PRESSURE VESSEL INCLUDING PROJECTIONS

Abstract

A pressure vessel includes a hollow body including a body, a first end, and a second end. The body includes a cylindrical body wall and each of the first and second ends includes a convex, rounded end wall. Each of the first and second ends forms a first and second juncture, respectively, where each end wall meets the body wall. The pressure vessel further includes first and second projections adjacent to the first and second juncture, respectively, and a fiber wrap surrounding the wall of the body between the first and second projections.

Claims

1. A pressure vessel comprising: a hollow body including a body, a first end, and a second end, wherein the body includes a cylindrical body wall and each of the first and second ends includes a convex, rounded end wall, and wherein each of the first and second ends forms a first and second juncture, respectively, where each end wall meets the body wall; first and second projections adjacent to the first and second juncture, respectively; and a fiber wrap surrounding the wall of the body between the first and second projections.

2. The pressure vessel of claim 1, wherein the fiber wrap comprises one of fiberglass fiber, carbon fiber, steel wire, and steel wire with a protective coating.

3. The pressure vessel of claim 1, wherein each of the first and second projections comprise a ring surrounding one of the body wall, the first end wall, and the second end wall.

4. The pressure vessel of claim 3, wherein the first and second rings comprise one of steel or plastic.

5. The pressure vessel of claim 1, wherein each of the first and second projections comprise first and second protrusions formed integrally with the body of the pressure vessel.

6. The pressure vessel of claim 1, wherein each of the first and second projections are on the body wall.

7. The pressure vessel of claim 6, wherein the body has an outer diameter, and wherein each of the first and second projections are on the body wall at a distance of about 5% of the outer diameter of the body from each of the first and second junctures, respectively.

8. The pressure vessel of claim 1, wherein each of the first and second projections are on each of the first and second end walls, respectively.

9. The pressure vessel of claim 8, wherein the first projection has a first inner surface that contacts the fiber wrap, wherein the second projection has a second inner surface that contacts the fiber wrap, and wherein each of the first and second inner surfaces are aligned with the first and second junctures, respectively.

10. The pressure vessel of claim 8, wherein the body has an outer diameter, wherein each of the first and second projections is on each of the first and second end walls, respectively at a distance of about 3% of the outer diameter of the body from each of the first and second junctures, respectively.

11. A method of manufacturing a pressure vessel comprising: providing the pressure vessel comprising: a hollow body including a body, a first end, and a second end, wherein the body includes a cylindrical body wall and each of the first and second ends includes a convex, rounded end wall, and wherein each of the first and second ends forms a first and second juncture, respectively, where each end wall meets the body wall; providing first and second metallic segments; bonding the first and second segments onto the pressure vessel adjacent to the first and second junctures, respectively; and fiber wrapping the pressure vessel between the first and second segments.

12. The method of claim 11, wherein the first and second segments comprise first and second rings.

13. The method of claim 11, wherein the bonding step comprises soldering the first and second segments onto the pressure vessel adjacent to the first and second junctures, respectively.

14. The method of claim 11, wherein the bonding step comprises brazing the first and second segments onto the pressure vessel adjacent to the first and second junctures, respectively.

15. The method of claim 14, further including the step of tempering the pressure vessel, and wherein the first and second segments are brazed onto the pressure vessel while the pressure vessel is tempering.

16. The method of claim 11, wherein the bonding step comprises gluing the first and second segments onto the pressure vessel adjacent to the first and second junctures, respectively.

17. The method of claim 11, wherein the bonding step comprises welding the first and second segments onto the pressure vessel adjacent to the first and second junctures, respectively.

18. The method of claim 11, wherein the first and second segments are bonded to the body wall.

19. The method of claim 11, wherein each of the first and second segments are bonded to each of the first and second end walls, respectively.

20. A method of manufacturing a pressure vessel comprising: hot forming the pressure vessel, wherein the pressure vessel comprises: a hollow body including a body, a first end, and a second end, wherein the body includes a cylindrical body wall and each of the first and second ends includes a convex, rounded end wall, and wherein each of the first and second ends forms a first and second juncture, respectively, where each end wall meets the body wall; forming first and second protrusions adjacent the first and second junctures, respectively; and fiber wrapping the pressure vessel between the first and second protrusions.

21. The method of claim 20, wherein the forming step comprises the step of pushing each of the first and second end walls into the body wall in order to displace material of the body to form the first and second protrusions.

22. The method of claim 20, wherein the forming step comprises the step of dragging first and second portions from the first and second end walls, respectively, during the hot forming process to form the first and second protrusions.

Description

DESCRIPTION OF THE DRAWINGS

[0077] FIG. 1 is an isometric view of the Crashworthy Underframe CNG Storage System, containing four 2 cylinder tank modules illustrating the integration and packaging of the system for locomotive underframe mounted applications.

[0078] FIG. 2A is a side view of the Crashworthy Underframe CNG Storage System with 2 of the 4 CNG cylinder modules removed. This view illustrates the tall slender vertical walls and the vertical wall gussets that have to absorb the vertical crushing loads when a derailed locomotive would be resting on the bottom surface of the CNG enclosure.

[0079] FIG. 2B is a detail view of FIG. 2A Illustrating the contact point where the CNG Module has a feature that helps to prevent the vertical wall from buckling under high crushing loads.

[0080] FIG. 3 is and isometric view of the CNG cylinder module illustrating the individual CNG cylinders and the straps that retain them to the CNG cylinder module frame.

[0081] FIG. 4A is an isometric exploded view of a Crashworthy Underframe LNG Storage System illustrating the assembly of the Siamese LNG pressure vessel into the Crashworthy Enclosure. The Siamese LNG pressure vessel would be slid into and supported inside the crashworthy enclosure on 6 movable supports and the end plate would then be welded to the enclosure completing the assembly.

[0082] FIG. 4B is a Detail View of FIG. 4A illustrating the LNG feed pipe and the vent pipe attachment to the Siamese LNG pressure vessel.

[0083] FIG. 4C is a Detail view of FIG. 4B illustrating movable support contact piece and its thermal insulating support where it rests upon the outer surface of the Siamese LNG pressure vessel.

[0084] FIG. 5A is a cross section view of the Crashworthy LNG Storage System illustrating the relationship between the Siamese LNG pressure vessel, the Crashworthy Enclosure and the 6 movable supports.

[0085] FIG. 5B is a Detail View of FIG. 5A illustrating in more detail the components and internal structure that support and locate the 6 movable supports.

[0086] FIG. 6A an isometric view illustrating the shared Siamese walls and the baffle plates that make up the internal support structure of the Siamese LNG tank.

[0087] FIG. 6B is a detail view of FIG. 6A and illustrates the direct load path of the angled movable support feature directly into the shared Siamese wall of the Siamese LNG pressure vessel.

[0088] FIG. 7A is an isometric view illustrating the Siamese LNG pressure vessel and the support structure that interfaces with the movable support plate that vertically supports it.

[0089] FIG. 7B is cross section view from the end of the Vertical Siamese LNG Tank Module illustrating the movable plate supports that vertically support the Siamese LNG pressure vessel inside.

[0090] FIG. 8 is a side view of a high capacity CNG tender car with a structural center bulkhead.

[0091] FIG. 9 is a side view illustrating a crashworthy LNG tender car built from a modified ISO intermodal cryogenic tank and intermodal well car.

[0092] FIG. 10A is an isometric view illustrating the ISO LNG tank module with its structural improvements and optional LNG pump installation.

[0093] FIG. 10B is a Detail view of FIG. 10A further detailing the minor structural improvements to the standard ISO Intermodal cryogenic tank.

[0094] FIG. 11 is an isometric view of a large Type 4 CNG cylinder with a recessed end cavity, pilot and plate mounting arrangement and a protective cover for the fuel line. A system which both increases safety and storage capacity.

[0095] FIG. 12A is a cross section view of a large Type 4 CNG cylinder illustrating the recessed end cavity for protective installation of the pressure relief and shutoff valve.

[0096] FIG. 12B is a detail view of FIG. 12A further illustrating the plate and pilot mounting feature.

[0097] FIG. 13A is a side view of a locomotive illustrating a LNG storage system with an attached LNG pump module.

[0098] FIG. 13B is a detail view of FIG. 13A further detailing the LNG pump module components.

[0099] FIG. 14 is a block diagram of the LNG pump module system.

[0100] FIG. 15 is an isometric view of a Type 2 cylinder without a neck.

[0101] FIG. 16A is a side view of a CNG enclosure with one large diameter CNG cylinder installed and one empty bay for a second CNG cylinder.

[0102] FIG. 16B is a detail view of FIG. 16A illustrating the bottom plate and mid wall vertical gusset overlap.

[0103] FIG. 17 is an isometric detail view of the enclosure illustrating the vertical gusset and cylinder bottom plate.

[0104] FIG. 18 is an isometric view of a removable enclosure panel illustrating the adjustable cylinder contact pads at a compound angle to the axis of the CNG cylinder.

[0105] FIG. 19 is an isometric detail view of the adjusting bolt for the adjustable contact pad.

[0106] FIG. 20 is a cross section view of a conventional Type 2 cylinder.

[0107] FIG. 21A is a section view of a modified Type 2 cylinder with a brazed on blocking ring and corresponding extended wire wrap.

[0108] FIG. 21B is a close up detail of FIG. 21A.

[0109] FIG. 22 is a cross sectional view of a cylinder including a stubbed neck.

DETAILED DESCRIPTION OF THE INVENTION

[0110] FIG. 1 illustrates a CNG storage system 1 that is composed of one Crashworthy Enclosure 2 and at least one CNG cylinder module 3. In this embodiment, CNG storage system 1 incorporates four CNG cylinder modules 3.

[0111] The Crashworthy Enclosure 2 is a semi monocoque structure configured in such a way as to withstand and/or distribute external loads allowing it to meet the structural and crashworthiness requirements while maintaining the integrity and maximizing the storage volume of the cylinders within it.

[0112] Because the CNG cylinder modules 3 have combined plumbing that can be accessed from one side, it allows the Crashworthy Enclosure 2 to have one removable side panel and one permanent side panel. This permanent side panel is welded in place and offers more structural rigidity than the removable side panel on the opposite side from it. This will either add strength or allow thinner and lighter materials to be used in the enclosure structure.

[0113] In FIG. 1 Crashworthy Enclosure 2 is shown with its removable door not present in order to illustrate removal of CNG cylinder module 3. As removable door panels are common in the art of enclosures no further discussion is needed.

[0114] FIG. 1 further illustrates the removal of CNG cylinder module 3. Also visible are six bolts 6 that are used to retain each CNG cylinder module 3 to the Crashworthy Enclosure 2. Less or more than six bolts 6 may be needed for CNG cylinder module 3 retention depending on the particular design.

[0115] FIG. 2A is a side view of the CNG storage system 1, again with the removable side panel missing from Crashworthy enclosure 2. In this view the 2 left CNG cylinder modules 3 are removed. Because this embodiment of crashworthy enclosure 2 can hold four CNG cylinder modules 3, there will be 3 thin vertical walls 9 and two outer thicker vertical walls 9. Also visible are gussets 8 that help support the top and bottom of the thin vertical walls 9 by shortening their center span where the thin material can easily deflect and the thin vertical wall 9 can buckle allowing crashworthy enclosure 2 to collapse.

[0116] Each CNG cylinder module 3 will have its own set of six bolts 6. When bolts 6 are in place they offer additional stiffness to the thin vertical walls 9 to help prevent buckling. This could allow the fixed vertical walls 9 to be made from thinner material.

[0117] FIG. 2B is a detail view of FIG. 2A. It illustrates the anti-buckling contact point 10 where the horizontal plate of the CNG module frame 4 is in close proximity of the neighboring vertical wall, either thin vertical wall 9 or thicker vertical wall 9. This helps to prevent any of the vertical walls from buckling by connecting them together along this plane formed by the CNG module rack 4 horizontal plates.

[0118] FIG. 3 Illustrates a CNG tank module 3 that contains two CNG cylinders 5 mounted to the module frame 4. Visible are the tank mounting straps 6 that are installed at a 45 degree angle for compactness. It is apparent that the fasteners required to attach straps 6 would be challenging to manipulate if the module frame 4 was permanently installed into crashworthy enclosure 2. In that case the spacing between thin vertical walls 9 would need to be several inches greater.

[0119] In this embodiment the CNG tank module 3 contains a pair of CNG cylinders 5. CNG tank module 3 can be composed of 1 or more CNG cylinders fixed to the module frame 4 in such a way as to make the CNG tank module 4 compatible with and mountable in a crashworthy enclosure.

[0120] The removable CNG tank module 3 has several advantages besides providing an efficient use of space while still allowing service access to the tanks:

[0121] The primary advantage is structural as the vertical stacking of the pair of 16 or 17 diameter CNG cylinders 5 allows a vertical structural wall 9 every 18 or so. These vertical walls of the frame allow the enclosure to withstand the crushing loads that the tank would suffer in a derailment without the larger vertical load passing through and possibly compromising the CNG cylinders 5.

[0122] The plumbing can be significantly simplified, as both CNG cylinders 5 in each CNG cylinder module 3 can be plumbed on the rack to one high pressure outlet fitting and one vent fitting. During a CNG cylinder module 3 installation and removal only the single pressure and vent line need to be connected or disconnected in the field.

[0123] Each pair of CNG cylinders 5 could be connected to a single PRD valve with a pair of temperature sensors on each rack

[0124] FIG. 4A illustrates a possible underframe locomotive LNG tank system that is crashworthy, simple and high capacity. In this design siamese pressure vessel 33 is slid into crashworthy enclosure 35 on six movable supports 34. After that end plate 32 is welded into place becoming an integral part of crashworthy enclosure 35. This creates a vacuum insulation cavity between the crashworthy enclosure 35 and siamese pressure vessel 33.

[0125] FIG. 4B is a detail view of FIG. 4A illustrating LNG feed pipe 41 and vent pipe 40 which are both welded to siamese pressure vessel 33. In this embodiment both of these are corregated for flexibility. When end plate 32 is welded to crashworthy enclosure 35, end plate 35 is also welded to LNG feed pipe 41 and vent pipe 40. These two metallic pipes are the only non insulated direct heat path between the siamese pressure vessel 33 and the crashworthy enclosure 35. If the tank system had 3 independent tanks, there would be 6 of these heat paths instead of 2.

[0126] FIG. 4C is a detail view of FIG. 4B illustrating one of the 6 mounting points for the siamese pressure vessel 33. In direct contact with the surface of the pressure vessel 33 is an insulator block 42, and captured inside insulator block 42 is support pivot 43. Insulator block 42 is captured by locating features on siamese pressure vessel 33 and is made from some hard but insulating material such as resin impregnated phenolic cloth. Support pivot 43 will be subject to a concentrated load so it is likely to be made of a metallic material such as steel.

[0127] FIG. 5A is a cross section view of the tank assembly. Inside of siamese pressure vessel 33 are 3 shared vertical walls 36 and multiple baffle plates 38.

[0128] FIG. 5B is a detail view of FIG. 5A illustrating one of the six movable supports 33 and the components that locate and transmit load through it. Directly contacting each end of movable support 33 are support pivots 43. Capturing each support pivot 43 is an insulator block 42. This set of components is designed to transmit load with a minimal transfer of heat between the siamese pressure vessel 33 and crashworthy enclosure 35. There is a set above and below siamese pressure vessel 33. There are also four angled sets of these parts that not only transmit vertical force, but due to their opposing angles, they locate siamese pressure vessel 33 laterally inside of crashworthy enclosure 35.

[0129] The pressure induced stresses in siamese pressure vessel 33 are carried by arched plates 37 that make up the exposed surface of pressure vessel 33 and by the vertical plates 36 which are shared by the neighboring siamese pressure chambers. Due to geometric conditions inherent in pressure vessels shared, vertical wall 36 should be at least twice the thickness of arched plates 37. The vertical load paths created by movable supports 3 are transmitted to pressure vessel 33 and carried through the pressure vessel 33 by the shared vertical wall 36.

[0130] FIG. 6A is an isometric view of the internal structural components of siamese pressure vessel 33. This illustrates how multiple baffle plates 38 will help prevent the 3 shared vertical walls 36 from buckling when subject to the very high vertical loading forces during a derailment accident. This is when the locomotive has derailed and the locomotive fuel tank bottom is resting on a piece of track rail and supporting the weight of the locomotive.

[0131] FIG. 6B is a detail view of FIG. 6A illustrating how the vertical load path generated by an angled movable support is still transmitted directly through a vertical wall 36.

[0132] FIG. 7A is an isometric view of a siamese pressure vessel 51. There is a shared wall 54 in the middle of the two siamese cylindrical pressure vessels that form one pressure vessel cavity. Shared wall 54 will have holes in it that connect the two cylindrical pressure vessel shapes into one sealed pressure vessel cavity. Support pivot 55 runs along the bottom sides of Siamese pressure vessel 51. Support pivot 55 may be made up of multiple components so that is can absorb a concentrated vertical load as it support the weight of the siamese pressure vessel 51 while transferring as little heat as possible.

[0133] FIG. 7B is an end view of the Vertical Siamese Tank Module 50. Shown are the main vertical supports 53 that vertically support the weight of the siamese pressure vessel 51. Around siamese pressure vessel 51 is the outer pressure vessel 52. In between siamese pressure vessel 51 and outer pressure vessel 52 is a vacuum cavity needed to keep the cryogenic LNG liquid from boiling off too rapidly.

[0134] Movable support 53 support contacts support pivot 55 and transfers the weight of siamese pressure vessel 51 to the outer pressure vessel 52 which is then attached to the rail vehicle that the Vertical Siamese Tank Module 50 is installed in. Not shown are other structural connections between the siamese pressure vessel 51 is the outer pressure vessel 52 that will absorb the axial and side loading on the tank and help the outer pressure vessel 52 maintain its shape. These supports will typically be placed in a direction normal to the outer pressure vessel 52 wall and will be much smaller in cross section and offer less of a heat leak potential. These standard lightly loaded supports are common in the art and not detailed here.

[0135] FIG. 8 Illustrates a side view of CNG tender car 56. In this embodiment CNG Tender car 56 is built upon a rail car 57 with a structural bulkhead 58 in the middle. Rail car 57 is similar in construction to an intermodal well car in that it has long slender walls that maximize internal volume for installing cargo or equipment while providing the axial structure needed to transmit the axial coupling loads of a railcar in a train. Bulkhead 58 will connect the left and right walls together to stiffen the long slender side walls by cutting the effective length in half. This adds significantly to the crashworthiness of the CNG tender car 56. For fuel storage crashworthiness, FRA regulations require that a locomotive fuel system be able to withstand a side impact from a class 8 truck.

[0136] Bulkhead 58 also supports one end of each CNG cylinder 59. In the preferred embodiment, each CNG cylinder 59 would have a fixed mount at bulkhead 58 and a sliding mount at the opposite end of the CNG cylinder 59. This sliding mount allows the CNG cylinder 59 to expand axially act as it is filled to a high pressure.

[0137] This embodiment of CNG tender car 56 contains twelve CNG cylinders 59. The upper 8 would be approximately 33 feet long and the lower four would be 25 feet long.

[0138] It would be possible to make these tender cars using Lincoln's standard 38 foot tanks replacing the 33 foot tanks in a longer rail car. Modern diesel electric locomotives have been produced up to 98 feet in length. This would add an additional 16% of fuel storage at a tender car length of approximately 85.

[0139] With the larger diameter CNG cylinders designed for 4500 psi operating pressure, the tender car will be capable of storing 10,000 DGE of CNG fuel. This is only of what an LNG rail car can carry, but is enough fuel to get two main line freight locomotives the distance they can now travel on their existing diesel tanks. Currently the larger mainline diesel electric locomotives carry 5000 gallons of diesel fuel. As the railroad industry converts to natural gas over the next few years it will be using dual fuel locomotives that can only consume 50-70% natural gas so it would be capable of taking 3 or 4 locomotives the full distance on natural gas and would still have at least 30% of its diesel fuel remaining.

[0140] FIG. 9 illustrates a locomotive consist with two locomotives 60 connected to an LNG tender car 63 that is built from a conventional intermodal well car 61 with a modified intermodal tank module 62.

[0141] FIG. 10 illustrates an ISO intermodal tank container modified for LNG tender car service. ISO LNG module 62 is built from an ISO intermodal tank container and modified for crashworthiness by incorporating a structural feature that acts as a bulkhead. This structural feature connects the outer frame structure 64 to the outer pressure vessel shell 68.

[0142] with the structural bulkhead added. In this case there is only one bulkhead added at the center of the tank. In some cases there may be multiple bulkheads used to create even shorter zones for the side wall to resist buckling.

[0143] FIG. 10B illustrates a preferred embodiment of the structural bulkhead feature; it could be constructed from steel plates 65 and steel c-channel 66. These components would be welded to both the outer frame structure 64 and the steel outer pressure vessel 68. There are many different ways this bulkhead could be constructed, this is an economical and practical one.

[0144] Another embodiment is to add another metal hoop of steel around the tank that fits close to the outer pressure vessel shell 68. This second hoop may or may not be welded to the outside of the pressure vessel. The bulkhead could be welded to this hoop instead of the outer wall. In any case the outer wall of the pressure vessel is still acting as a structural element as it prevents the second hoop from collapsing.

[0145] It is the structural bulkhead feature utilizing the outer pressure vessel wall as part of its structure that makes this unique. This allows the structural bulkhead feature to act as a virtual solid wall without passing any of the potential side impact loads to the more critical inner pressure vessel that contains the hazardous LNG fuel.

[0146] FIG. 11 Illustrates a Type 4 CNG cylinder 71 with a mounting plate mount 72 at each end. The mounting plate 72 act as springs allowing the CNG cylinder 71 to expand and contract without the need for a sliding surface. The mounting plates 72 could have tapered spring arm sections 73 designed as depicted. These would offer the appropriate lateral stiffness needed to handle vehicle side loads, but would minimize the torque load applied to the CNG cylinder 71 metal tank insert when the mounting plates 72 flexed. The mounting plates 72 will have to flex when the tank grows in length during filling or contracts as it is emptied.

[0147] Also visible is a CNG fuel line protector 74.

[0148] With the tank pilot and mount plate design it is possible to minimize or eliminate the exposure of the CNG lines and valves past the end of the CNG cylinder and its mount structure. This embodiment of the CNG line protector will cover an exiting CNG line as it crosses the pilot at the end of the tank. Once it crosses this area is can be routed back behind the mounting plate so that it is protected from crushing and cutting by intrusion of material from past the tank in an incident. This CNG line protector could take many shapes including a complete cover of the recessed area for further protection.

[0149] FIG. 12A is a cross section of one end of the CNG cylinder 71 further illustrating the recessed area 75 for the valves and the low profile of the CNG fuel line protector 74. In this case the recessed area 75 is part of a CNG tank end fitting 76 and has a standard 1.125-12 threaded hole that would be machined into the boss of a standard CNG cylinder. CNG tank end fitting could also be redesigned so that a valve assembly could be bolted in with an o-ring. This valve assembly could be an on off valve that was electrically or air operated and would automatically shut off with a loss of power or pressurized air in a catastrophic event.

[0150] In FIG. 12A the CNG tank end fitting 76 is shown as a solid piece, it would most likely be cast or machined to have structural webbing making the part lighter and leaving more internal space for compressed gaseous fuel.

[0151] FIG. 12B is a Detail View of FIG. 12A illustrating how the cylinder pilot feature 77 is captured by the piloting hole in mounting plate72, and the two components are held together by bolts 78. This direct bolting arrangement solves another mounting issue that strap mounting systems can suffer from. Each time a strap mounted CNG cylinder expands and contracts slightly during a fill and empty cycle, it can pivot slightly in its mounts. As rail equipment stays in service for many decades, this possible pivoting of tanks over time that can't be seen inside of a protective enclosure could be a problem. Pivoted far enough it could pinch or rupture a CNG fuel line.

[0152] FIG. 13A a locomotive 85 is shown fitted with LNG tank assy 86 and the LNGPM 87. The LNGPM 87 can be mounted directly to the LNG tank as shown or mounted remotely in applications where necessary to do so.

[0153] In FIG. 13B the LNGPM 87 is shown connected to the LNG pressure vessel 88 through the fill port 93 and the vent port 89. The fill port 93 connects to the LNGPM 87 at the pump manifold 92; LNG is then pumped from the pump manifold into the riser tube 91 that is contained within a vacuum sealed pressure vessel 90.

[0154] FIG. 14 illustrates a functional block diagram of the preferred embodiment of the LNGPM 87. With the possible exception of the sensors 99 and controller 98, these components are built into a compact, insulated module that can be mounted locally or remotely making it easily integrated into various mobile applications. The pump manifold 92 can serve as the primary structure of the LNGPM 87 and can contain the motor 97, inlet pump 95 and main pump 96. The inlet and mounting interface on the pump manifold 92 can be the side face of the side face of the pump manifold 92 allowing it to be mounted near or directly to the end of an LNG storage tank. The top surface of the manifold can have the necessary provisions to house the riser tube 91 inside a vacuum insulated sealed pressure vessel 90. The pressure vessel 90 will contain the output port and vent port interfaces necessary to attach and interface with vent port 89 and the locomotive 85 fuel system.

[0155] The pump manifold 92 can contain an the electric motor 98 which in this embodiment is to be a wet electric motor sealed within the pump manifold 92 to avoid the need for mechanical seals that present reliability issues. The motor 98 can be sized and configured within the pump manifold 92 such that it may drive the main pump sufficiently to generate the necessary flow and pressure. An inlet pump 95 can be included to address low inlet pressure conditions and serve to prime the main pump 96 by filling the riser tube 91 within the pressure vessel 90 above the pump manifold 92. The bearings for the motor 97 will be selected based on the load, temperature and lubrication conditions. The two pump stages can be positive displacement type (gerotor or gear) as the flow and pressure of the pumps is directly proportional to the speed and torque applied to the inlet pump 95 and main pump 96 through direct or indirect interface with the shaft of the motor 97.

[0156] Control and monitoring of the LNGPM output flow and pressure is to be managed via external interface with the controller 98. Controller 98 can be software configurable to allow the pump to provide user defined LNG flow and pressure over its operating range by varying the motor 97 speed.

[0157] FIG. 15 illustrates a preferred embodiment of a Type 2 cylinder 110 for use in an underframe enclosure. In this case the end of the cylinder 110 is spherical in shape, a purely spherical shape has an advantage of allowing flexibility in how and where the restraining system contacts the cylinder 110 and makes it easier to have it contact the cylinder surface easily. This system would still function with a more elliptical shaped cylinder end, but he contact system would have to accommodate that shape.

[0158] Offset porting is illustrated with a single visible port 112 offset to the side at 45 degrees. In the preferred embodiment, there would be four such ports 112, located symmetrical left to right and on both ends of the cylinder 110 for flexibility in mounting of the system, but the system could function with only one port 112 machined into the cylinder 110.

[0159] Also visible is the cylinder liner end plug 111, an optional feature. The cylinders 110 could be made with closed ends with no fitting or plug at the end, but the addition of the this plug 111 allows for some manufacturing options and easy visual inspection as needed throughout the service life of the cylinder 110.

[0160] Also illustrated in are the cylinder side plate 113 and the cylinder bottom plate 114. In this configuration it allows for restraining features to push the cylinder 110 down against the floor and axially along the locomotive length against one wall of the enclosure. In this embodiment they are designed as low cost aluminum extrusions, but they could be designed from any material that allows them to safely protect the wire wrapping of the Type 2 cylinder 110 as it contacts the surface of the enclosure. These conformal bottom and side plates could also be used with any Type pressurized cylinder in this application from Type 1 to Type 5.

[0161] In the cylinder bottom plate 114 is visible the extra feature on each side that will overlap with the vertical midwall plate gussets 117. These will be further detailed in another figure.

[0162] FIG. 16 is a partial side view of a single 37 diameter Type 2 cylinder 110 in one of two bays of a CNG enclosure that would mount below a locomotive frame. This enclosure is likely to include from two to six bays for insertion of CNG cylinders 110.

[0163] In the empty bay on the right side of FIG. 16 is visible the fixed compound angle cylinder contact pad 115. This pad 115 will be at a compound angle, and when the hemispherical head of the Type 2 cylinder is pressed against it, it will react to that force by pushing the cylinder 110 both against the left vertical wall and down towards the ground. In this embodiment, the pad 115 is fixed and not adjustable. Also in this instance, the fixed pad 115 is mounted to a flexible mounting plate 116 that is specifically designed with some capability for displacement to allow for axial cylinder growth when filled to its maximum operating pressure. When the cylinder 110 attempts to expand axially going from no pressure to its maximum fill pressure, the flexible plate 116 will allow the contact pad 115 to move slightly accommodating the cylinder axial length increase. This mounting plate 116 could be designed more rigid, as long as the opposing contact pad mounting system has enough displacement capability to make up for the lack of displacement capability of the fixed contact pad 115.

[0164] One of the requirements for a crash worthy fuel cylinder system on a locomotive is that the bottom of the system be able to absorb the vertical loading from a Jackknife Derailment incident. This is defined in 49 CFR Part 238 Appendix D, that the fuel cylinder shall support a sudden loading of one-half the locomotive at a vertical acceleration of 2 g without exceeding the ultimate tensile strength of the material. The load is assumed on one piece of rail distributed between the longitudinal centerline and the edge of the cylinder bottom. With a typical six-axle locomotive this would be approximately 400,000 pounds of force pushing up vertically through a 2-inch wide rail along approximately 48 of enclosure floor surface. If this load were directly under the vertical midwall, then the load would be carried by the midwall, which may buckle and deform slightly until the nearby CNG cylinder surfaces prevented further wall displacement. In physical testing of subsections, a mild steel wall with a total gap between the cylinder and enclosure wall surfaces was able to withstand this loading. An alternate loading has the rail surface applying the vertical load directly underneath the center of the CNG cylinder. In this case the CNG cylinder would absorb most of the vertical load and transmit it into the locomotive underframe through vertical displacement of the floor and CNG cylinder 110 until the CNG cylinder 110 contacted the top surface of the enclosure that would be in contact with the locomotive under frame.

[0165] It is the third, midspan scenario of the jackknife derailment loading where the vertical load is applied in between the vertical wall and the center of cylinder 110 that is most challenging. Illustrated in FIGS. 16A and 16B is the overlap area 118 where a section of the vertical midwall gusset plates 117 protrudes horizontally underneath the cylinder bottom plate 114. If there were a condition where the bottom of the enclosure was subject to a vertical load between the center of the cylinder 110 and the vertical midwall, this would attempt to rotate the vertical midwall gusset 117 and force it up into the outer surface of the CNG cylinder 110. As the vertical midwall gusset 117 is a plate of steel, where it would contact the cylinder 110 could have an edge that cuts through some of the wire winding. Even if not a sharp edge, the blunt plate body could displace the winding fibers enough to have them rupture or snap. A combination of vertical loading and side impact could force the CNG cylinder 110 to move axially along this intruding metal plate damaging even more fibers. Either cutting or rupturing the fibers will reduce the CNG cylinder's 110 ability to contain the high pressure gasses without a liner rupture. This overlap area 118 allows the protruding part of the vertical midwall gusset 117 to move up until it contacts the overlapping part of the cylinder bottom plate 114. At this point the Type 2 cylinder 110 would absorb some of the vertical load. Because the vertical gusset 117 is stopped by the conformal cylinder seat plate 114, the sharp edges of the vertical gusset 117 are unlikely to travel far enough towards the cylinder 110 to damage the wire winding of the Type 2 cylinder 110.

[0166] FIG. 17 is an isometric cropped view similar to FIG. 16 but from a different angle. It again illustrates the overlap area 118 where the vertical midwall gusset 117 would move up into the cylinder bottom plate 114 under certain vertical loading conditions.

[0167] The FIG. 18 is an isometric view of a removable side panel 119 to a CNG enclosure. This door panel 119 would cover the bays for three CNG cylinders 110. Contact pads 120 that contact the spherical end of the cylinder 110 will be opposite the fixed pads 115 at the back of the enclosure. Both pads 115, 120 push at compound angles pushing the cylinder 110 against the same side wall and down against the floor. In the illustrated embodiment, each contact pad 120 is mounted on a fixed mounting plate 121. In other embodiments, the mounting plate 121 and/or the door panel 119 could be flexible.

[0168] The Type 2 cylinders 110 are located by these four points of contact; one side wall, the floor and the pair of opposing compound angle pads 115, 120.

[0169] FIG. 19 is a close up view of the same removable side panel 119 from the previous figure. In this figure is visible the adjusting bolt 122 and locking nut 123 that push the movable pad 120 into the Type 2 cylinder 110. This movement of approximately .sup.3/.sub.4 of an inch allows for manufacturing tolerances and also preloading the plates 116, 121 that mount the pads 115, 120 at each end of the enclosure.

[0170] The removable side panel 119 is attached to the enclosure after the cylinders 110 are inserted into the enclosure and the gas plumbing lines are attached. After this the movable pads 120 can be adjusted from outside of the enclosure. Each pad 120 will likely be tightened until it contacts its cylinder 110, and then tightened additionally to move the cylinder 110 to its installed position. It could then be loosened and set to a nominal low torque to preset the cylinder 110. After this is done to all the cylinders 110, all of the individual pad locating bolts 122 can each be turned a specified number of degrees to preload the pads 115, 120 and the plates 116, 121 they are attached to. These locating plates 116, 121 can act as springs, as can the structure of the removable side panel 119.

[0171] In the examples shown, an example of an enclosure 100 for containing cylinders 110 includes an upper surface 101, a lower surface 102, opposing side walls 103 spanning the upper and lower surfaces 101, 102, and an end surface 104 spanning the upper and lower surfaces 101, 102, the upper surface 101, lower surface 102, side walls 103, and end surface 104 defining an enclosed space 105. A plurality of inner walls 106 divide the enclosed space 105 to define bays 107 that receive cylinders 110. A removable door panel 119 is opposite the end surface 104 and includes dividers 108 defining portions 109 of the door panel 119 corresponding to the bays 107. The enclosure 100 includes a plurality of first contact pads 115 and a plurality of first mounting plates 116, each first contact pad 115 mounted on a first mounting plate 116 on the end surface 104. At least one first contact pad 115 is positioned in a corner 107-a of each bay 107 at an angle that is neither parallel or perpendicular to either the side walls 103 or the upper surface 101 and contacts the received cylinder 110. The enclosure 100 also includes a plurality of second contact pads 120 and a plurality of second mounting plates 121, each second contact pad 120 mounted on a second mounting plate 121 on the removable door panel 119, wherein at least one second contact pad 120 is positioned in a corner 109-a of each portion 109 at an angle that is neither parallel or perpendicular to either the side walls 103 or the upper surface 101 and contacts the received cylinder 110 when the removable door panel 119 is secured to the enclosure 100.

[0172] In one embodiment, the enclosure 100 includes a plurality of vertical gussets 117, each secured to the lower surface 102 and one of the inner walls 106 and side walls 103. Each received cylinder 110 includes a cylinder plate bottom 114, and a lower edge of each gusset 117-a is positioned below the adjacent cylinder plate bottom 114. In another embodiment, the enclosure 100 also includes horizontal gussets 124, each secured to the end surface 104 within each bay 107.

[0173] In some embodiments, each of the plurality of first contact pads 115 is fixed. In other embodiments, each second flexible mounting plate 121 is mounted to the removable door 119 by an adjusting bolt 122 and locking nut 123 that push the second contact pad 121 against the cylinder 110. In still further embodiments, the plurality of first mounting plates 116 is integral with the end surface 104. In other embodiments, the plurality of second mounting plates 121 is integral with the removable door panel 119. In another embodiment, one of the plurality of first mounting plates 116 and the plurality of second mounting plates 121 is flexible.

[0174] FIG. 20 illustrates a conventional wire wound Type 2 cylinder 110, clearly visible is the wire or fiber wrapping 126 stopping short of the tangency point 127. The tangency point or juncture is the point at which a body wall of the cylinder or pressure vessel 110 meets an end wall. Although there is no wire wrap 126 reinforcing at the tangency point 127, some of the hoop stress at the tangency point 127 is taken up by the neighboring material that is supported by wire wrapping 126. Possibly the wire wrapping 126 can be thicker at the end 111 before it tapers off to increase this effect. It is the reliance on this neighboring material to transmit the hoop stresses to the wire wrapping 126 that forces the compromise to using a thicker liner than ideal.

[0175] FIGS. 21A and 21B are one solution to the problem of building up a wall or projection 129 for the wire wrap 126 to lead up to. In one embodiment, this approach will add first and second rings 129 of material such as low carbon steel or another suitable metal to the tank surface. In other embodiments, first and second projections 129 are first and second protrusions formed during the process of hot forming the pressure vessel. The projections 129 may include one or more segments of material that extend around the circumference of the pressure vessel in whole or in part.

[0176] In the illustrated embodiment, the projections 129 are positioned on the pressure vessel on the end wall of the pressure vessel 110 adjacent to the juncture. In a preferred embodiment, the projections 129 are positioned on the end walls at a distance equal to or less than about 3% of an outer diameter of the body from the juncture. In still further embodiments, an inner surface of the projections 129 contacting the fiber wrap may be aligned with the tangency point or juncture. In other embodiments, the projections may be positioned on the body wall adjacent to the juncture, such as at a distance equal to or less than about 5% of the thickness of the body wall from the juncture.

[0177] When the projection 129 is a ring attached to the pressure vessel, the proposed method of attaching the ring 129 is a low temperature brazing or solder process which should be done at a temperature equal to or lower than the tempering temperature of the heat treated liner. It should be noted that the solder and braze process are the same, the difference is in the melting point of the filler material with solder filler material having a liquidus temperature below 450 degrees C. and braze filler above that temperature. The terms braze and solder can be interchanged when describing the process of bonding the ring to the cylinder body outer surface with a metallic filler material that is melted. Thick sections of 4130 can be tempered at 480 C. and retain 110 ksi yield, typical Type 1 cylinder material properties call for a minimum yield of 88 ksi. The ring may also be bonded with adhesive (typically glue or epoxy) or welded to the tank surface. In alternative embodiments, the ring may comprise a plastic material that is glued to the tank surface.

[0178] Using an external ring 129 will require an extra part to be made and preparation for the brazing process. It is possible that the brazing process can be done the same time as the tempering process. As the force attempting to move the wrapping wires 126 axially is relatively small compared to the hoop stress of the cylinder 110, the ring 129 can be made of weaker and more ductile material than the cylinder liner. There is a large area available for the braze joint to absorb the axial load on the ring 129. The wire or fiber wrap 126 may be made of fiberglass fibers, carbon fiber, steel wire, and steel wire with a protective coating.

[0179] For initial production, the rings 129 could be manufactured out of arc shaped segments cut from plate that are rolled into cones and welded into one piece. As the ring weld joint is not structurally required to absorb the hoop stress of the cylinder 110, welding should be allowable for cylinder design certification and initial low volume production. Another feature making the weld joint in the ring less of a concern is that in front of the blocking wall feature is an area of lower hoop stress, and possibly a thicker wire wrap as the cylinder liner surface is moving down the tapered surface of the cylinder liner end dome.

[0180] After welding into a cone and heat treating or annealing, the ring 129 will only need a single turning operation on a lathe to be the appropriate size. This operation would establish the blocking wall angle and height and add the appropriate curvature to the surface of the ring 129 that will be brazed to the cylinder dome. In this surface, the braze bond gap can be manipulated from one side of the ring 129 to the other. One possible configuration of this surface is to have the braze gap start out larger, reduce to some minimal gap and then increase again. As the thicker braze gaps will be at each edge of the ring, there will be less of a chance of cracking due to pressure cycling of the cylinder.

[0181] Once accepted into an acceptable technique for wire wound Type 2 tanks, special press tooling could be acquired and these rings could be stamped in a single process from plate material or rings cut from large diameter seamless tubing. 36 OD seamless 4130 tubing is available in and wall.

[0182] If making the part from seamless tubing, a more economical rolling process could be used where the ring is rolled between two roller forms. The rollers establish the ring contours and shape; then the final gap between the rollers at the end of the process determines the final diameter.

[0183] Described above are economical ways to both fabricate prototypes and then later produce in higher volumes a large diameter blocking ring for 36 OD Type 2 cylinder liners. Also described is the opportunity to low temperature braze or solder these rings on to the cylinder liner during the tempering process of the cylinder liner. With economically produced rings and minimal additional processing of the cylinder liners, it is possible to further lower the weight and cost of Type 2 liners while also adding storage capacity.

[0184] There may be alternate ways to build up the wire wrap blocking wall feature without the addition of this blocking ring, but the use of a brazed on blocking ring allows for further reducing the wall thickness of wire wound Type 2 cylinder liners with minimal or no changes to current spin forming tooling or processes.

[0185] In an embodiment where the projection is a protrusion that is formed integral with the body of the pressure vessel, an alternate way to build up material on the cylinder liner surface with a modified forming process is by moving material during the hot forming process of the cylindrical tube that the cylinder liner is formed from. With advanced forming processes, the tube end face could be pushed back towards the cylinder body during forming causing the wall thickness to be locally increased leaving the extra material protruding from the liner body exterior surface. This process likely will require controlled localized heat to create a zone of soft easily displaced material far from the tube end face that is being pushed upon. It may also require an inside roller to ensure that the material is displaced more in the outer direction than towards the inside of the tube. Further a second guide roller just inside the tube end face would help keep the tube end section straight. Both of these rollers could be combined into one long roller. A third roller pushes in a direction perpendicular to the first two rollers against the tube end face. All three of these rollers could be on the same moving tool fixture.

[0186] Another method of raising up external material near the juncture on the cylinder is by using the hot forming roller that is forming the tube end shape to also drag material up from the thicker material accumulated on the hot and soft recently formed tube end surface. This is a simple reversal of the typical process of dragging material from the outer areas of the tube end to the cylinder neck. Now the material is dragged in the opposite direction when soft and molten. Additional hot forming operations could be used to shape this extra material to form a consistent surface with which to wind the fibers up against.

[0187] Additionally, the blocking ring can be molded in-place with a low temperature braze or solder material that can be poured at a temperature lower than the tempering temperature of the steel cylinder liner. In this case a mold assembly would be attached to the cylinder and the molten casting material poured into the mold. In another embodiment, this can be accomplished with a high strength epoxy material substituted for the molten metal if a material with the appropriate strength and thermal expansion characteristics is found.

[0188] Both of the previous forming operations or molding of additional material onto the cylinder liner body will eliminate the need to add the additional blocking rings to the cylinder liner body.

[0189] Referring to FIG. 21A, the cylinder 110 is neckless. FIG. 22 illustrates an alternative embodiment of a cylinder 110 having a stubbed neck 130. The enclosures described above may receive neckless cylinders as well as cylinders including stubbed necks 130 and these cylinders could be type 1 as well as type 2.

[0190] It should be noted that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the present invention and without diminishing its attendant advantages.