Patent Publication Number: US-9896161-B2

Title: Locking device for a damping apparatus for a moon pool

Description:
CROSS-REFERENCE(S) TO RELATED APPLICATION 
     This application is a continuation application of U.S. patent application Ser. No. 13/877,145 filed Jul. 17, 2013, now abandoned, which claims priority to and the benefit of Korean Patent Application No. 10-2010-0094027, filed on Sep. 29, 2010, the disclosures of which are incorporated herein by reference in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a damping device of a moonpool, and more particularly, to a locking apparatus for a damping device of a moonpool, which can automatically lock or unlock an opened state of the damping device of the moonpool. 
     Description of the Related Art 
     With the development of offshore drilling techniques, drill ships equipped with drilling equipment suitable for development of small marginal fields or deep-sea oil fields have been developed. 
     In a conventional offshore drilling, rig ships or fixed type platforms have been mainly used, which can be moved only by tugboats and are anchored at a position on the sea using a mooring gear to conduct an oil drilling operation. In recent years, however, so-called drill ships have been developed and used for offshore drilling The drill ships are provided with advanced drilling equipments and have structures similar to typical ships such that they can make a voyage using their own power. Since drill ships have to frequently move in order for development of small marginal fields, they are constructed to make a voyage using their own power, without assistance of tugboats. 
     Meanwhile, a moonpool through which a variety of equipments for a drilling operation pass is installed in an offshore platform such as a drill ship or a drill rig. In order to couple a riser, a moonpool may also be installed in a ship such as an LNG-RV and offshore platforms such as LNG FPSO, oil FPSO or LNG FSRU. The moonpool has a hollow parallelepiped or cylindrical structure through which a variety of equipments are vertically moved between an upper deck and a bottom of an offshore platform. 
     As the size of an offshore platform increases, a moonpool also becomes larger. Accordingly, in the case of a parallelepiped moonpool, a large moonpool with a size of 12-13 m (a length in a width direction of an offshore platform)×14-25 m (a length in a front and rear direction of an offshore platform) has been used. Such a moonpool is indispensable in terms of the purpose of a drill ship, but is very disadvantageous in terms of anchoring of the ship, voyage stability and voyage performance of the ship. 
     In particular, a sloshing phenomenon is induced by a relative movement between seawater flowing into the moonpool and seawater outside the hull of the ship. The sloshing phenomenon may cause an increase in voyage resistance, a decrease in voyage speed, an increase in power consumption and fuel consumption, and a damage of a hull. 
     In addition, an overflowing phenomenon is induced by a fluid movement inside the moonpool. The overflowing phenomenon may serve as a factor that deteriorates a worker&#39;s safety and work efficiency. 
     Accordingly, a damping device which opens and closes the moonpool is installed in order to minimize the movement resistance of the hull and effectively prevent the overflowing phenomenon caused by high waves. One or two damping devices are hinged to a sidewall of the moonpool to open and close the moonpool. Driving wires are coupled to the damping devices such that the opening and closing operation of the damping devices is carried out. 
     Meanwhile, in the case where such a damping device is not used, that is, the damping device maintains an opened state, a worker has climbed down a ladder to reach a storage position and then locks the opened state of the damping device by turning a locking lever. 
     As described above, since the locking and unlocking operation of the conventional damping device is carried out by a worker&#39;s action that manually locks and unlocks the opened state of the damping device, a worker is in danger of falling and the locking and unlocking operation is very inconvenient. 
     SUMMARY OF THE INVENTION 
     An aspect of the present invention is directed to a locking apparatus for a damping device of a moonpool, which can automatically lock and unlock an opened state of a damping device of a moonpool. 
     According to an embodiment of the present invention, a locking apparatus for a damping device of a moonpool, which automatically locks and unlocks one or more damping devices opening and closing the moonpool in an opened state, includes: one or more first locking members installed in a sidewall of the moonpool; one or more second locking members installed in a side of the damping device; and a holding unit separably holding the first locking members and the second locking members when the damping devices are in the opened state. 
     The first locking member may have one or more first locking holes, and the second locking member may have one or more second locking holes. 
     The first locking member may be installed in a sidewall of the moonpool adjacent to an end of the damping device when the damping device is in the opened state, the second locking member may be installed at the end of the damping device, and the first locking member and the second locking member may be disposed not to be interfered with each other when the damping device is in the opened state. 
     The holding unit may include: a driving cylinder disposed on the first locking member; and a holding shaft installed to be vertically movable by the driving cylinder, such that the holding shaft moves vertically and is inserted into or released from the first and second locking holes when the first locking hole of the first locking member and the second holding hole of the second holding member are matched with each other, whereby the holding unit separably holds the first locking member and the second locking member. 
     The locking apparatus may further include one or more guide members above the first locking member, wherein the guide members have guide holes. 
     The locking apparatus may further include a pair of regulation plates on left and right sides of the holding shaft. 
     According to another embodiment, a locking apparatus for a damping device of a moonpool, which automatically locks and unlocks one or more damping devices opening and closing the moonpool, is characterized in that, when the damping device is in an opened state, the damping device is automatically unlockably held at a storage position of the moonpool. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a view illustrating a locking apparatus for a damping device of a moonpool according to an embodiment of the present invention. 
         FIG. 2  is an enlarged view illustrating a portion indicated by an arrow A of  FIG. 1 . 
         FIG. 3  is a plan view looked in a direction of an arrow B of  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Throughout the disclosure, like reference numerals refer to like parts throughout the various figures and embodiments of the present invention. 
       FIGS. 1 to 3  illustrate a locking apparatus for a damping device, configured as moonpool door, according to an embodiment of the present invention. 
     As illustrated in  FIG. 1 , a locking apparatus for a damping device of a moonpool according to the present invention may be applied to a moonpool structure in which one or more damping devices  2  are pivotally installed in a sidewall of a moonpool to open and close the moonpool. 
       FIG. 1  exemplarily illustrates a structure in which a pair of damping devices  2 , which are configured as a pair of moonpool doors, opens and closes the moonpool, and the locking apparatus of the present invention is installed corresponding to the respective damping devices  2 . To open and close the moonpool, a pair of damping devices may be installed as illustrated in  FIG. 1 , or only one damping device may be installed. In either case, the opening and closing operation of the damping device may be carried out in a front and rear direction or a left and right direction of a hull. 
     The locking apparatus for the damping device of the moonpool according to the embodiment of the present invention includes one or more first locking members  11  installed in a sidewall of the moonpool, one or more second locking members  12  installed in a side of the damping device  2 , and a holding unit  20  unlockably holding the first locking members  11  and the second locking members  12  when the damping devices  2  are in the opened state. 
     The first locking member  11  is installed in a sidewall of the moonpool.  FIGS. 2 and 3  exemplarily illustrate the installation of three first locking members  11 . The first locking member  11  has a first locking hole  11   a.    
     The second locking member  12  is installed in a side of the damping device  2 .  FIGS. 2 and 3  exemplarily illustrate the installation of one second locking member  12 . The second locking member  12  has a second locking hole  12   a . As illustrated is  FIGS. 1 and 2 , the second locking member  12  is attached to a slanted portion at a top of the damping device  2 . The slanted portion provides a space between the moonpool sidewall and the top of the damping device  2  when the damping device  2  is in its open position standing against the sidewall. 
     According to one embodiment, the first locking member  11  is installed in a sidewall of the moonpool adjacent to the end of the damping device  2  when the damping device  2  is in an opened state, and the second locking member  12  is installed in the end of the damping device  2 . As illustrated in  FIGS. 2 and 3 , when the damping device  2  is in the opened state, the first and second locking members  11  and  12  are disposed alternately such that they are not inferred with each other. Meanwhile,  FIGS. 2 and 3  exemplarily illustrate the installation of three first locking members  11  and one second locking member  12 . 
     Due to such a structure, the second locking member  12  of the damping device  2  is positioned such that it is inserted between the first locking members  11  of the moonpool when the damping device  2  is opened. In this case, the first and second locking holes  11   a  and  12   a  may be arranged in a straight line. 
     In this embodiment, the state in which the damping device  2  is opened refers to a state in which the damping device  2  is rotated to the sidewall of the moonpool. This means that the damping device  2  is located at a storage position of the moonpool in order not to use the damping device  2 . 
     The holding unit  20  is configured to separably hold the first and second locking members  11  and  12  such that the opened state of the damping device  2  is unlockably locked. 
     The holding unit  20  according to one embodiment of the present invention includes a driving cylinder  21  which is installed at an upper portion of the first locking member  11 , and a holding shaft  22  which is vertically movable by the driving cylinder  21 . 
     The driving cylinder  21  is installed in a sidewall of the moonpool. One end of the driving cylinder  21  may be pivotally hinged to the sidewall of the moonpool. 
     An upper portion of the holding shaft  22  is coupled to a lower portion of a driving rod  21   a  of the driving cylinder  21 . Accordingly, when the driving rod  21   a  of the driving cylinder  21  is operated, the holding shaft  22  is vertically movable. 
     Due to such a structure, when the damping device  2  is opened and the first and second locking holes  11   a  and  12   a  are matched with each other, the holding shaft  22  may move vertically along the first and second locking holes  11   a  and  12   a  and separably hold the first and second locking members  11  and  12 . 
     Meanwhile a pair of regulation plates  23  is installed on left and right sides of the holding shaft  22 . The regulation plates  23  prevent the holding shaft  22  from being released to left and right. 
     In addition, one or more guide members  13  are installed above the first locking member  11 , and the guide members  13  have guide holes  13   a . The holding shaft  22  can ensure the precision of the upward/downward movement along the guide holes  13   a  of the guide members  13 . 
     A remote controller (not shown) is coupled to the driving cylinder  21 . The driving of the driving cylinder  21  is controlled by the remote controller (not shown). Accordingly, the opened state of the damping device  2  can be automatically locked and unlocked. 
     According to the present invention, the opened state of the damping device  2  can be automatically locked and unlocked by the locking members  11  and  12  and the holding unit  20  that separably hold the locking members  11  and  12 . As compared to the conventional passive method, a worker is not in danger of falling and the locking and unlocking operation is very convenient. 
     While the embodiments of the present invention has been described with reference to the specific embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.