GB2538745A

GB2538745A - Method of assembly

Info

Publication number: GB2538745A
Application number: GB1509048.3A
Authority: GB
Inventors: Pimblott Stephen; Lobato Hugo; Stoddart David
Original assignee: Rolls Royce Power Engineering PLC; Rolls Royce PLC
Current assignee: Rolls Royce Power Engineering PLC; Rolls Royce PLC
Priority date: 2015-05-27
Filing date: 2015-05-27
Publication date: 2016-11-30
Anticipated expiration: 2035-05-27
Also published as: GB2538745B; GB201509048D0

Abstract

A method comprising providing a series of plate support structures 32 and loading a plate or baffle (24, figure 3a) onto each plate support structure, wherein each plate comprises a plurality of holes or apertures (26 figure 3a). A tube (28, figure 3b) is fed through each hole of the plates, each tube passing through respective holes in each plate of the series as to create a tube bundle. A shell (22, figure 2) is provided and moved relatively towards the bundle. The plates are progressively released from the support structures by collapsing the support structures such that as the shell moves relative to the bundle so that it may be installed within the shell. The collapsed support structures provide no obstruction to the shell during bundle installation. The plate support structures and/or the shell may be provided on a rail arrangement. The plate support structures may comprise vertically adjustable arms 32 which may pivot in direction R and slide along slots 38 as to avoid causing obstruction.

Description

Method of assembly

Technical Field

The present disclosure concerns a method of assembly of a shell and tube heat 5 exchanger.

Background

A nuclear power plant includes a primary circuit around which primary fluid flows and is heated by a reactor, and a secondary circuit around which cooler secondary fluid flows. The secondary fluid is heated by the primary fluid in a heat exchanger, e.g. a steam generator, and the heated fluid is used to drive a turbine to generate electricity.

The principle type of heat exchanger currently used in nuclear power plants is a shell and tube heat exchanger. These heat exchangers are generally large in size, for example they may have a diameter of 1.5 to 2m and a length of 5 to 6m.

A shell and tube heat exchanger includes a plurality of plates that support a plurality of tubes within a shell of the heat exchanger. Due to the large size of 20 the heat exchanger, assembly of the heat exchanger during the manufacturing process can be time consuming.

Summary of Disclosure

Accordingly, the present disclosure seeks to provide a method of assembly of a shell and tube heat exchanger that is faster than current prior art methods.

According to a first aspect there is provided a method of assembly of a tube and shell heat exchanger. The method comprises providing a series of plate support structures; loading a plate onto each plate support structure. Each plate comprises a plurality of holes. The method comprises feeding a plurality of tubes through the holes of the plates, each tube passing through one hole in each of the plates. The method comprises providing a shell and moving the shell relatively towards the plates and tubes. The method comprises progressively releasing the plates from the support structures by collapsing the support structures.

As the shell moves relative to the plates and tubes the collapsed support structures may provide no obstruction to the shell surrounding the plates and tubes.

Each support structure may comprise an arm that is moveable between a support position (e.g. an upright position) and a collapsed position. The method may comprise moving the arm to the collapsed position so as to collapse the plate support structure.

Each support may comprise a further arm, so that each support structure comprises a pair of arms. Each arm of the pair of arms may be moveable between a support position (e.g. upright position) and a collapsed position. The method may comprise moving each arm of the pair of arms to the collapsed position so as to collapse the plate support structure.

The support position or upright position may be transverse to the collapsed position.

The support position or upright position may be orthogonal to the collapsed position.

The plate support structure may comprise a strut and the or the pair of arms may be connected to the strut. Each arm may be connected to the strut using a releasable fastener, for example a bolt. The fastener may be released to collapse the arm. The arm may be rotatable to a collapsed position, e.g. once the fastener has been released. The strut may comprise a slot and an arm may comprise a member arranged to be slidable in the slot. The arm may be rotated and as the arm is rotated the member may slide in the slot such that the arm can be positioned adjacent the strut.

The method may comprise providing the plate support structures and/or the shell on a rail arrangement and moving the shell relatively towards the plates and tubes by sliding the plate support structures and/or the shell along the rail arrangement The plate support structure may comprise a mount that is adjustably connected to the remainder of the plate support structure (e.g. adjustably connected to the or an arm of the plate support structure). The method may comprise adjusting the position of the mount relative to the remainder of the support structure.

When the plate support structure comprises a pair of arms, the plate support structure may comprise a pair of mounts, one mount may be adjustably mounted to one of the arms and the other mount may be adjustably mounted to the other of the arms.

The mount may be threadingly engaged to the remainder of the support structure (e.g. to the arm of the support structure).

The plate support structures may be provided in axial alignment.

The length of the tubes may be greater than or equal to 4m (e.g. greater than or equal to 5m, or greater than or equal to 6m, for example the tubes may have a length between 4m and 6m) and the diameter of the shell may be greater than or equal to lm (e.g. greater than or equal to 1.5m, or greater than or equal to 2m, for example the diameter of the shell may be between lm and 2m).

A second aspect of the invention provides assembly apparatus for assembly of a shell and tube heat exchanger for a nuclear power plant. The apparatus comprises a series of plate support structures each for supporting a plate of a shell and tube heat exchanger. The plate support structures are arranged to be moveable between two positions: a support position (e.g. an upright position) where the plate support structure can support a plate of a shell and tube heat exchanger, and a collapsed position that is orthogonal to the support position.

Each arm of the apparatus may be connected to a base. For example, in the case of a plurality of pairs of arms being provided (where each pair of arms is for supporting one plate), the base may comprise a plurality of struts, each strut extending between the pair of arms.

A guide (e.g. a slot) may be provided in the base. A guide member may be provided on the arm (e.g. connected there to). The guide member may be arranged to slide in the guide. The guide and guide member may be arranged so as to guide the arms to pivot away from a plate that was previously supported by the support structure, when the arms are moved to the collapsed position.

A mount may be provided on each arm for supporting a plate. The mount may be connected to the respective arm via an adjustable fastener. For example, the mount may be threadingly engaged to the arm.

The plate support structures may be provided in axial alignment.

The plurality of support structures may extend for an axial length greater than or equal to 3m, for example greater than or equal to 4m.

The apparatus may comprise a rail arrangement. The support structures may be positioned on the rail arrangement such that the support structures can slide along rails of the rail arrangement.

The apparatus may comprise a shell support for supporting a shell of a shell and tube heat exchanger. The shell support may be provided on a rail arrangement such that the shell support can move along rails of the rail arrangement. The rail arrangement on which the shell support is provided may be the same or may be a different rail arrangement to that which the support structures are provided on.

The skilled person will appreciate that except where mutually exclusive, a 15 feature described in relation to any one of the above aspects of the invention may be applied mutatis mutandis to any other aspect of the invention.

Description of the drawings

Embodiments of the invention will now be described by way of example only, with reference to the Figures, in which: Figure 1 is a simplified schematic of a nuclear power plant; Figure 2A is an end view of an example shell of a shell and tube heat exchanger; Figure 2B is a side view of an example shell of a shell and tube heat 25 exchanger; Figure 3A shows a plan view of an example plate of a shell and tube heat exchanger; Figure 3B shows a plan view of an example tube of a shell and tube heat exchanger; Figure 4 shows a side view of plate and tube assembly equipment; Figure 5 shows an end view of the plate and tube assembly equipment of Figure 4; Figure 6A shows a perspective view of a support used to support the shell of Figure 2; Figure 6B shows an end view of the shell of Figure 2 supported on the support of Figure 6A; Figure 7 shows a perspective view of rails and a frame used to support the shell of Figure 2; and Figure 8 shows a flow diagram illustrating steps in a method of assembly of a heat exchanger.

Detailed Description

Referring to Figure 1, a nuclear power plant is indicated generally at 10. The plant includes a nuclear reactor 12, a primary circuit 14, a heat exchanger 16, a secondary circuit 18 and a turbine 20. The primary fluid in the primary circuit is heated by the nuclear reactor. The primary fluid then flows to the heat exchanger, where it heats secondary fluid in the secondary circuit. The heated secondary fluid is then used to drive the turbine 20.

The heat exchanger 16 may be a shell and tube heat exchanger. The primary fluid may pass through tubes of the heat exchanger and the secondary fluid may be outside the tubes and contained by a shell of the heat exchanger, or vice versa.

Figures 2A, 2B, 3A and 3B illustrate the components of a shell and tube heat exchanger. The shell of the heat exchanger is illustrated in Figure 2A and 2B and is indicated generally at 22. In the present example the shell is made in three sections 23a, 23b, 23c connected together, e.g. welded together, but in alternative embodiments the shell may be made as a single component. The example shell is cylindrical. In use, the shell will be closed at each end, and have an inlet and an outlet for the fluid to enter and exit the heat exchanger. The heat exchanger may be closed using a hemi-spherical shaped cap. Generally, in the nuclear industry heat exchangers are large structures, and in the present example the heat exchanger has a length of approximately 6m and a diameter of approximately 2m. In the present example the heat exchanger is a steam generator.

Referring now to Figure 3A, a plate for location within the shell 22 is indicated at 24. A plurality of plates are provided in the shell of the heat exchanger 16 and provide the function of supporting the tubes within the heat exchanger. Genrally, each of the plates will have similar geometry and construction. Each plate is dimensioned to be seated within the shell 22, and various locating features may optionally be used to fix the plates in position with respect to the shell. Each plate 24 includes a plurality of holes 26. The holes are dimensioned to receive and support a tube.

Referring now to Figure 3B, a tube 28 is illustrated. A plurality of tubes similar to tube 28 is provided in the heat exchanger 16. When assembled, the plates 24 are axially spaced in the shell 22 of the heat exchanger. The holes 26 of each plate are aligned, and a tube 28 passes through the corresponding hole in each plate so as to be supported by a plurality of plates.

As will be appreciated, the length of the tubes and the shell means that aligning all the component parts of the heat exchanger is difficult and time consuming and incorrect alignment can further increase assembly time.

The following describes equipment and a method of assembly of a tube and shell heat exchanger that can ease the assembly and can reduce the time needed for the assembly of a heat exchanger.

Referring now to Figures 4 and 5, plate and tube assembly equipment is indicated generally at 30. The assembly equipment includes a series of plate support structures 32. In the present example, nine support structures are provided, but in alternative embodiments any suitable number of support structures may be provided.

Each support structure 32 includes an arm 34. In this example each support structure has a pair of arms 34. The arms are opposed to each other. The support structure also includes a strut 36. The strut is provided towards or at the base of the support structure. The arms are connected to the strut. In the present example, the arms 34 are pivotally connected to the strut such that the arms can move between a position generally orthogonal to the strut and a position generally parallel to the strut. A slot 38 is provided in the strut. In the present example two slots 38 are provided one at each lateral side of the strut. The arms are connected to the strut by a member 40 positioned in the slot 38 and by a fastener, e.g. a bolt 42, that connects the arm to the strut. The member is configured to be slidable in the slot 38.

A mount 44 is provided at one end of the arm 34. The mount is shaped to support a plate 24 of the heat exchanger. In this example, the mount includes two (axially) opposed curved members 46 and a further curved member 45 positioned adjacent the member 46. The members 45 and 46 support the plate 24 so as to hold it in a relative fixed vertical and horizontal position and to restrict tilting of a plate.

The mount 44 is connected to the arm 34 via an adjustable fastener. In this example the adjustable fastener is a threaded member 50. The threaded member 50 can be used to adjust the position of mount 44 with respect to the arm 34, i.e. to move the mount towards or away from the arm 34.

In the present example each support structure 32 is connected, e.g. bolted, to a base member 52. The base member 52 is mounted on rails 54 such that the assembly equipment 30 is slidable along the rails 54.

Referring now to Figures 6A, 6B and 7, shell support equipment for supporting the shell 22 will be described. The shell support equipment includes a series of shell support members 56. Each shell support member includes a curved surface 58 on to which the shell can be seated, a base 60 and legs 62 connecting the curved surface to the base. A cross piece 64 may connect between the base, legs and curved surface to provide additional rigidity to the support member 56 The shell support members 56 can be bolted to a shell support frame 66. The support frame 66 includes a pair of opposing, and in this case parallel, elongate members 68 that are connected together using brace members 70. In the present example rails 72 are provided and the elongate members 68 are configured to be slidable along the rails 72.

The method of using the described assembly equipment will now be described 5 with reference to the flow diagram shown in Figure 8.

Firstly the shell support members 56 are connected to the shell support frame 66. The shell support frame is positioned in alignment with the plate and tube assembly equipment. The shell 22 is then positioned on the shell support members and frame, as indicated at block 74. Lifting equipment may be used to manoeuvre the shell onto the shell support members. The curved surface 58 of each support member rests against the curved outer surface of the shell. The curve of the support member has similar curvature to the shell so that the shell is restricted from movement relative to the support frame.

Now turning to the plate and tube assembly equipment, the plate and tube support structures 32 may optionally be moved relative to each other so as to optimise the spacing between the support structures 32. At block 76, the arms 34 of each support structure are raised to be orthogonal to the struts 36, if they are not already. Optionally, not all of the arms may be raised, depending on the size of the shell 22 and the number of plates 24 required. To secure the arms 34 in a position orthogonal to the struts 36, the arms are fastened in position using bolts 42.

At block 78, if not already attached (e.g. if block 78 is performed before block 76), the mounts 44 are attached to the arms 34. The height and the tilt of the mounts may be adjusted so as to be positioned such that a plate 24 positioned on the mounts will be substantially aligned with the shell 22. The height of the mounts is adjusted by turning the threaded connector 50. The tilt may be changed by loosening the bolts that attach the members 45 and 46 to the remainder of the mount, adjusting the position of member 45 and/or 46, and tightening the bolts to fix the members in the desired position.

At block 80, a plate is positioned on one of the support structures 32, by positioning it on the respective mounts 44. The positioning of the plate 24 with respect to the shell is then checked, and if required the position of the mounts is adjusted so as to adjust the position of the plate, as indicated at block 82. This process is repeated as required, as indicated by blocks 84 and 86. That is, all the plates required for the heat exchanger assembly are positioned on respective plate support structures 32. The position of the plates is adjusted by adjusting the respective mounts, such that all the plates are aligned with each other and with the shell 22.

Once all the required plates 24 are positioned on the support structures 32 and are correctly aligned, tubes 28 are fed through the holes 26 in the plates, as indicated at block 88. That is, a single tube is fed through one hole in each of the plates. The holes of the plates are aligned and support the tube at multiple points along the length of the tube.

Once the plates 24 and tubes 28 are assembled, the shell 22 is moved relative to the assembled plates and tubes, as indicated at block 90. In the present example the shell 22 is moved on rails 72 towards the plates and tubes, but in alternative embodiments the plates and tubes may be moved on rails towards the shell (e.g. along rails 54).

As indicated at block 92, as the shell is moved the arms of the support structure are moved from the upright position to a collapsed position that is parallel to the strut (and orthogonal to the upright position). That is, the shell 22 is moved towards the support structures 32, once the shell is close to the support structure and plate 24 proximal to the shell, the arms 34 of said support structure are collapsed. To collapse the arms, bolts 42 are released. The arm is then pivoted in a direction away from the plate (as indicated by arrow R in Figure 5). The arm is pivoted and the member 46 slides along the slot 38 provided in the strut 36 until the arm is substantially parallel with the strut 36.

Once the support structure 32 nearest to the shell 22 is collapsed, the shell is moved relatively towards the next plate 24 and support structure, and the arms of the next support structure are moved to a collapsed position in a similar manner as previously described. This process is continued until all the plates are positioned within the shell of the heat exchanger.

Providing support structures that progressively collapse can ease the manufacturing process making it much faster and easier to assemble a shell and tube heat exchanger. The provision of adjustable mounts also means that the alignment of the plates can be easily adjusted, further improving the ease with which the heat exchanger can be assembled. The provision of the plate and shell support structures and the rails also means that the components of the heat exchanger can be manipulated and assembled without the need or with a reduced need for heavy lifting equipment.

It will be understood that the invention is not limited to the embodiments above-described and various modifications and improvements can be made without departing from the concepts described herein. Except where mutually exclusive, any of the features may be employed separately or in combination with any other features and the disclosure extends to and includes all combinations and sub-combinations of one or more features described herein.

In the present application each plate support structure has been described as having a pair of arms. However, in alternative embodiments the plate support structure may only have a single arm, for example an arm positionable centrally to the plate. In further alternative embodiments, each plate support structure may have more than two arms.

Claims

Claims 1. A method of assembly of a tube and shell heat exchanger, the method comprising: providing a series of plate support structures; loading a plate onto each plate support structure, wherein each plate comprises a plurality of holes; feeding a plurality of tubes through the holes of the plates, each tube passing through one hole in each of the plates; providing a shell and moving the shell relatively towards the plates and 10 tubes and progressively releasing the plates from the support structures by collapsing the support structures such that as the shell moves relative to the plates and tubes the collapsed support structures provide no obstruction to the shell surrounding the plates and tubes.
2. The method according to claim 1, wherein each support structure comprises an arm that is moveable between a support position and a collapsed position, and the method comprising moving the arm to the collapsed position so as to collapse the plate support structure.
3. The method according to claim 1, wherein each support structure comprises a pair of arms, each arm being moveable between a support position and a collapsed position, and the method comprising moving each arm to the collapsed position so as to collapse the plate support structure.
4. The method according to claim 2 or 3, wherein the support position is orthogonal to the collapsed position
5. The method according to any one of the previous claims, comprising providing the plate support structures and/or the shell on a rail arrangement and moving the shell relatively towards the plates and tubes by sliding the plate support structures and/or the shell along the rail arrangement.
6. The method according to any one of the previous claims, wherein the plate support structure comprises a mount that is adjustably connected to the remainder of the plate support structure, and wherein the method comprises adjusting the position of the mount relative to the remainder of the support structure so that the plates of the assembly are axially aligned.
7. The method according to claim 6, wherein the mount is threadingly engaged to the remainder of the support structure.
8. The method according to any one of the previous claims, wherein the plate support structures are provided in axial alignment.
9. The method according to any one of the previous claims wherein the length of the tubes is greater than or equal to 4m.
10. A method of assembly substantially as hereinbefore described with reference to and as shown in the accompanying drawings.