The present invention relates generally to compressors and compressor components, and, more particularly, to systems and methods for providing lubrication to such compressors and compressor components. In one aspect, the present invention relates to systems and methods for providing lubrication to compressors having internal gearboxes.
Compressors are used, for example, in compression systems (e.g., refrigeration systems) to compress gas, such as “halocarbon”, ammonia, natural gas, or the like. Typically, compressors employ a wide variety of components in operational association with one another. When the compressor is operated, many of these components contact each other such that surfaces of the components rub, and/or wear against each other. Therefore, it is necessary to provide the compressor components with lubrication.
If the components are not adequately lubricated, numerous undesirable conditions can be encountered. For example, shifting, sliding, abrading, of rotating components, as well as other components that are in “intimate” contact with each other, can subject such components to wear and tear due to friction. As such, without adequate lubrication, friction tends to inhibit, or potentially prevent altogether, relative movement of the components. Abrasion of non-lubricated, or sparsely lubricated, components in intimate engagement or contact can cause surfaces of the components to become scored, pitted, gouged, or otherwise damaged.
Often, to provide lubrication effectively and efficiently, one or more pumps are used within a compressor system. Although sufficient in many respects, such pumps may not be adequate in at least some circumstances. For example, in the event of a pump becoming inoperative, the flow of lubricant to the portions of the compressor system lubricated by that pump is obstructed. Additionally, if unobserved, substantial damage to certain compressor components can potentially occur and can thus affect the overall functioning of the compressor system. It would therefore be advantageous if a system that continuously provided lubrication to the various components of the compressor is developed and more specifically, if such continuous lubrication was not impeded or obstructed upon a pump or similar mechanism used with or within the compressor system becoming inoperative.
In accordance with one aspect of the invention, a compressor system is disclosed. In at least some embodiments of the present invention, the compressor system includes: (i) a compressor oil circuit in operable association with a compressor for compressing fluids, (ii) a gear pump in operable association with a gearbox, wherein the gearbox comprises a plurality of gears mounted on a gear shaft for driving the compressor, and (iii) a lubrication system including at least two lubricant feeds for carrying lubricant to the compressor and the gearbox from a lubricant source. Also provided is a connection line connecting the compressor and the gearbox for transferring lubricant from the compressor oil circuit to the gear pump and/or from the gear pump to the compressor oil circuit.
In another aspect of the present invention, a method of lubricating the compressor system is disclosed. The method includes providing a compressor, a gearbox having a plurality of gears, a compressor oil circuit, a gear pump and a lubrication system comprising a lubricant source and at least two lubricant feeds. The method further includes providing a connection line between the compressor and the gearbox for transferring lubricant from the compressor oil circuit to the gear pump and/or from the gear pump to the compressor oil circuit. The method additionally includes transferring lubricant from the lubricant source via the at least two lubricant feeds to the compressor and the gearbox.
In still another aspect of the present invention, a compressor system in combination with a lubrication system is provided. The compressor system further includes a rotary screw compressor and a gearbox in operational association with the compressor, while the lubrication system for lubricating the compressor system includes a lubricant source and at least two lubricant feeds for transferring lubricant from the lubricant source to the compressor and the gearbox. Also provided is a connection line connecting the gearbox and the compressor for transferring lubricant from the compressor oil circuit to the gear pump and/or from the gear pump to the compressor oil circuit.
Various other aspects, objects, features and embodiments of the present invention are disclosed with reference to the following specification, including the drawings.
Features of the present invention which are believed to be novel are set forth with particularity in the appended claims. Embodiments of the invention are disclosed with reference to the accompanying drawings and these embodiments are provided for illustrative purposes only. The invention is not limited in its application to the details of construction or the arrangement of the components illustrated in the drawings. Rather, the invention is capable of other embodiments and/or of being practiced or carried out in other various ways. The drawings illustrate a best mode presently contemplated for carrying out the invention. Like reference numerals are used to indicate like components. In the drawings:
Referring to
The compressor 4 includes a compressor housing 10, and a plurality of compressor components within the compressor housing in operable association with another (explained below). As shown, the compressor housing 10 houses a single cylindrical main rotor 12 in intermeshing arrangement with first and second cylindrical star rotors (also referred herein as gate rotors and star-shaped rotors) 14 and 16, respectively. The main rotor 12 is mounted for rotation on a main rotor shaft 18, that is rotatably supported at opposite ends on compressor bearing assemblies 20 within a cylindrical bore 22. The main rotor 12 further includes a plurality of helical grooves formed thereon, which in association with the star rotors 14 and 16 define compression chambers.
In particular, each of the first and the second star rotors 14 and 16, respectively, are located diametrically opposite (i.e., 180 degrees apart) the main rotor 12. The star rotors 14 and 16 further include a plurality of gear teeth 24, such that rotation of the star rotors about an axis perpendicular to and spaced from an axis of rotation of the main rotor 12 causes the gear teeth of the star rotors to successively engage a helical groove of the main rotor. By virtue of such engagement of the helical grooves of the main rotor 12 with the gear teeth 24 of the star rotors 14 and 16, compression chambers for compressing a gas are defined. Each of the star rotors 14 and 16 is additionally mounted for rotation on gate rotor shafts 26 and 26a, respectively, within spaces 28 and 28a, respectively, defined within the compressor housing 10. The gate rotor shafts 26 and 26a are further supported on opposite ends by bearing assemblies (not shown).
Although not shown, the compressor housing 10 is provided with one gas suction port and with two gas discharge ports (one near each star rotor). Two dual slide valve assemblies can additionally be provided on the compressor housing 10 (one assembly near each gate rotor) wherein each slide valve assembly comprises a suction slide valve (also referred to as a “capacity slide valve”) and a discharge slide valve (also referred to as a “volume slide valve”) for controlling the associated suction port and the associated discharge port, respectively. The slide valves can additionally be employed for accomplishing loading and unloading of the compressor by controlling admission and discharge of gas into and from the compression chambers, described above. U.S. Pat. Nos. 4,610,612, 4,610,613, 4,704,069, the teachings and disclosures of which are incorporated herein in their entireties, are assigned to the same assignee as the present application, and disclose a slide-valve assembly described above,
In operation, gas is drawn in through the gas suction port and is routed through the compression chambers for compression therewithin. Typically, compression of the gas is achieved by rotation of the star rotors 14 and 16 in synchronism with the main rotor 12 causing the gear teeth 24 of the star rotors to intermesh with the helical grooves of the main rotor. By virtue of such intermeshing engagement between the gear teeth 24 of the star rotors 14 and 16 and the helical grooves of the main rotor 12, the volume of the gas is reduced, thereby achieving compression of the gas. The compressed gas from each associated compression chamber then exits through its associated discharge port. In general, the operation of compressors for compressing gas (e.g., rotary screw compressors) is generally well known in the art and is therefore, not explained here in detail for conciseness of expression.
Also provided within the compressor housing 10 is the gearbox 6 for driving various components of the compressor 4 including the main rotor 12 and the star rotors 14 and 16. The gearbox 6 includes a gearbox housing 30 mounted within the compressor housing 10 by way of a plurality of gearbox bearings 32. In at least some embodiments of the present invention, the gearbox 6 is integrally mounted within the compressor housing 10. The gearbox 6 itself is typically driven by way of one motor (not shown) present either within the compressor housing 10 or otherwise located external to the compressor housing and connected to the gearbox. Additionally, the type of motor(s) for driving the gearbox can vary.
The gearbox further includes a plurality of intermeshing gear 34 mounted on a gear shaft 36 and gear 34a mounted on the main rotor shaft 18. By virtue of driving the gearbox 6 via the motor(s), the gear shaft 36 can drive the plurality of gears 34, which in turn drive the gears 34a. The gears 34a further drive the main rotor shaft 18 for transmitting power from the motor to the various components of the compressor 4 (e.g., the main rotor 12 and the star rotors 14 and 16).
Additionally, to effectively provide lubrication to various compressor components and gearbox components, the present invention employs a gear pump 40. The gear pump 40 is a conventional type of pump that is commonly available and frequently employed in compressor systems. Typically, the gear pump 40 is mounted within the compressor housing 10 for encouraging lubricant flow from the lubrication system 8 and injecting such lubricant to the various portions of the compressor 4 and the gearbox 6. Notwithstanding the fact that in the present embodiment, the gear pump 40 is mounted as described herein, in at least some other embodiments of the present invention, the location of the compressor and the gear pumps can vary to convenience.
With respect to the lubrication system 8, a lubricant source 42 capable of providing a supply of lubricant for lubricating the compressor system 2 is provided within the lubrication system. In at least some embodiments of the present invention, the lubricant source 42 is an oil sump, capable of storing and supplying a lubricant. In some other embodiments, the lubricant source 42 can be an oil tank, a lubricant supply line or possibly even storage containers storing a fixed quantity of lubricant. Additionally, the lubricant can be any of a wide variety of lubricants that are commonly employed for lubricating compressors and gearboxes and/or used for reducing friction between various contacting components. For example, in at least some embodiments of the present invention, the lubricant can be compressor oil, lubricating oil and the like.
Also provided within the lubrication system 8 is a plurality of lubricant feeds, extending from the lubricant source 42 and supplying lubricant to the compressor system 2. In particular, at least some embodiments of the present invention employ a first lubricant feed 44 extending up to the gear pump 40, and a second lubricant feed 46 extending to the compressor 4. Typically, each of the lubricant feeds 44 and 46 can be any of a conduit, a pipe or a member for carrying lubricant to the gearbox 6 and the compressor 4, respectively. By virtue of providing the lubricant feeds 44 and 46 connected to the gear pump 40 and the compressor 4, respectively, lubricant can flow from the lubricant source 42 to the compressor 4 and the gearbox 6 through the lubricant feeds on activation of the associated pump for providing lubrication thereto.
Upon reaching the gear pump 40 and/or the compressor 4, lubricant from the first and the second lubricant feeds 44 and 46, respectively, is distributed to various portions of the gearbox 6 and the compressor. For example, as shown in each of
Additionally, during operation of the compressor system 2, lubricant can typically be supplied to the compression chambers to provide point seal 56 at points (as shown by exemplary communication link 54), where the main rotor 12 meshes with the star rotors 14 and 16, and with the compressor housing 10 to thereby effectively seal the chambers against gas leakage during gas compression. Seal points other than those shown within the compressor system 2 can be provided. Additionally, as shown by the communication link 58, lubricant to the seal point 56a is provided by the gear pump 40. Nevertheless, in other embodiments, such seal points can be supplied with lubricant from the compressor 4 (e.g., by the oil circuit 38) as well. Lubricant can additionally be provided to various components of the motor(s) employed for driving the gearbox 6. Subsequent to lubricating the various components of the compressor 4 and the gearbox 6 via lubricant flowing through the first and the second lubricant feeds 44 and 46, respectively, the lubricant is discharged from the discharge ports, recovered and re-circulated. Recovering of the lubricant is well known in the art and therefore, not explained here.
In general, the gear pump 40 is driven by the main rotor shaft 18 for providing power to the pump for pumping lubricant from the lubricant source 42 through the lubricant feeds 44 and 46, and injecting and supplying lubricant from the lubricant feeds to the various components of the compressor system 2. Upon the gear pump 40 becoming inoperative, the lubricant flow to the gearbox 6 and the seal points 56a can be disrupted. Relatedly, upon the second lubricant feed 46 becoming inoperative, lubrication to various components of the compressor 4 can be disrupted. If unnoticed, such obstruction can cause severe damage to the components of the compressor system 2 and can significantly reduce the overall performance of the compressor system.
To prevent such occurrences, an additional lubricant feed 60 (also referred herein as oil connection, connection line, and oil line) connecting the first and the second lubricant feeds 44 and 46, respectively, is provided in the present invention. In particular, as shown in the present embodiment, the connection line 60 extends from the gear pump 40 to the compressor 4 (and, particularly to the oil circuit 38). Nevertheless, in alternate embodiments, the connection line 60 can be provided from any point of the first lubricant feed 44 to any point of the second lubricant feed 46. By virtue of providing such a connection line, lubricant can be fed from the compressor 4 to the gearbox 6 and vice versa. Similar to the first and the second lubricant feeds 44 and 46, respectively, the connection line 60 can be any of a conduit, pipe or a member for supplying lubricant. Additionally, the connection line 60 is capable of transferring the lubricant from the compressor 4 to the gearbox 6 and/or from the gearbox to the compressor when the gear pump 40 is inoperative. Relatedly, the connection line 60 is capable of transferring the lubricant from the compressor 4 to the gearbox 6 and/or from the gearbox to the compressor when the second lubricant feed 46 supplying lubricant to the compressor oil circuit 38 is inoperative. In case of poor lubricant flow or on occasions when one of the gear pump 40 or the second lubricant feed 46 becomes inoperative, the other system takes over (e.g., through the connection line 60) and lubricates the appropriate rotating parts. In this way the connection line 60 serves to ensure, and further enhance lubrication during, for example, start up and operation of the compressor system 2.
Further, the connection line 60 can be located internally within the compressor housing 10 or potentially external to the compressor housing. Relatedly, the first and the second lubricant feeds 44 and 46, respectively, can be positioned either internal or external to the compressor housing 10. When placed external to the compressor housing 10, the lubricant feeds, including the first the second lubricant feeds 44 and 46, respectively, and the connection line 60, can be used as a retrofit to the compressor system 2. Replacement and maintenance of the lubricant feeds can be simplified by providing the lubricant feed assembly exterior to the compressor housing. However, externally located lubricant feeds are more prone to damage and breakage. Leakage from broken or ruptured feeds is significantly reduced by providing the feeds internal to the compressor housing 10. Therefore, depending upon the embodiment, the lubricant feeds can be located either internal or external to the compressor system 2.
Additionally, as shown in
Although not shown, a similar secondary pump can also be positioned adjacent the gear pump 40 and/or the first lubricant feed 44. Additionally, instead of providing a separate secondary pump for the gear pump, a secondary pump can be provided at the originating point of the first and the second lubricant feeds 44 and 46, respectively, (e.g., close to the lubricant source 42), as can be seen in
Notwithstanding the embodiments of the present invention described above with respect to
As indicated above, the lubricant feeds need not be present within the compressor housing, but can rather be located external to the compressor housing. Similarly, the gearbox need not be integral but can otherwise be external to the compressor housing. The shape, size, type and number of the various components within the compressor system 2 can vary in alternate embodiments.
Further, despite any methods being outlined in a step-by-step sequence, the completion of acts or steps in a particular chronological order is not mandatory. Further, elimination, modification, rearrangement, combination, reordering, or the like, of acts or steps is contemplated and considered within the scope of the description and claims.
Accordingly, it is specifically intended that the present invention not be limited to the embodiments and illustrations contained herein, but include modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come within the scope of the following claims.
This application claims the benefit of pending U.S. Provisional Patent Application No. 60/989,527 filed Nov. 21, 2007, which is hereby incorporated by reference herein.
Number | Date | Country | |
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60989527 | Nov 2007 | US |