Assembly for compressing gas having a housing comprising coolers in a central section, method for cooling, and use of such an assembly

Abstract

A method for cooling an assembly (1) for compressing a gas containing a housing (2) having a plurality of elements for compressing gas, the method comprising: allowing a cooling air flow (21) to flow from an environment into a first section 3 of a housing (2); passing the cooling air flow (21) through a plurality of coolers (14, 16, 18) that are arranged in a central section (5) of the housing (2), the cooling air flow (21) being passed from the first section (3) to a second section (4) of the housing (2); allowing the cooling air flow (21) to flow out from the second section (4) of the housing (2) into the environment.

Claims

1. An assembly for compressing a gas, containing a housing that comprises a plurality of components, the plurality of components containing at least: a first liquid-injected element for compressing gas; a first motor for driving the first liquid-injected element; a second liquid-injected element for compressing gas; a second motor for driving the second liquid-injected element; a first liquid separator in fluid communication with a gas outlet of the first liquid-injected element for the gas compressed by the first liquid-injected element; a second liquid separator in fluid communication with a gas outlet of the second liquid-injected element for the gas compressed by the second liquid-injected element; the plurality of components being distributed across a first section and a second section of the housing, and a central section also being provided in the housing, which central section separates the first section and the second section from each other, the central section containing: a first cooler for cooling a first liquid in a first liquid injection line for the first liquid-injected element in fluid communication with a liquid outlet of the first liquid separator; a second cooler for cooling a second liquid in a second liquid injection line for the second liquid-injected element in fluid communication with a liquid outlet of the second liquid separator, wherein the first cooler and the second cooler each have one or more fans to force a cooling air flow through the first cooler and second cooler in a same direction, each cooling air flow being provided to flow from the first section to the second section.

2. The assembly according to claim 1, a non-return valve being provided at a gas outlet of the first liquid separator for the gas compressed by the first liquid-injected element and at a gas outlet of the second liquid separator for the gas compressed by the second liquid-injected element.

3. The assembly according to claim 2, the central section also containing a third cooler for cooling the gas compressed by the first liquid-injected element and second liquid-injected element in fluid communication with the gas outlet of the first liquid separator and with the gas outlet of the second liquid separator.

4. The assembly according to claim 3, the third cooler having one or more additional fans in order to force an additional cooling air flow through the third cooler, the additional cooling air flow being provided to flow from the first section to the second section.

5. The assembly according to claim 3, the housing having a gas outlet that is in fluid communication with a gas outlet of the third cooler.

6. The assembly according to claim 1, each of the first section and second section comprising at least one of the plurality of components.

7. The assembly according to claim 6, the central section also having a lead-through for at least one line selected from a gas line and a liquid line in order to place at least one of the plurality of components in the first section and at least one of the plurality of components in the second section in fluid communication with each other.

8. The assembly according to claim 1, the housing having at least one opening at an upper segment of the first section and/or the second section to allow cooling air to flow from an environment of the housing to and into the first section or the second section of the housing and/or vice versa.

9. The assembly according to claim 8, a roof element of the housing being formed at least in part by a grid element in order to implement the at least one opening.

10. The assembly according to claim 1, side walls of the housing being formed by side wall panels, at least part of the side wall panels being openable or removable in order to gain access to the plurality of components in the housing.

11. The assembly according to claim 1, the central section forming a partition wall between the first section and the second section, which partition wall extends across a full width (b) and/or height (h), or across substantially the full width (b) and/or height (h) of the housing.

12. The assembly according to claim 1, the first liquid in the first liquid injection line and/or the second liquid in the second liquid injection line being oil.

13. The assembly according to claim 1, wherein the assembly is configured to supply compressed gas by gearing the first motor that drives the first liquid-injected element and gearing the second motor that drives the second liquid-injected element based on a demand for compressed gas.

14. The assembly according to claim 13, wherein the first motor and the second motor operate under varying operating characteristics.

15. The assembly according to claim 14, wherein the first motor is a first type of motor having a substantially fixed rotational speed.

16. The assembly according to claim 14, wherein the second motor is a second type of motor having a continuously variable adjustable rotational speed.

17. The assembly according to claim 15, wherein the first motor is configured to only being switched on if the second liquid-injected element on its own cannot supply the demand for compressed gas.

18. The assembly according to claim 17, wherein the first motor has a lower maximum operating power than the second motor.

19. A method for cooling an assembly for compressing a gas containing a housing having a plurality of elements for compressing gas, the method comprising: allowing a cooling air flow to flow from an environment into a first section of the housing; passing the cooling air flow through a plurality of coolers that are arranged in a central section of the housing the separates the first section of the housing and a second section of the housing from each other, the cooling air flow being passed from the first section to the second section of the housing by way of one or more fans of the plurality of coolers forcing the cooling air flow to flow through the plurality of coolers in a same direction; allowing the cooling air flow to flow out from the second section of the housing into the environment.

20. The method according to claim 19, wherein the allowing the cooling air flow to flow out comprises allowing the cooling air flow to be carried out at an upper segment of the first section and/or the second section at a roof element of the housing.

21. The method according to claim 19, wherein the plurality of coolers contain at least one first cooler for cooling a first liquid for a first liquid-injected element for compressing the gas and a second cooler for cooling a second liquid for a second liquid-injected element for compressing the gas, and a third cooler for cooling the compressed gas.

Description

(1) The invention will be explained in more detail below using the embodiment examples depicted in the drawings.

(2) In the drawings:

(3) FIG. 1 is a schematic side view of an assembly according to an embodiment of the invention;

(4) FIG. 2 is a cross section of the central section of the assembly from FIG. 1;

(5) FIG. 3 is a flow chart of an assembly according to an embodiment of the invention;

(6) FIG. 4 is a first perspective view of an assembly according to a practical embodiment of the invention; and

(7) FIG. 5 is a second perspective view of the assembly from FIG. 4.

(8) In the drawings, the same reference sign is assigned to the same or comparable components of the assembly.

(9) The primary purpose of the assembly 1 is to supply compressed gas. To this end, each liquid-injected element 6, 8 in the assembly 1 is primarily provided for compressing the gas to be compressed. By supplying a liquid such as oil or water in the element 6, 8, a flow coming from the element 6, 8 will not only contain compressed gas, but will also contain a significant amount of liquid. By putting a gas outlet of each element 6, 8 in fluid communication with an inlet of a liquid separator 10, 12 that, for example, contains a cyclone separator, most of the liquid can be separated from the flow. This offers the further possibility of returning the separated liquid to the element 6, 8 so that a substantially closed circuit is created in which liquid can be reused. In practice, a liquid flow and, optionally, a gas flow coming from a liquid separator are cooled by a liquid cooler and a gas cooler, respectively. Preferably, a non-return valve is provided downstream of each liquid separator 10, 12. In particular, a minimum pressure valve is placed in the proximity of a gas outlet of each liquid separator 10, 12. This valve ensures that no compressed gas flows back from lines downstream of the liquid separator 10, 12 to the liquid separator 10, 12. Indeed, this ensures that the liquid circuits are completely separated from each other in terms of pressure, and that the two elements 6, 8 can thus operate independently of each other. A further non-return valve is preferably placed near a gas inlet of each liquid-injected element 6, 8 to ensure that, if the element 6, 8 stops working, it does not reverse due to the compressed gas still present in the associated liquid separator 10, 12.

(10) FIG. 1 shows a construction of an assembly 1 according to one embodiment of the invention. The assembly 1 contains a plurality of components for producing compressed gas, which plurality of components are assembled together in a housing 2. The housing 2 has a first section 3 and a second section 4. The first section 3 is separated from the second section 4 by a central section 5. The central section 5 divides the housing 2 into two parts, not necessarily two equal parts. The plurality of components are distributed across the various sections. An embodiment example is described below.

(11) In FIG. 1, the assembly 1 contains a plurality of element 6 and 8 in one housing 2. The advantage of a plurality of elements 6 and 8 in one housing 2 is that a greater flow fluctuation of compressed gas can be accommodated by the assembly 1 having a plurality of elements 6 and 8 in comparison with a single element. Furthermore, the efficiency of making compressed gas with a varying flow rate is higher if a plurality of elements 6 and 8 are provided. The figures show embodiments with two elements 6 and 8. It is clear that the same principles of the invention can be applied to assemblies 1 having three or more elements. The invention is not limited to an assembly 1 having only two elements 6 and 8.

(12) The elements 6 and 8 can be the same elements or different elements. The motors 7 and 9 that drive the elements 6 and 8, respectively, can be the same motors or different motors and/or can be controlled in the same manner or in different manners. In one embodiment, the two motors 7 and 9 are both fixed-speed motors. Alternatively, the two motors 7 and 9 are pole changing motors due to the presence of at least two different coils, as a result of which they can run at at least two fixed speeds. As a further alternative, the two motors 7 and 9 are both variable-speed motors, which are typically controlled by a frequency regulator. As an even further alternative, one of the two motors 7 and 9 is a fixed-speed motor or pole changing motor and a second of the two motors 7 and 9 is a variable-speed motor. The invention is not limited to motors having the same power. The two motors 7 and 9 can thus also have a mutually different power, which is additionally favorable in connection with regulation in the case of a varying demand for compressed gas. For example, if motor 7 is a fixed-speed motor and motor 9 is a variable-speed motor, it is favorable to choose a power of the variable-speed motor that is greater than a power of the fixed-speed motor so that no control gap arises when the fixed-speed motor is switched on and off. For the sake of clarity, a fixed-speed motor is a motor of a first type having a substantially fixed rotational speed, and a variable-speed motor is a motor of a second type having a variable adjustable rotational speed. In the embodiment shown, the two elements 6 and 8 and the two motors 7 and 9 are provided in the first section 3 of the housing 2.

(13) Each element 6 and 8 is connected to a liquid separator 10 and 12. As explained above, the element 6, 8 is primarily provided for supplying compressed gas. To this end, each element 6 and 8 has a gas outlet 11 and 13, respectively. The flow coming from said gas outlet 11 and 13 contains not only compressed gas but also a significant amount of liquid. The liquid separators 10 and 12 are in fluid communication with the gas outlets 11 and 13, respectively, in order to separate the liquid from the flow.

(14) Each liquid separator 10 and 12 can be constructed and optimized for the connected element 6, 8. The liquid separators 10 and 12 can thereby be constructed and/or dimensioned differently. Each liquid separator 10 and 12 preferably contains both a cyclone separator and one or more liquid filter elements. Each liquid separator 10 and 12 has a liquid outlet 15 and 17, respectively, and a gas outlet 19, 20, respectively. The liquid from the liquid outlets 15 and 17 is returned to the element 6, 8 via a respective cooler 14, 16. The compressed gas coming from the two gas outlets 19 and 20, after having passed through a minimum pressure valve having an integrated check valve, is combined and brought to a cooler 18 (not shown in FIG. 1) before feeding the compressed gas to a gas outlet 26 of the housing 2. The cooling air supply or exhaust of each of the first cooler 14, second cooler 16 and third cooler 18 (not shown in FIG. 1) can be controlled individually based on a cooling need for the respective cooler 14, 16, 18 so that the assembly 1 can operate optimally and efficiently.

(15) The first cooler 14, second cooler 16 and third cooler 18 are provided in the central section 5. FIG. 2 shows a cross section of the central section 5 and shows how the first cooler 14, second cooler 16 and third cooler 18 can be placed with respect to one another. Each cooler 14, 16, 18 is formed by a heat exchanger having slats for discharging heat to the cooling air. Hereby, each cooler 14, 16, 18 has one or more fans to force cooling air through the heat exchanger. The central section 5 forms one large cooling surface composed of the plurality of coolers 14, 16, 18, each cooler 14, 16, 18 having one or more fans. The fans are located substantially in one plane in the central section 5 and are provided to suck in and blow away cooling air in the same direction. In the embodiment shown, sucking in and blowing away cooling air is shown with a cooling air flow 21. In particular, the fans are provided to blow cooling air from the first section 3 to the second section 4. Because the plurality of fans are located next to each other and provided to suck in and blow away the cooling air in the same direction, an optimal whole is achieved in terms of cooling air flow in the housing 2 in which the various coolers 14, 16, 18 cannot influence each other in a significantly negative way.

(16) FIG. 1 also shows that a roof element 25 of each of the first section 3 and second section 4 of the housing 2 is provided with openings 24, for example formed by a grid in order to allow the cooling air flow 21 in and out of the relevant section 3, 4. This allows to draw in cooling air from above in the first section 3. This allows to blow away heated cooling air at the top in the second section 4. As a result, a person located somewhere around the housing 2 will not experience any direct burden or significant nuisance from the heated cooling air flow 21. A person skilled in the art understands that this effect is in particular relevant for blowing heated cooling air and that a position of the suction openings is less relevant. A person skilled in the art also understands that the openings 24 do not necessarily have to be placed in the roof element 25, but that the openings 24 can be provided in an upper segment 23 of the housing 2. As a further alternative, a predetermined wall panel of the housing 2 can be provided with the openings 24 in order to facilitate the cooling air flow 21. When selecting the wall panel, an environment where the housing 2 is positioned can be taken into account.

(17) FIG. 2 shows a cross section of the housing 2 at the central section 5. FIG. 2 shows that a cooler assembly of the first cooler 14, second cooler 16 and the third cooler 18 substantially forms a complete height h and width b of the housing 2. The central section 5 thus forms a physical separation between the first section 3 and second section 4 of the housing 2. The figure shows an arrangement in which the first and second coolers 14 and 16 are placed one above the other, thus defining the height h of the housing. Alternatively, the first and second coolers 14 and 16 can be placed next to each other so that they define the width b of the housing 2. In the embodiment shown, the third cooler 18 is placed next to the first and second coolers 14 and 16 so that they thus together define the width b of the housing 2. The third cooler 18 is placed at a distance from the upper side and at a distance from the underside of the housing 2. Alternatively, the third cooler 18 can also be placed completely at the top or bottom of the housing 2. The illustrated position of the third cooler 18 allows connections to the third cooler 18 and connections to the upper second cooler 16 to be implemented in a space above the third cooler 18. A space below the third cooler 18 can also be used to implement connections to the third cooler 18 and to the lower first cooler 14 and can also be used as a lead-through for lines. The plurality of components in the first section 3 and second section 4 of the housing 2 are placed in fluid communication with each other fully operationally. To this end, lines, including gas lines, liquid lines and electrical lines, are laid between the various components in order to make the operational functioning as optimal as possible. The lead-through is indicated in FIG. 2 by reference sign 22.

(18) FIG. 3 shows a schematic construction of the assembly 1 from which the operation and interrelationship of the various components is clear. FIG. 3 shows how a first element 6 is driven by a first motor 7. The first element 6 draws gas from a gas inlet 27. If a special gas, for example nitrogen or oxygen, has to be compressed, the gas inlet 27 is connected to a gas storage tank or to a gas production facility. The element 6 also has a liquid inlet for injecting a liquid for cooling, lubricating and/or sealing the element 6, and is provided to compress the gas and the liquid to a first gas outlet 11. Said gas outlet 11 is in fluid communication with a liquid separator 10 because not only compressed gas but also a significant amount of liquid comes out of the gas outlet 11. The liquid separator 10 separates the flow of the gas outlet 11 into a gas flow and a liquid flow. The liquid flow comes out of the liquid outlet 15 and is returned via the first cooler 14 to the element 6 so as to form a closed liquid circuit. The gas flow comes out of the gas outlet 19 of the liquid separator 10 and is fed to the gas outlet 26 of the housing 2, optionally via the third cooler 18.

(19) FIG. 3 further shows how a second element 8 is driven by a second motor 9. The second element 8 draws gas from a gas inlet 27. If a special gas, for example nitrogen or oxygen have to be compressed, the gas inlet 27 is connected to a gas storage tank or to a gas production facility. The element 8 also has a liquid inlet for injecting a liquid for cooling, lubricating and/or sealing the element 8, and is provided to compress the gas and the liquid to a second gas outlet 13. Said gas outlet 13 is connected to a liquid separator 12 because not only compressed gas but also a significant amount of liquid comes out of the gas outlet 13. The liquid separator 12 separates the flow of the gas outlet 13 into a gas flow and a liquid flow. The liquid flow comes out of the liquid outlet 17 and is returned via the second cooler 16 to the element 8 so as to form a closed liquid circuit. The gas flow comes out of the gas outlet 20 of the liquid separator 12 and is fed to the gas outlet 26 of the housing 2, optionally via the third cooler 18.

(20) FIG. 3 shows how the gas outlet 19 of the first liquid separator 10 and the gas outlet 20 of the second liquid separator 12 are brought together before going to the third cooler 18. The two gas flows out of the liquid separators 10, 12 are thus cooled by one cooler 18. Tests and simulations have shown that this does not entail a significant decrease in efficiency. FIG. 3 also shows how a controller 28 is provided to control the first motor 7 and second motor 9 based on a demand for compressed gas. The controller 28 can thus efficiently control the two elements 6 and 8 separately and/or together to respond to a demand for compressed gas. The controller 28 can also control a cooling air flow rate of the fans that are located in the central section 5.

(21) FIGS. 4 and 5 show different perspective views of a more practical embodiment of the assembly 1. The housing 2 is hereby shown as being open, in particular without side walls and roof walls. FIGS. 4 and 5 only show a bottom 2 of the housing 2. The first section 3, second section 4 and central section 5 are also indicated in FIGS. 4 and 5. Hereby, the first section 3 is larger than the second section 4. A first element 6 and a second element 8 are placed in the first section 3. Said elements 6 and 8 are placed next to each other in the housing 2 and preferably provided on rails that extend in the transverse direction of the housing 2. The transverse direction is equal to the direction of the width b of the central section 5. As a result, if a side wall of the housing 2 is partially or fully opened, an element 6 or 8 can be pushed out of or into the housing 2 via the opened side wall and be installed on and/or removed from the rails. This construction simplifies maintenance and repairs. The motors 7 and 9 can also be installed on rails in order to be installed and/or removed via the opposite side wall.

(22) FIGS. 4 and 5 also show how the first section 3 contains a control cabinet that can, for example, contain the controller 28 from FIG. 3. The control cabinet can also contain devices and cabling for connecting and controlling the different parts of the assembly 1. The control cabinet can read out sensors, contain switching modules for motors, for example a frequency regulator, contain protection devices, etc.

(23) FIGS. 4 and 5 show how the inlet of the elements 6 and 8 can contain an inlet filter 27A and 27B. The inlet filters 27A and 27B are positioned near a roof element of the housing 2, which roof element contains the openings to allow the cooling air flow 21 into the housing 2. In the embodiment shown, a rail or support structure is provided between the control cabinet and the central section 5 from which the inlet filters 27A and 27B can be hung. This simplifies the installation of the assembly 1.

(24) FIGS. 4 and 5 show how the central section 5 physically separates the first section 3 from the second section 4 into a so-called cold compartment with sucked in cooling air and a warm compartment with heated cooling air. In other words, the central section 5 forms a partition wall composed of a plurality of modules that are located between the first section 3 and the second section 4. The central section 5 contains the first cooler 14, the second cooler 16, and optionally the third cooler 18 and at least one lead-through 22. In the embodiment shown, the lead-through 22 is provided under the third cooler 18. Lines, tubes and cables can be placed through the lead-through 22 in order to operationally connect components and parts in the first section 3 to components and parts in the second section 4. In the figures shown, the gas outlets 11 and 13 of the elements 6 and 8 are operationally in fluid communication with the liquid separators 10 and 12.

(25) The liquid separators 10 and 12 are placed in the second section 4. Each liquid separator 10 and 12 in the embodiment shown has a cyclone separator and is provided with an extra liquid filter, indicated by reference sign 30. A person skilled in the art will understand that different kinds and types of liquid separators can be used and/or combined based on need and circumstances. FIG. 5 also schematically shows a component 29 that can contain different liquid connections, liquid filters, air vents, pressure regulators, temperature control valves and/or other parts.

(26) FIGS. 4 and 5 also show how a gas outlet 26 is provided at a wall of the housing 2 in order to supply the compressed gas outside the housing 2. A user can connect to the gas outlet 26 in order to use the compressed gas that is generated inside the housing 2. The components inside the housing 2 are also provided to respond to the demand for compressed gas, in particular to produce the compressed gas that is taken from the gas outlet 26.

(27) Each of the coolers 14, 16, and 18 is accessible from a side of the housing 2. This allows, for example, filters to be replaced by sliding a filter element in and out, transversely to the housing 2, to and from the outside of the housing 2. In addition, the coolers 14, 16, 18 themselves can also be slid laterally, transversely to the housing 2, on rails, for example, to chemically clean them. Because the coolers 14, 16 and 18 are provided in the central zone 5, the first zone 3 and the second zone 4 remain maximally accessible to carry out work, replacements and/or maintenance for the various parts of the assembly 1. FIGS. 4 and 5 show that the construction of the housing 2 having the first section 3 and the second section 4 is open with a lot of space around the various parts. This facilitates the installation and maintenance of the assembly 1.

(28) The figures also illustrate how the construction of the housing 2 improves the operation of the assembly 1. In particular, FIG. 1 shows how cooling air flows through the housing 2. Cooling air flows in at the location of a roof element of the first section 3. The cooling air is blown to the second section 4 via coolers 14, 16, 18 that are placed in the central section 5. Here, the cooling air is typically heated as a result of a heat exchange at the coolers 14, 16, 18. The heated cooling air is discharged at the location of a roof element of the second section 4.

(29) On the basis of the above description, it will be understood by a skilled professional that the invention can be implemented in different ways and based on different principles. In addition, the invention is not limited to the embodiments described above. The embodiments described above, as well as the figures, are merely illustrative and serve only to increase the understanding of the invention. The invention will therefore not be limited to the embodiments described herein, but is defined in the claims.