Abstract:
The invention described herein relates to a cleaning tool for cleaning subsea conduits, such as tendons, risers or strakes. This invention comprises a flotation collar and brush member which may be attached to a subsea conduit and which may travel up a subsea conduit as a result of buoyancy forces and be retracted using one or more winches.

Description:
BACKGROUND OF THE INVENTION 
     The invention described herein relates to a cleaning tool for cleaning subsea conduits, such as tendons, risers or strakes. This invention comprises a flotation collar and brush member which may be attached to a subsea conduit and which may travel up a subsea conduit as a result of buoyancy forces and be retracted using one or more winches. 
     Marine growth can accumulate on subsea conduits. For subsea conduits intended to suppress vortex induced vibration (VIV), such as strakes, marine growth can reduce their ability to suppress VIV. The invention disclosed herein is useful for removing marine growth from a VIV suppression device, such as a strake. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a first isometric view of a preferred embodiment of the invention disclosed herein. 
         FIG. 2  is a second isometric view of a preferred embodiment of the invention disclosed herein. 
         FIG. 3  is a third isometric view of a preferred embodiment of the invention disclosed herein. 
         FIG. 4  is a block diagram of one embodiment of a winch, power supply and latches, as described herein. 
         FIG. 5  is a side view of a preferred embodiment of the first arm, anchoring member and first end of the first flexible connector described herein. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A first preferred embodiment of the invention is directed toward a subsea conduit cleaning tool. This embodiment is shown in  FIGS. 1-4 . This preferred embodiment comprises a flotation collar  10  comprising an upper surface  11 , a lower surface  12 , and a central channel  13  sized to fit around a subsea conduit  14 , as shown in  FIGS. 1-2 . In another preferred embodiment, the flotation collar comprises foam. 
     The first preferred embodiment further comprises a brush member  16  attached to the lower surface of the flotation collar, as shown in  FIGS. 1-3 . The brush member comprises an outer housing  18  comprising a first arm  17  and a second arm  19  opposite the first arm, a central opening, and bristles  15  mounted in the central opening, as shown in  FIGS. 1-3 . The flotation collar possesses sufficient buoyancy to ascend upward with the brush member, when not restrained by external mechanical forces. 
     The first preferred embodiment further comprises a first flexible connector  20  having a first end  21  attached to the first arm and a second end opposite the first end. The first preferred embodiment further comprises a second flexible connector  24  having a first end  25  attached to the second arm, and a second end opposite the first end. The first and second flexible connectors possess sufficient tensile strength to restrain the upward movement of the flotation collar and brush member as a result of their buoyancy. In another preferred embodiment, the first and second flexible connectors are ropes. In another preferred embodiment, the ropes comprise para-aramid fibers. In another preferred embodiment, the first and second flexible connectors comprise wires. 
     The first preferred embodiment further comprises a first winch  30  attached to the second end of the first flexible connector, such that rotation of the first winch in a first direction will wind up the first flexible connector and rotation of the first winch in a second direction will unwind the first flexible connector. 
     The first preferred embodiment further comprises a second winch  32  attached to the second end of the second flexible connector, such that rotation of the second winch in a first direction will wind up the second flexible connector and rotation of the second winch in a second direction will unwind the second flexible connector. 
     The first preferred embodiment further comprises a winch mounting plate  34  on which are mounted the first and second winches in substantial radial alignment with the first and second arms, respectively. In another embodiment, the invention further comprises a first latch  36  attached to the first winch and positioned to stop rotation of the first winch, and a second latch  37  attached to the second winch and positioned to stop rotation of the second winch, as shown in  FIG. 4 . 
     In another preferred embodiment, the cleaning tool comprises winch rotation measuring instrument  50  operatively coupled to the first and second winches to measure their rotations. In another preferred embodiment, winch rotation measuring device is operatively coupled to actuate the first and second latches to stop the rotation of the first and second winches, respectively, in response to a measured predetermined amount of rotation of the first and second winches, as shown in  FIG. 4 . 
     In another embodiment, a variety of sensors may be mounted on the flotation collar or the brush member. Such sensors may include sensors for measuring water depth, water temperature, or water current. These sensors may be used to generate a signal to stop the upward travel of the flotation collar and brush member, or to cause the winches to rotate in the first direction, described above. 
     The first preferred embodiment further comprises a power supply  38  attached to the mounting plate and operatively connected to the first and second winches. In another embodiment, the power supply is a battery. In another embodiment, the invention further comprises a waterproof container  39 , such as a canister, housing the battery, as shown in  FIG. 4 . In another embodiment, the power supply is hydraulic. 
     The first preferred embodiment further comprises a lower clamp  40  comprising an upper surface, attached to the winch mounting plate and a central channel sized to fit around a subsea conduit. 
     In another embodiment, the invention comprises a subsea conduit  14  having a lower end to which the lower clamp is attached and a body above the lower end to which the flotation collar and brush member are attached. The subsea conduit extends through the central channel of the flotation collar, the central opening of the brush member, and the central channel of the lower clamp. In a preferred embodiment, the subsea conduit may be a tendon, riser, or strake. 
     In another embodiment, the winches are capable of freewheeling in a second direction, thereby permitting the buoyancy of the flotation collar and brush member to raise the flotation collar and brush member up a subsea conduit to which they are attached until the first and second flexible connectors are fully extended or unwound. When the brush member is rising in this manner, its brushes are scraping against the outer surface of the subsea conduit and cleaning it. 
     When the first and second winches are operated to wind up the first and second flexible connectors, respectively, the flotation collar and brush member are pulled downward along a subsea connector to which they are attached. During the downward travel, the brushes also scrape against the outer surface of the subsea conduit and clean it. 
     In another embodiment, the invention comprises a first anchoring member  44  attached to the first arm and the first end of the first flexible connector; and a second anchoring member  44  attached to the second arm and the first end of the second flexible connector, as shown in  FIG. 5 , for the first arm. In a preferred embodiment, the anchoring means is a hook. 
     The foregoing disclosure and description of the inventions are illustrative and explanatory. Various changes in the size, shape, and materials, as well as in the details of the illustrative construction and/or an illustrative method may be made without departing from the spirit of the invention.