FR2522897A1 - DYNAMO-ELECTRIC MACHINE PROVIDED WITH A SCREEN FOR THE RADIANT HEAT OF ITS ROTOR AND METHOD FOR MANUFACTURING SUCH A SCREEN - Google Patents

Abstract

THE INVENTION RELATES TO A SUPRA-CONDUCTION GENERATOR INCLUDING A SCREEN FOR RADIANT HEAT FORMED BY EXPLOSION WELDING OF AN OUTER TUBE 12 AROUND AN INSIDE TUBE 10 INCLUDING COOLING CHANNELS AT ITS OUTER CYLINDRICAL SURFACE. THESE CHANNELS ARE FILLED WITH A SUBSTANCE THAT CAN BE ELIMINATED BEFORE EXPLOSION WELDING OF THE TWO PIPES AND THEN ELIMINATED.

Description

dynamo-electric machine equipped with a screen for the radiant heat of

  its rotor and method of manufacturing such a screen. the present invention relates to a machine

  dynamo-electric, in particular, to a general-purpose rotor

  superconductive ratrix and concerns more specifically-

  its screen for radiant heat.

  In general, a superconductive generator

  has a super-cooled rotor that includes a coil

  superconductive inducer and a structure for sup-

  wear The winding The rotor is super-cooled to a cryogenic temperature by a corded refrigerant

  1 O of the helium contained in the rotor During operation

  nonrmal generator, Liquid helium in the

  rotor is transformed into vapor or gas by a boil

  relatively slow but continuous.

  The function of the screen for radiant heat is to intercept the heat radiated by the environment

  of the rotor which is generally at the temperature ax-

  biante, in order to prevent this radiated heat from heating up

  the cryogenic cold zone in the rotor A screen can

  radiant heat generally consists of a structure

  tubular or cylindrical structure arranged radially to the ex-

  inside of the superconductive windings of the rotor This tubular structure is provided with several channels of coolant with a device so that the refrigerant passes radially in the screen for radiant heat, crosses it axially and leaves through another

  radial passage to the inner part of the rotor above

  conduction US Patent No. 4,250,118 describes screen designs for radiant heat. An object of the invention is therefore to propose

  a screen for radiant heat intended for a generation

  superconductive ratrix, which is designed to be manufactured

  safe but economical.

  In a normal superconducting generator, the dimensions of the screen can exceed> 300 mm in length and 7 i O mm in diameter and, since the screen must be cooled by several channels of agent

  cooling located inside its cy-

  lindrique, these design parameters impose essential

  tie Llement that it be made in two shells The assembly of these two coaxial shells must form

  a network of effective coolant channels-

  waterproof, and should not deform the screen or weaken

blir its structural integrity.

  According to the invention, a dynanoelectric machine comprises a screen for radiant heat constituted by an inner tube with several axia Les grooves to

  its outer cylindrical surface, this inner tube

  taking a first and a second circumferential groove

  tial at its outer cylindrical surface, the first circumferential groove being in communication for the fluids with an axial end of each of the axial grooves, the second circumferential groove being in communication for the fluids with the other axial end of each of the axial grooves, the inner tube comprising at least one radial hole opening into each

  circumferential groove and establishing communication

  tion for the fluid between the associated circumferential grooves and the inner surface of the inner tube an outer tube being disposed around the inner tube, coaxially or concentric with it, this outer tube being exploded on the inner tube along

  of their adjacent cylindrical surfaces.

  A screen for the heat ray-

  born, produced according to the invention, comprises a cylindrical tube

  that inside and an outside cylindrical tube, associated

  coaxially or concentrically The inner tube

  has two circumferential grooves formed at its top

  outer cylindrical face These two circumferential grooves

  are formed on the inner tube at a distance

  predetermined axial tension from each other Several axially arranged grooves are formed on the surface

  cylindrical outer of the inner tube, each rai-

  axial groove meeting and connecting the two grooves

  circumference The above mentioned Each circumferential groove

  also has at least one radial hole which opens into it and which establishes a communication for the fluid between it and the inner part of the tube

  inside An outside cylinder is arranged radia Le-

  lies outside the inner tube and is metallurgically welded to the inner tube to form

  a unitary screen structure for the radiant heat

  The outer tube encloses the outer part radially of each of the above-mentioned grooves and forms

  therefore a closed network of coolant channels

  which in turn establishes communication for fluids between the radial hole which meets one of the circumferential grooves and the radial hole which

  meets the other circumferential groove L Le.

  Preferably, according to the invention, the tube

  inner tube and outer tube are welded together by explosion In order to avoid potential sagging of the outer tube in the grooves of the inner tube

  during the explosion welding operation, the grooves

  res can be filled with a substance which can be removed before the explosion welding operation in order to provide local support for the outer tube during welding. Depending on the relative thicknesses of the inner tube and the outer tube, the use of this substance May not be necessary But to ensure that no subsidence occurs in the region of the aforementioned grooves, a screen for the radiant heat produced according to the invention comprises, within its framework,

  a solid material which can be placed in the rai-

  which can be eliminated after the end of the sou-

  exploding This substance can be fusible, like a low-melting meta L, or sulfur, or combustible like polystyrene Experiments have been done using a low melting alloy, Cerrotru, which can be melted and eliminated from cooling channels after Explosion welding operations Similarly, embedded steel parts

  have been used to provide lo-

  cal in the region of the cooling channels and were subsequently eliminated by attack with an acid Of course, i L is obvious that this technique of attack by an acid is only possible if the tubes constituting

  The screen to radiation heat resist.

  acid as is the case When Inconel 706 or Inoonel 718 is used for manufacturing After having provided the Localized support mentioned above, the fusible, attackable or combustible substance is eliminated by the

the aforementioned radial holes.

  The invention therefore relates to a screen for the cha-

  their radiant with good contact between surfaces

  adjacent to the inner tube and the outer tube, assu-

  rant excellent thermal conductivity between them and avoiding leakage of coolant between

  adjacent axial grooves or between the network of ca-

  cooling environment and its environment, which is

usually under vacuum.

  Before assembling the inner tube and the outer tube can be initially oversized S so

  that they can be machined exactly to the dimension you want

  read after the explosion welding operations Mime, the radial holes can be machined again

  after explosion welding to correct defects

  minor formations appearing during the operation of

metallurgical welding.

  Other features and advantages of the

  vention will appear during the description which goes

  follow from an exemplary embodiment and with reference to the appended drawing in which FIG. 1 represents a partial section Le of a screen for radiant heat, and FIG. 2 is a cross section of 1 '

screen of Fig 1.

2522897

  The present invention relates generally

  nera Le with superconducting rotors and more particularly

  rement, to the manufacture of a screen for heat

  radiant, used with such a rotor.

  FIG. 1 therefore represents a screen for radiant heat It has an inner tube 10 and

  an outer tube 12, arranged coaxially and concentrated

  The inner cylindrical tube 10 has

  a first circumferential groove 14 and a second

  of circumferential groove 16 formed on its outer cylindrical surface Several axial grooves

  18 meet these circumferential grooves and

  communicate between them for fluids.

  The circumferential groove 14 has a radial hole 20 which opens therein and which establishes a communication for the fluids between it and the lower part of the inner tube 10 The second circumferential groove 16 has a radial hole 22 which opens therein and which establishes

  communication for fluids between it and the

  inner tie of the inner tube 10 The combination of the first and second circumferential grooves 14 and 16 with the axial grooves 18 and the radial holes 20 and 22 establishes communication for the fluids between the inner part of the inner tube 10 adjacent to the radial hole 20 and the inner part of the inner tube 10

  adjacent to the radial hole 22 The inner tube 10 and the tu-

  be exterior 12 are made of a material of great rigi-

  dity, as one of those called superalloys which have an elastic limit sufficient for the use in superconduction These materials include, without limitation, those known by their brand name as Inconel 706 and Inconel 718 fa material used must have a elastic limit equal to or greater than 90 da N / mm 2 and maintain its rigidity at cryogenic temperatures

about 4 K.

  The outer tube 12 is welded by explosion to the inner tube l O to form an outer seal

  radiaiewent for the above-mentioned nirconferential grooves-

252 289 7

  6- The 14 and 16 and axial 18 -This arrangement forms a

  network of cooling channels leading to a

  liquid or gaseous fermenting between elements which are dis-

  placed inside the inner tube 10 near the radial hole 20 and other elements arranged in the

  inner tube 10, near the radial hole 22.

  Before the outer tube 12 is welded by

  explosion on the inner tube 10, the circumferential grooves

  and 14 and lb and the axial grooves L 8 can be filled with a substance to prevent the outer tube 12 from collapsing locally in the grooves

  on the outer surface of the inner tube O 10 Well understood

  of, this substance must be able to be eliminated after the explosion welding operation A screen for

  radiant heat produced according to the invention can use

  read a fuse like low point metal

  or sulfur, or a combustible substance-

  like polystyrene I 1 has been found to be a weak alloy The melting point like Cerrotru

  even carbon steel was used experimentally-

  ment for local support and it has been 6 eliminate 6

  then by an acid The attack by an acid is not pos-

  only if the inner cylinder l O and the cylinder ex-

  12 are made of a material that resists Pacide

  such as Inconel 706 or lnconel 718 These specific substances

  fiques or others that can be eliminated assure a-

  local support for the outer cylinder 12 in the re-

  grooves at the outer cylindrical surface of the

  inner tube 10 during the welding operation e.g.

  plosion, and are then eliminated by the radial holes

or 22 after this operation.

  The explosion welding of the inner tube 10 and the outer tube 12 together forms a safe seal for fluids in the outer axial and L JO regions.

  and 32 which lie between the circumferential grooves-

  14 and 16, and the environment, and also form an asr seal for fluids in regions 40 between

the adjacent axial channels 18.

  Figure 2 is a section of the screen of La

  Figure 1 showing the inner tube 10 and the tulle ex-

  12 E It also shows the radial positions

  relative of the axial grooves 18 and of the circular groove

  14 It appears that the radial hole 20 opens into the circumferential groove 14 and establishes a communication for the fluids between the latter and the inner part of the inner tube 10 Fig 2, together with Fig 1 shows how an agent

  cooling can circulate radially towards the ex-

  térieur by the radial hole 20, circumferentially au-

  inner tube turn in the circumferential grooves-

  the 14, axially between the inner tube 10 and the outer tube 12 in the channels 18, circumferentially around the circumferential channel L 6 and radially towards

  the interior through the radial hole 22, thus forming a

  bucket for the coolant circulating in it, for

  reduce the screen temperature for the heat ray-

nante.

  Coming back to Fig 1, it is well-

  tight that a tight weld could also be provided on the contact surface of the inner tube 10 and the tube

  outside 12, at their axial ends 50 in order to pre-

  see additional safety measure for water

  fluidity between the cooling channel network

  display and the environment of the screen which is generally

  It is understood that in most applications, the explosion welding of

  inner tube 10 and outer tube 12 provides tightness

  sufficient fluidity in the regions 30 and 32 between the circumferential grooves and the environment of the screen, so that the aforementioned sealed weld

  is generally not necessary.

  It thus appears that the invention relates to a screen for radiant heat intended for a rotor with

  superconduction, which is mechanically rigid and which con-

  maintains a cooling network.

Claims (8)

CLAIMS 1, dynamo-electric machine, characterized in that it has a screen for radiant heat comprising an inner tube (o 10) with axial grooves (L 8) on its outer cylindrical surface, j Said tube interior having first and second circumferential grooves (14, 10) as an external cylindrical surface, said first circumferential groove being in communication for fluids with an axial end of each of said several axial grooves, said second circumferential groove being in communication for the fluids with the other axial end of each of said several axial grooves, said inner tube comprising at least one radial hole (20, 22) opening towards each circumferential groove-   1 day and establishing communication for fluids   be its circumferential groove associated therewith and the inner surface of said inner tube, and an outer tube (12) disposed around said inner tube, coaxially and concentrically with it, said outer tube being explosion welded to said inner tube along   their cylindrical surfaces ad Jacentes.   2 Machine according to claim 1, charac-   terized in that said grooves (14, 16, 18) are filled with a substance which can be removed before said outer tube is welded by explosion to said inner tube.   3 machine according to claim 2, charac-   terized in that said eliminable substance is eliminated by a predetermined one of said radial holes (20, 22).   4 lachine se Lon any of the res-   dications 1 to 3, characterized in that it includes a   superconduction rotor, said rotor comprising a pre-   mier tube (l O) with two circumferential grooves Lles (1 s, 3 j I) on its outer cylindrical surface, said circumferential grooves being disposed at a predetermined axial distance from each other, said first tube comprising several axial grooves (l 8) on its outer cylindrical surface, each of which comprises several axial grooves opening into each of said two   circumferential grooves L Les and establishing a joint   cation for fluids between said two circumferential grooves, a second tube (l 2) arranged around said first tube, coaxially with it, said second tube being welded by explosion to said first tube, and said first tube having a radial hole (20, 22)   opening into each of said circumferential grooves   and establishing communication for fluids between each of said circumferential grooves and La   inner part of said first tube.   Machine according to claim 4, character-   in that said circumferential grooves (14, 16) and said axial grooves (i S) are filled with a substance capable of preventing said second   tube is deformed in said circumferential grooves   axial and axial when said second tube is welded by   explosion on said first tube, said substance could   before being eliminated by a predetermined one of said radial holes.   6 'lachine according to claim 5, character-   laughed in that said substance is selected from a group comprising a metal with a low melting point, Or polystyrene or sulfur, or a material susceptible to be attacked by an acid.   7 Method of manufacturing a screen for the radiant heat of a superconductive generator, method characterized in that it essentially consists in preparing a first tubular part (10), to be formed   two circumferential channels (l 4, lb) on the cy-   the outer lindric of said first tubular part, said circumferential channels being positioned at a predetermined axial distance from each other, at   form several axial channels (l 8) in the cy-   the outer lindric of said first tubular part each of said several axial channels opening into each of the two circumferential channels and establishing communication for the fluids between said two circumferential channels, to form two radial holes (20, 22) through the wall of said first part you-   bular, One of the two holes opening into one prede-   finished of said two circumferential channels, and the other of said two holes opening into the other of said two circumferential channels, having a second tubular part (12) around said first tubular piece   and coaxially with it, and to explosion weld them-   say first and second tubular parts together.   8 Method according to claim 7, character-   laughed in that Oil further consists of filling said axial (18) and circumferential (14, b 16) channels with a   substance that can be removed before the operation   by explosion and to eliminate said substance which may   be eliminated after said welding operation e.g. plosion -   9 Method according to claim 8, character-   laughed at in that it further consists in eliminating said sub-   stance can be eliminated by a predetermined one of- called two radial holes.   A method according to any of the res-   dications 7 to 9, characterized in that the said substance is chosen from a group comprising a substance with low   melting points, or combustible, or capable of being eliminated-   born with an acid, or sulfur or polystyrene.