Cargo hatch
Patent Information
- Application Number
- JP2024123567
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-08-04
- Filing Date
- 2024-07-30
- Publication Date
- 2025-02-17
Smart Images
Figure 2025023832000001_ABST
Abstract
Description
[Technical field]
[0001] The present invention relates to cargo hatches, particularly but not exclusively to cargo hatches on bulk carriers. [Background technology]
[0002] Bulk carriers are merchant ships that transport cargoes known as bulk cargo, such as coal, cement, ores, and grains. Typically, bulk cargoes are loaded directly into the holds of a bulk carrier without packaging or additional containers, but bulk carriers may also be used to transport other cargoes (e.g. packaged cargo). In a bulk carrier, the cargo holds are accessed through hatch openings in the ship's deck, which are covered by one or more hatch covers. The hatch covers rest on top of hatch coamings (vertically extending flat surfaces / plates) that completely surround the hatch openings and provide a seal to protect the cargo holds from weather and seawater.
[0003] Traditionally, the seal is achieved by means of a compression bar attached to the top of the hatch coaming and a cooperating gasket (e.g., a rubber gasket) mounted in a channel (e.g., a steel channel) in the bottom of the hatch cover. When the hatch cover is in its closed position, the gasket rests on the compression bar and the weight of the hatch cover causes the gasket to conform to the shape of the compression bar to form a seal. This type of prior art arrangement is known to provide protection against rainwater, but may provide only limited protection against the ingress of seawater into the cargo holds, for example during heavy weather at sea.
[0004] Furthermore, over the life of a bulk carrier, damage to the components of the cargo hatches (e.g. hatch coamings, hatch covers, gaskets, compression bars) can reduce the effectiveness of this traditional type of seal. Such damage can occur through weathering or corrosion, or through accidents while loading and discharging the vessel. As a result, one of the most frequent problems in the carriage of bulk and other cargoes by bulk carriers is contamination by ingress of seawater or rainwater into the cargo holds. This can result in damage to the cargo (especially as the cargo is often unpacked) and subsequent insurance claims.
[0005] The present invention has been devised in light of the above considerations. Summary of the Invention
[0006] Most generally, the disclosure relates to a cargo hatch for a bulk carrier including a hatch coaming surrounding a hatch opening and a hatch cover configured to be removably positioned on the hatch coaming such that the hatch cover reversibly closes at least a portion of the hatch opening, the cargo hatch including two sealing systems (e.g. a dual sealing arrangement) configured to provide respective and separate seals between the hatch coaming and the hatch cover in use.
[0007] In a first aspect, there is provided a cargo hatch for a bulk carrier comprising: a hatch coaming surrounding a hatch opening; a hatch cover configured to be removably placed on the hatch coaming such that the hatch cover reversibly closes at least a portion of the hatch opening; a first sealing system comprising a gasket and a compression bar, the first sealing system configured to provide a seal between the hatch coaming and the hatch cover in use; and a second sealing system comprising an expandable seal, the second sealing system configured to provide a seal between the hatch coaming and the hatch cover in use.
[0008] As used herein, "in use" means that the hatch cover is on the hatch coaming and therefore the hatch opening is closed by the hatch cover. In this situation, the cargo hatch is said to be in a closed condition.
[0009] By providing a cargo hatch according to the first aspect, the sealing between the hatch cover and the hatch opening (e.g. defined by the hatch coaming) may be improved. In particular, water ingress into the hold and contamination of the cargo therein may be reduced or eliminated. In particular, the second sealing system including an expandable seal may contribute to improving the waterproofness of the cargo hatch and the cargo hold. Furthermore, by providing a second sealing system including an expandable seal, the cargo hatch may maintain a watertight seal even with repeated use, despite physical changes (e.g. dimensions) of the hatch cover and / or hatch coaming, for example due to weathering and / or corrosion.
[0010] The hatch cover may be configured to be removably placed on the hatch coaming such that the hatch cover reversibly closes the hatch opening (e.g., the entire hatch opening), in other words, a single, one-piece hatch cover may be used to close the hatch opening.
[0011] By providing a hatch cover that reversibly closes the entire hatch opening, there may be fewer potential paths for water ingress into the cargo hold compared to conventional side-rolling hatch covers that typically consist of two cooperating hatch covers, each covering half of the hatch opening and meeting at a center seam when closed. In this conventional type of side-rolling hatch cover design, the center seam provides an additional path for water ingress into the cargo hold in addition to the area around the edge of the hatch opening where the hatch cover meets the hatch coaming. In other words, the length of the sealing system required for the cargo hatch is reduced in embodiments where the hatch cover reversibly closes the entire hatch opening.
[0012] The operation of the cargo hatch according to the first aspect is as follows: After cargo is loaded into the hold through the hatch opening, the hatch cover is moved into position so as to be placed on the hatch coaming. The hatch opening is then closed by the hatch cover. This process may also be referred to as closing the hatch cover. A gasket and a compression bar may be placed on the opposite faces of the hatch cover and the hatch coaming. For example, the compression bar may be placed on the hatch coaming and the gasket may be placed on the hatch cover. When the hatch cover is placed on the hatch coaming, the gasket abuts (e.g. rests on) the compression bar and the gasket conforms to the shape of the compression bar (e.g. under the weight of the hatch cover) and a seal is provided between the hatch coaming and the hatch cover. This is the first sealing system.
[0013] During the closing of the hatch cover, the expandable seal is in a non-expanded state. When the hatch cover is placed on the hatch coaming, the expandable seal is expanded to an expanded state. In the expanded state, the expandable seal abuts both the hatch cover and the hatch coaming and conforms to the shape of the hatch cover (e.g., the hatch cover skirt, see below) and the hatch coaming, thereby providing a seal between the hatch cover and the hatch coaming. This is the second sealing system. In the expanded state, the volume of the expandable seal is greater than the volume of the expandable seal in the non-expanded state.
[0014] When access to the cargo hold is required, the hatch cover can be removed from the hatch opening, thereby providing access to the cargo hold through the hatch opening. When the hatch cover is removed from the hatch opening, the cargo hatch is said to be in an uncovered state. In the uncovered state, the hatch cover can be adjacent to the hatch opening, thereby providing access to the cargo hold through the hatch opening.
[0015] The expandable seal may be a reversibly expandable seal. In other words, the expandable seal may be expanded from a non-expanded state to an expanded state, and also (e.g., subsequently) contracted (i.e., reduced in volume) from the expanded state to the non-expanded state. In an embodiment in which the expandable seal is a reversibly expandable seal, the operation of the expandable seal may be as follows: When the cargo hatch is in a closed state, the expandable seal may be expanded from a non-expanded state to an expanded state, providing a seal between the hatch cover and the hatch coaming as described above. When the hatch cover is removed, the expandable seal may be contracted from an expanded state to a non-expanded state, thereby no longer providing a second seal between the hatch cover and the hatch coaming. This may allow the hatch cover to be more easily removed from the hatch opening in order to open the hatch. This also means that the expandable seal may return to a non-expanded state, ready for the next closing of the hatch cover, for example after new cargo has been loaded into the hold through the hatch opening.
[0016] The expandable seal may be an inflatable seal. For example, the seal may be expanded from a non-expanded state to an expanded state by directing inflation gas (e.g., air) into an expansion volume defined within the inflatable seal. Additionally, the seal may be contracted from an inflated state to a non-expanded state by deflation by ventilation or removal of inflation gas from the inflatable volume. For example, the expandable seal may include a skin surrounding a cavity. The volume of the cavity may be increased (e.g., from a non-expanded state to an inflated state) by injecting gas, and may be decreased (e.g., from an expanded state to a non-expanded state) by removing gas in embodiments having a reversibly expandable seal.
[0017] The hatch cover may include a bottom surface which, in use, faces a hatch opening, for example a hold of a bulk carrier. The hatch cover may include a top surface opposite the bottom surface which, in use, faces away from the hatch opening. In use, the top surface may form part of a deck of the bulk carrier.
[0018] The hatch opening may have a major axis. The hatch cover may also have a corresponding major axis. The major axes of the hatch opening and hatch cover may extend vertically, for example the major axis may be parallel to the vertical axis of the bulk carrier. When the cargo hatch is in the closed state, the major axis of the hatch cover may be collinear with the major axis of the hatch opening.
[0019] The width of the hatch opening may for example be about 10m to 25m, such as about 15m to 20m, for example about 15m, in the direction between the port side and the starboard side of the bulk carrier. The length of the hatch opening may be substantially perpendicular to the width and thus parallel to the centerline of the bulk carrier. The length of the hatch opening may be less than the width. For example, the length of the hatch opening may be about 5m to 20m, such as about 10m to 15m, for example about 10m.
[0020] The hatch coaming may include a compression bar of the first sealing system. For example, the hatch coaming may have an upper surface (e.g., facing away from the deck of the bulk carrier, e.g., facing substantially vertically) to which the compression bar is attached. The hatch cover may include a corresponding gasket that abuts (e.g., sits on) the compression bar in use and conforms to the shape of the compression bar, thereby providing a seal between the hatch coaming and the hatch cover. The seal may be maintained by the downward force that the hatch cover exerts on the compression bar.
[0021] The first sealing system may extend over the entire connection area between the hatch cover and the hatch coaming. For example, the compression bar may extend over the entire periphery of the hatch coaming. For example, the compression bar may extend over the entire periphery of the top of the hatch coaming. In such an embodiment, the gasket of the first sealing system may extend over the entire periphery of the hatch cover area (when the cargo hatch is in the closed state) and correspond (e.g., via a gasket) to the area of the hatch cover that is connected to the compression bar. For example, the gasket of the first sealing system may extend over the entire periphery of the hatch cover (e.g., on the bottom surface of the hatch cover) and be spaced inward from the periphery of the hatch cover, such that the shape of the gasket (when viewed from below) corresponds to the shape of the compression bar on the hatch coaming (when viewed from above).
[0022] In some embodiments, the hatch opening may have a quadrilateral (e.g., rectangular) shape. In other words, the hatch opening may be a quadrilateral hole (e.g., opening) in the deck of the bulk carrier. Thus, the hatch coaming that extends around the entire periphery of the hatch opening may have a quadrilateral shape when viewed from above. Furthermore, the compression bar (e.g., on the upper surface of the hatch coaming) also has a quadrilateral shape when viewed from above, thereby surrounding the periphery of the hatch opening.
[0023] In embodiments in which the compression bar has a quadrilateral shape, the corresponding gasket of the first sealing system may also have a quadrilateral shape to correspond to the shape of the compression bar. For example, the gasket of the first sealing system may be on a bottom surface of the hatch cover, so that when viewed from below, the gasket of the first sealing system forms a quadrilateral on the bottom surface of the hatch cover, which may correspond to the shape of the compression bar.
[0024] The hatch cover may include an inner gasket channel (e.g., a steel channel) configured to accommodate a gasket of the first sealing system. The inner gasket channel may be in a bottom surface of the hatch cover. The inner gasket channel may have a quadrilateral shape such that the gasket of the first sealing system has a quadrilateral shape as described above.
[0025] The hatch coaming may include one or more side surfaces. The one or more side surfaces may face in a direction substantially perpendicular to the major axis of the hatch opening. The expandable seal may be disposed on one or more side surfaces of the hatch coaming. For example, the expandable seal may be disposed on one or more side surfaces near the top of the hatch coaming such that in the expanded state, the expandable seal abuts against the hatch cover to form a seal as described above.
[0026] By providing an expandable seal on one or more sides of the hatch coaming, the expandable seal can be spaced from a first sealing system that may be located on an upper surface of the hatch coaming, thereby not interfering with the operation of the first sealing system.
[0027] In some embodiments, the hatch coaming may include a channel (e.g., a half-pipe channel having a substantially semicircular cross-section) configured to accommodate the expandable seal. For example, one or more sides of the hatch coaming may comprise said channel. For example, the channel may extend (e.g., continuously) around all sides of the hatch coaming. The channel may define an outward opening. Upon expansion from an unexpanded state to an expanded state, the expandable seal may expand through the opening.
[0028] The channel may be connected (e.g., attached) to the hatch coaming via a channel support. The channel support may extend away from the hatch coaming (e.g., in a direction substantially perpendicular to the major axis of the hatch opening) such that the channel is spaced from the hatch coaming (e.g., in a direction substantially perpendicular to the major axis of the hatch opening). In some embodiments, one or more sides of the hatch coaming may include said channel support, e.g., the channel support may extend around (e.g., continuously) all sides of the hatch coaming. The channel may be spaced from the hatch coaming by about 100 mm to about 500 mm, e.g., about 150 mm to about 450 mm, e.g., about 200 mm to about 400 mm, e.g., about 250 mm to about 350 mm, e.g., about 300 mm to about 350 mm, e.g., about 300 mm (e.g., the extension from one or more sides of the channel support may be that length). The depth of the channel may be about 20 mm to about 100 mm, for example, about 30 mm to about 90 mm, for example, about 40 mm to about 80 mm, for example, about 50 mm to about 70 mm, for example, about 50 mm to about 60 mm, for example, about 60 mm. Here, "channel depth" refers to the dimension of the channel extending from the opening of the channel, for example, the dimension in a direction perpendicular to the major axis of the hatch opening and / or in a direction in which the channel support extends away from the side of the hatch coaming. In an embodiment in which the channel is a half-pipe channel, the diameter of the half-pipe channel may be about 40 mm to about 200 mm, for example, about 60 mm to about 180 mm, for example, about 80 mm to about 160 mm, for example, about 100 mm to about 140 mm, for example, about 100 mm to 120 mm, for example, about 120 mm.
[0029] One or more sides of the hatch coaming may be the outer side of the hatch coaming, respectively, facing away from the hatch opening (e.g., towards the gunwale side of a bulk carrier). In other words, the one or more sides may face outward.
[0030] By providing an expandable seal on the outer side of the hatch coaming, in use the second sealing system may provide a seal between the hatch coaming and the hatch cover and isolate the first sealing system from the outside environment, such that the second sealing system may reduce the likelihood of the first sealing system being damaged by weathering or corrosion.
[0031] The second sealing system may extend across the entire connection area between the hatch cover and the hatch coaming, for example, the expandable seal (and a channel configured to accommodate the expandable seal) may extend all around the hatch coaming and hatch opening.
[0032] In embodiments in which the hatch opening has a quadrilateral shape (as described above), the expandable seal may extend (e.g., extend continuously) along each side of the quadrilateral shape. In these embodiments, the hatch coaming may include an expandable seal (and, e.g., a channel to accommodate the expandable seal) on each side of the quadrilateral shape.
[0033] Bulk carriers (like all other vessels) have a centerline. In embodiments where the hatch opening is a quadrilateral, the quadrilateral may be substantially aligned with the centerline of the bulk carrier. In other words, the hatch opening may have four sides facing forward, aft, port and starboard, respectively. Additionally, other features having a corresponding quadrilateral shape (as described above) may be aligned with the centerline of the bulk carrier as well. For example, a hatch coaming may have four outer sides facing forward, aft, port and starboard, respectively.
[0034] The hatch cover may include a skirt. The skirt may extend away from the hatch cover, e.g., a bottom surface of the hatch cover. For example, the hatch cover may include a skirt that extends from the bottom surface of the hatch cover towards the hatch opening in use. The skirt may resemble a plate attached to the hatch cover (e.g., a plate attached to the bottom surface of the hatch cover) and is substantially perpendicular to the hatch cover. For example, the skirt may include a plate that forms a continuous loop and extends from the hatch cover and is substantially perpendicular to the hatch cover. The skirt may include one or more sides that face in a direction substantially perpendicular to the major axis of the hatch cover.
[0035] In use, the skirt may extend around the entire perimeter of the hatch opening. The shape of the skirt (when viewed from below) may be mathematically similar to the shape of the hatch coaming (when viewed from above). In embodiments where the hatch coaming is quadrilateral in shape when viewed from above, the skirt may be a complementary quadrilateral in shape when viewed from below.
[0036] In use, the skirt (e.g., a side of the skirt) may overlap the hatch coaming (e.g., a side of the hatch coaming). In preferred embodiments, in use, the hatch coaming may be located on the side of the skirt closest to the hatch opening. In these embodiments, the skirt is between the hatch coaming and the outside environment and is therefore said to be located outboard of the hatch coaming. The spacing between the hatch coaming and the skirt may be uniform around the periphery of the hatch opening.
[0037] When the hatch opening is closed by the hatch cover, the inner gasket channel (and gasket) may be disposed inside the skirt such that the skirt is disposed between the inner gasket channel and an edge of the hatch cover. An outer wall of the inner gasket channel (e.g., the wall closest to the edge of the hatch cover) may be proximate to (e.g., connected to and optionally aligned with) the skirt such that the gasket of the first sealing system is proximate to (e.g., connected to) the skirt.
[0038] By providing a hatch cover with a skirt that extends from the bottom surface of the hatch cover toward the hatch opening in use, a seal and sealing system may be more easily provided between the hatch cover and the hatch coaming. Furthermore, a longer and / or more complex path may be provided between the external environment and the hatch opening to reduce water ingress into the hold through the hatch opening. In particular, by providing a skirt on the outside of the hatch coaming in use, the water ingress path requires the water to travel upwards before passing over the top of the hatch coaming. Furthermore, by providing a skirt on the outside of the hatch coaming in use, the first sealing system and the expandable seal are protected from the external environment by the skirt. This may reduce damage from weathering and / or corrosion and increase the life of the sealing system.
[0039] The skirt may extend from the bottom surface of the hatch cover by about 100 mm to about 400 mm, such as about 150 mm to about 350 mm, for example about 200 mm to about 300 mm, for example about 200 mm to about 300 mm, for example about 270 mm.
[0040] The skirt may include one or more reinforcing members. Such reinforcing members may be provided on one or more sides of the skirt, for example on one or more outer sides of the skirt. By one or more outer sides of the skirt, it is meant the sides that face away from the hatch opening in use. The reinforcing members may be spaced apart from one another along the skirt. The reinforcing members may extend away from the bottom surface of the hatch cover. The reinforcing members are referred to as brackets.
[0041] The skirt (e.g., one or more sides of the skirt) may include a cleat notch about its periphery. Some or all of the plurality of reinforcing members may include respective cleat notches.
[0042] In embodiments where the skirt overlaps the hatch coaming in use, the expandable seal may abut the skirt (e.g., one or more sides of the skirt) and the hatch coaming (e.g., one or more sides of the hatch coaming) when in the expanded state. For example, in embodiments where the expandable seal is disposed on one or more outer sides of the hatch coaming and the skirt is disposed outboard of the hatch coaming, the expandable seal may abut the skirt and conform to the shape of the skirt (e.g., the shape of one or more sides of the skirt), thereby providing a seal between the hatch cover and the hatch coaming. In other words, the second sealing system may include an expandable seal and a skirt, whereby in the expanded state, the expandable seal abuts the skirt to provide a seal between the hatch coaming and the hatch cover.
[0043] By providing a second sealing system including an expandable seal and a skirt, the expandable seal can abut and conform to the shape of the skirt when in an expanded state, thereby providing a seal between the hatch cover and the hatch coaming. The skirt provides a surface for the expandable seal to abut against and create a high quality seal. Additionally, the skirt protects the expandable seal from the external environment.
[0044] As mentioned above, the hatch cover is moved into position to be located on the hatch coaming after cargo has been loaded into the hold through the hatch opening. Prior to being moved into position, the hatch cover is positioned adjacent to the hatch opening, thereby leaving the hatch opening uncovered (referred to as an uncovered state). The cargo hatch can be (reversibly) transitioned between a covered state (where the hatch cover covers the hatch opening) and an uncovered state. Between the covered and uncovered states, the hatch cover can be moved in a direction substantially parallel to the bulk carrier centreline.
[0045] In the covered state, the hatch cover is positioned over the hatch opening but is not positioned on the hatch coaming, and thus the cargo hatch can be reversibly moved (e.g., lowered and raised) between the covered and closed states.
[0046] To ensure that the hatch cover fits correctly in its closed position when the cargo hatch is in the closed state, the cargo hatch may include means for correctly locating the hatch cover, such as a wedge slide.
[0047] The hatch coaming may include one or more friction pads (bearing pads) to support the hatch cover. For example, the upper surface of the hatch coaming may include multiple (e.g., four) friction pads to support the hatch cover. The friction pads may be bolted or welded to the hatch coaming. The hatch cover rests on the compression bar (or compression bars) described herein through respective gaskets and may also rest on the friction pads.
[0048] The hatch covers may be mounted on tracks, e.g., on wheels, such that the hatch covers may move along the tracks to transition between covered and uncovered states. For example, the cargo hatch may include two tracks. The tracks may extend approximately parallel to the centerline of the bulk carrier. One track may be on the starboard side of the hatch opening and the other track may be on the port side of the hatch opening. The hatch covers may include wheels. The one or more wheels may be configured to run along the respective tracks, e.g., stationary and rotating on the respective tracks. For example, the hatch covers may include two wheels configured to stationary and rotating on the starboard track and two wheels configured to stationary and rotating on the port track. In some embodiments, the hatch covers may include, for example, four such wheels located near each corner of the hatch covers.
[0049] One or more motors can be used to drive the wheels along the track. The hatch cover may include one or more motors. For example, each wheel may have a corresponding motor. The track and wheels may have teeth (e.g., the track resembles a rack and the wheels resemble an interlocking pinion).
[0050] When closing the hatch cover, it can be moved over the hatch opening, for example by moving it along a track. At this stage the cargo hatch is covered but not yet closed. The hatch can include means for lowering the hatch cover onto the hatch coaming. For example, one or more hydraulic jacks can be provided for lowering the hatch cover onto the hatch coaming. For example, four hydraulic jacks can be provided, one at each corner of the hatch cover. The hatch cover can thus be placed onto the hatch coaming (e.g. so that the hatch is in a closed state) and the sealing system can then be operated as described herein.
[0051] When access to the hold is required, the hatch cover may be lifted (e.g., via a hydraulic jack) and the cargo hatch transitioned from a closed to a covered state, and then moved away from the hatch opening (e.g., via a truck) and the cargo hatch transitioned from a covered to an uncovered state.
[0052] In use, the hatch cover may extend beyond the hatch opening, e.g., the hatch coaming. For example, in use, the hatch cover may extend laterally beyond the hatch opening, e.g., toward the port and / or starboard side of the bulk carrier. In some embodiments, the portion of the hatch cover that extends beyond the hatch opening may, in use, cover a portion of the crew passageway and / or workspace adjacent the hatch opening. The workspace may be provided between the crew passageway and the hatch coaming (e.g., on one or both sides of the bulk carrier).
[0053] In embodiments where the hatch cover extends beyond the hatch coaming, one or more edges of the hatch cover (in use) may be connected to (e.g., rest on) a support area of the bulk carrier. For example, the support area may be part of the deck of the bulk carrier. In some embodiments, an additional sealing system may be provided between the hatch cover and the support area (e.g., the deck of the bulk carrier). The additional sealing system may include a gasket and a compression bar. For example, the support area (e.g., the deck) may include a compression bar and the hatch cover may include an additional gasket for the additional sealing system. In use, the gasket of the additional sealing system may abut (e.g., rest on) the compression bar on the support area and conform to the shape of the compression bar to provide a seal between the hatch cover and the support area. The seal may be maintained by the downward force exerted by the hatch cover on the compression bar.
[0054] The support area of the bulk carrier may extend around the entire periphery of the hatch opening. The additional sealing system may extend between all areas of the connection between the hatch cover and the support area of the bulk carrier. For example, the compression bar of the additional sealing system may extend around the entire periphery of the hatch opening. In these embodiments, the gasket of the additional sealing system may extend around the entire periphery of an area of the hatch cover that corresponds to an area of the hatch cover that connects to the compression bar of the additional sealing system when the hatch cover is closed. For example, the gasket of the additional sealing system may extend around the entire periphery of the hatch cover. The shape of the gasket of the additional sealing system (when viewed from below) may match the shape of the compression bar on the support area, such as the deck of the bulk carrier (when viewed from above).
[0055] The compression bars of the additional sealing system may have a quadrilateral (e.g., rectangular) shape when viewed from above to surround the hatch opening. The corresponding gasket of the additional sealing system may have a quadrilateral shape to correspond to the shape of the compression bars of the additional sealing system. For example, if the hatch cover is quadrilateral, the gasket of the additional sealing system may extend around the edge of the bottom surface of the hatch cover, also being quadrilateral.
[0056] The hatch cover may include an outer gasket channel, e.g., a steel channel, configured to accommodate a gasket of the additional sealing system. The outer gasket channel may be in a bottom surface of the hatch cover. The outer gasket channel may have a quadrilateral shape, such that the gasket of the additional sealing system has a quadrilateral shape as described above.
[0057] In a second aspect, there is provided a bulk carrier including one or more cargo hatches according to the first aspect. In some embodiments, a bulk carrier according to the second aspect may include a plurality of cargo hatches according to the first aspect, each cargo hatch including a respective hatch cover configured to be removably positioned on a respective hatch coaming, the hatch cover reversibly closing a hatch opening (e.g. the entire hatch opening).
[0058] A bulk carrier hatch cover according to the second aspect is movable in a direction substantially parallel to the centreline of the bulk carrier to cover and open the hatch opening.
[0059] In a third aspect, there is provided a method of closing a cargo hatch on a bulk carrier, the method comprising the steps of removably positioning a hatch cover on a hatch coaming of the cargo hatch; providing a first seal between the hatch coaming and the hatch cover with a first sealing system, the first sealing system comprising a gasket and a compression bar (e.g. on opposing surfaces of the hatch coaming and the hatch cover); providing a second sealing system comprising an expandable seal; and expanding the expandable seal such that a second seal is provided between the hatch coaming and the hatch cover.
[0060] Removably positioning the hatch cover on a hatch coaming of the cargo hatch may include moving the hatch cover over the hatch opening (e.g., such that the cargo hatch transitions between an uncovered state and a covered state) and lowering the hatch cover so that it is positioned on the hatch coaming.
[0061] To access the hold of the bulk carrier through the hatch opening, the method according to the third aspect may further comprise the steps of contracting the expandable seal such that the second seal is removed, and moving the hatch cover away from the hatch coaming so that the hatch opening can be accessed.
[0062] Moving the hatch cover over the hatch opening may, for example, include moving the hatch cover in a direction substantially parallel to a centerline of the bulk carrier.
[0063] The invention includes combinations of the described aspects and preferred features, except where such combinations are clearly not permitted or explicitly avoided. For example, the method of the third aspect may relate to a method of closing a cargo hatch according to the first aspect.
[0064] Throughout this specification the cargo hatch of the first embodiment is referred to as being on a bulk carrier. However, it should be understood that the cargo hatch of the first embodiment may be provided on any type of vessel, not just bulk carriers. Thus, a person skilled in the art will understand that a reference to a bulk carrier is also a reference to other vessels or boats.
[0065] In relation to this specification, "when viewed from above" means looking towards the deck of the bulk carrier. In relation to hatch covers and their components (skirts, gaskets, etc.), "when viewed from below" means looking towards the bottom of the hatch covers.
[0066] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments and experiments illustrating the principles of the present invention will now be described with reference to the accompanying drawings. [Brief description of the drawings]
[0067] [Figure 1] FIG. 1 shows a top view of a bulk carrier having a cargo hatch according to a first embodiment, the cargo hatch being shown in an uncovered state. [Diagram 2] FIG. 2 shows a rear view of the hatch cover of the cargo hatch shown in FIG. [Diagram 3] FIG. 3 shows a side view of the hatch cover of FIG. 2 as seen from the starboard side. [Figure 4] FIG. 3 is a bottom view of the hatch cover of the cargo hatch shown in FIG. [Diagram 5] FIG. 2 shows a top view of the bulk carrier of FIG. 1 with the cargo hatches shown in covered position. [Figure 6] FIG. 2 shows a cross-sectional view of the starboard side of the bulk carrier of FIG. 1, with the cargo hatches in the covered position. [Figure 7] FIG. 2 shows a cross-sectional view of the bulk carrier of FIG. 1 with the cargo hatches in a closed position. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0068] Aspects and embodiments of the present invention are described below with reference to the accompanying drawings. Further aspects and embodiments will be apparent to those skilled in the art. All documents mentioned in the text are incorporated herein by reference.
[0069] FIG. 1 shows a top view of a longitudinal section of a bulk carrier 1 having a cargo hatch 100 according to a first embodiment.
[0070] The bulk carrier 1 has a starboard upper water ballast tank 2 and a port upper water ballast tank 3 separated by an area of the deck 4 provided with a cargo hatch 100. The two upper water ballast tanks 2, 3 are separated from the area of the deck 4 provided with the cargo hatch 100 by longitudinally extending crew gangways 5a, 5b respectively. The cargo hatch 100 is symmetrical about the centre line 91 of the bulk carrier 1.
[0071] Although only one cargo hatch 100 is shown in the figures, the bulk carrier 1 may have multiple cargo hatches 100, each having the same or similar structure as the cargo hatch 100 described herein. Each cargo hatch 100 is typically spaced apart from the other cargo hatches along the centerline 91 of the bulk carrier 1 (i.e., longitudinally).
[0072] The cargo hatch 100 has a hatch opening 101 which is a rectangular hole formed in the deck 4 of the bulk carrier 1. The hatch opening 101 allows cargo to be loaded therethrough and into the hold of the bulk carrier.
[0073] The hatch coaming 110 surrounds the hatch opening 101 such that it extends around the entire perimeter of the hatch opening 101. As will be appreciated by those skilled in the art, the hatch coaming 110 comprises a vertically extending flat surface / plate that surrounds the hatch opening 101. Here, the hatch coaming 110 resembles the side of a rectangular prism such that it surrounds the entire perimeter of the hatch opening 101.
[0074] In Figure 1 the cargo hatch 100 is shown in an uncovered state, with the hatch cover 130 positioned towards the stern of the bulk carrier 1 adjacent the hatch opening 101, thereby allowing access to the hold via the hatch opening 101. In Figure 1 the components below the hatch cover 130 are shown for clarity.
[0075] The hatch cover 130 rests on two longitudinally extending wheel tracks 20a, 20b located on either side of the hatch opening 101. The hatch cover 130 has a larger area than the hatch opening when viewed from above and extends across the port and starboard crew passages 5a, 5b. Near each corner of the hatch opening 101, hydraulic jacks 120a, 120b, 120c, 120d are provided in alignment with the wheel tracks 20a and 20b, respectively.
[0076] Figure 2 is an aft view of the hatch cover 130 shown in Figure 1. The hatch cover 130 is a flat plate (e.g. metal such as steel). In this embodiment, the hatch cover 130 has a thickness of about 450mm, a width of about 19m and a length (longitudinal) of about 11.5m. A person skilled in the art will appreciate that the dimensions of the hatch cover 130 may vary depending on the size of the cargo hatch 100 and / or the bulk carrier 1.
[0077] The hatch cover 130 includes a skirt 131 extending from a bottom surface of the hatch cover 130. The skirt 131 extends around the periphery of the hatch cover 130 and is spaced inwardly from the edge of the hatch cover 130. The hatch cover 130 has a major axis 93 extending vertically through the center of the hatch cover 130. The skirt 131 includes an outer side 134 that faces in a direction substantially perpendicular to the major axis of the hatch cover in use. The outer side 134 of the skirt 131 can be said to include four continuously connected outer side surfaces 134 that face in different directions (forward, aft, port, starboard). FIG. 2 shows the outer side surface 134 of the skirt 131 facing in the aft direction. The skirt includes a plurality of reinforcing members 135 spaced along the skirt 131 on the outer side surface 134. The reinforcing members 135 (which may resemble ribs) extend away from the bottom surface of the hatch cover 130.
[0078] 3 shows a side view of the hatch cover 130 as viewed from the starboard side, where the outer surface 134 of the starboard-facing skirt 131 can be seen, along which are spaced stiffening members 135.
[0079] The hatch cover 130 includes four wheels 121a, 121b, 121c, 121d on its underside (mounted on the bottom surface). Each wheel is disposed between the skirt 131 and the side of the hatch cover 130. As shown in FIG. 3, there are two wheels 121a, 121b on the starboard side, which are aligned with each other laterally and spaced apart longitudinally. There are also two wheels 121c, 121d on the port side, which are aligned with each other laterally and similarly spaced apart longitudinally (see FIG. 4). The wheels 121a, 121b on the starboard side rest on the starboard side wheel track 20a, and the wheels 121c, 121d on the port side rest on the port side wheel track 20b, and the hatch cover 130 is movably supported on the wheel tracks 20a, 20b. The wheels 121a, 121b, 121c, 121d are configured to rotate along the wheel tracks 20a, 20b, so that the hatch cover 130 can move along the wheel tracks. Each wheel 121a, 121b, 121c, 121d is provided with a motor 122a, 122b, 122c, 122d, respectively, which drives the wheels 121a, 121b, 121c, 121d, so that the hatch cover 130 moves along the wheel tracks 20a, 20b.
[0080] Figure 4 shows the hatch cover 130 as viewed from below. In Figure 4, the four wheels 121a, 121b, 121c, 121d and their respective motors 122a, 122b, 122c, 122d are visible near the corners of the hatch cover 130. As shown in Figure 4, the skirt 131 is rectangular in shape when viewed from below.
[0081] The hatch cover 130 includes an inner gasket channel 132 provided on the inside of the skirt 131, which is disposed between the inner gasket channel 132 and an edge of the hatch cover 130. The inner gasket channel 132 extends around the entire periphery of the interior of the skirt 131. The inner gasket channel 132 follows a path having a corresponding rectangular shape when viewed from below. An outer wall of the inner gasket channel 132 is aligned with the skirt 131. The inner gasket channel 132 is configured to accommodate an inner gasket.
[0082] The hatch cover 130 further includes an outer gasket channel 133 that extends around the periphery of the bottom surface of the hatch cover 130. The outer gasket channel 133 also follows a rectangular path when viewed from below. The outer gasket channel 133 is configured to receive an outer gasket.
[0083] The hatch cover 130 shown in FIG. 4 has horizontal and vertical symmetry when oriented as shown in FIG.
[0084] Next, the operation of the cargo hatch 100 will be described.
[0085] As explained above, Fig. 1 shows the cargo hatch 100 in an uncovered state. In Fig. 5 the cargo hatch 100 is shown in a covered state with the hatch cover 130 positioned over the hatch opening 101 (parts below the hatch cover 130 are shown in Fig. 5 for clarity). The hatch cover 130 is reversibly movable between the uncovered state shown in Fig. 1 and the covered state shown in Fig. 5. This is achieved by moving the hatch cover 130 along the wheel tracks 20a, 20b on wheels 121a, 121b, 121c, 121d driven by motors 122a, 122b, 122c, 122d.
[0086] In the covered state, the hatch cover 130 is located over the hatch opening 101. Figure 6 shows a cross-sectional view of the starboard side of a bulk carrier with the cargo hatch 100 in the covered state (i.e. the cargo hatch 100 is covered but not yet closed).
[0087] FIG. 6 shows three sealing systems: a first sealing system 140, a second sealing system 150 and an additional sealing system 160.
[0088] The first sealing system 140 includes an inner gasket 141 housed within the inner gasket channel 132 of the hatch cover. The first sealing system 140 also includes an inner compression bar 142 disposed on the top of the hatch coaming 110. The compression bar 142 extends all around the top of the hatch coaming 110 and is rectangular in shape when viewed from above (similar to the hatch coaming 110). As shown in Figure 6, when the cargo hatch 100 is in the covered state, the inner gasket channel 132 is vertically aligned with the compression bar 142.
[0089] The second sealing system 150 includes an expandable seal 151 and the skirt 131 of the hatch cover 130. The expandable seal 151 is accommodated in a half-pipe channel 158 located on the outer side 111 of the hatch coaming 110 near the top of the hatch coaming 110. In particular, the outer side 111 of the hatch coaming 110 is provided with a channel support 159 extending outwardly away from the hatch coaming 110 (in a direction substantially perpendicular to the major axis 92 of the hatch opening 101). The half-pipe channel 158, having a semicircular cross section, is located at the end of the channel support 159 and is located approximately 300 mm away from the hatch coaming 110. The half-pipe channel 158 extends around the entire circumference of the hatch coaming 110. The radius of the half-pipe channel 158 is approximately 60 mm.
[0090] The expandable seal 151 is configured to reversibly expand from an unexpanded state to an expanded state. When the expandable seal 151 expands from the unexpanded state to the expanded state, it expands through an outward opening 157 of a half-pipe channel 158 that faces away from the hatch coaming 110.
[0091] The additional sealing system 160 includes an outer gasket 161 housed in an outer gasket channel 133 of the hatch cover 130. The additional sealing system 160 also includes an outer compression bar 162 arranged on the deck 4 of the bulk carrier 1. The outer compression bar 162 has a rectangular shape when viewed from above, and when the cargo hatch 100 is in the covered state, the outer gasket channel 133 is vertically aligned with the compression bar 162, as shown in FIG. 6. In other words, when the cargo hatch 100 is in the covered state, all parts of the outer gasket channel 133 are vertically aligned with parts of the compression bar 162. As a result, the outer compression bar 162 surrounds the hatch opening 101 and the hatch coaming 110 and is spaced apart from the hatch opening 101 and the hatch coaming 110.
[0092] Figure 7 shows a cross-section of the bulk carrier 1. In Figure 7, the cargo hatch 100 is shown in a closed state, with the hatch cover 130 resting on the hatch coaming 110. To close the cargo hatch 100, the cargo hatch 100 is lowered from the covered state, shown in Figure 6, to the closed state, shown in Figure 7. In particular, the hatch cover 130 is lowered from the covered state position to the closed state (on the hatch coaming 110) position by hydraulic jacks 120a, 120b, 120c, 120d. As will be appreciated by those skilled in the art, in the closed state, the hatch cover 130 can be secured in a conventional manner, for example via cleats provided around the skirt 131.
[0093] In the closed state, the inner gasket 141 of the first sealing system 140 rests on the inner compression bar 142. The weight of the hatch cover 130 causes the inner gasket 141 to conform to the shape of the inner compression bar 142, providing a weatherproof seal between the hatch cover 130 and the hatch coaming 110, thereby sealing the hold from the outside environment.
[0094] In the closed state, the outer gasket 161 of the additional sealing system 160 rests on the outer compression bar 162. The weight of the hatch cover 130 causes the outer gasket 161 to conform to the shape of the outer compression bar 162, providing an additional seal between the hatch cover 130 and the deck 4. The additional sealing system thus provides a weather-tight seal between the crew passageways 5a, 5b and the outside environment.
[0095] In the closed position, the skirt 131 of the hatch cover 130 closely surrounds the hatch coaming 110. The shape of the skirt 131 when viewed from below is mathematically similar to the shape of the hatch coaming 110 when viewed from above (i.e., rectangular in the illustrated embodiment). The close proximity between the hatch coaming 110 and the skirt 131 facilitates a second sealing system 150.
[0096] The expandable seal 151 is maintained in an unexpanded state while the cargo hatch moves from an uncovered state (as shown in FIG. 1 ) to a covered state (as shown in FIGS. 5 and 6 ) and then to a closed state (as shown in FIG. 7 ). When the cargo hatch 100 is in a closed state, the expandable seal 151 is expanded from an unexpanded state to an expanded state through an opening 157 in the half-pipe channel 158 and abuts the skirt 131. When so expanded, the expandable seal 151 conforms to the shape of the skirt 131 and provides a seal between the hatch cover 130 and the hatch coaming 110. The second sealing system 150 thereby provides a watertight seal between the hatch opening 101 and the outside environment. Furthermore, since the second sealing system 150 is outside the first sealing system 140, the second sealing system 150 protects the first sealing system 140.
[0097] When access to the cargo hold is required through the hatch opening 101, the expandable seal 151 is retracted from the extended to the unextended state and the hydraulic jacks 120a, 120b, 120c, 120d are operated to lift the hatch cover 130 and transition the cargo hatch 100 from a closed to a covered state. The hatch cover 130 is then moved along the wheel tracks 20a, 20b so that the hatch opening 101 is no longer covered (i.e. the cargo hatch 100 transitions from a covered to an uncovered state).
[0098] It will be appreciated that the expandable seal 151 may be expanded in a variety of ways. In some embodiments, for example, the expandable seal 151 may be pneumatically inflated by directing a volume of inflation gas into an interior volume of the expandable seal 151. In some such examples, the inflation gas is air and may be directed by a compressor device 180 into the expandable seal in a manner known per se. As will be appreciated, such embodiments may further include a venting device configured to vent the interior volume of the expandable seal 151 to release the inflation air and thereby transition the expandable seal 151 from the expanded state to the unexpanded state.
[0099] Alternate embodiments are also envisioned in which the expandable seal 151 may instead be hydraulically expanded by pumping a quantity of suitable hydraulic liquid into the interior volume of the expandable seal 151. In some such configurations, the hydraulic liquid may be provided in a closed hydraulic circuit (not shown) that includes a liquid reservoir and one or more flow conduits in fluid communication with the interior volume of the expandable seal 151. A reversibly operable hydraulic pump may be provided to i) pump hydraulic liquid from the reservoir to the interior volume of the expandable seal 151 to expand the expandable seal 151, and ii) pump hydraulic liquid from the interior volume of the expandable seal 151 to the reservoir to contract the expandable seal 151.
[0100] Also shown in Figure 7 are the workspaces 6a, 6b provided between the hatch coaming 110 and the respective crew aisles 5a, 5b.
[0101] In figures 6 and 7 the main axis 92 of the hatch opening 101 is shown. In figures 2 and 3 the main axis 93 of the hatch cover 130 is shown. These main axes are parallel to the vertical axis of the bulk carrier. Throughout this specification references to directions such as vertical, up, down etc. refer to the direction when the bulk carrier is in its normal upright position, such as when it is in a dock. In other words, when the centre line of the bulk carrier is horizontal and the longitudinal axis of the hatch opening is vertical (e.g. as shown in the figures). Those skilled in the art will understand that the orientation of the bulk carrier and the cargo hatches may change, for example when the bulk carrier is at sea. It should therefore be understood that any directions mentioned are not intended to limit the invention to the orientation of the cargo hatches shown in the figures.
[0102] The features disclosed in the foregoing description or the following claims or in the accompanying drawings, which may be suitably presented in terms of specific forms thereof or means for performing a disclosed function or methods or processes for obtaining a disclosed result, may be utilized to realize the invention in various of its forms, either separately or in any combination of such features.
[0103] Although the present invention has been described in conjunction with the above exemplary embodiments, many equivalent modifications and variations will be apparent to those skilled in the art given this disclosure. Accordingly, the above exemplary embodiments of the present invention are considered to be illustrative and not limiting. Various modifications to the described embodiments may be made without departing from the spirit and scope of the present invention.
[0104] For the avoidance of doubt, the theoretical explanations provided herein are provided for the purpose of enhancing the understanding of the reader, and the inventors do not wish to be bound by any of these theoretical explanations.
[0105] The section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described.
[0106] Throughout this specification, including the claims which follow, unless the context indicates otherwise, the words "comprise" and "including", as well as variations such as "comprises", "including", "comprising", and the like, are understood to mean the inclusion of a stated integer or step or group of integers or steps, but not the exclusion of any other integer or step or group of integers or steps.
[0107] It should be noted that, as used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Ranges can be expressed herein as from "about" one particular value and / or to "about" another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by using the antecedent "about," it will be understood that the particular value forms another embodiment. The term "about" with respect to numerical values is optional and means, for example, + / - 10%.
Claims
1. A cargo hatch of a bulk carrier, comprising: A hatch coaming surrounding the hatch opening; a hatch cover configured to be removably positioned on the hatch coaming such that the hatch cover reversibly closes at least a portion of the hatch opening; and a first sealing system including a gasket and a compression bar, the first sealing system being configured to provide a seal between the hatch coaming and the hatch cover in use; and a second sealing system including an expandable seal, the second sealing system being configured to provide a seal between the hatch coaming and the hatch cover in use; and Includes cargo hatch.
2. 10. The cargo hatch of claim 1, wherein the expandable seal is a reversibly expandable seal.
3. 3. A cargo hatch as claimed in claim 1 or 2, wherein the expandable seal is an inflatable seal.
4. A cargo hatch according to any one of claims 1 to 3, wherein the hatch coaming includes a side surface and the expandable seal is disposed on the side surface.
5. 5. The cargo hatch of claim 4, wherein the side is an exterior side facing away from the hatch opening.
6. 6. A cargo hatch as claimed in any one of the preceding claims, wherein the hatch cover includes a skirt extending from a bottom surface of the hatch cover towards the hatch opening so as to overlap the hatch coaming in use.
7. 7. A cargo hatch as claimed in claim 6, wherein in use the skirt is located outboard of the hatch coaming.
8. 8. A cargo hatch as claimed in claim 6 or 7, wherein the second sealing system includes the skirt, whereby in an expanded state the expandable seal abuts the skirt to provide a seal between the hatch coaming and the hatch cover.
9. 9. A cargo hatch as claimed in any one of the preceding claims, wherein the hatch cover is configured to be removably placed on the hatch coaming such that the hatch cover reversibly closes the entire hatch opening.
10. 10. A cargo hatch as claimed in any one of the preceding claims, wherein the hatch cover is movable in a direction substantially parallel to a centreline of the bulk carrier between a covered position in which the hatch opening is covered by the hatch cover and an open position in which the hatch opening is not covered.
11. A bulk carrier comprising one or more cargo hatches according to any one of claims 1 to 10.
12. 1. A method of closing a cargo hatch on a bulk carrier, comprising the steps of: removably positioning a hatch cover over a hatch coaming of the cargo hatch; providing a first seal between the hatch coaming and the hatch cover using a first sealing system including a gasket and a compression bar; providing a second sealing system including an expandable seal; expanding the expandable seal such that a second seal is provided between the hatch coaming and the hatch cover. The method includes:
13. 13. The method of claim 12, wherein the step of removably positioning the hatch cover on the hatch coaming of the cargo hatch comprises the steps of moving the hatch cover over a hatch opening in a direction substantially parallel to a centerline of the bulk carrier, and lowering the hatch cover so that it is positioned on the hatch coaming.
14. contracting the expandable seal such that the second seal is removed; moving the hatch cover away from the hatch coaming to provide access to the hatch coaming. The method of claim 12 or 13, comprising: