Screw-type compressor

Abstract: Screw-type compressor containing a gearcase (1) with at least one pressure stage (2); a lubricating device (3) having as components at least a lubricant reservoir (9), a pump (10), a lubricant cooler (13), a filter (15) and nozzles or distribution elements (23) and which moreover has conduits for lubricant (20-21-22-24-25-26-27) between these components; and a cooling arrangement (4) having as components at least a compressed air cooler (41) and the lubricant cooler (13), and which moreover has a number of conduits (44-46-47-48-49-50-54) for cooling fluid between these components, characterized in that at least a number of components of the lubricating device (3) and of the cooling arrangement (4) are mounted directly on the gearcase (1) or are integrated in the gearcase (1), whereas a number of the conduits between different components (9-10-13-15-23-41) are integrated at least partially in the gearcase (1), such that the number of conduits between components or parts thereof (49-50-54) situated outside the gearcase (1) or the lubricating device or cooling arrangement (3 and 4) is limited.

Description: The present invention concerns a screw-type compressor containing a gearcase with at least one pressure stage; a lubricating device having as components at least a lubricant reservoir, a pump, a lubricant cooler, a filter and nozzles or distribution elements and which moreover has conduits for lubricant between these components; and a cooling arrangement having as components at least a compressed air cooler and the above-mentioned lubricant cooler, and which moreover has a number of conduits for cooling fluid between these components. With the known screw-type compressors of this kind, the gearcase, the lubricating device and the cooling arrangement are set up individually and they are physically connected to one another by means of separate supports. Practically, they are connected to one another by means of a large number of conduits for lubricant and for cooling fluid. These conduits consist of pipes and/or hoses and coupling elements and contain a large number of connections and sealings. These conduits must be sufficiently flexible or adjustable to absorb mutual differences in position of the components which are connected by said conduits. Also, these known screw-type compressors require a large number of separate components, and mounting all these components is, partly because of the necessary adjustments rather time-consuming. Moreover, the risk of leaks and large pressure drops is great with these known compressors. US-A-5.199.858 discloses a screw-type compressor of the above-mentioned type, whereby moreover at least a number of the components of the lubricating device are already mounted directly on the gearcase or are integrated in the gearcase, such that the number of conduits between components or parts thereof situated at the outside of the gearcase or the lubricating device is limited. The cooling arrangement is still separate from the gearcase. A screw-type compressor having a number of conduits between different components integrated at least partially in the gearcase is disclosed in GB-A-2.059.511. The gearcase is incorporated in a housing wherein not only the rotors but also a number of components are mounted such as an air filter and a liquid separator. A number of components are also mounted on the outside of this housing, such as the lubricant cooler and the lubricant filter. The compressed air cooler is mounted on the lubricant cooler. The invention aims a screw-type compressor whereby these and other disadvantages are excluded, and which as a consequence has a simple construction and requires only a minimum of adjustments, and which contains a minimum of connections and thus a minimum risk of leaks or large pressure drops. This aim is reached in a screw-type compressor of the type defined in the first paragraph, whereby moreover at least a number of the components of the lubricating device are already mounted directly on the gearcase or are integrated in the gearcase, by the fact that also a number of the components of the cooling arrangement are mounted directly on the gearcase or are integrated in the gearcase and that a number of the conduits between the different components are integrated at least partially in the gearcase, such that a number of conduits between components of parts thereof situated outside the gearcase or the lubricating device or cooling arrangement is limited, and in that a number of functions such as the fixing, positioning and connecting are integrated in the main components consisting of the gearcase, the lubricating device and the cooling arrangement. Preferably, at least the compressed air cooler and the lubricant cooler of the cooling arrangement are mounted directly on the gearcase. The supply line for cooling fluid which is connected to the lubricant cooler and the conduit for this cooling fluid which connects the lubricant cooler to the pressure stage can be at least partially integrated in the gearcase. The conduits for lubricant between the pump and the lubricant cooler, between said lubricant cooler and the filter and between the filter and the nozzles or distribution elements can also be at least partially integrated in the gearcase. In order to better explain the characteristics of the invention, the following preferred embodiment of a screw-type compressor according to the invention is described, as an example only without being limitative in any way, with reference to the accompanying drawings, where: figure 1 schematically represents the gearcase of a screw-type compressor according to the invention with the lubricating device only; figure 2 schematically represents the gearcase of figure 1, but with the cooling arrangement only; figure 3 shows a front view of a practical embodiment of the gearcase of the figures 1 and 2, whereby components of the lubricating device and the cooling arrangement are represented as a chain line; figure 4 shows a side view of the practical embodiment of the gearcase of figure 3, whereby components mounted thereupon are also represented as a chain line. The screw-type compressor represented in the figures 1 and 2 contains a gearcase 1 with one or more, for example two pressure stages 2, a lubricating device 3 with preferably oil as a lubricant and a cooling arrangement 4 with preferably water as a cooling fluid. These main components 1 to 4 are fixed directly to one another and all the functions such as the fixing, positioning and connecting are mainly integrated in these main components, such that practically all connections outside these main components can be omitted, and no separate supports are required for the main components. In the gearcase 1 is mounted a gear wheel transmission 5 in the usual manner which is driven by a motor which is not represented in the figures and with which gear wheels of the pressure stages 2 are driven. These pressure stages 2 are fixed directly on the outside of the gearcase 1 with their housing by means of fastening means 6 such as bolts, and they are positioned with taper pins 7. The sealing is obtained with a metal-metal contact between the housing and the gearcase 1 and through a flexible ring 8. Said gearcase 1 is provided with supports 61 at the bottom, with which the entire compressor is supported. As is schematically represented in figure 1, the lubricating device 3 contains a number of components which are mounted directly on the gearcase 1 or which are integrated in this gearcase. Thus, the lubricating device 3 contains an oil reservoir 9 which forms a whole with the bottom side of the gearcase 1, an oil pump 10 which is erected in a part 12 of the gearcase 1 sealed by means of a lid 11, an oil cooler 13 which is fixed directly on the outside of the gearcase 1 by fixing means 14, for example bolts, and an oil filter 15, whose housing 16 is also fixed directly on the outside of the gearcase 1 by fixing means 17, by bolts or a threaded connection. The sealing between the lid 11 and the part 12, between the housing of the oil cooler 13 and the gearcase 1 and between the housing 16 of the oil filter 15 and the gearcase is formed by a metal-metal contact and a flexible sealing ring 18. The oil reservoir 9 is equipped with a draining aperture 19. The conduit 20 which connects said oil reservoir 9 to the oil pump 10, the conduit 21 between the oil pump 10 and the oil cooler 13 and the conduit 22 between the oil cooler 13 and the filter 15 are entirely integrated in the gearcase 1 and are formed during the casting of said gearcase. The filter 15 is connected by means of conduits 24-25-26 to nozzles or distribution elements 23 for the lubrication of the bearings and the gear wheels of the two pressure stages 2 and for the lubrication of the main bearings of the gear wheels in the gearcase 1. The conduits which lead to the pressure stages 2 consist of an internal common part 24 against the filter 15 and in internal separate part 25 which, as well as the part 24, is integrated in the gearcase 1, and of a part 26 which is integrated in the housing of the pressure stage 2 concerned and which is connected to the part 25 via the fastening of said housing on the gearcase 1. Only the return lines 27 for oil are external lines which are fixed on the housing of a pressure stage 2, for example by means of flanges 28 at their ends, and on the outside of the gearcase 1 around an opening 29 by means of fixing means 30. The sealing is provided for by means of flexible rings 31. The gearcase 1 is further provided with openings or connections 32, 33 and 34 to which are connected an overflow or maximum pressure valve 35, an oil-pressure gauge 36 and an oil-temperature gauge 37 respectively. Further, the gearcase 1 is provided with a filling opening 38, a fastening 39 for an oil-level gauge and a fastening 40 for de-aeration. As represented in figure 2, the cooling arrangement contains the above-mentioned oil cooler 13 and a compressed air cooler 41 consisting of an intercooler and an after-cooler built-in in one casing 42 and whose casing 42 is fixed directly against the outside of the gearcase 1 by means of fixing means 43. The positioning is carried out by means of taper pins which are not represented in figure 2 and the sealing by means of flexible rings 64. In this casing 42 is formed a cooling-water intake 44 which is connected to a supply 60 which is divided in two inside the casing, namely a first branch or conduit 45 integrated in the compressed air cooler 41 for cooling the compressed air and a second branch or conduit 46-47 which opens into the oil cooler 13 and which contains a part 46 which is integrated in the compressed air cooler 41 and a part 47 which extends through the gearcase 1 and is integrated in this gearcase. The oil cooler 13 is connected to the pressure stages 2 by means of a conduit 48-49 for cooling water which contains a part 48 which is integrated in the gearcase 1 and a connection 49 connected onto it which is fixed against the outside of the gearcase 1 and the outside of one of the pressure stages 2 respectively by means of flanges at the ends. Between the two pressure stages 2 is provided a connection 50 which is also fixed against the housings of the pressure stages 2 by means of flanges at the ends. The fixing of the ends of the external connections 49 and 50 is realized by means of connecting means 51, for example bolts, and the sealing is ensured by means of flexible rings 52. The reflow of the cooling fluid to a drain 57 goes via an external conduit 54 which is fixed by means of fixing means 55 with flanges 53 at the ends, to one of the pressure stages 2 and to the casing 42 of the compressed air cooler 41 respectively, on the side of the exit 56 thereof which is connected to the drain 57 for cooling fluid. The sealing is provided for by means of flexible rings 58. The cooling arrangement is further provided with a filling and draining aperture and a de-aeration, whereas two connections 59 for chemical cleaning are provided on the casing 42 of the compressed air cooler 41. As is represented by means of arrows in figure 1, lubricating oil is pumped out of the reservoir 9 by the oil pump 10 and is pumped via the conduit 21 to the oil cooler 13, where it is cooled down by the cooling fluid. From there on, the oil flows via the conduit 21, over the filter 15 and from there on via the conduits 24-25-26 to the pressure stages 2. The oil flows back to the reservoir 9 via the conduits 27. As is represented by means of arrows in figure 2, the cooling water is divided over the compressed air cooler 41 and the oil cooler 13, which is reached via the conduit 46-47. From the oil cooler 13, the cooling water flows via the conduit 48-49 to the pressure stages and it returns via the conduit 54 to the output of the compressed air cooler 41. Figures 3 and 4 show how the screw-type compressor according to the above description and represented schematically in figures 1 and 2 can be realized in practice. The gearcase 1 is drawn as a full line, and a number of the components of the lubricating device 3 and the cooling arrangement 4 mounted thereupon, as well as the pressure stages 2 are drawn as a chain line. The gearcase 1 is provided with supports 61 at the bottom with which the entire compressor is supported. Around the openings 62 for the connection of the pressure stages 2 and opposite the compressed air holder 41, the holes 63 for the taper pins used for positioning are visible. The above-mentioned whole is compact, with a minimum of supports and connections. The mounting can be done very fast, with a minimum risk of leaks or large pressure drops. The present invention is by no means limited to the above-described embodiment, represented in the accompanying drawings; on the contrary, such a screw-type compressor can be made in all sorts of variants while still remaining within the scope of the invention.

Claims: Screw-type compressor containing a gearcase (1) with at least one pressure stage (2); a lubricating device (3) having as components at least a lubricant reservoir (9), a pump (10), a lubricant cooler (13), a filter (15) and nozzles or distribution elements (23) and which moreover has conduits for lubricant (20-21-22-24-25-26-27) between these components; and a cooling arrangement (4) having as components at least a compressed air cooler (41) and the lubricant cooler (13), and which moreover has a number of conduits (44-46-47-48-48-50-54) for cooling fluid between these components, whereby at least a number of the components of the lubricating device (3) are mounted directly on the gearcase (1) or are integrated in the gearcase (1), characterized in that also a number of the components of the cooling arrangement (4) are mounted directly on the gearcase (1) or are integrated in the gearcase (1) and that a number of the conduits between the different components (9-10-13-15-23-41) are integrated at least partially in the gearcase (1), such that a number of conduits between components of parts thereof (49-50-54) situated outside the gearcase (1) or the lubricating device (3) or cooling arrangement (4) is limited, and in that a number of functions such as the fixing, positioning and connecting are integrated in the main components consisting of the gearcase (1), the lubricating device (3) and the cooling arrangement (4). Screw-type compressor according to any of the preceding claims, characterized in that the sealing of mutual connections between the gearcase (1) and the different components is provided for by metal-metal contacts and by flexible rings (18-52-58-64). Screw-type compressor according to any of the preceding claims, characterized in that, as far as the cooling arrangement (4) is concerned, at least the compressed air cooler (41) and the lubricant cooler (13) are mounted directly on the gearcase (1). Screw-type compressor according to claim 3, characterized in that the supply line (44-46-47) for cooling fluid which is connected onto the lubricant cooler (13) and the conduit (48-49) for this cooling fluid which connects the lubricant cooler (13) to the pressure stage (2) are at least partially integrated in the gearcase (1). Screw-type compressor according to any of the preceding claims, characterized in that the reservoir (9) for cooling fluid is integrated in the bottom of the gearcase (1). Screw-type compressor according to any of the preceding claims, characterized in that the pump (10) for lubricant is mounted in a part (12) of the gearcase (1) which is sealed by means of a lid (11). Screw-type compressor according to claim 6, characterized in that the conduit (21) for lubricant is integrated in the gearcase (1) between the pump (10) and the lubricant cooler (13). Screw-type compressor according to any of the preceding claims, characterized in that the housing (16) of the filter (15) is fixed directly on the gearcase (1). Screw-type compressor according to claims 7 and 8, characterized in that the conduit (22) between the lubricant cooler (13) and the housing (16) for the filter (15) is integrated in the gearcase (1). Screw-type compressor according to claim 8 or 9, characterized in that the conduits (24-25-26) between the housing (16) of the filter (15) and the nozzles or distribution elements (23) are integrated at least partially in the gearcase (1). Screw-type compressor according to any of the preceding claims, characterized in that at least a number of the components (2, 13, 41) which are mounted on the gearcase (1) are positioned by means of taper pins (7). Screw-type compressor according to any of the preceding claims, characterized in that two connections (59) for chemical cleaning are provided on the casing (42) of the compressed air cooler (41) .

Inventors: LUYTS GUIDO JAN, LUYTS, GUIDO JAN.
Applicants: ATLAS COPCO AIRPOWER NV, ATLAS COPCO AIRPOWER N.V.
Application year: 1996
Main classification: F04C23
IPC codes: F16N39, F04C11, F04C29, F04C23, F04C18