Method of installing fittings on a module frame

Abstract: A method of installing one or more fittings (8, 12, 13) onto a module frame (1), the outer extremities (6) of which define a hypothetical hexahedron, comprises defining a datum point (X) adjacent one edge (18) of the hexahedron defined by two adjacent vertical surfaces (A,B) of the hexahedron, defining two reference points (Y₁,Y₂) on the upper and lower surfaces (C,D) of the hexahedron, respectively, positioning the or each fitting transversely and longitudinally with respect to the datum point (X) and vertically with respect to the reference points (Y₁,Y₂) and installing it on the module frame (1).

Description: The present invention relates to a method of installing fittings on a module frame. In an engine room of a ship, fittings, such as machines, pipes, electrical cables, etc., are installed and fixed in the hull structure during the fitting out process. Normally, a deck of the hull is built and then fittings are brought onto or below the deck to be installed or fixed on or beneath the deck. This conventional method of fitting out involves many shore-based and onboard installation and fixing operations which are carried out under poor environmental conditions so that its efficiency is low and the length of time required is considerable. The onboard installation and fixing operations will require frequent adjustments as they proceed due to dimensional errors and this further reduces the working efficiency. In order to solve these problems, a modular fitting out method has been proposed in which fittings are divided into a plurality of groups and the groups of fittings are installed onto respective module frames onshore in a factory or the like. The fitted out module frames are then loaded onto a ship for installation and appropriate interconnection. This proposed method would drastically reduce the amount of fitting out done onboard and shorten the time required for installation and fixing since merely the module frames manufactured and fitted out onshore need be brought onboard for connection. However, the proposed method is regarded as impractical because, even if the module frames can be fabricated with a relatively high degree of accuracy in a factory or the like, dimensional errors accumulate with regard to mounting the fittings onto the module frames and positioning the module frames with respect to the hull of the ship. These errors will require adjustments between adjacent module frames and between the fittings on the frames. Such adjustments will require a considerable amount of time and are very labour intensive. For example, in the case where a straight pipe system extends over several module frames, inaccuracies in the individual module frames and errors in the fabricated dimensions of the pipe sections are cumulative, so that considerable gaps or interferences may occur between pipe sections between adjacent modules due to the fact that the pipe sections are too short or too long. The previously common solution to this problem was the use of adjustable pipes to absorb the dimensional errors, but this is disadvantageous in that a number of extra parts (adjustable pipes) are required and the installation period is prolonged as the result of inefficient adjustments performed in the ship. According to the present invention a method of installing one or more fittings onto a module frame, the outer extremities of the module frame defining a hypothetical hexahedron, comprises defining a datum point adjacent one edge of the hexahedron defined by two adjacent vertical surfaces of the hexahedron, defining two reference points on the upper and lower surfaces of the hexahedron, respectively, positioning the or each fitting transversely and longitudinally with respect to the datum point and vertically with respect to the reference points and installing it on the module frame. The fittings are thus positioned and installed at points whose position is determined precisely with respect to the datum point and the reference points which means that when a plurality of such frame modules are placed adjacent one another and connected together the fittings on adjacent modules are in precisely predetermined positions with respect to one another and can thus be simply connected together without any subsequent positional adjustments being necessary. The module frame may comprise a plurality of interconnected elongate members, the free ends of at least some of which carry a respective connector, the relative positions of the connectors being precisely predetermined, whereby the connectors define a hypothetical hexahedron. The datum point and the reference points are preferably disposed on the surface of respective connectors. The method of the present invention is particularly applicable to a method of installing fittings which are to be used in a ship and in this event the said edge is preferably that edge of the hexahedron which will be closest to the bow of the ship and the longitudinal centre line of the ship. The present invention also embraces a method of fitting out a ship with a plurality of fittings which includes installing the fittings onto a plurality of module frames by the method described above and subsequently positioning the module frames in the ship, preferably by positioning the datum point in a precisely predetermined position with respect to a predetermined installation point on the ship, and then preferably interconnecting the fittings on adjacent module frames, as appropriate. The fittings to be installed on the module frame may include pipes which are subsequently to be connected to further pipes on adjacent module frames and in this event the pipes may be dimensioned so that they terminate short of the associated surface of the hexahedron on those sides on which they are to be connected to further pipes. Alternatively or in addition, the pipes may have a bend formed in them, e.g. of 90°, which can absorb errors in the positioning of the pipe with respect to its module frame. Further features and details of the invention will be apparent from the following description of one specific embodiment which is given with reference to the accompanying drawings, in which:- Figure 1 is a perspective view showing a module frame to be used in the method in accordance with the invention; Figure 2 is a scrap diagrammatic plan view of an engine room of a ship illustrating the datum point of a number of module frames as shown in Figure 1; Figure 3 is a view illustrating a number of module frames carrying pipes to be interconnected; Figure 4 is a detailed view showing one of the module frames of Figure 3; and Figure 5 is a detailed view showing another module frame of Figure 3. Figure 1 shows an example of the basic shape of module frame 1 to be used for the method according to the present invention. The module frame 1 comprises two transverse, spaced main girders 2 extending parallel to one another, two spaced longitudinal beam members 3 extending transversely to and connected to the main girders by welding, and upper and lower support columns 4 and 5 fixed by welding to each junction of the main girders 2 with the beam members 3 and extending upwardly and downwardly, respectively. Each end of each girder 2 and beam 3 carries a flange connector 6. The outer or connection surfaces of the planar connectors 6 may be considered to define a virtual or hypothetical hexahedron. In Figure 1, reference number 7 denotes auxiliary beams added to support heavy components 8;3′, extensions by which the module frame 1 may be connected to a hull structure 9, such as a bulkhead shown in Figure 2, when the module frame 1 is installed in a ship; 10, reinforcing ribs; and 11, reinforcing brackets. In addition to the components 8, the module frame 1 may be fitted with various other components, such as pipes 12 and electrical cables 13. Reference numeral 14 indicates connectors such as flanges, on the pipes 12 which are provided to enable adjacent pipes to be interconnected. The module frame 1 is constructed by assembling the main girders 2, the beam members 3, the upper and lower support columns 4 and 5 etc. by welding or the like to form a frame structure. After removal of any welding distortion, the individual members 2, 3, 4 and 5 are connected by welding or the like to the connectors 6 which are positioned with respect to one another with a high degree of accuracy, thereby defining a virtual hexahedron with a high degree of accuracy. In installing the components 8, 12 and 13 on the module frame 1, a single point X (for example, the centre) on one connector 6, which is positioned adjacent an edge 18 defined by one longitudinal surface and one transverse surface of the virtual hexahedron, is taken as a datum point in the longitudinal and transverse directions for the positioning and installation of the fittings 8, 12 and 13 and the connectors 14. The datum point X will be selected to be located on the connector 6 which is positioned at the edge 18 defined by that surface A of the bow-side transverse face virtual hexahedron which extends transversely at the forward end of the module frame and that surface B which extends longitudinally and is closest to the longitudinal centre line 17 of the ship. Two reference points Y₁ and Y₂ are also selected. The point Y₁ lies in the upper surface C of the virtual hexahedron and is a point (for example the centre) on the connector 6 carried by that upper support column 4 which is closest to the datum point X. The point Y₂ lies in the lower surface D of the virtual hexahedron and is a point (for example the centre) on the connector 6 carried by that lower support column 5 which is closest to the datum point X. The fittings 8, 12 and 13 and the connectors 14 are then positioned and connected to the frame module. The positioning in the vertical direction is effected with respect to the reference points Y₁ and Y₂ and the positioning in the transverse and longitudinal directions is effected with respect to the datum point X. Consistent utilisation of the datum point X in the transverse and longitudinal directions and the reference points Y₁ and Y₂ in the vertical direction enables all of the components 8, 12 and 13 and the connectors 14 to be positioned and installed with a high degree of accuracy. In one specific method of positioning and installing the fittings on a module frame, perpendicular intersecting reference lines are provided on a plate or table and the module frame is positioned so that its defined datum point is in alignment with the intersection of the reference lines. The level of the module frame is then adjusted to compensate for fabrication inaccuracies of the frame. If necessary, the position of the various connectors is determined in order to determine the fabrication errors, if any, of the frame and to ensure that these are within acceptable limits. Marks are then made on the module frame for positioning the fitting mounting bases and pipe supports with respect to the datum and reference points. When the end of a fitting is to be in space, the position of its end is marked on the plate. It is not possible to mark the end of a fitting on an upper face of the module. The fittings are then secured at the marked positions. Special means are needed to measure the position of the end of a fitting on the upper face of the module frame. For instance, a ruler placed on top of a column. As mentioned above, the datum point is selected to be on or adjacent an edge 18 which is closest to the bow and the centre line of the hull. The former is desirable because module frames which are to be vertically stacked in a ship are concentrated towards the bow of the ship. The latter is desirable because it results in the dispersion of accumulated errors outwardly towards the sides of the ship. When the module frames 1 carrying the various fittings are installed inside the engine room 16 of a ship 15, they are positioned and installed sequentially such that the datum point X for each module frame 1 is aligned with the planned installation point on the ship 15, as shown in Figure 2, thereby preventing accumulation of dimensional errors of the individual module frames 1. When fittings, such as pipes 12 and electrical cables 13, are to be installed onto a module frame 1, the length of the electrical cables 13, which have a relatively high degree of flexibility, can be readily adjusted and connections made between adjacent module frames 1. On the other hand, the pipes 12, if not fabricated with a high degree of accuracy, may be either so short that a gap is formed between the connectors 14 upon interconnection of the module frames 1 or may be so long that the connectors 14 project through the associated surface A, A′, B, B′, C or D of the notional hexahedron thereby making interconnection of the pipes 12 impossible. To solve this problem, the pipes 12 which are to be connected together to extend through the surfaces A and A′, B and B′ or C and D (see Figure 1) defining the virtual hexahedron are fabricated somewhat undersized by an amount of, for example, 0 to 2mm so that their length is equal to or less than the length (distance) between the corresponding surfaces. Thus, the pipes 12 which extend through the surfaces A and A′ are fabricated to a length L₁ equal to the length of the virtual hexahedron or a length L₂ which is, for example, 0 to 2mm shorter than L₁, as shown in Figure 4. This will prevent an inability to interconnect the module frames 1. Whilst the module frames 1 shown in Figure 3 carry straight pipes 12, other module frames 1′ to be connected to the module frames 1 carry a bent pipe 19 which is bent for example at 90° in relation to the axis of the pipes 12, as shown in Figures 3 and 5. Providing such bent pipes 19 is advantageous in that any accumulated dimensional errors resulting from interconnection of the straight pipes 12 can be readily absorbed by the bent pipes 19, as shown by the solid and broken lines in Figure 5. As is clear from the foregoing, the method according to the present invention can completely eliminate the necessity for positional adjustments between the module frames and between the components on them, thereby substantially reducing the time required for installation of the module frames in a ship. Moreover, the high degree of accuracy obtained will ensure interchangeability of the module frames. It is to be understood that the method of installing fittings on a module frame according to the present invention is not limited to the above embodiment and that modifications may be effected. For example, when the module frame 1 includes a plate on which components are to be installed, the datum point X may be selected to be at that corner of the plate which is closest to the bow of the ship and the centre line of the hull.

Claims: A method of installing one or more fittings onto a module frame, the outer extremities (6) of the module frame defining a hypothetical hexahedron, the method comprising defining a datum point (X) adjacent one edge (18) of the hexahedron defined by two adjacent vertical surfaces (A,B) of the hexahedron, defining two reference points (Y₁,Y₂) on the upper and lower surfaces (C,D) of the hexahedron, respectively, positioning the or each fitting transversely and longitudinally with reference to the datum point (X) and vertically with respect to the reference points (Y₁,Y₂) and installing it on the module frame (1). A method as claimed in claim 1 in which the module frame comprises a plurality of interconnected elongate members (2, 3, 4, 5), the free ends of at least some of which carry a respective connector (6), the relative positions of the connectors (6) being predetermined, whereby the connectors (6) define the hypothetical hexahedron. A method as claimed in claim 2 in which the datum point (X) and the reference points (Y₁,Y₂) are disposed on the surface of respective connectors (6). A method as claimed in any one of the preceding claims in which the module frame (1) is subsequently to be installed in a ship, the said edge (18) being that edge of the hexahedron which will be closest to the bow of the ship and the longitudinal centre line (17) of the ship. A method as claimed in any one of the preceding claims in which one of the fittings is a pipe (12) which is subsequently to be connected to further pipes (12,19) on adjacent module frames (1), the method including dimensioning the pipe (12) so thatit terminates short of the associated surface of the hexahedron on those sides on which it is to be connected to futher pipes. A method as claimed in any one of the preceding claims in which one of the fittings is a pipe (19) which is subsequently to be connected to further pipes (12,19) on adjacent module frames (1), the pipe (19) having a bend formed in it, e.g. of 90°, which can absorb errors in the positioning of the pipe.

Inventors: FUJIMITSU RYOICHI, HANDA KAZUHISA, HIRAMOTO ETSURO, IMASHIMIZU YOSHINORI, MORIOKA KUNIHITO, SUDA YOSHIAKI, FUJIMITSU, RYOICHI, HANDA, KAZUHISA, HIRAMOTO, ETSURO, IMASHIMIZU, YOSHINORI, MORIOKA, KUNIHITO, SUDA, YOSHIAKI
Applicants: ISHIKAWAJIMA HARIMA HEAVY IND, ISHIKAWAJIMA-HARIMA JUKOGYO KABUSHIKI KAISHA
Application year: 1991
Main classification: B63B3
IPC codes: B63H21, B63B3