Claims:We claim:
1. A vacuum sleeve (100) for a rotating cryostat (402) of a high temperature superconducting (HTS) synchronous machine (306), the vacuum sleeve (100) comprising:
a cylindrical body (102);
a drive end side flange (104) formed with a groove (106) at drive end side of the cylindrical body (102); and
a non-drive end flange (108) formed with a knife edge (110) and holes (112) at the non-drive end side of the cylindrical body (102).
2. The vacuum sleeve (100) as claimed in claim 1, wherein the non-drive end side flange (108) of the vacuum sleeve (100) is connected with a non-drive end side shaft (202) of the HTS synchronous machine (306) using bolts (404, 406), so as to form a conflate joint.
3. The vacuum sleeve (100) as claimed in claim 2, wherein both the non-drive end side flange (108) and non-drive end side shaft (202) have knife edges, which are indenting on a soft copper gasket during their connection.
4. The vacuum sleeve (100) as claimed in claim 2, wherein the drive end side flange (104) of the vacuum sleeve (100) is connected with a drive end side shaft (310) of the HTS synchronous machine (306) using at least two split rings (312).
5. The vacuum sleeve (100) as claimed in claim 4, wherein an O-ring (304) is placed in a groove formed on the drive end side shaft (310), before connecting the drive end side flange (104) and the drive end side shaft (310).
6. The vacuum sleeve (100) as claimed in claim 1, wherein the drive end side flange (104) and the non-drive end side flange (108) are detachably connected with shafts of the HTS synchronous machine (306).
7. The vacuum sleeve (100) as claimed in claim 1, wherein the vacuum sleeve (100) is adapted to maintain vacuum magnitude of equal to or more than 10-6 mbar in the rotor of the HTS synchronous machine (306).
8. The vacuum sleeve (100) as claimed in claim 1, wherein the vacuum sleeve (100) is made up of a non-magnetic material so as to maintain original signature of magnetic field lines in the HTS synchronous machine (306).
9. A high temperature superconducting (HTS) synchronous machine (306), comprising:
a vacuum sleeve (100) for a rotating cryostat (402) of the HTS synchronous machine (306), the vacuum sleeve (100) comprises:
a cylindrical body (102);
a drive end side flange (104) formed with a groove (106) at drive end side of the cylindrical body (102); and
a non-drive end flange (108) formed with a knife edge (110) and holes (112) at the non-drive end side of the cylindrical body (102).
10. The HTS synchronous machine (306) as claimed in claim 9, wherein the drive end side flange (104) and the non-drive end side flange (108) are detachably connected with shafts of the HTS synchronous machine (306).
, Description:VACUUM SLEEVE FOR ROTATING CYROSTAT OF HIGH-TEMPERATURE SUPERCONDUCTING SYNCHRONOUS MACHINE
TECHNICAL FIELD
[0001] The present disclosure, in general, relates to a high temperature superconducting (HTC) synchronous machine and, in particular, relates to vacuum sleeve for rotating cryostat of HTC synchronous machine.
BACKGROUND
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] High temperature superconducting (HTS) synchronous machines typically include but are not limited to, rotary generators, rotary motors, and linear motors. These HTC synchronous machines generally include a stator and a rotor that are electromagnetically coupled. The rotor may include a multi-pole rotor core and one or more coil windings mounted on the rotor core.
[0004] Recently, superconducting coils have been developed for rotors of HTS machines. The superconducting coils have effectively no resistance and are highly advantageous over conventional rotor coil windings made from copper. However, the high temperature superconducting coils are formed of ceramic based superconducting materials and required to be cooled up to or below a cryogenic temperature, so as to achieve and maintain superconductivity.
[0005] The superconducting coils are kept in cryostat and cooled using a cryocooler provided in a closed loop circuit with the cryostat. The cryostat is a chamber or apparatus in which an object is maintained at a very low temperature. The cryostat contains the super-conducting coils along with its electrical and electronic connections.
[0006] Additionally, the cryostat is enclosed within a cylindrical-shaped vacuum sleeve, in which a high degree of vacuum can be maintained, so as to reduce convective heat transfer. The vacuum sleeve is generally rigidly connected onto shafts of the HTS synchronous machines, which rigid connection restricts operational and maintenance activities required for the HTS synchronous machines.
[0007] Accordingly, there is a need for a vacuum sleeve which can be detachably connected to the shafts of the HTS synchronous machines to facilitate various advantages.
OBJECTS OF THE DISCLOSURE
[0008] Some of the objects of the present disclosure, which at least one embodiment herein satisfy, are listed hereinbelow.
[0009] It is an object of the present disclosure to provide a detachable vacuum sleeve for a rotating cryostat of a high temperature superconducting (HTS) synchronous machine.
[0010] It is another object of the present disclosure to provide a vacuum sleeve for a rotating cryostat of an HTS synchronous machine, wherein the vacuum sleeve is formed of a non-magnetic material so that it does not disturb the signature of magnetic field lines even at cryogenic temperatures.
[0011] It is yet another object of the present disclosure to obtain a vacuum of magnitude 10-6 mbar or better in a rotor of an HTS synchronous machine.
[0012] It is yet another object of the present disclosure to provide a vacuum sleeve with an optimum torsional strength which can safely transfer a portion of electromagnetic torque generated in the HTS synchronous machine to shafts and ultimately to load.
[0013] It is yet another object of the present disclosure to provide and assemble a vacuum sleeve with minimum allowable ovality and eccentricity.
[0014] It is yet another object of the present disclosure to provide a vacuum sleeve with a material having inherently low degassing characteristic under high vacuum of the order of 10-6 mbar.
[0015] It is yet another object of the present disclosure to provide a buckle-free vacuum sleeve along with flanges, where environmental atmospheric pressure outside it is l bar and inside vacuum is 10-6 mbar.
SUMMARY
[0016] This summary is provided to introduce concepts related to a vacuum sleeve for a rotating cryostat of a high temperature superconducting (HTS) synchronous machine. The concepts are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
[0017] In an embodiment, a vacuum sleeve for a rotating cryostat of a high temperature superconducting (HTS) synchronous machine is described. The vacuum sleeve includes a cylindrical body, a drive end side flange formed with a groove at drive end side of the cylindrical body, and a non-drive end flange formed with a knife edge and holes at the non-drive end side of the cylindrical body.
[0018] In an aspect, the non-drive end side flange of the vacuum sleeve is connected with a non-drive end side shaft of the HTS synchronous machine using bolts, so as to form a conflate joint. In said aspect, both the non-drive end side flange and non-drive end side shaft have knife edges, which are indenting on a soft copper gasket during their connection.
[0019] In another aspect, the drive end side flange of the vacuum sleeve is connected to a drive end side shaft of the HTS synchronous machine using at least two split rings. In said aspect, an O-ring is placed in a groove formed on the drive end side shaft, before connecting the drive end side flange and the drive end side shaft.
[0020] In another aspect, the drive end side flange and the non-drive end side flange are detachably connected with shafts of the HTS synchronous machine.
[0021] In another aspect, the vacuum sleeve is adapted to maintain vacuum magnitude of equal to or more than 10-6 mbar in the rotor of the HTS synchronous machine, and there is no considerable change in vacuum due to degassing of the vacuum sleeve.
[0022] In another aspect, the vacuum sleeve is made up of a non-magnetic material so as to maintain original signature of magnetic field lines in the HTS synchronous machine.
[0023] In another embodiment, a high temperature superconducting (HTS) synchronous machine is described. The HTS synchronous machine includes a vacuum sleeve for a rotating cryostat of the HTS synchronous machine. The vacuum sleeve includes a cylindrical body, a drive end side flange formed with a groove at drive end side of the cylindrical body, and a non-drive end flange formed with a knife edge and holes at the non-drive end side of the cylindrical body.
[0024] In an aspect of the other embodiment, the drive end side flange and the non-drive end side flange are detachably connected with shafts of the HTS synchronous machine.
[0025] Thus, with the present disclosure, the vacuum sleeve is assembled with minimum allowable ovality and eccentricity. Also, the vacuum sleeve can be multiple times detachably connected, on the requirement, to the HTS synchronous machine rotor. Further, the vacuum sleeve described herein is developed with an optimum torsional strength which can safely transfer a portion of electromagnetic torque generated in the HTS synchronous machine to shafts and ultimately to load. Also, the vacuum sleeve described herein is able to maintain mechanical integrity of complete setup and there is no sign of buckling.
[0026] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The illustrated embodiments of the subject matter will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, and processes that are consistent with the subject matter as claimed herein, wherein:
[0028] FIG. 1 illustrates an exemplary longitudinal cross-section of a vacuum sleeve, in accordance with an exemplary embodiment of the present disclosure;
[0029] FIG. 2 illustrates exemplary non-drive end side conflat joint details of the vacuum sleeve, in accordance with an exemplary embodiment of the present disclosure;
[0030] FIG. 3 illustrates an exemplary drive end side split ring details of the vacuum sleeve, in accordance with an exemplary embodiment of the present disclosure; and
[0031] FIG. 4 illustrates an exemplary assembly of a vacuum sleeve for a rotating cryostat of a high temperature superconducting (HTS) synchronous machine, in accordance with an exemplary embodiment of the present disclosure.
DETAILED DESCRIPTION
[0032] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0033] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0034] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the “invention” may in some cases refer to certain specific embodiments only. In other cases, it will be recognized that references to the “invention” will refer to subject matter recited in one or more, but not necessarily all, of the claims.
[0035] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all groups used in the appended claims.
Exemplary Embodiments:
[0036] Various embodiments are further described herein with reference to the accompanying figures. It should be noted that the description and figures relate to exemplary embodiments, and should not be construed as a limitation to the subject matter of the present disclosure. It is also to be understood that various arrangements may be devised that, although not explicitly described or shown herein, embody the principles of the subject matter of the present disclosure. Moreover, all statements herein reciting principles, aspects, and embodiments of the subject matter of the present disclosure, as well as specific examples, are intended to encompass equivalents thereof. Yet further, for the sake of brevity, operation or working principles pertaining to the technical material that is known in the technical field of the present disclosure have not been described in detail so as not to unnecessarily obscure the present disclosure.
[0037] FIG. 1 illustrates an exemplary longitudinal cross-section of a vacuum sleeve 100 for a rotating cryostat of a high temperature superconducting (HTS) synchronous machine, in accordance with an exemplary embodiment of the present disclosure. The vacuum sleeve 100 has a cylindrical body 102 with two ends, say, a drive end and a non-drive end. The vacuum sleeve 100 has different flanges at each end. For instance, a drive end side flange 104 is formed with a groove 106 for fastening slip rings, while a non-drive end flange 108 of the HTS synchronous machine is a conflat flange having a knife edge 110 and holes 112 for bolt connections.
[0038] Further, in an aspect, both of these flanges 104 and 108 are connected to the respective drive and non-drive end shafts at which drive end and non-drive end torque tubes are fastened.
[0039] FIG. 2 illustrates exemplary non-drive end side conflat joint details of the vacuum sleeve 100, in accordance with an exemplary embodiment of the present disclosure. The non-drive end side flange 108 is joined or connected with a non-drive end shaft 202 using bolts 204. In an aspect, such connection forms a conflat joint between both the non-drive end side flange 108 and the non-drive end shaft 202.
[0040] Further, both the non-drive end side flange 108 and the non-drive end shaft 202 have knife edges 110 over which a soft copper gasket 206 is disposed inside a groove. The soft copper gasket 206 is pressed/disposed against the knife edges 110 maintains the vacuum inside the HTS synchronous machine.
[0041] Yet further, as shown in FIG. 2, the non-drive end side flange 108 of the vacuum sleeve 100 is also connected with a non-drive end side flange 208 of a non-drive end side torque tube 210.
[0042] FIG. 3 illustrates an exemplary drive end side split ring details of the vacuum sleeve 100, in accordance with an exemplary embodiment of the present disclosure. The vacuum sleeve 100 has a split ring 302 and an O-ring 304 provision at the drive end side to maintain the vacuum inside the HTS synchronous machine 306. Also, a groove 308 is provided on a drive end side shaft 310 for placement of the O-ring 304. After placement of the O-ring 304, the vacuum sleeve 100 is slided over the drive end side shaft 310. In the end, two split rings 312 fastened to keep the vacuum sleeve 100 intact with respect to the drive end side shaft 310. Further, a drive end side torque tube 314 is connected to the drive end side shaft 310 by using its drive end side flange 316.
[0043] FIG. 4 illustrates an exemplary assembly of a vacuum sleeve 100 for a rotating cryostat with end shafts of a high temperature superconducting (HTS) machine rotor, in accordance with an exemplary embodiment of the present disclosure. As can be seen from FIG. 4, the superconducting coils of the HTS machine rotor are kept in a cryostat 402 along with its electrical and electronic connections. Further, two torque tubes are used to transfer the torque to load at drive end side 314 and non-drive end side 210 locations. These torque tubes are fastened with drive end side shaft 310 and the non-drive end side shaft 202 for ultimate torque transfer to load. At the non-drive end side, a conflat joint along with bolts 404, 406 is provided, while at the drive end side, the split ring 302 along with the O-ring 304 is arranged.
[0044] Thus, with the configurations described with reference to FIGs. 1-4, the vacuum sleeve 100 is made detachable, as the vacuum sleeve can be removed from the rotor shafts by unlocking bolts from non-drive end side and by removing split and O rings from the drive end side. Such detachable configuration of the vacuum sleeve 100 provides many operational and maintenance advantages to operators of the HTS synchronous machine 306. Sometimes, electrical connections need de-rusting and re-tightening for minimization of contact resistances and contact heat losses, while instrumentation/electronics connections need multiplicity and redundancy. This is made possible through the detachable design of the vacuum sleeve 100. Replacement of instrumentation sensors, touch-up of leaking weld joints, and the like, are also possible easily by disassembly of the vacuum sleeve 100. It also saves the time of breakdown or major repair considerably.
[0045] Furthermore, since the HTS synchronous machine 306 works at high flux densities, the vacuum sleeve 100 must not deteriorate the original magnetic flux profile. The mechanical integrity of the vacuum sleeve is also of utmost importance and should also be looked into with caution because the environment, where this vacuum sleeve 100 can be employed, has a steep pressure gradient from 10-6 mbar vacuum level in the HTS rotor to atmospheric pressure in the surroundings. If challenges are met holistically, the advantages can be reaped from the development of the detachable vacuum sleeve 100.
[0046] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. It will be appreciated that several of the above-disclosed and other features and functions, or alternatives thereof, may be combined into other systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may subsequently be made by those skilled in the art without departing from the scope of the present disclosure as encompassed by the following claims.
[0047] The claims, as originally presented and as they may be amended, encompass variations, alternatives, modifications, improvements, equivalents, and substantial equivalents of the embodiments and teachings disclosed herein, including those that are presently unforeseen or unappreciated, and that, for example, may arise from applicants/patentees and others.
[0048] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.