EP0049691A2 - Erdbebensicheres Abstützungsgitter für Rohre - Google Patents

Erdbebensicheres Abstützungsgitter für Rohre Download PDF

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Publication number
EP0049691A2
EP0049691A2 EP81830152A EP81830152A EP0049691A2 EP 0049691 A2 EP0049691 A2 EP 0049691A2 EP 81830152 A EP81830152 A EP 81830152A EP 81830152 A EP81830152 A EP 81830152A EP 0049691 A2 EP0049691 A2 EP 0049691A2
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EP
European Patent Office
Prior art keywords
strips
earthquake
fact
support grid
slots
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EP81830152A
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English (en)
French (fr)
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EP0049691A3 (de
Inventor
Vincenzo Soligno
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Individual
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Individual
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Publication of EP0049691A2 publication Critical patent/EP0049691A2/de
Publication of EP0049691A3 publication Critical patent/EP0049691A3/de
Ceased legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F9/00—Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
    • F28F9/007—Auxiliary supports for elements
    • F28F9/013—Auxiliary supports for elements for tubes or tube-assemblies
    • F28F9/0135—Auxiliary supports for elements for tubes or tube-assemblies formed by grids having only one tube per closed grid opening
    • F28F9/0136—Auxiliary supports for elements for tubes or tube-assemblies formed by grids having only one tube per closed grid opening formed by intersecting strips

Definitions

  • the invention proposes new and original technical solutions of the structure of a support grid for tubes of steam generators, heat exchangers and the like, as to solve the problem of the reliability and of the safety of such a support, problem which is acquiring more and more importance and which is urging more and more the manufacturers and the users of such supports, especially as concerns their use for the support of the tubes in nuclear steam generators of P. W. R. type, that is of pressure water reactor;
  • the international rules, particularly the USA ones, concerning nuclear safety prescribe that the apparatus used in a nuclear power plant have to be so designed as to withstand the dynamic stresses to which they can be subjected when occurs the highest grade seismic event together with the greatest accident, such as the burst of a pipe of the steam generator primary circuit.
  • the said forces can stress a group of tubes of the local zone of the tube bundle, where the said forces burst out and by acting on the supports of the said tubes can cause the permanent deformation of the same and consequently the tube cracking and the burst of the same with the outflow of radioactive water and consequent heavy damages to the nuclear power plant and to the operation personnel.
  • the present invention proposes new and original solutions for the stiffening of the reticular structure, of the connection of the said reticular structure with the external frame and for the stiffening of the same external frame.
  • the present invention proposes the stiffening of the reticular structure through a non axially sliding coupling (that is according to the strip axis) between secondary strips and main strips, the stiffening of the strip-frame joint by adopting special mechanical blocking joints (that is of the non sliding type) between the ends of the said strips and the said frame, and the stiffening of the same frame by adopting original constructive solutions which greatly improve the stiffening of the above frame and of the support of the reticular structure on the said frame.
  • the present invention proposes different embodiments for the manufacturing of an earthquake-proof support grid principally used for the support of the tubes in nuclear steam generators type PWR, the said embodiments all having as aim the problem solution of the tearing or the extracting of the strips' ends from the external frame and of the deformation of this under the action of external forces acting inside the structure of the strips.
  • the invention proposes the increase of its stiffness by connecting with a non-sliding joint all secondary strips or only some of them (according to the stiffness requirements of the said structure) with portions of main strips, at the intersecting zones with the same.
  • the said joining is obtained with slots in above-said secondary strips at the said intersection zones, the above said slots having a height equivalent to about 1/5 or 1/6 of the strips height and adapted to receive without clearance portions of main strips.
  • Different construction versions of the said reticular structure are possible with different quantity combinations of main strips with slots and of the secondary strips with or without joining slots.
  • the reticular structure of the support grid can be stiffened in comparison with the well-known conventional ones (for example in comparison with the one described in the Canadian patent n. 1022410 allowed to the same applicant of the present invention) by adopting a combination which uses a quantity of main strips equal to 1/6 of the total amount of all strips and a quantity of secondary strips having interengaging slots with the main ones equal to 5/6 of the total amount in all those cases where the calculation of the reticular structure requires the maximum stiffness, obviously for particular dimensions of the strips.
  • the invention proposes a quantity of secondary strips with interengaging slots joining with the main ones equal to 2/6 of the strips total and a quantity of the secondary strips without the said slots equal to the remaining difference and i. e. equal to 3/6 of the strips total.
  • the height of the secondary strip with slots is equal to the sum of the height of the secondary strip without slots and of the height of the slots.
  • the present invention proposes some construction versions which completely solve the problem of the tearing that is of the drawing out of the strips' ends from the frame under the action of external forces acting inside the structure of the said strips, either at room temperature, or at operative temperature.
  • the invention proposes a joint with constant thickness and variable height.
  • a thickness of the strips of about 6 - 10 mm. or more the choice, according to the invention, can fall on both construction types, that is either on the type with constant thickness and variable height, or on the type with variable thickness and constant height, according to the economic convenience of the pertinent mechanical machining and of the external frame machining.
  • the present invention proposes some construction embodiments for the stiffness of the external frame, embodiments which confer a raised stiffness to the same, either cold or hot, in comparison with the well-known conventional solutions, either in the case that the said frame is formed of materials having the same coefficient of thermal expansion of the grid strips, or in the case that the said frame is formed of an internal frame formed of material having the same coefficient of thermal expansion of the strips and of an external frame formed of material having a lower coefficient of thermal expansion than that of the strips.
  • the increased stiffness of the support grid frame in comparison with the well-known conventional support grids is guaranteed, according to the present invention, by new and original solutions concerning the structure of the said frame, structure that is extending generally axially in order not to narrow the useful passage section of the tubes of the steam generator or heat exchanger through the grating of the support grid.
  • the stiffness of the external frame, according to the invention, can also be increased by the assembling with a tight fit of the various elements forming the same.
  • Substantially the frames built with materials having the same coefficient of thermal expansion of the strips have a compact structure generally formed of three rings (two of which generally structurally alike) enclosing without clearance the strips-frame joints and an annular portion of the reticular structure adjacent to the joint itself as to transmit the external forces (which act in accordance with the axis of the tube bundle) directly to the external frame and not through the strips-frame joint, avoiding in this way the fatigue stresses of the said joint and assuring to the same a long life.
  • the frames built with materials having different coefficient of thermal expansion are formed, according to the present invention, of 5 rings, 3 rings of which for the compact internal frame enclosing without clearance the strips-frame joints and an annular external portion of the reticular structure adjacent to the joint itself and two rings for the external frame enclosing with radial clearance (as to allow the differential thermal expansion between the various elements) the internal frame.
  • the present invention proposes furthermore two construction versions, one solution with axial holes passing in all 5 rings (the said holes used, some for the passage of the peripheral tension rods of axial fixing of the grids' group to the tube plate of the steam generator, and others for the passage of the spacers and of the tension rods locking the external frame) and one solution with the said holes passing only through-the two rings of the external frame.
  • Fig. 2(1). 2(1'), 2(2), 2(2') each represents a typical tern of three different types of lower and upper strips having at each end a non-sliding connection, according to the invention, with variable section, with constant thickness and variable height. respectively in the shape of dovetail fig. 2(1), half-dovetail fig. 2(1'), hammer-head fig. 2(2), half-hammer-head fig. 2(2').
  • Fig. 2(3), 2(3'), 2(4), 2(4') each represents a typical tern of three different types of lower and upper strips, having at each end a non-sliding connection, according to the invention, with variable section, with constant height and variable thickness, respectively in the shape of dovetail fig. 2(3), half-dovetail fig. 2(3'), hammer-head fig. 2(4), and half-hammer-head fig. 2(4').
  • Fig. 2(5) represents a typical tern of three different types of lower and upper strips, having at each end a non-sliding connection, with variable section, with constant thickness and constant height, with central hole for the insertion of a locking pin in the said connection.
  • Fig. 3 represents schematically a partial view of a nuclear steam generator of a P. W. R. reactor in a typical cross-section to which the present invention applies.
  • Fig. 4 represents in a larger partial plan view and in a partial horizontal section the upper and intermediate zone of the typical components of the annular frame of the earthquake-proof support grid.
  • Fig. 5 represents in a larger partial plan view and in a partial horizontal section the lower and intermediate zone of the said typical components of the annular frame of the earthquake-proof support grid.
  • Fig. 6(1), 6(1'), 6(2), 6(2') each represents the perspective exploded view of a typical pair, according to the invention, of lower and upper slots with variable section, with constant width and variable height. formed in the annular frame for the fitting respectively of the said connections of the strips with constant thickness and variable height, in the shape of dovetail fig. 6(1), half-dovetail fig. 6(1'), hammer-head fig. 6(2). half-hammer-head fig. 6(2').
  • Fig. 6(3), 6(3'), 6(4), 6(4') each represents the perspective exploded view of a typical pair, according to the invention, of lower and upper slots with variable section, with constant height and variable width, formed in the annular frame for the fitting respectively of the said connections of the strips, with constant height and variable thickness, in the shape of dovetail fig. 6(3), half-dovetail fig. 6(3'), hammer-head fig. 6(4), half-hammer-head fig. 6(4').
  • Fig. 7(1), 7(1'), 7(2), 7(2') each represents a perspective exploded view of a typical pair, according to the invention, of connections with variable section, with constant thickness and variable height, of the ends of the lower and upper strips, respectively in the shape of dovetail fig. 7(1), half-dovetail fig. 7(1'), hammer-head fig. 7(2), half-hammer-head fig. 7(2').
  • Fig. 7(3), 7(3'), 7(4), 7(4') each represents a perspective exploded view of a typical pair, according to the invention, of connections with variable section, with constant height and variable thickness, of the ends of the lower and upper strips having the profile respectively in the shape of dovetail fig. 7(3), half-dovetail fig. 7(3'), hammer-head fig. 7(4), half-hammer-head fig. 7(4').
  • Fig. 8 represents the exploded cross-section VIII-VIII of Fig. 1, in order to show the typical assembling between a tube support grid and the shell 500 wherein are mounted and spaced the various support grids.
  • This figure 8 shows the well-known spacers 600 between any two grids for the axial positioning of the same and the well-known wedges 700 for the radial positioning of each support grid.
  • Fig. 8(1), 8(1'), 8(2') each represents a perspective view of a typical section, according to the invention. of the lower and upper annular chambers of the annular frame for the fitting of the said connections . of the ends of the strips and of the spacers between the said connections, the said chambers having the profile of the vertical section respectively in the shape of dovetail fig. 8(1), half-dovetail fig. 8(1') and half-hammer-head fig. 8(2').
  • Fig. 9(la) and 9(2a) each represents a typical section, according to the invention, F(x)-F(x) of Fig. 1 and refers to the execution of the annular frame of the 3 rings support grid with the said lower and upper inner annular chambers having the profile of the vertical section respectively in the shape of dovetail fig. 9(la), half-dovetail according to the interrupted line of fig. 9(la) and half-hammer-head fig. 9(2a).
  • Fig. 9(lb) and 9(2b) each represents a typical section F(x)-F(x) of Fig. 1 and refers to the execution of the annular frame of the 5 rings support grid, according to the invention, 3 intermediate rings of which forming the intermadiate frame and 2 external rings forming the external annular frame formed of material having lower expansion coefficient than the intermediate frame, the said intermediate frame having in the inner zone the said lower and upper annular chambers, the vertical section of which has a profile respectively in the shape of dovetail fig. 9(lb), half-dovetail according to the interrupted line of fig. 9(lb) and half-hammer-head fig. 9(2b).
  • Fig. 9(lb') and 9(2b') each represents an alternative solution to the one illustrated respectively in the figures 9(lb) and 9(2b) and concerns the execution of the annular frame with 5 rings with axial holes (for the passage of the tension rod 200 fixing the support grid to the tube-plate of the steam generator and of the peripheral tension rods 800 locking the annular frame) formed in the two external rings instead in the 5 rings as in figures 9(lb) and 9(2b).
  • Fig. 9(la') and 9(2a') each represents a typical section F(x)-F(x) of Fig. 1 and refers to the execution of the 3 rings annular frame with lower and upper milled axial slots, with variable section, with constant width and variable height, formed in the intermediate ring and having the profile respectively in the shape of dovetail fig. 9(la'), half-dovetail according to the interrupted line of Fig. 9(la'), hammer-head fig. 9(2a') and half-hammer-head according to the interrupted line of fig. 9(2a').
  • Fig. 9(3a') and 9(4a') each represents a typical section of the said intermediate ring in an execution in alternative to the one illustrated respectively in figures 9(Ia') and 9(2a'), with lower and upper milled axial slots with variable section, with constant height and variable width, formed in the said intermediate ring and having the profile respectively in the shape of dovetail fig. 9(3a'), half-dovetail according to the interrupted line of fig. 9(3a'), hammer-head fig. 9(4a') and half-hammer-head according to the interrupted line of fig. 9(4a').
  • Fig. 10 represents a typical vertical section of the intermediate ring in the execution of the 3 rings annular frame of fig. 9(2a) as well as in the 5 rings execution of fig. 9(2b), 9(2b').
  • Fig. 11(3), 11(4) each represents a typical horizontal section M(x)-M(x) of the intermediate ring of Fig. 10 and refers to the execution of the annular frame in alternative to the one represented in fig 9(la), 9(lb), 9(lb'), 9(2a), 9(2b) and 9(2b'), with lower and upper slots, delimited by spacers with variable section, with constant height and variable width, having the profile respectively in the shape of dovetail fig. 11(3), half-dovetail according to the interrupted line of fig. 11 (3), hammer-head fig. 11 (4) and half-hammer-head according to the interrupted line of fig. 11(4).
  • Fig. 11(5) represents a vertical section and a typical plan view of the annular frame containing the connections of the ends of the strips of the pin type represented in fig. 2(5), in variant to the execution with 3 and 5 rings represented in fig. 9(la), 9(lb), 9(1b'), 9(2a), 9(2b), 9(2b'), the said variants referring only to the pin connection of the ends of the strips and to the type of spacers between the said connections.
  • Fig. 12(la') and 12(2a') each represents a typical vertical section and a partial plan view of the intermediate ring represented respectively in fig. 9(la') and 9(2a').
  • Fig. 13(lb), 13(1b'), 13(2b) and 13(2b') each represents the components of the earthquake-proof support grid, according to the invention, in an exploded view and refers to the 5 rings execution of the annular frame respectively represented in fig. 9(lb) for the fig. 13(lb); 9(lb') for the fig. 13(lb'); 9(2b) for the fig. 13(2b) and 9(2b') for the fig. 13(2b').
  • Fig. 25(1), 25(1'), 25(2), 25(2') represent in a vertical section according to a plan parallel to the strips and in a lateral view the shaped lower spacers between the connections with constant thickness and variable height of the ends of the lower strips, respectively fig. 25(1) represents the lower spacers of the dovetail type 25'(1); the fig. 25(1') the lower spacers of the half-dovetail type 25(1'); the fig. 25(2) the lower spacers of the hammer-head type 25'(2) and the fig. 25(2') the lower spacers of the half-hammer-head type 25(2').
  • Fig. 26(1), 26(1'), 26(2), 26(2') represent the shaped upper spacers between the connections with constant thickness and variable height of the ends of the upper strips; respectively the fig. 26(1) represents the upper spacers of the dovetail type 26'(1); the fig. 26(1') the upper spacers of the half-dovetail type 26(1'); the fig. 26(2) the upper spacers of the hammer-head type 26'(2) and the fig. 26(2') the upper spacers of the half-hammer-head type 26(2').
  • Fig. 26(3), 26(4), 26(5) represent the vertical section V-V according to a plan parallel to the strips respectively of the lower spacers and of the upper spacers represented in the fig. 11(3), 11 (4), 11(5); respectively the fig. 26(3) represents the spacers of the dovetail type, lower spacers 25(3), upper spacers 26(3) and of the half-dovetail type lower spacers 25(3'), upper ones 26(3') ; the fig. 26(4) represents the spacers of the head-hammer type - lower ones 25(4), upper ones 26(4) and of the half-hammer-head type, lower ones 25(4'), upper ones 26(4'); the fig. 26(5) represents the spacers of double "I" type , lower ones 25(5) and upper ones 26(5), between the connections of the ends of the locking pin type strips.
  • Fig. 26(3'), 26(4') represent the horizontal section 0-0 of the spacers of the type respectively half-dovetail 25(3'), 26(3') and half-hammer-head 25(4'), 26(4') represented respectively in the fig. 26(3) and 26(4).
  • Fig. 27(5) represents in section and in view the locking pin 107 inserted in the hole 106 of the connection of the ends of the locking pin type strips.
  • the reticular structure of the earthquake-proof support grid has been diffusely illustrated at the beginning of the present description as concerns the stiffness of the said structure.
  • Fig. 2 clearly shows the different types of lower and upper strips - forming the said reticular structure.
  • the main lower 1(x) and upper 2(x) strips have the main slots 19 equally spaced having a depth equal to the half of the strip height.
  • the said slots 19 are necessary for the engagement of the main lower strips with the upper ones at the intersecting zones. Between the said main slots 19 are obtained the secondary slots 20 equally spaced for the fitting of the secondary lower 3(x), 5(x) and upper 2(x), 4(x) strips.
  • the said slots 20 have a depth generally equal to 1/3 - 1/4 of the height of the main strip.
  • the secondary lower 3(x) and upper 4(x) strips have also slots 21, according to the invention, equally spaced, with distance equal to the distance existing between the slots 19 of the main strips.
  • the said slots 21 have a depth equal to 1/4 - 1/6 of the height of the said secondary strip 3(x), 4(x) and are provided for the engagement of the said strips with corresponding portions of main strips, at the intersecting zones therebetween, according to the invention, in order to stiffen considerably the reticular structure.
  • the height of the said secondary strips 3(x) and 4(x) with slots 21 is equal, according to the invention, to the sum of the height of the secondary strips 5(x), 6(x) without slots and of the depth of the said slots 21.
  • connection 1 For example, by combining the connection 1 with the annular frame a the support grid of type la is obtained; by combining the connection 1 with the annular frame a' the support grid la' is obtained and the same applies to the supports 1b and Ib'; the same for the connections 1' which in combination respectively with the annular frames of type a, a', b, b', leads respectively to the support grids 1'a, 1'a', 1'b, 1'b'.
  • construction types of connections of the ends of the strips, except the locking pin type are 8 and the alternative solutions of the annular frame are 4, it is possible to get 32 different construction types for the earthquake-proof support grid.
  • connection type 5 of the end of the strips - with the central hole 106 and locking pin 107 with the three construction solutions of the annular frame a, b and b' enclosing the said connections and the spacers therebetween, it is possible to obtain three other different types 5a, 5b, and 5b' of the earthquake-proof support grid and therefore in all it is possible to get n. 35 different construction types of the support grid. These 35 different support grids, if adequately dimensioned, will be all suitable to withstand, in more or less measure, according to the project requirements, the intense mechanical stresses, which can be caused by seismic event, combined with mechanical stresses that can be caused by localized overpressures which are contemporaneous and consequent to the said seismic event.
  • the choice of any one of the 35 different construction types of the earthquake-proof support grid depends on the different requirements of dimensioning and stiffening of the single components and on the support assembly, on the space availability, on the materials used, particularly as concerns the coefficient of thermal expansion of the same, as well as on the economy requirement of the manufacture in relation to the availability of adequate shop equipment and on the mounting requirements of the assembly of the said support grid.
  • the different components represented in the different illustrative figures have been indicated with a number followed by an index determinating the construction type; for example the connection of the end of the lower strips of the dovetail type 7(1) is indicated with the number 7 which refers to the connection of any lower strip followed by the index 1 in parentheses that specifies the connection type and i. e.
  • the number 7 indicates the component i. e. the connection of any lower strip and the x in parentheses indicates any construction type of connection which can be 7(1), 7(2), 7(3), etc.
  • 23(x) indicates the lower slots obtained by milling in any central ring 31(x) of any annular frame of type a' for the fitting of the connections 7(x) of the ends of the lower strips 1(x), 3(x), 5(x); furthermore the same marking 23(x) designates the lower closed slots delimited by the lower spacers 25(x), by the central ring 31 (x) and by the lower ring 33 (x) of any annular frame of the construction type a, b and b'; the said slots 23(x) are suitable to receive and to put in position the said connections 7(x) of the ends of the lower strips 1(x), 3(x), 5(x).
  • the numbers 13 and 14 individualize the free ends of the connections respectively of the ends of the lower strips 7(x) and of the upper strips 8(x); a further example, the number 309 marks the inside diameter of any ring 31 (x), the said diameter aligned with the roots 9 and 10 respectively of the connections of the ends of the lower strips 7(x) and of the upper strips 8(x) and the number 313 marks the intermediate or outside diameter of any ring 31 (x) generally aligned with the ends 13 and 14 respectively of the connections of the ends of the lower strips 7(x) and of the upper strips 8(x).
  • construction types l'a, 2'a, 3'a, 4'a are marked respectively in the figures mentioned with interrupted line only for those components, the geometric configuration of which is to be modified in order to adapt the profile of the said components to the profile of the connection respectively of half-dovetail type 7(1'), 8(1'), 7(3'), 8(3') and of half-hammer-head type 7(2'), 8(2'), 7(4'), 8(4') of the ends of the strips.
  • the invention proposes one sole central ring 31 (la), 31(2a) with an inner central flange 310, having smaller thickness 311 at the root 313 of the said flange and greater thickness 312 at the free end 309 of the said flange.
  • the inner lower and upper surface of the said sole ring 31 (la), 32(2a) is shaped according to the profile of the outline delimited respectively by the sides 9, 11, 13 of the connection 7(x) of the ends of the lower strips and/or the profile of the spacers 25(x) therebetween and by the sides 10, 12, 14 of the connection 8(x) of the ends of the upper strips and/or the profile of the spacers 26(x) therebetween.
  • the annular frame 30(a) of the construction types above mentioned is - substantially formed of 3 rings, the central one of which 31(la) and 31 (2a) has been already previously described.
  • cover-rings respectively lower one 33(a), 33(la) and upper one 32(a), 32(la), have a geometric configuration substantially equal.
  • the said annular chambers are formed respectively of the spaces enclosed by the central ring 31(la), 31(2a) and by the lower cover-ring 33(a), 33(la) and by the upper cover-ring 32(a), 32 (1a) overlapped to the said central ring and to external annular zones 17, 18 respectively of the lower and upper reticular structure adjacent respectively to the connection 7(x), 8(x).
  • the said cover-rings 33(a), 33(la) and 32(a), 32(la) have the inside diameter respectively 339 and 329 smaller than the inside diameter 309 of the flange 310 of the said central ring 31 (la), 31 (2a).
  • the said lower and upper annular chambers have the greater height 332 at the root 313 of the flange 310 of the said central ring 31 (a), 31 (2a) and the smaller height 331 at the free end 309 of the said flange 310.
  • the opening of the said annular chambers having height 331 is facing the inside of the reticular structure.
  • the said annular chambers are suitable to receive and to put in position the different types of connections of the ends of the strips and the different types of spacers therebetween.
  • the slots 23(x), 24(x) for the fitting of the connections 7(x), 8(x) respectively of the ends of the lower and upper strips are obtained by shaping (generally by turning) the surfaces of the central ring 31 (la), 31 (2a) and the surfaces respectively of the lower cover-ring 33(a), 33(la) and of the upper cover-ring 32(a), 32(la) according to the profile delimited respectively by the sides 9, 11, 13, 15 of the connections 7(x) of the ends of the lower strips and by the sides 10, 12, 14, 16 of the connections 8(x) of the ends of the upper strips and by shaping (generally by milling) the surfaces respectively of the said lower spacers 25(x) and upper ones 26(x) according to the surfaces of the said central ring and respectively of the said lower and upper cover-rings and to the surface of the said lower connections 7(x) and upper
  • the said slots 23(x), 24(x) with variable section can have constant width 100 and variable height, greater height 132 and therefore greater section at the root 313 of the flange 310 of the said central ring 31 (1 a), 32(2a) and smaller height 131 and therefore smaller section at the free end 309 of the flange 310 of the said central ring.
  • the said slots 23(x), 24(x) with variable section can have constant height 130 and variable width, greater width 105 and therefore greater section at the root 313 of the flange 310 of the said central ring 31(1a), 32(2a) and smaller width 104 and therefore smaller section at the free end 309 of the flange 310 of the said central ring.
  • the lower spacers 25'(1) and 25'(2) have lower lateral projecting portions respectively 250(1') and 250(2') with upper surface shaped according to the profile 15 of the lower surface respectively of the connection 7(1) and 7(2) of the ends of the lower strips and the spacers 26'(1) and 261(2) have upper lateral projecting portions respectively 260(1') and 260(2') with lower surface shaped according to the profile 16 of the upper surface respectively of the connection 8(1) and 8(2) of the ends of the upper strips.
  • the spacers 25(1') and 25(2') have lower lateral projecting portions 250(o) with upper flat horizontal surface, i. e. according to the profile 15 of the lower flat surface respectively of the connection 7(1'), 7(2') of the ends of the lower strips and the spacers 26(1') and 26(2') have upper lateral projecting portions 260(o) with lower horizontal flat surface, i. e. according to the profile 16 of the upper flat surface respectively of the connection 8(1'), 8(2') of the ends of the upper strips.
  • the above mentioned lateral projecting portions 250(x) and 260(x) have a depth 120 equal to the thickness 110 of the connections 7(x), 8(x) of the ends of the strips.
  • the said spacers 25(x), 26(x) which form the annular frames of the support grids above mentioned have the height 27 greater than the height 142 of the pertinent connections 7(x), 8(x) with which they are in contact, so that the said spacers 25(x), 26(x) result imprisoned in the annular chambers respectively 315(x) and 316(x) of the said annular frame 30(a).
  • the said spacers 25(x), 26(x) (also owing to the half-hammer-head profile 345 of the vertical section, according to a plan parallel to the strips, of the said spacers) have the function of transmitting the horizontal forces going towards the inside of the support grid and acting on the said connections 7(x), 8(x) of the strips 1 (x) - 6(x) directly on the 3 rings forming the said annular frame 30(a), when the above mentioned forces, owing to the particular geometric configuration of the connections 7(x), 8(x) and of the spacers 25(x), 26(x), are not directly transmitted by the above connections 7(x), 8(x) to the said 3 rings forming the annular frame 30(a).
  • the turning operations of rings having diameters generally not greater than 3,5 meters, are normal operations that can be executed by any mechanical shop of middle dimensions.
  • the milling operations of the strips with the pertinent connections and of the spacers therebetween are also common operations which can be executed on milling machines of small and/or middle dimensions of normal type or with numerical control system, available generally in any average mechanical work-shop.
  • the assembly of the support grid does not require special and expensive mounting jigs as is necessary on the contrary for the conventional support grids, as that described in the Canadian patent n. 1022410. '
  • the sole central ring 31(1a), 31 (2a) is sufficiently rigid as to replace the conventional mounting jig.
  • the positioning marking of the main lower 1 (x) and main upper 2(x) strips can be made directly respectively on the lower and upper surface of the flange 310 of the ring 31 (la), 31 (2a).
  • the gauges themselves for the milling of the slots and of the connections of the ends of the strips, owing to the stiffness of the said central ring 31(1a), 31 (2a) can be built by copying the profiles of the lower and upper surfaces of the said flange 310 and of the cylindrical surfaces 309 and 313 respectively of the free end and of the root of the said flange.
  • the mounting of the support grid can be executed in one phase only, as all support grid components, strips 1(x) - 6(x), spacers 25(x), 26(x), and rings 31 (x), 32(x) and 33(x) are built beforehand with adequate tolerances, which can be more strict than those concerning a conventional grid, as the one described in the Canadian patent n. 1022410, in that the mounting is executed by assembling the different parts in a vertical position and by slightly pressing, if necessary, with a small hammer of hard-wood, the parts that have to come into contact.
  • the said vertical mounting of all strips presents two advantages in comparison with the traditional mounting system of the secondary strips in horizontal position described in the above mentioned Canadian patent.
  • the first advantage is that of non-running the risk of scoring the surfaces of the strips, scorings which are possible with the old system of mounting the strips horizontally.
  • the second advantage is that of being in position to build the grid grating with null clearances between the coupled intersecting strips, owing to the vertical mounting of the said parts and therefore to obtain as a result a more compact and therefore more rigid grating.
  • the mounting sequence proposed by the present invention which is valid for all 35 different construction types of the support grid, is as follows:
  • construction types I'(a'), 2'(a'). 3'(a') and 4'(a') are marked with interrupted lines for those components, the profile of which is to be modified according to the profile respectively of the connections 1', 2'. 3', 4'.
  • the said construction types a' of the grid support are different from the construction types a previously described as concerns the structure of the central ring 31 (x) and the structure of the lower ring 33(x).
  • the central ring 31 (x) is a ring which has a plurality of milled lower slots 23(x), spaced and parallel to each other, suitable to receive the connections 7(x) of the ends of the lower strips 1(x), 3(x); 5(x) and a plurality of milled upper slots 24(x), spaced and parallel to each other, but forming a certain angle, generally 60°, with the plurality of lower slots; the said upper slots suitable to receive the connections 8(x) of the ends of the upper strips 2(x), 4(x), 6(x).
  • the said central ring 31 (x) can be executed in 8 different construction types 31(la'), 31(1'a'), 31(2a'), 31(2'a'), 31(3a'), 31(3'a'), 31(4a'), 31(4'a'), the rings of which have respectively a plurality of lower slots with constant width 100 and variable height 23(1), 23(1'), 23(2), 23(2'), with constant height 130 and variable width 23(3), 23(3'), 23(4), 23(4'), suitable to receive and to put in position, generally without clearance, respectively the connections 7(1), 7(1'), 7(2), 7(2'), 7(3), 7(3'), 7(4), 7(4') of the ends of the lower strips, and a plurality of upper slots with constant width 100 and variable height 24(1), 24(1'), 24(2), 24(2'), with constant height 130 and variable width 24(3), 24(3'), 24(4), 24(4'), suitable to receive and to put in position, generally without clearance, respectively the connections 8
  • the lower ring 33(x) of the said construction a' of the support grid has a lower flange 330(a') facing the inside of the support and overlapped without clearance to the lower surface of the said central ring 31 (x), to the surfaces 15 of the connections 7(x) of the ends of the lower strips and to an external annular zone 17 of the reticular structure adjoining the said connections 7(x), the said ring 33(x) having generally an axial inner length equal to the height of the said central ring 31 (x).
  • the said lower ring 33(x) has the inner surface shaped in accordance with the different profiles of the external surface of the said ring 31(x), with the surface of which it is in contact.
  • the rings 33(la'), 33(2a'), represented respectively in the figures 9(la') and 9(2a') are used in the construction types respectively la', 2a' of the support grid, while the lower cover-ring type 33(a') is used in the construction types 1'a', 2'a', 3a', 3'a', 4a' and 4'a' of the support grid.
  • the said lower ring 33(x) is mounted with a tight fit on the intermediate ring 31 (x) at the "L" shaped external annular zone 53(a') adjoining the root of the flange 330(a') of the said lower ring.
  • the upper cover-ring 32(x) in the different construction versions 32(a'), 32(1'a'), 32(2a') is overlapped without clearance to the external upper surface of the said intermediate ring 31(x), to the external upper surfaces 16 of the upper connections 8(x) of the upper strips 2(x), 4(x), 6(x) and an external annular zone 18 of the reticular structure adjoining the said connections 8(x).
  • the said upper cover-ring 32(x) is mounted with a tight fit on the said intermediate ring 31(x) at the "L" shaped external annular zone 54(a') of the said intermediate ring.
  • the other construction solution lb, 2b, of the earthquake-proof support grid are to be considered as construction solutions equivalent to the support grid types la, 2a, previously described as concerns the inner annular frame 30(b), which has the axial holes 203 (for the passage of the spacers and tension rods 800 for the locking of the external frame and the tension rods 200 for the fixing of the grid to the tube plate 400) increased by the quantity 202 in order to allow the free expansion of the different material making up the inner annular frame 30(b) and the external annular frame 40(b). Therefore for the description of the said inner annular frame 30(b), refer to the previous description of the annular frame 30(a) with 3 rings of the construction types la and 2a of the support grid.
  • Said support grids of type 1b and 2b illustrated in the figures 9(lb), 9(2b), 13(lb) and 13(2b), are formed of the following components:
  • the upper external cover-ring 42(b) is overlapped to the upper surface of the intermediate annular frame 30(b) generally with small axial clearance and with a tight fit at the "L" shaped inner annular zone 52(b) and to the upper surface of the lower ring 43(b) without axial clearance and with a tight fit at the "L" shaped external annular zone 56(b)..
  • the support grids of type b' are different from the support grids of type b previously described for the different radial sizing (the axial one is substantially equal) of the inner annular frame 30(b') and of the external annular frame 40(b').
  • the supports of type b have an inner annular frame 30(b) having a total radial thickness such as to receive in the inner zone in the proper annular chambers 315(x) and 316(x) respectively the connections 7(x), 8(x) of the strips and in the external zone :the said spacers and tension rods 800 and the said tension rods 200.
  • the support grids of type b' have on the contrary an inner annular frame. 30(b') with smaller radial thickness and are suitable to receive therefore only the said connections 7(x), 8(x) of the ends of the strips.
  • the support grids of type b' have an external annular frame 40(b') having a radial thickness such as to permit the passage of the tension rods 800 and of the tension rods 200.
  • the support grids of type b have on the contrary an external annular frame 40(b), having a smaller radial thickness sufficient only to permit an adequate fixing of the support grid by wedges to the external shell of the steam generator or heat exchanger.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
  • Vibration Prevention Devices (AREA)
EP81830152A 1980-10-08 1981-09-03 Erdbebensicheres Abstützungsgitter für Rohre Ceased EP0049691A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT8025181A IT8025181A0 (it) 1980-10-08 1980-10-08 Supporto antisismico a griglia per tubi di generatori di vapore, scambiatori di calore, particolarmente per generatori di vapore tipo pwr.
IT2518180 1980-10-08

Publications (2)

Publication Number Publication Date
EP0049691A2 true EP0049691A2 (de) 1982-04-14
EP0049691A3 EP0049691A3 (de) 1982-08-18

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Application Number Title Priority Date Filing Date
EP81830152A Ceased EP0049691A3 (de) 1980-10-08 1981-09-03 Erdbebensicheres Abstützungsgitter für Rohre

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EP (1) EP0049691A3 (de)
IT (1) IT8025181A0 (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0122544A1 (de) * 1983-04-15 1984-10-24 BELLELI S.p.A. Rohrtraggitter für Wärmetauscher
EP0259575A1 (de) * 1986-09-08 1988-03-16 MAN Gutehoffnungshütte Aktiengesellschaft Rohrabstandsgitter zum Führen der Rohre von beispielsweise Dampferzeugern
DE19511265A1 (de) * 1995-03-27 1996-10-02 Siemens Ag Gitterförmiger Abstandshalter

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2415242A1 (de) * 1973-04-02 1974-10-17 Breda Termomeccanica Spa Gitterfoermiger fuehrungshalter fuer rohre mit veraenderlichen elastischen verbindungsstellen fuer dampferzeuger, waermetauscher u.dgl
DE2541986A1 (de) * 1975-06-09 1976-12-16 Breda Termomeccanica Spa Verfahren zum herstellen eines aus zwei verschiedenen werkstoffen bestehenden gitterrostes, der anfaenglich steif bleiben kann und nach inbetriebnahme unterschiedliche thermische ausdehnungen ermoeglicht
EP0005681A1 (de) * 1978-05-17 1979-11-28 Vincenzo Soligno Gitterrost zur Halterung von Rohren und Herstellungsverfahren

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2415242A1 (de) * 1973-04-02 1974-10-17 Breda Termomeccanica Spa Gitterfoermiger fuehrungshalter fuer rohre mit veraenderlichen elastischen verbindungsstellen fuer dampferzeuger, waermetauscher u.dgl
DE2541986A1 (de) * 1975-06-09 1976-12-16 Breda Termomeccanica Spa Verfahren zum herstellen eines aus zwei verschiedenen werkstoffen bestehenden gitterrostes, der anfaenglich steif bleiben kann und nach inbetriebnahme unterschiedliche thermische ausdehnungen ermoeglicht
EP0005681A1 (de) * 1978-05-17 1979-11-28 Vincenzo Soligno Gitterrost zur Halterung von Rohren und Herstellungsverfahren

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0122544A1 (de) * 1983-04-15 1984-10-24 BELLELI S.p.A. Rohrtraggitter für Wärmetauscher
EP0259575A1 (de) * 1986-09-08 1988-03-16 MAN Gutehoffnungshütte Aktiengesellschaft Rohrabstandsgitter zum Führen der Rohre von beispielsweise Dampferzeugern
DE19511265A1 (de) * 1995-03-27 1996-10-02 Siemens Ag Gitterförmiger Abstandshalter

Also Published As

Publication number Publication date
IT8025181A0 (it) 1980-10-08
EP0049691A3 (de) 1982-08-18

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