The present invention relates to single screw compressors and, more particularly, to single screw compressors having high output and increased capacity.
Compressors are used in various compression systems, such as refrigeration systems, to compress gas, such as Freon, ammonia, natural gas, or the like. One type of compressor is a single screw gas compressor, which is generally comprised of three basic components that rotate and complete the work of the compression process. These components include a single cylindrical main screw rotor with helical grooves separated by a plurality of identical lands, and two gate rotors (also known as star or star-shaped rotors), with each gate rotor having a plurality of teeth that extend radially outwardly from its center. The rotational axes of the gate rotors are parallel to each other and mutually perpendicular to the axis of the main screw rotor. This type of compressor employs a housing in which the helical grooves of the main rotor mesh with the teeth of the gate rotors on opposite sides of the main rotor to define gas compression chambers. The housing is provided with two gas suction ports, typically one near each gate rotor, for inputting the gas and with two gas discharge channels, again typically one near each gate rotor, for entry and exit of the gas to the gas compression chambers. It is known to provide two dual slide valve assemblies on the housing, with one assembly typically positioned near each gate rotor, with each slide valve assembly comprising a suction valve (also referred to as a “capacity slide valve”) and a discharge slide valve (also referred to as a “volume slide valve”) for controlling an associated intake channel and an associated discharge channel, respectively. In operation, an electric motor imparts rotary motion through a driveshaft to the compressor's main rotor, which in turn rotates the two intermeshed gate rotors, and gas is compressed in the gas compression chambers.
Known main rotors comprise identical lands consisting of a single wrap angle. More particularly, the single wrap angle corresponds to, or otherwise describes, a starting point on the outer diameter of a respective one of the lands of the main rotor as the point travels, during rotation of the rotor about its rotational axis, from the starting point on the respective land of the rotor to a final point on the respective land of the rotor.
It has been determined that an increase in the wrap angle of the main rotor (i.e., particularly the single wrap angle of the respective identical lands of the main rotor) results in an increase in compressor output. In general, for a given main rotor diameter, for example, an outside diameter corresponding to outside surfaces of the lands, and a given gaterotor diameter, the wrap angle of any given main rotor must remain below 180 degrees so as to permit mounting of the gaterotor with respect to the main rotor when the main rotor is already positioned in the housing of the compressor, as is typically the case during assembly of the compressor.
It would be advantageous to provide a single screw compressor with high output that overcomes the problems associated with the above.
Features of the present disclosure which are believed to be novel are set forth with particularity in the appended claims. Embodiments of the disclosure are disclosed with reference to the accompanying drawings and are for illustrative purposes only. The disclosure is not limited in its application to the details of construction or the arrangement of the components illustrated in the drawings. The disclosure is capable of other embodiments or of being practiced or carried out in other various ways. Like reference numerals are used to indicate like components. In the drawings:
In one aspect, a single screw compressor is disclosed. The compressor, in at least some embodiments, includes: a housing including a cylindrical bore; a pair of gate rotors mounted for rotation in the housing, each gate rotor having a plurality of gear teeth; and a main rotor rotatably mounted in the bore and having a plurality of grooves, a plurality of lands, an additional groove, and an additional land; wherein the plurality of lands of the main rotor comprises a first wrap angle and the additional land comprises a second wrap angle, and the second wrap angle is distinct and different from the first wrap angle.
In another aspect, a method of assembling a gate rotor in relation to a main rotor that is positioned within a housing of a single screw gas compressor configured for high output, the gate rotor having a plurality of gear teeth, the main rotor having a plurality of grooves, a plurality of lands, an additional groove, and an additional land is disclosed. In at least some embodiments, the method comprises positioning the gaterotor such that at least one of the plurality of gear teeth is configured to be received within the additional groove, the additional groove being positioned adjacent the additional land; and wherein the plurality of lands of the main rotor comprises a first wrap angle and the additional land comprises a second wrap angle, and the second wrap angle is distinct and different from the first wrap angle.
In another aspect a main rotor device for use with a single screw compressor configured for high output is disclosed. In at least some embodiments, the main rotor comprises a main rotor body having formed therein a plurality of grooves, a plurality of lands, an additional groove, and an additional land; and wherein the plurality of lands of the main rotor comprises a first wrap angle and the additional land comprises a second wrap angle, and the second wrap angle is distinct and different from the first wrap angle.
Other aspects, features, objects, and embodiments will be apparent in view of the present disclosure.
Referring to
Compressor housing 12 includes a cylindrical bore 24 in which main rotor 14′ is rotatably mounted. Bore 24 is open at its discharge end 27 and is closed by an intake end wall 29. Main rotor 14′, which is a generally cylindrical main rotor body 31, has a plurality of helical grooves 25 formed therein (e.g., six grooves) defining gas compression chambers 35, is provided with a rotor output shaft 26 which is rotatably supported at opposite ends on bearing assemblies 28 mounted on housing 12. The grooves 25, 25′ of main rotor 14′ are separated from each other via respective lands 15, 15′ (land 15′ and groove 25′ described further below). In accordance with embodiments of the present disclosure, each of the plurality of lands 15, 15′ corresponds to or comprises a respective wall that is located between a respective pair of adjacent grooves.
Compressor housing 12 includes spaces 30 therein in which the gate rotors 16 and 18 are rotatably mounted and the gate rotors 16 and 18 are located on opposite sides (i.e., 180 degrees apart) of main rotor 14′. Each of the gate rotors 16 and 18 has a plurality of gear teeth 32 (for example, eleven are illustrated) and is provided with a respective gate rotor shaft 34 which is rotatably supported at opposite ends on bearing assemblies 34A and 34B (
The compressor housing 12 is provided with gas suction ports 40 (one near each gate rotor) and with a gas discharge port (not shown). Each slide valve assembly 20 comprises a suction slide valve and a discharge 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 gas compression chambers, in a known manner.
In operation, gas is drawn in through the gas suction port and is routed through the compression chambers 35 for compression therein. Typically, compression of the gas is achieved by rotation of the gate rotors 16, 18 which are synchronized with the main rotor 14′, which is driven, as by a drive motor (not shown), causing the gear teeth 32 of the gate rotors to intermesh with the helical grooves 25, 25′ of the main rotor. By virtue of such intermeshing engagement between the gear teeth 32 of the gate rotors 16, 18 and the helical grooves of the main rotor 14′, the volume of the gas is reduced, thereby achieving compression of the gas. The compressed gas from each associated compression chamber 35 then exits through its associated discharge port. In general, the operation of compressors for compressing gas (e.g., single rotary screw compressors) is well known in the art.
Still referring to
As depicted, and in accordance with embodiments of the present disclosure, a small portion of one of the plurality of lands 15, denoted by numeral 60 in
The truncated land 15′ can be formed or otherwise obtained in any of a number of ways. For example, in accordance with embodiments of the present disclosure, truncated land 15′ may be created by cutting away or removing for example, by a milling or similar operation, a portion, such as portion 56, of one of the lands 15. It is further contemplated that truncated land 15′, in accordance with embodiments of the present disclosure, need not necessarily be formed by removing material from a land, such as land 15. Rather, land 15′ may be provided directly.
In accordance with embodiments of the present disclosure, the main rotor 14′ comprises a first wrap angle of greater than 180 degrees, associated with or corresponding to lands 15. In addition, in accordance with embodiments of the present disclosure, the main rotor 14′ further comprises a second wrap angle of less than 180 degrees, corresponding to or comprising truncated land 15′. In accordance with embodiments of the present disclosure, the second wrap angle is distinct and different from the first wrap angle. In addition, truncated land 15′ provides for an enlarged groove opening 51 in groove 25′ adjacent land 15′, which provides or is configured to provide additional clearance for positioning of a gaterotor as described further below.
In accordance with embodiments of the present disclosure, main rotor 14′ comprises a first wrap angle corresponding to a plurality of lands, such as in the present embodiment, five lands, and a distinct and different second wrap angle, as in the present embodiment corresponding to a single land, and which is different and distinct from the first wrap angle. In accordance with embodiments of the present disclosure, a land, for example truncated land 15′, is obtained such that at least one of a point, an edge, and a surface of the truncated land corresponds to a wrap angle that is less than a wrap angle that corresponds to, or is otherwise associated with, the each of the other or remaining lands of the main rotor.
As noted, it has been determined that an increase in the wrap angle of the main rotor, and particularly the wrap angles of the respective lands of the main rotor, results in an increase in compressor output. Advantageously, and in accordance with embodiments of the present disclosure, by increasing the wrap angle associated with the main rotor 14′ from or about 179 degrees to at least about 184 degrees, as described herein, output of compressor 10 (see
In addition, for a given compressor, the internal leakage rate will remain constant. That is, advantageously, there is no resulting additional leakage due to the main rotor having an overall increased wrap angle in accordance with embodiments of the present disclosure. Still further, for a given compressor, it has been found that the amount of the rate of leakage will decrease proportionally with the increase in the capacity or output of the compressor. Thus, in accordance with embodiments of the present disclosure, overall efficiency of a given compressor is increased along with the increased wrap angle, when compared to a compressor of the same or similar size, but using a main rotor having a smaller wrap angle.
As schematically illustrated in
The precise amount or size of the removed portion, or more generally the shape of the surface, such as surface 56, provided for in the high output land, such as land 15′, corresponds to, or can be configured to correspond to, the wrap angle that is desired. In accordance with at least some embodiments, the main rotor comprises a land that is distinct or different from the remaining lands. In at least some embodiments, the land is a truncated land having a flat or substantially flat edge or surface which permits a gate rotor designed for assembly and use with the main rotor to be assembled or otherwise positioned with respect to the main rotor. In at least some embodiments, such assembly is provided by increasing a gaterotor clearance associated with one of the grooves, particularly the groove positioned adjacent to the truncated or high output land having a reduced wrap angle.
The invention is not limited to the embodiments disclosed herein. For example, the term “wrap angle” is defined in a representative fashion and in conjunction with a representative main rotor. Further, it is appreciated that the main rotor may vary and is not limited to having threads (including grooves) of the particular geometry or shape shown and described. Similarly, it will be appreciated that the precise shape or portion of the removed portion of the main rotor can vary (and the resultant profile of the main rotor including the profile of the portion having reduced wrap angle as shown and described can vary), provided that there a reduction in wrap angle is achieved.
In accordance with at least some embodiments of the present disclosure, a single screw gas compressor is disclosed that comprises: a housing including a cylindrical bore; a pair of gate rotors mounted for rotation in the housing, each gate rotor having a plurality of gear teeth; and a main rotor rotatably mounted in the bore and having a plurality of grooves, a plurality of lands, an additional groove, and an additional land; wherein the plurality of lands of the main rotor comprises a first wrap angle and the additional land comprises a second wrap angle, and the second wrap angle is distinct and different from the first wrap angle. In at least some embodiments, the first wrap angle is greater than 180 degrees and the second wrap angle is less than 180 degrees. Further, in at least some embodiments, the first wrap angle is about 184 degrees and the second wrap angle is about 179 degrees. Further, in at least some embodiments, the additional land includes a surface that corresponds to a plane that passes through an axis of rotation of the main rotor. Further, in at least some embodiments, the additional groove is positioned adjacent the additional land and is configured to receive, by way of an enlarged opening, a respective one of the plurality of teeth of the gaterotor. Still further, in at least some embodiments, the first wrap angle is greater than 180 degrees and the second wrap angle is less than 180 degrees and, in at least some embodiments, the first wrap angle is about 184 degrees and the second wrap angle is about 179 degrees. Further, in at least some embodiments, the plurality of grooves comprises five grooves, the plurality of lands comprises five lands and, additionally, in at least some embodiments, each gate rotor includes eleven teeth. Further, in at least some embodiments, the additional land is a truncated land. And, in at least some embodiments, the additional land is a high output land.
Moreover, in accordance with at least some embodiments of the present disclosure, disclosed herein is a method of assembling a gate rotor in relation to a main rotor that is positioned within a housing of a single screw gas compressor configured for high output, the gate rotor having a plurality of gear teeth, the main rotor having a plurality of grooves, a plurality of lands, an additional groove, and an additional land. The method comprises, in at least some embodiments, positioning the gaterotor such that at least one of the plurality of gear teeth is configured to be received within the additional groove, the additional groove being positioned adjacent the additional land; wherein the plurality of lands of the main rotor comprises a first wrap angle and the additional land comprises a second wrap angle, and the second wrap angle is distinct and different from the first wrap angle. In accordance with at least some embodiments, the first wrap angle is greater than 180 degrees and the second wrap angle is less than 180 degrees and further, in at least some embodiments, the first wrap angle is about 184 degrees and the second wrap angle is about 179 degrees. In at least some embodiments, the method comprises receiving, in the additional groove, a respective one of the plurality of teeth of the gaterotor and, further, in at least some embodiments, the receiving is accomplished by way of an enlarged opening that is at least one of adjacent to and formed at least partially along with the additional groove.
In accordance with at least some embodiments of the present disclosure, a main rotor device for use with a single screw compressor configured for high output is disclosed and which comprises a main rotor body having formed therein a plurality of grooves, a plurality of lands, an additional groove, and an additional land; wherein the plurality of lands of the main rotor comprises a first wrap angle and the additional land comprises a second wrap angle, and the second wrap angle is distinct and different from the first wrap angle. In at least some embodiments, the plurality of grooves and the additional groove is operable to meshingly engage with a plurality of gear teeth of a gate rotor. Further, in at least some embodiments, the main rotor is a high output main rotor. Still further, in at least some embodiments, the first wrap angle is greater than 180 degrees and the second wrap angle is less than 180 degrees. Further still, in at least some embodiments, the plurality of grooves and the additional groove are operable to meshingly engage with a plurality of gear teeth of a gate rotor. Moreover, in at least some embodiments, the first wrap angle is about 184 degrees and the second wrap angle is about 179 degrees. Further, in at least some embodiments, meshing engagement of the additional groove and a respective one of the plurality of teeth of the gaterotor is by way of an enlarged opening. Still further, in at least some embodiments, the plurality of grooves comprises five grooves, the plurality of lands comprises five lands. And, in at least some embodiments, the additional land includes a surface, or at least a portion of a surface, that corresponds to a plane that passes through an axis of rotation of the main rotor.
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 U.S. Provisional Application No. 61/562,721, filed Nov. 22, 2011, the disclosure of which is incorporated by reference in its entirety herein.
Number | Date | Country | |
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61562721 | Nov 2011 | US |