Cargo Hatch

Abstract

A cargo hatch for use on a bulk carrier or other ship to allow access to the cargo hold. Cargo hatches include one or more hatch covers resting on hatch coaming which surrounds a hatch opening through which the cargo hold is accessible. A seal is often provided between the hatch cover and the hatch coaming in order to prevent water ingress into the cargo hold from the outside environment. The seal may be prone to deterioration. The present disclosure proposes a cargo hatch for a bulk carrier including a hatch coaming surrounding a hatch opening and a hatch cover configured to be removably located on the hatch coaming such that the hatch cover reversibly closes the hatch opening, wherein the cargo hatch includes two sealing systems configured to provide respective and separate seals between the hatch coaming and the hatch cover in use.

Claims

1. A cargo hatch for a bulk carrier comprising: a hatch coaming surrounding a hatch opening; a hatch cover configured to be removably located on the hatch coaming such that the hatch cover reversibly closes at least a part of the hatch opening; a first sealing system comprising a gasket and a compression bar, and configured to provide a seal between the hatch coaming and the hatch cover in use; and a second sealing system comprising an expandable seal and configured to provide a seal between the hatch coaming and the hatch cover in use.

2. The cargo hatch according to claim 1, wherein the expandable seal is a reversibly expandable seal.

3. The cargo hatch according to claim 1, wherein the expandable seal is an inflatable seal.

4. The cargo hatch according to claim 1, wherein the hatch coaming comprises a side surface, wherein the expandable seal is located on the side surface.

5. The cargo hatch according to claim 4, wherein the side surface is an outer side surface which faces away from the hatch opening.

6. The cargo hatch according to claim 1, wherein the hatch cover comprises a skirt extending from a bottom surface of the hatch cover towards the hatch opening so as to overlap with the hatch coaming in use.

7. The cargo hatch according to claim 6, wherein in use, the skirt is located to the outside of the hatch coaming.

8. The cargo hatch according to claim 6, wherein the second sealing system comprises the skirt such that, in an expanded state, the expandable seal abuts the skirt to provide a seal between the hatch coaming and the hatch cover.

9. The cargo hatch according to claim 1, wherein the hatch cover is configured to be removably located on the hatch coaming such that the hatch cover reversibly closes the entire hatch opening.

10. The cargo hatch according to claim 1, wherein the hatch cover is moveable in a direction substantially parallel with 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 uncovered.

11. A bulk carrier comprising one or more cargo hatches according to claim 1.

12. A method of closing a cargo hatch for a bulk carrier, the method comprising the steps of: removably locating a hatch cover on hatch coaming of the cargo hatch; providing a first seal between the hatch coaming and the hatch cover with a first sealing system comprising a gasket and a compression bar; 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.

13. The method according to claim 12, wherein the step of removably locating the hatch cover on the hatch coaming of the cargo hatch comprises the steps of: moving the hatch cover over the hatch opening in a direction substantially parallel with a centreline of the bulk carrier, and lowering the hatch cover such that it is located on the hatch coaming.

14. The method according to claim 12 comprising the steps of: collapsing the expandable seal such that the second seal is removed; moving the hatch cover away from the hatch coaming such that the hatch coaming is accessible.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0067] The terms Fig., Figs., Figure, and Figures are used interchangeably to refer to the corresponding figures in the drawings.

[0068] Embodiments and experiments illustrating the principles of the invention will now be discussed with reference to the accompanying figures in which:

[0069] FIG. 1. shows a top view of a bulk carrier having a cargo hatch according to the first aspect the cargo hatch being shown in an uncovered state.

[0070] FIG. 2. shows an aft view of the hatch cover of the cargo hatch shown in FIG. 1.

[0071] FIG. 3. shows a side view of the hatch cover in FIG. 2, viewed from the starboard side.

[0072] FIG. 4. shows a bottom view of the hatch cover of the cargo hatch shown in FIG. 2.

[0073] FIG. 5. shows a top view of the bulk carrier in FIG. 1, the cargo hatch being shown in a covered state.

[0074] FIG. 6. shows a cross-section view of the starboard side of the bulk carrier in FIG. 1, showing the cargo hatch is in a covered state.

[0075] FIG. 7. shows a cross-section view of the bulk carrier in FIG. 1, showing the cargo hatch in a closed state.

DESCRIPTION OF THE INVENTION

[0076] Aspects and embodiments of the present invention will now be discussed with reference to the accompanying figures. Further aspects and embodiments will be apparent to those skilled in the art. All documents mentioned in this text are incorporated herein by reference.

[0077] FIG. 1 shows a top view of a longitudinal portion of a bulk carrier 1 having a cargo hatch 100 according to the first aspect.

[0078] The bulk carrier 1 has a starboard topside water ballast tank 2 and a port topside water ballast tank 3 separated by a region of the deck 4 through which the cargo hatch 100 is provided. The two topside water ballast tanks 2, 3 are separated from the region of the deck 4 having the cargo hatch 100 by respective longitudinally extending crew passageways 5a, 5b. The cargo hatch 100 is symmetric about the centreline 91 of the bulk carrier 1.

[0079] Although only one cargo hatch 100 is shown in the Figures, a bulk carrier 1 may have more than one cargo hatch 100, each with a structure identical or similar to the structure of the cargo hatch 100 described herein. Each cargo hatch 100 is usually spaced from the others along the centreline 91 of the bulk carrier 1 (i.e. in a longitudinal direction).

[0080] The cargo hatch 100 has a hatch opening 101 which is a rectangular aperture 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.

[0081] Hatch coaming 110 surrounds the hatch opening 101 such that it extends around the entire perimeter of the hatch opening 101. As will be understood by a person skilled in the art, the hatch coaming 110 comprises a vertically extending flat surface/plate which surrounds the hatch opening 101. Here the hatch coaming 110 resembles the side faces of a cuboid such that it surrounds the entire perimeter of the hatch opening 101.

[0082] In FIG. 1, the cargo hatch 100 is shown in an uncovered state, with a hatch cover 130 positioned adjacent the hatch opening 101 towards the aft of the bulk carrier 1 such that the hold is accessible via the hatch opening 101. In FIG. 1, components under the hatch cover 130 are shown for clarity.

[0083] The hatch cover 130 rests on two longitudinally extending wheel tracks 20a, 20b located on respective sides of the hatch opening 101. The hatch cover 130 has a larger area when viewed from above than the hatch opening and extends across the crew passageways 5a, 5b on the port and starboard sides. Proximate each corner of the hatch opening 101 and aligned with the wheel tracks 20a and 20b there is provided a respective hydraulic jack 120a, 120b, 120c, 120d.

[0084] FIG. 2 shows an aft view of the hatch cover 130 shown in FIG. 1. The hatch cover 130 is a flat plate (e.g. metal such as steel). In this embodiment, the hatch cover 130 is about 450 mm thick, about 19 m wide and about 11.5 m in length (in the longitudinal direction). The skilled person will understand that the hatch cover 130 may be dimensioned differently depending on the size of the cargo hatch 100 and/or bulk carrier 1.

[0085] The hatch cover 130 comprises a skirt 131 which extends from a bottom surface of the hatch cover 130. The skirt 131 extends around the perimeter of the hatch cover 130 and is spaced inwardly from the edge of the hatch cover 130. The hatch cover 130 has a principal axis 93 which extends vertically through the centre of the hatch cover 130. The skirt 131 comprises an outer side surface 134 which, in use, faces a direction substantially perpendicular to a principal axis of the hatch cover. The outer side surface 134 of the skirt 131 may be said to comprise four continuously connected outer side surfaces 134 facing different directions (forwards, aft, port and starboard). FIG. 2 shows an outer side surface 134 of the skirt 131 which faces the aft direction. The skirt comprises a plurality of strengthening members 135 spaced along the skirt 131 on the outer side surface 134. The strengthening members 135 (which may resemble ribs) extend away from the bottom surface of the hatch cover 130.

[0086] FIG. 3 shows a side view of the hatch cover 130, as viewed from the starboard side. Here an outer surface 134 of the skirt 131 facing the starboard side can be seen, having strengthening members 135 spaced along it.

[0087] The hatch cover 130 comprises four wheels 121a, 121b, 121c, 121d underneath (attached to the bottom surface). Each wheel is located between the skirt 131 and the sides of the hatch cover 130. There are two wheels 121a, 121b on the starboard side as shown in FIG. 3, which are transversely aligned with one another and longitudinally spaced apart. There are also two wheels 121c, 121d on the port side which are transversely aligned with one another and longitudinally spaced apart in a similar manner (see FIG. 4). The starboard side wheels 121a, 121b rest on the starboard side wheel track 20a and the port side wheels 121c, 121d rest on the port side wheel track 20b such that the hatch cover 130 is moveably supported on the wheel tracks 20a, 20b. The wheels 121a, 121b, 121c, 121d are configured to roll along the wheel tracks 20a, 20b such that the hatch cover 130 can move along the wheel tracks. Each wheel 121a, 121b, 121c, 121d is provided with a respective motor 122a, 122b, 122c, 122d which drives the wheel 121a, 121b, 121c, 121d such that the hatch cover 130 moves along the wheel tracks 20a, 20b.

[0088] FIG. 4 shows the hatch cover 130 as viewed from below. In FIG. 4, all four wheels 121a, 121b, 121c, 121d and respective motors 122a, 122b, 122c, 122d are visible proximate the corners of the hatch cover 130. As seen in FIG. 4, the skirt 131 is rectangular in shape when viewed from below.

[0089] The hatch cover 130 comprises an inner gasket channel 132 provided inside the skirt 131 such that the skirt 131 is positioned between the inner gasket channel 132 and the edge of the hatch cover 130. The inner gasket channel 132 extends entirely around the interior of the skirt 131. The inner gasket channel 132 follows a path having a corresponding rectangular shape when viewed from below. The outer wall of the inner gasket channel 132 is aligned with the skirt 131. The inner gasket channel 132 is configured to house an inner gasket.

[0090] The hatch cover 130 further comprises an outer gasket channel 133 which extends around the perimeter of the bottom surface of the hatch cover 130 at its peripheral edge. The outer gasket channel 133 also follows a rectangular path when viewed from below. The outer gasket channel 133 is configured to house an outer gasket.

[0091] The hatch cover 130 shown in FIG. 4 has horizontal and vertical symmetry when in the orientation shown in FIG. 4.

[0092] The operation of the cargo hatch 100 will be described next.

[0093] 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 such that the hatch cover 130 is positioned over the hatch opening 101 (in FIG. 5, components under the hatch cover 130 are shown 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 the wheels 121a, 121b, 121c, 121d which are driven by the motors 122a, 122b, 122c, 122d.

[0094] In the covered state, the hatch cover 130 is located over the hatch opening 101. FIG. 6 shows a cross-section view of the starboard side of the bulk carrier where the cargo hatch 100 is in the covered state (i.e. the cargo hatch 100 is covered but not yet closed).

[0095] FIG. 6 shows three sealing systems: a first sealing system 140; a second sealing system 150; and an additional sealing system 160.

[0096] The first sealing system 140 comprises an inner gasket 141 which is housed in the inner gasket channel 132 of the hatch cover. The first sealing system 140 also comprises an inner compression bar 142 which is located on the top of the hatch coaming 110. The compression bar 142 extends entirely around the top of the hatch coaming 110 such that it is rectangular in shape when viewed from above (like the hatch coaming 110). When the cargo hatch 100 is in the covered state as illustrated in FIG. 6, the inner gasket channel 132 is vertically aligned with the compression bar 142.

[0097] The second sealing system 150 comprises an expandable seal 151 and the skirt 131 of the hatch cover 130. The expandable seal 151 is housed in a half-pipe channel 158 which is located on the outer side surfaces 111 of the hatch coaming 110, proximate the top of the hatch coaming 110. Specifically, the outer side surfaces 111 of the hatch coaming 110 have a channel support 159 which extends outwardly away from the hatch coaming 110 (in a direction substantially perpendicular to the principal axis 92 of the hatch opening 101). The half-pipe channel 158, which has a semi-circular cross-section, is located at the end of the channel support 159 such that it is positioned about 300 mm from the hatch coaming 110. The half-pipe channel 158 extends entirely around the hatch coaming 110. The radius of the half-pipe channel 158 is about 60 mm.

[0098] The expandable seal 151 is configured to reversibly expand from an unexpanded state to an expanded state. When expanding from an unexpanded state to an expanded state, the expandable seal 151 expands through the outwardly facing opening 157 of the half-pipe channel 158 which faces away from the hatch coaming 110.

[0099] The additional sealing system 160 comprises an outer gasket 161 which is housed in the outer gasket channel 133 of the hatch cover 130. The additional sealing system 160 also comprises an outer compression bar 162 which is located on the deck 4 of the bulk carrier 1. The outer compression bar 162 is rectangular in shape when viewed from above, such that the outer gasket channel 133 is vertically aligned with the compression bar 162 when the cargo hatch 100 is in the covered state as illustrated in FIG. 6. In other words, every part of the outer gasket channel 133 is vertically aligned with a part of the compression bar 162 when the cargo hatch 100 is in the covered state. As a result, the outer compression bar 162 surrounds and is spaced from the hatch opening 101 and the hatch coaming 110.

[0100] FIG. 7 shows a transverse cross-section view of the bulk carrier 1. In FIG. 7, the cargo hatch 100 is shown in a closed state such that the hatch cover 130 is located on the hatch coaming 110. To close the cargo hatch 100, the cargo hatch 100 is lowered from the covered state shown in FIG. 6 to the closed state shown in FIG. 7. Specifically, the hatch cover 130 is lowered from its position in the covered state by the hydraulic jacks 120a, 120b, 120c, 120d to its position in the closed state (on the hatch coaming 110). As the skilled person will understand, in the closed state, the hatch cover 130 may be secured in a conventional way, for example via cleats provided around the skirt 131.

[0101] In the closed state, the inner gasket 141 of the first sealing system 140 sits on the inner compression bar 142. The inner gasket 141 conforms to the shape of the inner compression bar 142 under the weight of the hatch cover 130 such that a weatherproof seal is provided between the hatch cover 130 and the hatch coaming 110, thereby sealing the hold from the outside environment.

[0102] In the closed state, the outer gasket 161 of the additional sealing system 160 sits on the outer compression bar 162. The outer gasket 161 conforms to the shape of the outer compression bar 162 under the weight of the hatch cover 130 such that an additional seal is provided between the hatch cover 130 and the deck 4. The additional sealing system thus provides a weatherproof seal between the crew passageways 5a, 5b and the outside environment.

[0103] In the closed state, 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 a mathematically similar shape to the shape of the hatch coaming 110 when viewed from above (i.e. a rectangular shape in the embodiment illustrated). The proximity between the hatch coaming 110 and the skirt 131 facilitates the second sealing system 150.

[0104] During movement of the cargo hatch from the uncovered state (as shown in FIG. 1), to the covered state (as shown in FIGS. 5 and 6), and then to the closed state (as shown in FIG. 7), the expandable seal 151 is maintained in an unexpanded state. When the cargo hatch 100 is in a closed state, the expandable seal 151 is expanded from the unexpanded state to an expanded state, through the opening 157 of the half-pipe channel 158, such that it abuts the skirt 131. When expanded in this manner, the expandable seal 151 conforms to the shape of the skirt 131 such that it provides a seal between the hatch cover 130 and the hatch coaming 110. The second sealing system 150 thereby provides a waterproof seal between the hatch opening 101 and the outside environment. Further, because the second sealing system 150 is outside the first sealing system 140, the second sealing system 150 protects the first sealing system 140.

[0105] When access to the hold is desired via the hatch opening 101, the expandable seal 151 is collapsed from an expanded state to an unexpanded state and the hydraulic jacks 120a, 120b, 120c, 120d are operated to lift the hatch cover 130 such that the cargo hatch 100 transitions from the closed state to the covered state. The hatch cover 130 is subsequently moved along the wheel tracks 20a, 20b such that the hatch opening 101 is uncovered (i.e. the cargo hatch 100 transitions from a covered state to an uncovered state).

[0106] It is to be understood that the expandable seal 151 can be expanded in various different ways. In some embodiments, for example, the expandable seal 151 by be pneumatically expanded, via inflation, by directing a volume of inflated gas into the internal volume of the expandable seal 151. In some such examples, the inflating has may be air and may be directed into the expandable seal by a compressor arrangement 180 in a manner known per se. As will be appreciated, such embodiments may further comprise a venting arrangement configured to vent the internal volume of the expandable seal 151 to release the inflating air and thereby transition the expandable seal 151 from its expanded state back to its unexpanded state.

[0107] Alternative embodiments are envisaged in which the expandable seal 151 may instead be hydraulically expanded by directing a volume of a suitable hydraulic liquid into the internal volume of the expandable seal 151. In some such arrangements the hydraulic liquid may be provided within a closed hydraulic circuit (not shown) comprising a liquid reservoir and one or more flow conduits in fluid communication with the internal volume of the expandable seal 151. A reversibly operable hydraulic pump may be provided to i) pump the hydraulic liquid from the reservoir to the internal volume of the expandable seal 151 to expand the expandable seal 151, and ii) pump the hydraulic liquid from the internal volume of the expandable seal 151 to the reservoir to collapse the expandable seal 151.

[0108] FIG. 7 also shows working spaces 6a, 6b provided between the hatch coaming 110 and the respective crew passageways 5a, 5b.

[0109] In FIGS. 6 and 7, the principal axis 92 of the hatch opening 101 is shown. In FIGS. 2 and 3, the principal axis 93 of the hatch cover 130 is shown. These principal axes are parallel to the vertical axis of the bulk carrier. Throughout this specification, references to directions such as vertical, top, bottom etc. refer to directions when the bulk carrier is in a normal upright position e.g. as it would be in a dock. In other words, when the centreline of the bulk carrier is horizontal, and the longitudinal axis of the hatch opening is vertical (e.g. as shown in the Figures). The skilled person will understand that the orientation of the bulk carrier and cargo hatch may change when e.g. the bulk carrier is at sea. As such, any directions referred to should not be understood to limit the invention to the orientation of the cargo hatch as shown in the Figures.

[0110] The features disclosed in the foregoing description, or in the following claims, or in the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for obtaining the disclosed results, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

[0111] While the invention has been described in conjunction with the exemplary embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art when given this disclosure. Accordingly, the exemplary embodiments of the invention set forth above are considered to be illustrative and not limiting. Various changes to the described embodiments may be made without departing from the spirit and scope of the invention.

[0112] For the avoidance of any doubt, any theoretical explanations provided herein are provided for the purposes of improving the understanding of a reader. The inventors do not wish to be bound by any of these theoretical explanations.

[0113] Any section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described.

[0114] Throughout this specification, including the claims which follow, unless the context requires otherwise, the word comprise and include, and variations such as comprises, comprising, and including will be understood to imply 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.

[0115] It must be noted that, as used in the specification and the appended claims, the singular forms a, an, and the include plural referents unless the context clearly dictates otherwise. Ranges may 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 the use of the antecedent about, it will be understood that the particular value forms another embodiment. The term about in relation to a numerical value is optional and means for example +/10%.