Element, device and method for compressing gas to be compressed having a low temperature

Abstract

An element for compressing a gas to be compressed at a low temperature of 40 C. or lower, which element (1) is provided with a housing (2) containing at least one rotor (3) that is rotatably arranged with respect to the housing (2) and having an inlet (6) for the gas to be compressed and an outlet (7) for compressed gas, characterized in that the element (1) is configured for compressing the gas to be compressed having the low temperature by providing the element (1) with a heating duct (8) that runs through the housing (2), the heating duct (8) being provided with an inlet (9) where a first heat medium is introduced into the housing (2) at a higher temperature than the aforementioned low temperature and an outlet (10) where the first heat medium is evacuated from the housing (2).

Claims

1. An element for compressing a gas to be compressed at a low temperature of 40 C. or lower, the element comprising: a housing comprising: at least one rotor that is rotatably arranged with respect to the housing; an inlet for the gas to be compressed; and an outlet for compressed gas; and a heating duct that extends through the housing, the heating duct comprising: an inlet where a first heat medium is introduced into the housing at a higher temperature than the low temperature; and an outlet where the first heat medium is evacuated from the housing, wherein the heating duct is configured such that the first heat medium flows, within the heating duct, from an inlet portion of the housing to an outlet portion of the housing, and the inlet portion is located according to an axial direction of a shaft of the at least one rotor on a first side of the housing where the inlet of the housing is located, and the outlet portion is located according to the axial direction of the shaft on a second side of the housing where the outlet of the housing is located.

2. The element according to claim 1, wherein the low temperature of the gas to be compressed is equal to or less than 60 C.

3. The element according to claim 1, wherein the first heat medium is a mixture of water and glycol having at least 40% glycol.

4. The element according to claim 1, wherein the inlet of the heating duct is positioned in such a way that heat is exchanged between the inlet of the housing and the inlet of the heating duct.

5. The element according to claim 1, wherein the outlet of the heating duct is positioned in such a way that heat is exchanged between the outlet of the housing and the outlet of the heating duct.

6. The element according to claim 1, wherein the heating duct is provided with branches that are positioned in such a way that heat is exchanged between the branches and the inlet of the housing.

7. The element according to claim 1, wherein the heating duct has a number of bends and/or curves that are positioned in such a way that heat is exchanged between the bends and/or curves and the inlet of the housing.

8. The element according to claim 1, wherein the at least one rotor is rotatably arranged with respect to the housing (2) by bearings (4), and the element further comprises an injection circuit that is configured to inject a second heat medium to the bearings at a higher temperature than the low temperature.

9. The element according to claim 8, wherein the injection circuit comprises: a first duct comprising a first feed point for receiving the second heat medium, the first duct located in a first portion of the housing that is on the first side of the housing.

10. The element according to claim 9, wherein the injection circuit further comprises: a second duct comprising a second feed point for receiving the second heat medium, the second duct located in a second portion of the housing that is on the second side of the housing.

11. The element according to claim 10, wherein the injection circuit further comprises a connection duct for the second heat medium in the housing, the connection duct interconnecting the first feed point and the second feed point.

12. The element according to claim 11, wherein at least one portion of the heating duct is positioned in such a way that heat is exchanged between the heating duct and the first duct, the second duct, and/or the connection duct.

13. The element according to claim 1, wherein the element is a screw compressor element, and the at least one rotor is at least one helical rotor.

14. The element according to claim 13, wherein the element is an oil-free screw compressor element.

15. A method performed by an element, the method comprising: receiving a gas at an inlet of a housing of the element, the gas having a low temperature of 40 C. or lower, and the housing including at least one rotor that is rotatably arranged with respect to the housing; compressing the gas in the housing; evacuating the gas at an outlet of the housing; receiving a first heat medium at an inlet of a heating duct of the housing, the heating duct extending through the housing, and the first heat medium being received at a temperature higher than the low temperature; and evacuating the first heat medium at an outlet of the heating duct, wherein the heating duct is configured such that the first heat medium flows, within the heating duct, from an inlet portion of the housing to an outlet portion of the housing, and the inlet portion is located according to an axial direction of a shaft of the at least one rotor on a first side of the housing where the inlet of the housing is located, and the outlet portion is located according to the axial direction of the shaft on a second side of the housing where the outlet of the housing is located.

16. The method according to claim 15, wherein the low temperature of the gas is equal to or less than 60 C.

17. The method according to claim 15, wherein the first heat medium is a mixture of water and glycol having at least 40% glycol.

18. The method according claim 15, wherein the temperature of the first heat medium is at least 60 C. at the inlet of the heating duct.

19. The method according to claim 15, wherein the at least one rotor is rotatably arranged with respect to the housing by bearings, and the method further comprises injecting a second heat medium to the bearings.

20. The method according to claim 19, wherein the second heat medium is a lubricating fluid.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) In order to better illustrate the features of the invention, some 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 below as examples without any limiting character with reference to the attached drawings, in which:

(2) FIG. 1 shows an element according to the invention for use in a device according to the invention schematically and in a perspective view;

(3) FIG. 2 shows a cross-section according to line II-II in FIG. 1;

(4) FIG. 3 shows a cross-section according to arrow F3 in FIG. 1.

DETAILED DESCRIPTION

(5) The element 1 according to the invention that is shown in the drawings for use in a device according to the invention is in this case a screw compressor element.

(6) The element 1 comprises a housing 2 containing at least one rotor 3, in this case two helical rotors.

(7) The screw compressor element is, in this case, an oil-free screw compressor element, meaning that in a compression chamber in the housing 2 of the element 1, no oil is injected for lubrication and/or sealing the helical rotors.

(8) The helical rotors are arranged with their shaft 5 rotatable with respect to the housing 2 by means of bearings 4.

(9) The housing 2 also comprises an inlet 6 for gas to be compressed at a low temperature and an outlet 7 for the compressed gas.

(10) According to the invention, the temperature of the gas to be compressed having a 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.

(11) It goes without saying that, as a result of the compression, the compressed gas will have a higher temperature than the gas to be compressed before the compression. Depending on the process, this temperature may be higher than 100 C., 60 C. or 40 C.

(12) According to the invention, the housing 2 is provided with a heating duct 8 that runs through the housing 2. The heating duct 8 is shown in FIG. 2.

(13) The heating duct 8 has an inlet 9 for introducing a first heat medium into the housing 2 and an outlet 10 for evacuating this first heat medium from the housing 2.

(14) The inlet 9 and the outlet 10 of the heating duct 8 are shown in FIGS. 1 and 3.

(15) The first heat medium is in this case, but not necessary according to the invention, a mixture of water and glycol, also called 1,2-ethanediol or ethylene glycol.

(16) The first heat medium preferably contains at least 40% glycol. That way, the first heat medium has a freezing temperature lower than 40 C.

(17) The first heat medium itself will have a temperature of, for example, 60 C.

(18) As shown in FIG. 3, the inlet 9 of the heating duct 8 is located near the inlet 6 of the housing 2, and the outlet 10 of the heating duct 8 is located near the outlet 7 of the housing 2.

(19) The inlet 6 of the housing 2 will be the coldest location as the gas to be compressed enters here at a low temperature. At the inlet 9 of the heating duct 8, the first heat medium will have the highest temperature because there has not yet been any heat exchange with the housing 2. When passing through the heating duct 8, the temperature of the first heat medium will decrease until it reaches the outlet 10 near outlet 7, which is typically the location of the housing 2 having the highest temperature.

(20) In this case, but not necessary according to the invention, the heating duct 8 is designed in such a way by means of bends and branches or bifurcations that the first heat medium can flow through the entire housing 2.

(21) This way it can be ensured that the entire housing 2 is heated up to ensure that the temperature of the housing 2 is as uniform as possible.

(22) In addition, the heating duct 8 is provided with branches located near the inlet 6 of the housing 2.

(23) Near the inlet 6 means that heat exchange may occur between the heat medium and the inlet 6 of the housing 2.

(24) This will ensure that the housing 2 near the inlet 6 will be heated more than in other portions of the housing 2, as here the first heat medium will circulate more, so more heat exchange will occur with the housing 2 near the inlet 6.

(25) It is also possible for the heating duct 8 to have a number of bends or curves near the inlet 6 of the housing 2 instead of or in addition to branches or bifurcations. This will allow to achieve the same effect as described here above for the branches near the inlet 6 of the housing 2.

(26) In the example shown, the element 1 is provided with an injection circuit 11.

(27) It should be noted that this injection circuit 11 is used to allow the injection of a second heat medium to the bearings 4. In other words, the injection circuit 11 is not used to inject oil into the compression chamber.

(28) As shown in FIG. 2, the injection circuit 11 is provided with two feed points 12, 13 for the second heat medium into the element 1 at two different locations in the housing 2.

(29) As shown, there is a feed point 12, 13 in the housing 2 at each end 14a, 14b of the rotor 3.

(30) As a result of this, the second heat medium can be injected into the housing 2 as close as possible to the bearings 4 at the ends 14a, 14b of the shaft 5 of the rotor 3.

(31) Ducts 15a, 15b will run through the housing 2 from the feed points 12, 13 to the bearings 4 for supplying the second heat medium to the bearings 4.

(32) Suitable nozzles 16 are provided at the bearings 4.

(33) As shown in FIG. 2, the two feed points 12, 13 are interconnected by means of a connection duct 17 for the second heat medium in the housing 2.

(34) Said connection duct 17 will be filled with the second heat medium while the device is being operated.

(35) In this case, a portion of the heating duct 8 will be located near the connection duct 17 and/or the aforementioned ducts 15a, 15b such that heat exchange is possible between the heat media in these ducts 8, 15a, 15b, 17.

(36) In other words, the first heat medium will be able to heat the second heat medium.

(37) The screw compressor element operates in a very simple manner and as follows.

(38) During the operation of the screw compressor element, the helical rotors will cooperatively rotate in an intermeshing way and draw in the gas to be compressed having a low temperature via the inlet 6 in the housing 2.

(39) The gas is compressed by the helical rotors 3 and will exit the screw compressor element 1 through the outlet 7 in the housing 2.

(40) In this case, the gas to be compressed at a low temperature will strongly cool the housing 2.

(41) 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.

(42) During the operation of the element 1, the first heat medium will flow through the heating duct 8, where it will heat the housing 2.

(43) A temperature of the first heat medium at the inlet 9 of the heating duct 8 is, for example, 60 C., but it should be clear that this temperature of the first heat medium will be chosen depending on a temperature of the gas to be compressed at a low temperature.

(44) The heating will be greater near the inlet 9, where the first heat medium will have the highest temperature, than near the outlet 10, where the first heat medium will have a lower temperature.

(45) Because the inlet 6 is the coldest location of the housing 2, most of the heating will be necessary here.

(46) By means of the branches near the inlet 6 of the housing 2, the first heat medium will undergo heat exchange with the portion of the housing 2 near the inlet 6 for a longer period of time than if said branches were not present such that sufficient heating of said portion of the housing 2 is possible.

(47) Then, the first heat medium will flow through the entire housing 2 along the heating duct 8 to heat the housing 2.

(48) It should be noted that by heating the housing 2, the rotor 3 is also heated by the first heat medium, though indirectly.

(49) As a result of this, the temperature of the entire element 1 will be kept as high as possible, said temperature also being uniform.

(50) As a result of the heating of the housing 2, the bearings 4 will also indirectly be partially heated.

(51) However, to ensure proper functioning of the bearings 4, the injection circuit 11 will inject the second heat medium onto the bearings 4 at a temperature higher than the low temperature of the gas to be compressed.

(52) For the bearings 4 on each end 14a, 14b of the shaft 5 of the rotor 3, a special feed point 12, 13 is provided in housing 2, allowing the second heat medium to be brought to the bearings 4 using the shortest possible duct 15a, 15b.

(53) In this way, a decrease in the temperature of the second heat medium when passing through the cold housing 2 can be limited as much as possible before the second heat medium reaches the bearings 4.

(54) Furthermore, because a portion of the heating duct 8 is located near the ducts 15a, 15b, this will help ensure that the temperature of the second heat medium on its way to the bearings 4 drops as little as possible so that the bearings 4 can be heated to the maximum extent possible.

(55) The purpose of the connection duct 17, which provides a connection between the two feed points 12, 13, is to allow heat exchange with the second heat medium, which is injected via two feed points 12, 13.

(56) Said connection duct 17 will be filled with the second heat medium and, although said second heat medium is normally stationary and will not reach the bearings 4, heat exchange will nevertheless be possible via the second heat medium in the connection duct 17 from the outlet 7 at a higher temperature to the very cold inlet 6.

(57) This will ensure a uniform temperature throughout the entire second heat medium in the housing 2, the entire housing 2 and the bearings 4.

(58) In this case, there is also no risk of the second heat medium cooling too much.

(59) Furthermore, because a portion of the heating duct 8 is located near the connection duct 17, this will help ensure that the temperature of the second heat medium drops as little as possible in the connection duct 17. In this way, it is possible to prevent the second heat medium from freezing and thereby the connection duct 17 from becoming dogged.

(60) The present invention is by no means limited to the embodiments described as examples or shown in the drawings, 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 can be realized in all kinds of shapes and dimensions without departing from the scope of the invention as defined in the claims.