 is used to inject heating medium to the end 9a of the shaft 5 of the rotor 3 located closest to the inlet 6. In other words, the first injection circuit 8 is not used to inject oil into the compression chamber.

[0079] This first injection circuit 8 comprises a first duct 10 with a first feed point 11 for heating medium in the element 1. Through this first feed point 11, heating medium is brought from a heating medium reservoir into the housing 2.

[0080] In addition, the first injection circuit 8 comprises a nozzle 12, situated at the aforementioned end 9a of the shaft 5, which nozzle injects heating medium directly on the aforementioned end 9a.

[0081] The nozzle 12, shown in FIGS. 3 and 4, is provided with a nozzle opening 13a for this purpose.

[0082] In the example shown, the element 1 is provided with a second injection circuit 14.

[0083] It should be noted that this second injection circuit 14 is used to allow the injection of heating medium to the bearings 4. In other words, the second injection circuit 14 is not used to inject oil into the compression chamber.

[0084] As shown in FIG. 3, the second injection circuit 14 is provided with two feed points 11, 15 for heating medium into the element 1 at two different locations in the housing 2.

[0085] As shown, there is a feed point 11, 15 in the housing 2 at each end 9a, 9b of the helical rotor 3.

[0086] As a result, heating medium can be injected into the housing 2 as closely as possible near the bearings 4 at the ends 9a, 9b of the shaft 5 of the rotor 3.

[0087] From the feed points 11, 15, ducts 10, 16 will run through the housing 2 to the bearings 4 to supply the heating medium up to the bearings 4.

[0088] At the location of the bearings 4, suitable nozzles 12 and 17 are provided.

[0089] The nozzles 12 and 17 are provided with nozzle opening 13b to spray heating medium on the bearings 4.

[0090] As shown in FIG. 3, the two feed points 11, 18 are interconnected by means of a connecting duct 18 for heating medium in the housing 2.

[0091] This connecting duct 18 will be filled with oil while the device is operating.

[0092] As can be seen in FIG. 3, the first injection circuit 8 and the second injection circuit 14 share in this case the feed point 11, the duct 10 and the nozzle 12.

[0093] In this case, but not necessary for the invention, the first injection circuit 8 is therefore part of the second injection circuit 14.

[0094] It is also possible that the second injection circuit 14 is connected to, is part of, is integrated into or forms a single unit with first injection circuit 8.

[0095] Of course, it is also possible that the first injection circuit 8 and the second injection circuit 14 are completely separated from each other.

[0096] It is also the case that the nozzle 12 sprays oil on the end 9a of the shafts 5, but also oil on the bearings 4.

[0097] In other words: the nozzle 12 has a double function in this case.

[0098] To this end, the nozzle 12 is provided with two nozzle openings 13a and 13b.

[0099] The screw compressor element operates in a very simple way and as follows.

[0100] During operation of the screw compressor element, the helical rotors will run cooperatively by intermeshing and draw in gas to be compressed at low temperature through the inlet 6 in the housing 2.

[0101] The gas to be compressed is compressed by means of the helical rotors and will exit the screw compressor element 1 through the outlet 7 in the housing 2.

[0102] Hereby, the gas to be compressed at low temperature will strongly cool the housing 2.

[0103] Although the temperature of the gas will increase during the compression process, the temperature of the gas will still be so low that after compression the compressed gas will still cool the housing 2.

[0104] During the operation of the element 1, heating medium will be conveyed via the feed point 11 and the duct 10 to the nozzle 12. The heating medium will be sprayed through the nozzle opening 13a on the end 9a of the shaft 5 of the rotor 3 located closest to the inlet 6.

[0105] The end 9a will be warmed up and the heat will spread through the shaft 5 over the entire rotor 3.

[0106] Since the inlet 6 is the coldest location of the housing 2, the strongest heating will be required here.

[0107] Due to the thermal conductivity of the shaft 5, the heat will go up to the end 9b of the shaft 5 located furthest away from the inlet 6.

[0108] As a result of this, the temperature in the entire rotor 3 will be kept as high as possible, and the temperature will also be uniform.

[0109] As a result of the heating of the rotor 3, the bearings 4 will also indirectly be partially heated.

[0110] However, in order to ensure proper operation of the bearings 4, the second injection circuit 14 will spray heating medium at a higher temperature than the low temperature on the bearings 4.

[0111] For the bearings 4 on each end 9a, 9b of the shaft 5 of the rotor 3, a special feed point 11, 15 is provided in the housing 2, allowing the heating medium to be brought to the bearings 4 using the shortest possible duct 10, 16.

[0112] Through the nozzles 12, 17 and their nozzle openings 13b, the heating medium is sprayed directly on the bearings 4.

[0113] This will minimize a drop in the temperature of the heating medium when passing through the cold housing 2, before the heating medium reaches the bearings 4.

[0114] The connecting duct 18, which provides a connection between the two feed points 11, 15, is intended to allow heat exchange between the heating medium injected through both feed points 11, 15.

[0115] This connecting duct 18 will be filled with heating medium and although this heating medium is normally stationary and will not reach the bearings 4, heat exchange will still be possible via the heating medium in the connecting duct 18 to the very cold inlet 6 from the outlet 7 at a higher temperature.

[0116] This will ensure an even temperature across the entire heating medium in the housing 2, the entire housing 2 and the bearings 4.

[0117] Hereby, there is also no risk that the heating medium will cool down too much.

[0118] The present invention is by no means limited to the embodiments described as example and shown in the figures, but an element for compressing a gas to be compressed having a low temperature according to the invention and a device provided with such an element may be implemented in all forms and dimensions without going beyond the scope of the invention as defined in the claims.