Field of the Invention

The present invention relates generally to tank car manway covers

Description of Related Art Cargo carrying equipment including, but not limited to barges, ships, rail cars, enclosed tanks or pressure vessels, and tanker trucks commonly use hatches to cover over an opening in the equipment for a variety of reasons. Typically a hatch cover seals against a nozzle ring or other hatch opening sealing surface and usually involve the use of a peripheral gasket of some kind to achieve a seal. The hatch cover is preferably hinged to the equipment to allow the cover to pivot between a closed position where the hatch cover generally seals the opening and the open position where the hatch cover leaves the opening clear for many different purposes including, but not limited to loading or unloading, entry into the tank or vessel, venting by opening the hatch cover, access to view or gauge commodity level, commodity sampling, and maintenance or repairs.

The contents of laded equipment are sometimes perishable or require

protection from contamination and the weather, or may be hazardous to people and require containment. Hatches can be located and oriented in any direction, but it has typically been found to be most convenient to locate hatches on the top or side of equipment. To provide the kind of integrity needed to transport a wide variety of commodities, hatch covers must be provided which are strong and provide a good seal.

Locking arrangements for securely sealing a hatch cover are well known in multiple fields of study, although the hatch cover may be called by different names. In a marine environment, it would typically be called a hatch, while in rail cars, tanks, and tanker trucks, it would typically be called a manway or manhole.

Tank cars are well known and useful for carrying fluid commodities. Respective side and front views of a conventional general purpose, non-pressurized generalized railroad tank car 100 is indicated in FIG. 1 . The tank car features a tank body 101 mounted on a pair of trucks 102A and 102B. A manway cover 103 is positioned on top of a sealing surface such as nozzle 104 which is generally mounted on the top of the tank body 101 . During use, a worker is provided access to the inner cavity (not shown) formed by body 101 via the nozzle 104 by manipulating the cover 103 to an open position.

A conventional manway cover system 200 is shown in FIGS. 2-4 and is

secured in the closed position on the nozzle body 201 (see e.g., FIG. 4) via a plurality of fasteners 202 spaced about the circumference of the manway cover 203. The typical quantity of fasteners, usually eyebolts, is usually either 6 or 8 fasteners, although there are often configurations with more or less fasteners. The eyebolt nuts 204 are

individually loosened or tightened in a star pattern with a wrench, impact, or similar tool when the manway cover 203 is opened or closed. The manway cover system 200 features a hinge 205 that permits it to be pivoted from the closed position, as shown in FIGS. 3 and 4, to an open position using a handle 206 so that access to the tank car interior is permitted. All of the eyebolts must be disengaged so that the cover may be pivoted open completely.

Prior art manway covers have been identified as a location where nonaccidental releases consistently occur. It has been identified by Rail Industry studies

that manway covers are the largest contributors to non-accidental releases (NAR's) for non-pressurized tank cars in transit. Although a number of hatch cover configurations are known in the art, the prior art typically involves the use of a multitude of pressure retaining threaded fasteners, typically eyebolts, in increasing quantities as the working pressure rises and sealing becomes more difficult, but nevertheless all of the hatch covers heretofore are known to suffer from a number of disadvantages.

It is common for the threaded fasteners to corrode, jam, or cross thread. It also takes a considerable amount of time, skill, and care to tighten the multitude of fasteners to achieve reasonably uniform gasket pressure, while not damaging the gasket. It is the most advisable to tighten the fasteners alternately and in stages as is done with the lugnuts for an automobile wheel.

The use of multiple fasteners in the prior art is an attempt to eliminate the problem of uneven sealing pressure (a good seal adjacent the fasteners and a poor seal between the fasteners). To improve the sealing capacity, the covers were made thicker and more rigid, thus increasing weight and material cost. There are many problems inherent with using a multitude of fasteners to secure the hatch cover so that pressure is applied evenly around the perimeter.

Depending on the nature of the hatch and the working pressures involved, torqueing of the hatch cover pressure retaining fasteners is usually required for proper sealing. Installation and torqueing of the pressure retaining fasteners could require utilizing multiple increments (typically 4-5 steps) of gradually increasing torque values, with idle intervals of 15 to 20 minutes between increments, so that the gasket relaxation can occur and compression can equalize as much as possible before the next interval. This serves to gradually compress the gasket as equally as possible to reduce the likelihood of gasket damage during the tightening process. Therefore, it can readily be appreciated that the ability to open and close the hatch cover quickly is of importance to users and hindered by a multitude of fasteners.

Other issues inherent with the design are severely limited gasket life (often single use), bent cover flanges, difficulty of system and disassembly, damaged eyebolt threads, and loose eyebolts.

Some applications, such as tank car manway covers, require a bubble leak test be performed before the tank car can be cleared for transit. Often hatch cover designs make this test difficult to perform due to the means by which they clamp the hatch cover and limit visibility near the gasket sealing surface.

Although great strides have been made in the area of tank car manway covers, many shortcomings remain. DESCRIPTION OF THE DRAWINGS

The novel features believed characteristic of the embodiments of the present application are set forth in the appended claims. However, the embodiments themselves, as well as a preferred mode of use, and further objectives and advantages thereof, will best be understood by reference to the following detailed description when read in conjunction with the accompanying drawings, wherein:

FIG. 1 is a side elevation view of a conventional railroad tank car with a nozzle and man way cover;

FIG. 2 is a view of a prior art hatch cover;

FIG. 3 is a top plan view of the hatch cover of FIG. 2 with fasteners installed;

FIG. 4 is a side elevation view of the hatch cover of FIG. 3;

FIG. 5 is a perspective view of an embodiment of the hatch cover system of the present invention on a generalized tank car in the closed configuration;

FIG. 6 is an enlarged perspective view of the hatch cover system of FIG. 5;

FIG. 7 is a cutaway view of the hatch cover system of FIG. 6;

FIG. 8 is a section view (plan view) of the locking cap and the jacking bolt of FIG.

6;

FIG. 9 is a section view (elevation view) of the locking cap and the jacking bolt of

FIG. 8;

FIG. 10 is a section view of the latch bracket showing the latch pin mechanism in the closed position;

FIG. 1 1 is a section view of the latch bracket showing the latch pin mechanism in the open position;

FIG. 12 is a perspective view of the hatch cover system of FIG. 6 pivoted to the open position; FIG. 13 is a section view of the hatch cover system of FIG. 12;

FIG. 14 is an enlarged view of the hinge and pivot stop area of FIG. 13;

FIG. 15 is a perspective view of an embodiment of a hatch cover assembly;

FIG. 16 is a view showing the disengagement of the locking screw of the hatch cover system of FIG. 15;

FIG. 17 is a perspective view of the hatch cover system of FIG 15 pivoted to the partially open position;

FIGS. 18-21 are perspective views of alternative hatch cover designs;

FIGS. 22-24 are perspective views of alternative locking bar designs;

FIGS. 25 and 26 are perspective views of alternative latch bracket designs;

FIGS. 27 and 28 are perspective views of alternative hinge bracket designs;

FIGS. 29A and 29B are perspective views of an example of handle attachment to a locking bar;

FIG. 30 is a perspective view of the handle assembled to a locking bar;

FIG. 31 shows perspective view of alternative handle designs; and

FIGS. 32-35 show sectional views of alternative gasket groove configurations.

While the system and method of use of the present application is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular embodiment disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present application as defined by the appended claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Illustrative embodiments of the system and method of use of the present application are provided below. It will of course be appreciated that in the development of any actual embodiment, numerous implementation-specific decisions will be made to achieve the developer's specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.

The system and method of use in accordance with the present application overcomes one or more of the above-discussed problems commonly associated with conventional systems. Specifically, the system and method of the present application may include a closure whereby the sealing force is transmitted through said closure structure such that the periphery of the closure seals an opening without peripheral clamps or clamping, a pivoting element that connects to said closure such that the closure can pivot between an open position and a closed position and incorporates a device to exert force on said closure, and a restraining element fixed in the general proximity of said opening such that the restraining element connects to and/or restrains the pivoting element whereby the force exerted by said pivoting element is utilized to seal the closure against the opening when in the closed position. These and other unique features of the system and method of use are discussed below and illustrated in the accompanying drawings.

The system and method of use will be understood, both as to its structure and operation, from the accompanying drawings, taken in conjunction with the

accompanying description. Several embodiments of the system are presented herein. It should be understood that various components, parts, and features of the different embodiments may be combined together and/or interchanged with one another ,all of which are within the scope of the present application, even though not all variations and particular embodiments are shown in the drawings. It should also be understood that the mixing and matching of features, elements, and/or functions between various embodiments is expressly contemplated herein so that one of ordinary skill in the art would appreciate from this disclosure that the features, elements, and/or functions of one embodiment may be incorporated into another embodiment as appropriate, unless described otherwise.

The preferred embodiment herein described is not intended to be exhaustive or to limit the invention to the precise form disclosed. It is chosen and described to explain the principles of the invention and its application and practical use to enable others skilled in the art to follow its teachings.

Referring now to the drawings wherein like reference characters identify corresponding or similar elements throughout the several views, the figures depict various views of a hatch system and method of use in accordance with a preferred embodiment of the present application. It will be appreciated that the system

overcomes one of more of the above-listed problems commonly associated with the conventional railway hatch assemblies. It will be appreciated that the present invention can be used for a multitude of applications, including but not limited to the cargo carrying equipment previously mentioned. For simplicity, the usage discussed in this application may be limited to railroad tank cars, where the hatch cover would typically be called a manway cover, but this is in no way intended to limit the broad scope of applicability of the invention. Referring now to FIG. 5, a top view a generalized tank car is shown in

accordance with one arrangement of a hatch cover system 400. Hatch cover system 400 includes a hatch cover 402 configured to rest on a nozzle 401 , which in turn is secured to and extending from a tank 403. During use, the hatch cover 402 provides sealing access to the inner area of the tank 403 via nozzle 401 . The hatch cover system 400 may be accessed by climbing a ladder at the sides or end of the rail car to reach the top platform. The hatch cover 402 permits access to the interior of the tank 403.

FIG. 6 shows the way in which the hatch cover system 400 may be utilized to seal the hatch opening nozzle 401 of a tank 403. The hatch opening nozzle 401 on a tank car may be a vertical cylindrical wall called a manway nozzle that generally terminates with a machined gasket surface at its top.

When the locking bar system 404 of FIG. 7 is pivoted into the closed hatch sealing position, the gasket 405 (typically elastomeric) may be compressed between the hatch cover 402 and the upper surface of nozzle 401 . The locking bar system 404 may include the locking bar 406 which may house a jacking nut 407 that may fit into a cavity 408 in the bottom of the locking bar 406. The locking bar 406 may have a cavity 408 that may be shaped such that it prevents rotation of the jacking nut 407 when a jacking screw 409 is inserted into the jacking nut 407. The jacking screw 409 may have threads sufficiently coarse enough to be resistant to fouling and damage, such as an acme thread or a buttress thread. When torque is applied to the jacking screw 409, the jacking nut 407 may advance towards the top of the locking bar 406. When the jacking nut 407 reaches the top surface of the cavity and is fully seated, the jacking screw 409 may begin to exert pressure against the top surface of a female bearing block 410 which may be positioned on top of a male bearing block 41 1 . In the preferred

embodiment, an expansion device is utilized to create a distance between the elongated locking bar and the hatch cover, which in the exemplary embodiment is a threaded screw; however, it will be appreciated that alternative embodiments could include other means to create the expansion. The locking bar system 404 may be retained on one side by a hinge bracket

412 and a hinge pin 413. The hinge bracket 412 and hinge pin 413 connection may allow the operator to pivot the locking bar system 404 between the closed position shown in FIG. 6 and the open position shown in FIG. 12 by using the handle 414. The hinge bracket 412 may be mounted to a fixed position relative to the hatch opening sealing surface 401 . The latch bracket 415 and latch pin 416 may prevent the locking bar system 404 from being pivoted when the latch 41 7 is secured in the closed and secure position by the latch pin 416.

When the hatch cover system 400 of FIG. 7 is in the closed and secure position, an application of torque to the jacking screw 409 may exert pressure on the female bearing block 410 which in turn exerts pressure on the male bearing block 41 1 which in turn exerts pressure on the hatch cover 402 such that the loads may be transmitted through the structure of the hatch cover 402 to exert sealing pressure against the gasket 405 and the hatch nozzle 401 at the periphery of the hatch cover 402.

The jacking screw 409 may require less torque to loosen than to tighten thereby making it desirable to have a locking element to prevent the jacking screw 409 from backing out in high vibration environments. A locking cap 418 on the top of the locking bar system 404 shown in FIG. 6 may be a pivotable closure that works in conjunction with the jacking screw 409 to provide locking whereby the flats on the interior surface of the locking cap 418 engage the flats on the jacking screw 409 as shown in FIGS. 8 and 9. This engagement may limit the rotation and loosening of the jacking screw 409 when the locking cap 418 is closed. The locking cap 418 may have a nearby locking cap security seal lug 419 to allow for a tamper-evident security seal to be applied when desirable. The locking cap 418 could also provide a measure of weather protection for the jacking screw 409. The locking cap 418 may include a locking cap lever slot 420 to act as a small handle for opening the locking cap 418. The locking cap lever slot 420 also may provide a place to insert a screwdriver or small prying tool to assist with opening the locking cap 418 if its movement is impeded by ice or debris.

The interface between the female bearing block 410 and the male bearing block 41 1 of the hatch cover system 400 may function as a spherical joint that allows the hatch cover 402 to pivot through a range of motion in any direction. This range of motion may allow the pressure exerted at the periphery of the hatch cover 402 to selfequalize.

The hatch cover 402 of FIG. 7 may be retained by a hatch cover retaining pin 421 that extends through one or more hatch cover lugs 422, the locking bar 406, and the female bearing block 410. The connection of the hatch cover retaining pin 421 may retain the hatch cover 402 when the locking bar system 404 may be pivoted to the open position while allowing the hatch cover 402 to pivot freely until gravity brings the hatch cover 402 to rest against the hatch cover guide 423. The hatch cover guide 423 may provide a standoff surface that maintains a gap between the hatch cover 402 and the locking bar 406 and hinge bracket 412 to prevent rubbing and potential surface coating wear or damage that could otherwise occur during the opening and closing operation.

To open the hatch cover system 400 of FIG. 6, torque on the jacking screw 409 may be reversed to release the pressure of the hatch cover 402. Reversing the jacking screw 409 may generate a gap between the top of the jacking nut 407 and the top of the cavity 408 in the locking bar 406. This gap may allow any internal pressure that may be contained in the vessel to force the hatch cover 402 upwards to create venting room around the periphery of the hatch cover 402 until the jacking nut 407 contacts the top of the cavity 408 in the locking bar 406. This feature may prevent a potentially dangerous situation where the hatch cover 402 could be forced to pivot open suddenly by pressure. After the excess pressure is vented, gravity may return the hatch cover 402 to rest upon the top of the gasket 405 or hatch opening sealing surface 401 .

With the pressure released, the latch pin 416 can be moved from the secure and closed position of FIG. 10 to the open position of FIG. 1 1 . In the closed position shown in FIG. 10, the latch pin 416 may be fully inserted through the latch 417 and the latch bracket 415 leaving the latch pin spring 424 minimally compressed. Withdrawing the latch pin 416 as shown in FIG. 1 1 may require compressing the latch pin spring 424 to move the latch pin 416 into the latch bracket 41 5 far enough to allow the latch 417 to clear the latch pin 416 such that the locking bar system 404 can be pivoted away from the latch bracket 415. A hole for a tamper-evident security seal may be incorporated into the end of the latch pin 416 if desired. Using a handle 414, an operator can raise the hatch cover system 400 from the closed position of FIG. 6 to the open position of FIG. 12. One or more instances of the handle 414 may be retained by fasteners and may be easily removed, replaced, or reconfigured based on the specifics of the particular handle design. The hinge bracket 412 may include a pivot stop 425 that is cast or machined into the locking bar 406 as shown in FIGS. 13 and 14. The pivot stop 425 limits the locking bar system 404 from opening beyond a particular angle that is set by the specific dimensions of the stop surface on the locking bar 406 and where it contacts the hinge bracket 412. The pivot stop 425 may prevent the hatch cover system 400 from slamming into car structure or nearby appurtenances such as top platform handrails when fully opening the hatch cover system 400.

Referring now to FIGS. 15-17, various views of an alternative embodiment are shown. FIG. 15 shows a perspective view of an additional embodiment of hatch cover system 500 that may utilize an attachment system 501 where a locking bot is used at the second end of the hatch and configured to engage with the outer perimeter of the nozzle. The locking screw 505 may be under tension rather than compression. The secured locking bar system 501 may include a locking bar 503 and hatch cover 506 that may swivel or pivot on a hatch cover retaining pin 507 and may exert compression on the central region of the hatch cover 506. In this configuration the latch bracket 508 may provide safety venting because the enlarged end of the locking screw 505 may remain engaged and retained by the latch bracket 508 cavity until the locking nut 509 on the locking screw 505 is sufficiently loosened to create a predetermined gap between the latch bracket 508 and the locking screw 505 to disengage the locking screw 505 as shown in FIG 16. This engagement between the locking screw 505 and the latch bracket 508 may allow any built up pressure contained in the vessel to force the locking bar 503 upwards a predetermined distance until the locking screw 505 contacts the top of the cavity in the bottom of the latch bracket 508 thereby allowing the hatch cover 506 to have clearance around the periphery of the hatch cover 506 to vent. This feature may prevent a potentially dangerous situation where the hatch cover 506 could be forced by internal pressure to pivot open suddenly by pressure if unrestrained. After any excess pressure is vented a handle 510 may be used to pivot the locking bar system 501 about a hinge pin 51 1 towards the open position as shown in FIG 17.

It will be appreciated that there are a multitude of configurations with regard to the components that make up hatch cover assemblies. Some variations of the constituent components are included herein. FIGS. 18-21 illustrate various contemplated oblique views of a hatch cover in accordance with alternative embodiments of the present application. For example, FIG. 18 is an oblique view of a hatch cover 601 with a rounded geometric shape with a recessed gasket groove for a locking bar assembly. In the preferred embodiment, the gasket fits within the gasket groove to create a seal fit between the cover and the nozzle. In FIG. 19, hatch cover 602 has a hatch cover lug with a different configuration of fastener relief for the hatch cover retaining pin. In FIG. 20, hatch cover 603 shows a sharper edged hatch cover with a recessed channel for the locking bar assembly. In FIG. 21 , hatch cover 604 shows cover configured for a forked locking bar. Hatch cover 604 also may utilize one or more separate locking bars configured for either a common hinge bracket or separate hinge brackets.

The bottom of the hatch covers can utilize any number of stiffener ribs although there is a practical limit in order and to leave adequate room for adding ports for pressure taps and valves that it is sometimes desirable to install in the top of the hatch cover.

In FIGS. 22-24, alternative embodiments of the locking bars are shown. In FIG. 22, a locking bar 701 similar to the additional embodiment but with a different configuration of latch. In FIG. 23, a locking bar 702 shows a beam configuration that is substantially an I-beam shape with a cast or welded reinforcement around the hatch cover retaining pin area. In FIG. 24, a locking bar 703 may include a forked locking bar configuration that could accompany a hatch cover similar to hatch cover 604.

It will be appreciated that alternative locking bar configurations may include locking bars that use one or more different lug positions for locking bars of either forked or non-forked configurations. Alternative locking bar configurations may include making the hatch cover integral with the locking bar by forming a single solid part although this may restrict the ability of the hatch cover to pivot or swivel. A In FIGS. 25-26, alternative embodiments of the latch bracket are shown. In FIG. 25, a latch bracket 801 similar to the additional embodiment but without the resting cavity on the top side for the locking screw to prop up the locking bar system for forced venting. In FIG. 26, a latch bracket 802 shows a configuration that accommodates a locking screw configuration with a T-shaped end that engages with the locking bar latch and includes a top side recess to prop up the locking bar system for forced venting. The design of the latch bracket will be influenced by whether the locking bar design is based on tension of the locking screw 506 or compression of the jacking screw 409 as well as the locking bar latch configuration.

In FIGS. 27 and 28, alternative embodiments of the hinge brackets are shown. FIG. 27 shows a hinge bracket 901 including an integral pivot stop. Hinge bracket 901 includes a configuration to stop the opening of the locking bar at predetermined angles determined by the geometry of the pivot stop pocket on top on the hinge bracket. FIG. 28 shows a hinge bracket 902 which may exhibit a vertical web that may provide an optional attachment point for a detachable swappable pivot stop. A separable stop can be added to the hinge bracket or to the locking bar to limit the travel of the locking bar and make the opening angle of the hatch cover system customizable for different applications.

In FIGS. 29A and 29B, an alternative configuration is shown for attaching a single stirrup-shaped handle 1001 to the locking bar 503 from the additional

embodiment. Such a configuration allows for a multitude of handle shapes to be attached to a multitude of handle lugs 1002 with fasteners for easy configuration changes. The detachable handle allows for easy replacement and customizability to suit customer needs. FIG 29B shows the handle 1001 fully seated on the handle lugs on the locking bar 503.

In FIG. 30 a single stirrup-shaped handle 1003 attached to the locking bar 503 is shown. In FIG 31 a handle 1004 may utilize a two piece handle design which may be identical or may utilize a left mirror side portion and right mirror side portion. It will appreciated that there are multiple designs of the handle that can be applied to the locking bar depending on the configuration of the locking bar. Some handle designs can be applied at different angles to allow for adjustable positioning at application. The handles may be removable and can be shaped for the end users if desired and can be applied with or without hot work.

It will be appreciated that the bearing blocks may have different cross sectional shapes such as round, square, hexagonal, or other shape and may exhibit concave or convex surfaces on one or more surfaces. The male bearing block and the hatch cover may be formed into a single component or may be separated into separate elements. The positions of the male bearing block and the female bearing block in the preferred embodiment may be interchanged. The female bearing block and the hatch cover may be formed into a single component. The locking screw and female bearing block may be formed into a single part. The locking screw and male bearing block may be formed into a single component.

While the above description contains many specificities, these should not be construed as limitations on the scope, but rather as an exemplification of one or more embodiments thereof. Many other variations are possible.

From the description above, a number of advantages of one or more aspects of some embodiments of the multipurpose hatch cover system are outlined below.

Operator inputs are reduced compared to prior art making operation easy, fast, and simple. A single coarse threaded fastener is more resistant to corrosion, jamming, cross threading, and thread damage thereby improving operation and reliability. Fewer inputs also provide a more efficient and more quickly operated device that can be more effectively operated by operators with less training and skill. The device of applying force to the gasket surface without peripheral clamping provides for flexibility to set a desired range of gasket pressure based upon the gasket material and the specifics of the application for reduced gasket lifecycle costs as the device typically allows for more gasket reuse without the limitations that are normally associated with flanged and bolted connections. This is important because typically flanged and bolted connections of pressure vessels and that of some prior art usually require clamping forces at the peripheral hatch fasteners to be much higher than what is actually required for the typically soft and elastomeric gasket to seal. The higher clamping forces normally required of flanged and bolted connections typically damage or ruin the gasket material requiring replacement after a single use but are necessary to prevent loosening of the fasteners due to relaxation of the gasket material.

The self-equalizing hatch cover configuration allows for reasonably uniform gasket compression to be applied in fewer steps or even a single step without requiring the multitude of tightening intervals that are normally required of flanged and bolted connections to prevent gasket damage at installation and subsequent leakage.

The self-equalizing hatch cover configuration provides for wider range of usable manufacturing tolerances in the fit-up and locating of the hinge bracket and latch bracket with respect to the hatch opening sealing surface. The self-equalizing configuration compensates for positional and orientation mismatches that may occur due to manufacturing variations.

Some hatch cover applications benefit from superior access and visibility around the periphery of the hatch cover. One such example is tank car manway covers which require a bubble leak test be performed before the rail car can be cleared for transit. Other hatch cover designs make this leak test difficult to perform due to the means by which they clamp the hatch cover which reduces access and visibility around the periphery of the hatch cover.

The hatch cover system has an adjustable pivot stop that allows the opening angle of the hatch cover system to vary between two angles based on the position the pivot stop is installed in. Also, different opening angles can be easily achieved by swapping the pivot stop to get the desired opening angles without requiring hot work.

Most of the hatch cover system parts and sub-systems can be replaced without hot work such as welding. In some applications the requirement that hot work such as welding be performed adds significant additional expense and extended out-of-service time.

The latch pin is contained within the latch bracket making the latch pin difficult to lose unlike loose pins or tethered pins which can be more easily lost.

The locking cap provides positive locking ensuring that the hatch cover system will greatly reduce the likelihood of unintentionally loosening and leaking.

Referring now to FIGS. 32-35 various sectional views of gasket groove configurations are shown in accordance with an alternative embodiment. In FIG. 32, a section view of an alternative gasket groove configuration is shown with a male tongue extending around the periphery of the bottom of the hatch cover 402 that mates with a gasket groove on the nozzle 401 . In FIG. 33, a section view of an alternative gasket configuration is shown with a male tongue extending around the periphery of the bottom of the hatch cover 402 that mates with a counterbore on the nozzle 401 . In FIG. 34, a section view of an alternative gasket configuration is shown with a male tongue extending around the periphery of the bottom of the hatch cover 402 with an external gasket groove that accepts a gasket 405 that mates with the inside of the nozzle 401 . FIG. 35, a section view of an alternative gasket configuration is shown with a male tongue extending around the periphery of the bottom of the hatch cover 402 with an external gasket groove that accepts a gasket 405 that mates with the inside of the nozzle 401 with an L-shaped or T-shaped flange around the periphery of the nozzle.

The particular embodiments disclosed above are illustrative only, as the embodiments may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. It is therefore evident that the particular embodiments disclosed above may be altered or modified, and all such variations are considered within the scope and spirit of the application. Accordingly, the protection sought herein is as set forth in the description. Although the present embodiments are shown above, they are not limited to just these embodiments, but are amenable to various changes and modifications without departing from the spirit thereof.