Patent Publication Number: US-2011057067-A1

Title: Reel with a Rotatable Reeling Device and Replaceable  Drum

Description:
The present invention is related to a frame structure arranged for carrying a cable drum. In particular it is a matter of a frame structure arranged for carrying a cable drum, where said frame structure comprises a reeling device for guiding of the cable. 
     By the expression frame structure it is hereby meant a frame or container arranged for carrying, driving and guiding a cable drum with cable, for example a so called “umbilical”. In the professional sphere a frame structure of the type in question is called “reel”. 
     A frame structure or “reel” that includes driving devices and a corresponding drum is commonly known in the industry related to offshore survey and exploration of petroleum. Examples of such reels are known from the US patents U.S. Pat. Nos. 5,950,953 and 7,210,647 and from the Australian publication AU-B 15080/92. 
     During such offshore operations and specifically in connection with the installation and rigging down of submarine production equipment at the sea bottom and during maintenance and measurements, so called “work over” in submarine wells, it is common to conduct the operations from the surface by means of the so called “umbilical”, which can comprise electric cables, hydraulic hoses and tubes and fibre optic cables. As said umbilical cable, in the following also referred to as “cable”, is a critical component during such installation and maintenance operations, there is a requirement that it should be possible to replace the umbilical cable if it should fail or be cut. 
     So far it has in practice not been possible to replace a damaged cable with a new one by just replacing the cable drum. Therefore it has been a normal requirement that a complete reel should be available in backup so that the entire reel including cable can be replaced with a new one if such a need should arise. 
     Reels of the type discussed here are very expensive, as they are complete units comprising supporting frame, motor and steering systems. As the supporting frame itself is a hoisting device several authorities also require an annual certification. 
     On an offshore installation the space is limited. Therefore there is normally not enough space to store a spare reel on the installation itself. Instead it is common practice to store such reels on land. A cable break therefore will entail a fairly long shut down of for example an offshore operation. 
     An object of the invention is to remedy or reduce at least one of the drawbacks of prior art. 
     This object is achieved by the features disclosed in the description set forth below and the subsequent patent claims. 
     In a first aspect of the present invention a frame structure adapted for carrying a cable drum is provided, said frame structure including a reeling device for guiding of the cable, the reeling device being arranged rotatable in relation to the frame structure in such a way that the cable drum can be removed from the frame structure. 
     In a preferred embodiment the frame structure is further provided with at least one driving device for providing a rotation of the cable drum for reeling cable thence and thereon. 
     It is an advantage if the reeling device is arranged for rotation about a side portion of the frame structure for enabling hoisting said cable drum out from and into the frame structure through the top portion of the frame structure so that for example a hoisting device may be used. 
     For facilitating release of the engagement between the cable drum and the frame structure the cable drum is provided with an external driving rim arranged for engagement with the at least one driving device. Furthermore it is an advantage if the frame structure is provided with a dividable bearing rim adapted for carrying a bearing arranged externally on the cable drum. In a preferred embodiment the driving rim and the bearing are each arranged externally on the corresponding drum flange. 
     In a second aspect of the invention a method is provided for replacing a first cable drum in a frame structure, with a second cable drum, the frame structure including a reeling device for guiding the reeling of cable out from and on to the cable drum, said method including the steps of: 
     releasing the first cable drum from engagement with the frame structure; 
     turning the reeling device away from the frame structure to establish an opening that is sufficient for removing the first cable drum from the frame structure; 
     hoisting the first cable drum out from the frame structure; and 
     carrying out the above listed steps in the opposite order for bringing the second cable drum into engagement with the frame structure. 
     It is an advantage if said frame structure is provided with detachable side panels for facilitating the access needed for disconnection and connection of the drum and the frame structure. 
    
    
     
       The following is a description of an example of a preferred embodiment, illustrated in the accompanying drawings, where: 
         FIG. 1  shows a perspective view of a frame structure according to the present invention, seen at an angle from above, said frame structure carrying a drum; 
         FIG. 2  shows the frame structure of  FIG. 1  having a cross member of an upper portion of said frame structure removed for enabling the swinging of the reeling device of the frame structure away from the top portion of the frame structure; 
         FIG. 3  shows the frame structure of  FIG. 2  after removal of side panels and during the removal of an upper portion of a bearing rim from said frame structure; 
         FIG. 4  shows the frame structure of  FIG. 3  after the turning away of the reeling device from the top portion of the frame structure; 
         FIG. 5  shows the drum during its removal from the frame structure; and 
         FIG. 6  shows the frame structure after the removal of the drum. 
     
    
    
     In the drawings reference numeral  1  denotes a frame structure according to the present invention. The frame structure comprises a framework  3 , two driving motors  5 ,  5 ′, a rotatable reeling device  7  and a bearing rim  11 . 
     For the sake of clarity only a limited number of the components shown in the drawings are given reference numerals. A person skilled in the art will understand the purpose of the components being shown but not further discussed in the description below. 
     The frame structure  1  is configured for carrying and driving is a drum  13 . It should be understood that during a working situation this drum  13  will be provided with a cable reeled thereon, but for clarity said cable is not shown in the drawings. 
     A driving rim  15  (see  FIG. 5 ) is arranged externally on one of the two flanges  17  of the drum  13 . The teeth of the driving rim  15  are arranged in a manner known per se to engage with the complementary cog wheel  15 ′ (see  FIG. 6 ) connected to the driving motors  5 ,  5 ′. It is to be understood that the frame structure  1  may also be provided with just one driving motor  5 ,  5 ′ or alternatively more than two driving motors  5 ,  5 ′. 
     A bearing  19  is provided externally on the other one of the two flanges  17  of the drum  13 . The bearing  19  is designed to be enclosed within the bearing rim  11  of the frame structure. 
     The bearing rim  11  is dividable. In the illustrated embodiment it is constituted by an upper and a lower semicircular portion. The bearing rim  11  is fixed to the frame structure  3  in a way known per se. 
     In  FIG. 1  the frame structure  1  is shown in a working position. Detachable panels  4  are arranged in portions of the frame  3 . The purpose of the panels  4  is partly to provide a protection of the content of the frame structure  1  and partly to reduce the risk of persons coming into contact with rotating parts within the frame structure  1 . The panels  4  are designed for removal and are provided with grips  21  for securing a firm grasp during handling. 
     In  FIG. 2  a cross member  3 ′ (see  FIG. 1 ) of the frame  3  is removed to allow a swinging out of the reeling device  7  from the frame structure  1 . The cross member  3 ′ is fixed to the frame  3  through screw connections. It is to be understood that the frame structure  1  can be designed so as to make the cross member  3 ′ superfluous, at least in the working situation. 
     In  FIG. 3  the frame structure  1  is shown after the removal of the panels  4  and after detaching the upper portion of the bearing rim  11  from the frame  3 , and during the removal of said portion therefrom. 
     In  FIG. 4  the reeling device  7  is shown after the turning approximately 90° about a hinged fastening portion, not specifically indicated, but of a type known per se. The reeling device  7  may be used for guiding the entrance of the cable on to the drum  13  even when it is in the shown position. 
     When said reeling device  7  is in the position shown in  FIGS. 1 and 2 , it abuts against hooks  23  fixedly arranged to the framework  3 ′. 
     In  FIG. 5  the drum  13  is shown when being inserted into or removed from the frame structure  1 . Neither the hoisting device nor the lifting devices connecting the drum  13  with said hoisting device is shown. 
     In the embodiment shown the cable feeding portion  8  of the reeling device  7  is provided with an angular form. Said cable feeding portion  8  is defined by a number of rollers  8 ′. Due to said angular form of the cable feeding portion  8 , the cable (not shown) may be fed stepless in the cable feeding portion  8  between a substantially horizontal position and a vertical position. 
     The present invention thus solves the problems related to the replacement of a cable in a reel as mentioned introductorily. In addition the present invention facilitates the replacement is of components of the frame structure  1 , as the access to such components is improved in a simplified way by temporarily removing the drum  13  from the frame structure  1 .