WO1994014165A1 - Compression joint of memory metal for reinforcement of a tubular component - Google Patents

Compression joint of memory metal for reinforcement of a tubular component Download PDF

Info

Publication number
WO1994014165A1
WO1994014165A1 PCT/SE1993/000926 SE9300926W WO9414165A1 WO 1994014165 A1 WO1994014165 A1 WO 1994014165A1 SE 9300926 W SE9300926 W SE 9300926W WO 9414165 A1 WO9414165 A1 WO 9414165A1
Authority
WO
WIPO (PCT)
Prior art keywords
sleeve
memory metal
compression joint
tension elements
winding
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/SE1993/000926
Other languages
French (fr)
Inventor
Hans Kornfeldt
Lars-Åke KÖRNVIK
Lars Törnblom
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Westinghouse Electric Sweden AB
Original Assignee
ASEA Atom AB
ABB Atom AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by ASEA Atom AB, ABB Atom AB filed Critical ASEA Atom AB
Priority to RU9395114400A priority Critical patent/RU2086011C1/en
Publication of WO1994014165A1 publication Critical patent/WO1994014165A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21C—NUCLEAR REACTORS
    • G21C13/00—Pressure vessels; Containment vessels; Containment in general
    • G21C13/02—Details
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E30/00—Energy generation of nuclear origin
    • Y02E30/30—Nuclear fission reactors

Definitions

  • the present invention relates to a compression joint for reinforcement of a tubular component, preferably a substan ⁇ tially cylindrical vessel, for example a reactor vessel.
  • the joint is designed to superimpose an axially contracting force on the component.
  • Compression joints for reinforcement of tubular components are known. These compression joints may consist of a pre- stressed winding of several layers of strip or wire around the location on the tubular component which is desirable to reinforce. The technique is based on the wire or strip being stretched such that a strong contraction takes place around the reinforcement point on the tubular component. The com- pression state which thus arises remains, with a suitable dimension of and tensile stress in the wire, also after the tubular component has been pressurized and loaded. To increase the axial strength somewhat in such a joint, it is also known to make the strip from a thin sheet which is so wide that one turn of the strip covers the reinforcement point satisfactorily. However, this embodiment does not superimpose any axially contracting forces on the tubular component.
  • the invention relates to a compression joint for reinforce ⁇ ment of a tubular component, preferably a substantially cylindrical vessel, for example a reactor vessel.
  • the compression joint comprises a first sleeve divided into a plurality of parts along axial sec ⁇ tions substantially parallel to the axial longitudinal direction of the component.
  • the sleeve is fixed around the component by means of at least one winding of strip or wire of memory metal.
  • a second sleeve which is also divided into a plurality of parts along axial sections, is fixed around the component at a certain distance from the first sleeve by means of a winding of strip or wire of memory metal.
  • this strip or wire Prior to being wound around the respective sleeves at a tempera ⁇ ture below the transition temperature of the memory metal, this strip or wire has been stretched into a suitable length to achieve the desired compressive stress in the joint after the winding on and a subsequent increase of the temperature of the winding above the transition temperature.
  • the sleeves are provided around their periphery with a number of fixing devices for a number of axially arranged tension elements tightened from the fixing devices on the first sleeve to the fixing devices on the second sleeve.
  • the above-mentioned type of com ⁇ pression joint can thus also transmit an axially contracting force to that part of the component which is situated between the two sleeves.
  • the axial strain on the weld can be reduced by placing the joint such that the tension elements lie across the weld and thus exert a contracting force on the welded- together components.
  • the tension elements be made of a material with a lower coefficient of linear expansion than the material in the components. It may then be sufficient that the tension elements, at a low temperature in relation to the working temperature of the vessel, be applied with only a small or no tensile stress around the vessel. The desired tensile stress then does not arise until the tempe ⁇ rature in the vessel is increased.
  • Another way is to manufacture the tension elements from memory metal. In that case the memory metal in the tension elements should have a higher transition temperature than the memory metal of the winding. This will cause the sleeve joints around the component to be fixed before the tension elements are activated.
  • Figure 1 shows a reactor vessel with an applied compression joint.
  • Figure 2 shows a cross section of the vessel wall and a part of a sleeve placed outside the vessel wall.
  • Figure 3 shows a part of a sleeve seen from the front with the fixing points formed as tree-shaped recesses.
  • Figure 4 shows a package of tension elements with a tree- like shape at their ends.
  • Figure 5 shows the package of Figure 4 seen from the side.
  • numeral 1 designates the tubular component which here consists of a reactor vessel la.
  • the reactor vessel comprises at least two cylindrical parts which are joined together by means of a weld 2 which thus runs around the vessel la.
  • the compression joint 3 is applied.
  • the compression joint 3 consists of a first sleeve 4 divided into several parts 5 placed around the vessel la on one side of the weld 2.
  • Each part 5 is provided at the bottom with a strong lug 6, in which fixing devices 7, not shown (see Fig. 2), for the tension elements 8 are arranged.
  • Figure 1 shows only a small number of tension elements 8.
  • the parts 5 of the sleeve 4 are fixed around the vessel by means of two windings 9 of wire or strip, suitably consisting of memory metal. Prior to winding around the first sleeve 4, this strip or wire is stretched at a temperature below the tran ⁇ sition temperature of the memory metal into a suitable length for achieving the desired compressive stress in the joint 3 after winding on and a subsequent increase of the temperature of the windings 9 above the transition tempe ⁇ rature.
  • the second sleeve 10 consisting of parts 11 and lugs 12, is fixed in a corre- sponding way, also by means of fixing devices 7.
  • the parts 11 of the sleeve 10 are fixed with the windings 13, which are only indicated in order to show more clearly what the different parts 11 look like.
  • the tension elements 8 can be tightened across the weld 2. Depending on the design of the tension elements 8, this can take place in several different ways.
  • FIG. 2 One embodiment of the tension elements is shown in Figure 2.
  • lb designates the vessel wall and 2 the weld around the vessel la.
  • the figure shows a section I-I through one of the parts 5 of the first sleeve 4 with a lug 6 and fixing devices 7 in the form of threaded holes.
  • threaded tension elements 8 in the form of threaded bars.
  • the tension elements 8 can be tightened by turning in one direction.
  • the tension elements 8 are arranged in double rows to achieve a sufficient tension.
  • FIG 3 Another type of tension elements is shown in Figure 3 which shows one part 5 seen from the front.
  • the lug 6 tree- shaped recesses 14 are arranged.
  • Tension elements 8 of memory metal are provided with a corresponding tree-like shape at their ends.
  • These tension elements 8 are suitably made in the form of flat laths as shown in Figures 4 and 5. It is thus possible to fit a package of several of these laths or tension elements 8 into a recess 14.
  • the tension elements 8 Before fitting these latter tension elements 8 into the recesses 14 of the lugs 6, 12, the tension elements are tightened below the transition temperature of the memory metal into a suitable length such that the desired tensile stress is obtained above the transition temperature of the memory metal.
  • the tran- sition temperature of the memory metal in the windings of the sleeves 4, 10 should be lower than the transition tempe ⁇ rature of the memory metal in the tension elements 8. This is to make it possible for the sleeves 4, 10, upon heating, to be fixed around the vessel la before the tension elements can take up any tensile forces. Otherwise, heating of win ⁇ dings and tension elements must take place in separate stages.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • General Engineering & Computer Science (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Non-Disconnectible Joints And Screw-Threaded Joints (AREA)
  • Butt Welding And Welding Of Specific Article (AREA)
  • Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)
  • Filling Or Discharging Of Gas Storage Vessels (AREA)

Abstract

The invention relates to a compression joint (3) for reinforcement of a tubular component (1), for example a reactor vessel (1). According to the invention, the compression joint (3) comprises a first sleeve (4) divided into a plurality of parts (5) along axial sections. The sleeve (4) is fixed around the component (1) by means of at least one winding (9) of strip or wire of memory metal. Also a second sleeve (10), in the same way divided into a plurality of parts (11), is fixed, at some distance from the first sleeve (4), around the component (1) by means of at least one winding (13) of strip or wire of memory metal. Before being wound around the respective sleeves (4, 10) at a temperature below the transition temperature of the memory metal, these strips or wires have been stretched into a suitable length to achieve the desired compressive stress in the joint after the winding on and a subsequent increase of the temperature of the winding above the transition temperature. The sleeves (4, 10) are provided around their periphery with a number of fixing devices (7) for a number of axially arranged tension elements (8) stretched from fixing devices (7) on the first sleeve (4) to fixing devices (7) on the second sleeve (10).

Description

COMPRESSION JOINT OF MEMORY METAL FOR REINFORCEMENT OF A
TUBULAR COMPONENT
TECHNICAL FIELD
The present invention relates to a compression joint for reinforcement of a tubular component, preferably a substan¬ tially cylindrical vessel, for example a reactor vessel. The joint is designed to superimpose an axially contracting force on the component.
BACKGROUND ART
Compression joints for reinforcement of tubular components are known. These compression joints may consist of a pre- stressed winding of several layers of strip or wire around the location on the tubular component which is desirable to reinforce. The technique is based on the wire or strip being stretched such that a strong contraction takes place around the reinforcement point on the tubular component. The com- pression state which thus arises remains, with a suitable dimension of and tensile stress in the wire, also after the tubular component has been pressurized and loaded. To increase the axial strength somewhat in such a joint, it is also known to make the strip from a thin sheet which is so wide that one turn of the strip covers the reinforcement point satisfactorily. However, this embodiment does not superimpose any axially contracting forces on the tubular component.
SUMMARY OF THE INVENTION
The invention relates to a compression joint for reinforce¬ ment of a tubular component, preferably a substantially cylindrical vessel, for example a reactor vessel. According to the invention, the compression joint comprises a first sleeve divided into a plurality of parts along axial sec¬ tions substantially parallel to the axial longitudinal direction of the component. The sleeve is fixed around the component by means of at least one winding of strip or wire of memory metal. A second sleeve, which is also divided into a plurality of parts along axial sections, is fixed around the component at a certain distance from the first sleeve by means of a winding of strip or wire of memory metal. Prior to being wound around the respective sleeves at a tempera¬ ture below the transition temperature of the memory metal, this strip or wire has been stretched into a suitable length to achieve the desired compressive stress in the joint after the winding on and a subsequent increase of the temperature of the winding above the transition temperature. The sleeves are provided around their periphery with a number of fixing devices for a number of axially arranged tension elements tightened from the fixing devices on the first sleeve to the fixing devices on the second sleeve.
Besides being able to transmit a radial pressure against the centre of the component, the above-mentioned type of com¬ pression joint can thus also transmit an axially contracting force to that part of the component which is situated between the two sleeves. In, for example, a reactor vessel which is composed of tubular components by means of a cir¬ cular weld, the axial strain on the weld can be reduced by placing the joint such that the tension elements lie across the weld and thus exert a contracting force on the welded- together components.
To prevent the tensile force in the tension elements from becoming reduced upon heating of, for example, the reactor vessel, it is important that the tension elements be made of a material with a lower coefficient of linear expansion than the material in the components. It may then be sufficient that the tension elements, at a low temperature in relation to the working temperature of the vessel, be applied with only a small or no tensile stress around the vessel. The desired tensile stress then does not arise until the tempe¬ rature in the vessel is increased. Another way is to manufacture the tension elements from memory metal. In that case the memory metal in the tension elements should have a higher transition temperature than the memory metal of the winding. This will cause the sleeve joints around the component to be fixed before the tension elements are activated.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 shows a reactor vessel with an applied compression joint.
Figure 2 shows a cross section of the vessel wall and a part of a sleeve placed outside the vessel wall.
Figure 3 shows a part of a sleeve seen from the front with the fixing points formed as tree-shaped recesses.
Figure 4 shows a package of tension elements with a tree- like shape at their ends.
Figure 5 shows the package of Figure 4 seen from the side.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to the accompanying figures a few embodiments of the invention will be shown. In Figure 1 numeral 1 designates the tubular component which here consists of a reactor vessel la. The reactor vessel comprises at least two cylindrical parts which are joined together by means of a weld 2 which thus runs around the vessel la. Over this weld 2 the compression joint 3 according to the invention is applied. The compression joint 3 consists of a first sleeve 4 divided into several parts 5 placed around the vessel la on one side of the weld 2. Each part 5 is provided at the bottom with a strong lug 6, in which fixing devices 7, not shown (see Fig. 2), for the tension elements 8 are arranged. For the sake of clarity, Figure 1 shows only a small number of tension elements 8. In reality a much larger number is required, possibly arranged in several rows. The parts 5 of the sleeve 4 are fixed around the vessel by means of two windings 9 of wire or strip, suitably consisting of memory metal. Prior to winding around the first sleeve 4, this strip or wire is stretched at a temperature below the tran¬ sition temperature of the memory metal into a suitable length for achieving the desired compressive stress in the joint 3 after winding on and a subsequent increase of the temperature of the windings 9 above the transition tempe¬ rature.
On the other side of the weld 2, the second sleeve 10, consisting of parts 11 and lugs 12, is fixed in a corre- sponding way, also by means of fixing devices 7. The parts 11 of the sleeve 10 are fixed with the windings 13, which are only indicated in order to show more clearly what the different parts 11 look like.
When the two sleeves 4, 10 have been fixed around the vessel la, the tension elements 8 can be tightened across the weld 2. Depending on the design of the tension elements 8, this can take place in several different ways.
One embodiment of the tension elements is shown in Figure 2. In Figure 2, lb designates the vessel wall and 2 the weld around the vessel la. The figure shows a section I-I through one of the parts 5 of the first sleeve 4 with a lug 6 and fixing devices 7 in the form of threaded holes. Into these holes are threaded tension elements 8 in the form of threaded bars. By providing the opposite fixing devices 7 with threads directed in different directions, the tension elements 8 can be tightened by turning in one direction. Further, as shown in Figure 2, the tension elements 8 are arranged in double rows to achieve a sufficient tension. As previously mentioned, it is suitable for the tension ele¬ ments 8 to be made of a material with a lower coefficient of linear expansion than the material in the vessel wall lb. In this way sufficient tension can be achieved in the elements 8 only by heating the vessel la. Since a reactor operates at temperatures above 200°C, this is easily done.
Another type of tension elements is shown in Figure 3 which shows one part 5 seen from the front. In the lug 6, tree- shaped recesses 14 are arranged. Tension elements 8 of memory metal are provided with a corresponding tree-like shape at their ends. These tension elements 8 are suitably made in the form of flat laths as shown in Figures 4 and 5. It is thus possible to fit a package of several of these laths or tension elements 8 into a recess 14.
Before fitting these latter tension elements 8 into the recesses 14 of the lugs 6, 12, the tension elements are tightened below the transition temperature of the memory metal into a suitable length such that the desired tensile stress is obtained above the transition temperature of the memory metal. In that case, as mentioned before, the tran- sition temperature of the memory metal in the windings of the sleeves 4, 10 should be lower than the transition tempe¬ rature of the memory metal in the tension elements 8. This is to make it possible for the sleeves 4, 10, upon heating, to be fixed around the vessel la before the tension elements can take up any tensile forces. Otherwise, heating of win¬ dings and tension elements must take place in separate stages.

Claims

1. A compression joint (3) intended to be arranged over a portion, preferably a weld (2), in a tubular component for reinforcement of said portion, characterized in that the compression joint (3) comprises a first sleeve (4) divided into a plurality of parts (5) along axial sections substan¬ tially parallel to the axial longitudinal direction of the component (1) and fixed around the component (1) by means of at least one winding (9) of strip or wire of memory metal, a second sleeve (10) divided into a plurality of parts (11) along axial sections and fixed around the component (1) at a certain distance from the first sleeve (4) by means of at least one winding (13) of strip or wire of memory metal, said strip or wire prior to being wound around the respec¬ tive sleeves (4, 10) at a temperature below the transition temperature of the memory metal being stretched into a suitable length to achieve the desired compressive stress in the joint (3) after winding on and a subsequent increase of the temperature of the winding above the transition tempera¬ ture, said sleeves (4, 10) being provided around their peri¬ phery with a number of fixing devices (7) for a number of axially arranged tension elements (8) tightened from the fixing devices (7) on the first sleeve (4) to the fixing devices (7) on the second sleeve (10) .
2. A compression joint (3) according to claim 1, characterized in that the tension elements (8) consist of bars made of a material with a lower coefficient of linear expansion than the material in the component (1) .
3. A compression joint (3) according to claim 2, characterized in that the fixing devices (7) are formed as tree-shaped recesses (14) for the tension elements (8) , which are formed as laths with a corresponding tree-like shape at their ends in order to fit and be locked into said recesses (14) .
4. A compression joint (3) according to claim 1, 2 or 3 , characterized in that the tension elements (8) are made of memory metal.
5. A compression joint (3) according to claim 1, characterized in that the tension elements (8) are made of memory metal whose transition temperature is higher than the transition temperature of the memory metal of the windings (9, 13) .
PCT/SE1993/000926 1992-12-15 1993-11-05 Compression joint of memory metal for reinforcement of a tubular component Ceased WO1994014165A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
RU9395114400A RU2086011C1 (en) 1992-12-15 1993-11-05 Compression joint of pipe assembly

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE9203772A SE500878C2 (en) 1992-12-15 1992-12-15 Memory metal compression joint to reinforce a tubular component
SE9203772-0 1992-12-15

Publications (1)

Publication Number Publication Date
WO1994014165A1 true WO1994014165A1 (en) 1994-06-23

Family

ID=20388127

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE1993/000926 Ceased WO1994014165A1 (en) 1992-12-15 1993-11-05 Compression joint of memory metal for reinforcement of a tubular component

Country Status (3)

Country Link
RU (1) RU2086011C1 (en)
SE (1) SE500878C2 (en)
WO (1) WO1994014165A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104197188A (en) * 2014-08-25 2014-12-10 上海宇航系统工程研究所 Gas jetting device driven by shape memory alloy wires

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE348585B (en) * 1968-11-28 1972-09-04 Coyne & Bellier
US4621844A (en) * 1982-01-25 1986-11-11 Shell Oil Company Memory metal connector
WO1990015418A1 (en) * 1989-05-31 1990-12-13 Abb Atom Ab A method for repair of system parts of a nuclear reactor which are contacted by process medium

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE348585B (en) * 1968-11-28 1972-09-04 Coyne & Bellier
US4621844A (en) * 1982-01-25 1986-11-11 Shell Oil Company Memory metal connector
WO1990015418A1 (en) * 1989-05-31 1990-12-13 Abb Atom Ab A method for repair of system parts of a nuclear reactor which are contacted by process medium

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104197188A (en) * 2014-08-25 2014-12-10 上海宇航系统工程研究所 Gas jetting device driven by shape memory alloy wires

Also Published As

Publication number Publication date
SE500878C2 (en) 1994-09-26
SE9203772L (en) 1994-06-16
RU2086011C1 (en) 1997-07-27
SE9203772D0 (en) 1992-12-15

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