Claims:We Claim:

1. A composite cylinder boss assembly 200, comprising:
a composite boss 100, wherein the composite boss 100 further comprises a metallic internal boss 101 covered by a polymer external boss 102, and wherein the metallic internal boss 101 and the polymer external boss 102 are joined together with a bonding interface joint 206, and wherein composite boss 100 is adapted to provide an uninterrupted opening 205 at the top for accommodating a valve of any type and shape employed for controlled flow of the compressed gas; and
a sealing means 201 for sealing the interface joint 206 between the metallic internal boss 101 and the polymer external boss 102 for preventing the gas leakage from the cylinder through the gaps of an interface joint 206 of the composite boss 100.

2. The composite cylinder boss assembly 200 of claim 1, wherein the gaps in an interface joint 206 of the composite boss 100 are at least formed due to different expansion and contraction of metallic internal boss 101 and the polymer external boss 102 during cyclic temperatures changes.

3. The composite cylinder boss assembly 200 of claim 1, wherein the material for internal metallic boss 101 is selected from the group of metals having a shear strength and wear resistance greater than that of the material of the valve such that the internal metallic boss 101 is sustainable to the shear strength and wear resistance in occurrence of a damage to the valve.

4. The composite cylinder boss assembly of claim 1, wherein the polymer external boss 102 is welded to an in-liner of the composite cylinder.

5. The composite cylinder boss assembly of claim 1, wherein the sealing means 201 is an O-ring with radial outline and with a cross section, wherein the cross section is either of a circular cross section, an oval cross section, and a rectangular cross section.

6. The composite cylinder boss assembly 200 of claim 1, wherein a plurality of bolting means is employed for pressurising a washer employed for providing equal pressurisation over the sealing means 201.

7. The composite cylinder boss assembly 200 of claim 6, wherein the washer is employed to compress the sealing means, and wherein the instalment of washer prevents the scratching or rubbing of the bolting means on the sealing means.

8. The composite cylinder boss assembly 200 of claim 5, wherein the material selected for O-rings 201 is based on the chemical compatibility with the gas present in the composite cylinder, and wherein the material comprises either of a nitride compound compatible with liquefied petroleum gas, silicone and its composite compounds, viton, buna-N, ethylene propylene diene monomer, neoprene and the like.

9. The composite cylinder boss assembly of claim 2, wherein different expansion and contraction of metallic internal boss 101 and the polymer external boss 102 during cyclic temperatures changes occur due to different positive and negative co-efficient of thermal expansion.
, Description:FORM 2

THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENT RULES, 2003

COMPLETE SPECIFICATION

(See Section 10 and Rule 13)

Title of invention:
COMPOSITE CYLINDER BOSS ASSEMBLY

APPLICANT:
Genex Science and Technologies Pvt. Ltd.,
a company incorporated as per the laws of India,
having address as
1,2,3, 'C' Wing, 2nd floor, Tex Centre, Chandivali road,
Andheri (East), Mumbai - 400072

The following specification describes the invention and the manner in which it is to be performed.
TECHNICAL FIELD

The present subject matter described herein, in general, relates to a field of sealing a passageway for the prevention of unwanted escape or loss of gas, more particularly, relates to a sealing assembly for a composite boss attached to a composite pressure cylinder.

BACKGROUND

The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also correspond to implementations of the claimed technology.
Leakage of gas through cylinders and other pressure vessels have proven dangerous for health and life. All compressed gases are hazardous because of the high pressures inside the cylinders. Gas can be released accidentally from a broken/leaking valve, from a safety device, from gaps or passages which may have their ends to the internal pressurised gas and the surrounding environment. Even at a relatively low pressure, gas can flow rapidly from an open or leaking cylinder.
The leakage of gas may further occur through gaps which are formed at the interface joints between a composite cylinder heads or boss. Such composite cylinder heads or boss may have a joining interface between their composite materials. For example, a metal-polymer interface. Theses interfaces even though sealed tightly and bonded together are prone to formation of gaps over time due their varying material properties. Such gaps may lead to constant leakage of the pressurised gas in lower discharge rates which may eventually result in loss of gas and also may further create a hazardous environment for a plurality of users.
Many of the gases are used because of their specific properties of compressed gases make them highly useful in various research activities. These gases, however, can be dangerous if not handled in an appropriate manner. Many of the odourless and colourless gases are highly toxic and flammable and this calls for utmost care while handling them. Flammable gas burns or explodes if it is mixed with air, oxygen or other oxidant, in the presence of a source of ignition. Further, there are many other gases which may cause danger to a human which may further lead to emergency or delicate medical conditions.
Presently, valves may provide sealing of the interface joints by employing sealing means. The sealing means are further engaged with the valve wherein such sealing means surround the shaft or rod of the valve wherein the sealing is employed as an obstruction at the starting of interface joint from the inner side which is prone to constant slips further leading to improper sealing. Such assembly further may make the assembling of the assembly complex because of the plurality of design considerations of composite valve, boss and sealing means. Such sealing means may not seal the interface joints directly. Further, such sealing may seal the gap between the valve and the inner surface of the boss which block or seal the interface joint directly.
Boss assemblies which are employed with sealing means around the valves or subsidiary valve inserts may consume unnecessary space which may cause an interrupted opening further leading to less or inconvenient opening. Such assembly may call for usage of specific and custom made valves which may suffice the valve control functions employed for a specific boss design or assembly. Such interrupted opening may not allow the implementation of simple or standardised universal valves available in the industry or market. Therefore, there is a long-standing requirement of a clear and uninterrupted opening to implement standard valves and to overcome the need of custom valves.
The present composite cylinder which may be equipped with sealing arrangement at the lower side of valves wherein such sealing unit may be in the form of O-rings which may be installed or implemented at two or more points to cover the gaps from upper and lower side. Such sealing assembly may result in unnecessary usage of more O-rings for sealing a single gap between which may prove expensive. An utmost provision is required to enable a fool-proof sealing assembly using only single O-ring.
Presently composite cylinders are either equipped with metallic bosses or by polymer bosses. Metallic bosses may have a drawback of not adhering properly to the liners of the composite cylinder which may lack in the required adhesion between the plastic and metal. Polymer bosses may have a drawback of not holding the metallic valves firmly due to their high elasticity. Further, if thermoset polymers are used then they may be subjected to formation of cracks due to unbearable generated force from the pressure.
Present composite closure system may comprise sealing means between the closure caps and the closure body or closure mouth. Such sealing means are subjected to frequent mechanical actions like compression, expansion and friction while closing and opening of the cap or closure. Such mechanical actions may further damage the sealing means and may make the sealing inappropriate.
The various forms of leakage through involuntary gaps created in the composite cylinder head or boss which are mostly attached to composite cylinders are required to sealed with a fool-proof solution. Furthermore, damages which may occur while operating the boss or closure of the composite cylinder is to be reduced or to nullified. Therefore, there is a long-standing need for a sealing of the interface gaps of the composite boss to prevent the leakage of gas through the composite cylinder.

SUMMARY

This summary is provided to introduce concepts related to a composite cylinder boss assembly and the concepts are further described below in the detailed description. This summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in determining or limiting the scope of the claimed subject matter.
In an implementation, a composite cylinder boss assembly is described. The composite cylinder boss assembly may comprise a composite boss. The composite boss may further comprise a metallic internal boss covered by a polymer external boss. The metallic internal boss and the polymer external boss may be joined together with a bonding interface joint. Further, the composite boss may be adapted to provide an uninterrupted opening at the top for accommodating a valve of any type and shape, wherein the valve is employed for controlled flow of compressed gas. The composite cylinder boss assembly may further comprise a sealing means for sealing the interface joint between the metallic internal boss and the polymer external boss for preventing the gas leakage from the cylinder through gaps of an interface joint of the composite boss. The composite cylinder boss assembly may further comprise a plurality of bolting means for pressurising a washer employed for equal pressurisation over the sealing means.
OBJECTS OF THE INVENTION

A primary object of the invention is to prevent leakage of gas from a composite cylinder by providing a composite cylinder boss assembly as described herein.

Yet another object of the invention is to prevent leakage of gas from an interface joint between the metallic internal boss and the polymer external boss by the sealing means.

Yet another object of the invention is to equally pressurise the sealing means by a washer which is further pressurised by a plurality of fastening means such as bolts.

Yet another object of the invention is to prevent the gas leakage from the cylinder through the gaps of an interface joint of the composite boss which are formed due to thermal expansion and contraction of metallic internal boss and the polymer external boss during cyclic temperatures changes.

BRIEF DESCRIPTION OF DRAWINGS
The detailed description is described with reference to the accompanying Figures. In the Figures, the left-most digit(s) of a reference number identifies the Figure in which the reference number first appears. The same numbers are used throughout the drawings to refer like features and components.
Figure 1 illustrates a three-dimensional model of the composite boss, in accordance with an embodiment of the present subject matter.
Figure 2 illustrates a sectional two-dimensional arrangement of the composite cylinder boss assembly, in accordance with an embodiment of the present subject matter.
Figure 3 illustrates a magnified image of the composite cylinder boss depicting the interface joints, in accordance with an embodiment of the present subject matter.
DETAILED DESCRIPTION

The present subject matter described herein, in general, relates to a field of sealing an interface joints for the prevention of unwanted escape or loss of gas, more particularly, relates to a composite cylinder boss assembly 200 preventing unwanted escape or loss of gas.
For the purpose of the present subject matter “fluid” may be a gaseous or liquidous compound which can be stored in high pressure cylinders employed for safe transportation to a desired location and for further usage of the gas for desired purpose.
For the purpose of the present subject matter “composite cylinder” is a cylinder with composite case further comprising an inliner, composite case, outer shell, pressure valves, composite boss and sealing means.

For the purpose of the present subject matter “composite boss” is a cylinder head which is attached to the inliner of the composite cylinder and which holds the valve and sealing means. The composite boss may further comprise a metallic internal boss and an outer covering of polymer external boss.

Referring Figure 1, a three-dimensional model of the composite boss is illustrated in accordance with an embodiment of the present subject matter. The composite boss 100 may further comprise of an internal metallic boss 101 which may be further covered by polymeric material forming an external polymer boss 102. The metallic internal boss 101 and the external polymer boss 102 joined firmly at their joining interface may collectively form the composite boss 100. The external polymer boss 102 is employed for adhering with the inliner of the composite cylinder. Such adhering may be performed by hot plate welding, frictional welding or by other adhering means.

Referring figure 2, a sectional two-dimensional arrangement of the composite cylinder boss assembly 200 is illustrated in accordance with an embodiment of the present subject matter. The composite cylinder boss assembly 200 may further comprise a composite boss 100, a sealing means 201, a washer 202, and nuts 203(s). Such sealing assembly 200 may be affixed to the neck of a composite cylinder.

The composite cylinder boss assembly 200 may also include a valve when the cylinder is operation which contains gas at high pressure. The valve may be employed for controlled delivery of the pressurized gas from the cylinder to the required destined target.

The sealing means 201 may be employed for sealing of the interface joint 206 of the composite boss 100. The interface joint 206 may be prone to formation of gaps due to expansion and contraction of the composite boss 100 due to thermal cyclic changes. In an embodiment, the gaps may be formed due to the different material properties in the composite boss. For example, the expansion and contraction rates are different for metals and polymers used for composite boss. This difference in the co-efficient of thermal expansion may result in the formation of gaps in the interface joint 206.

The sealing means 201 may be implemented in the form of O-ring (hereinafter sealing means may also be referred as O-ring) which may be further pressurized by a circular washer 202 kept over the sealing means 201. Such washer 202 may be further pressurized by and locked by a plurality of corresponding locking nuts 203. In an exemplary embodiment, any gaps present in the interface joint 206 leading to leakage of gas may be prevented by the O-ring 201 in compressed state.

In yet another embodiment, the O-ring 201 may be in a radial shape and with a plurality of sectional profiles comprising either of circular, rectangular, oval and the like. The material of the O-ring 201 is selected based on the chemical compatibility with the gas present in the composite cylinder. In one embodiment, the material may be selected from either of silicone and its composite compounds, viton, buna-N, ethylene propylene diene monomer, neoprene and the like.

In an embodiment, the sectional view may illustrate the obstructed pathway of the gas leakage from the cylinder inner space wherein such pathway is obstructed by the sealing means (O-ring) 201.

In an embodiment, the composite cylinder boss 100 may provide an uninterrupted opening 205 at the top for accommodating a valve of any type and shape, wherein the valve is usually employed for controlled flow of the compressed gas in the composite cylinder.

In an embodiment, the material for internal metallic boss is selected from the group of metals having a shear strength and wear resistance greater than that of the material selected for the valve such that the internal metallic boss 102 is sustainable to the sheer strength and wear resistance in occurrence of a damage to the valve. Such selection provides a safety factor for preventing the damage which may occur during installation of valve. In an example, damages if any caused while fastening or fixing the valve in the boss will be sustained by the valve. Such material selection may prevent the damage to the composite boss 100 further increasing the life of the composite boss 100 and cylinder in whole. As the composite boss 100 may be permanently affixed to the composite cylinder, the composite boss may not be replaced. Therefore, in any occurrence of damages to the composite boss, the whole cylinder may be considered as damaged which may not be considered fit for use and hence may need to be replaced. In order to prevent damage to the internal composite boss 101, the material selection may be such that the damage caused, if any, is sustained by the valve. In an example, the material for metallic internal boss 101 may be selected as a steel whereas for the valve, the material selected may be brass since brass is more elastic than steel.

Referring figure 3, a magnified image of the composite cylinder boss assembly 200 depicting the interface joint 206 is illustrated, in accordance with an embodiment of the present subject matter. The interface joint 206 starts from the internal space of the cylinder and ends where the O-ring 201 is placed. The interface joint 206 is depicted by a bold black colored outline in the figure. Such interface joint 206 is prone to formation of gaps as explained above.

In an exemplary embodiment, the pathway of gas leakage from the cylinder through the interface joint 206 is depicted by a series of arrows 301 when there is an occurrence of a gap in the interface joint 206. The composite cylinder assembly may further enable the composite cylinder boss 100 to provide an uninterrupted opening 205 at the top for accommodating a valve of any type and shape employed for controlled flow of the compressed gas.

Although implementations for composite cylinder boss assembly 200 have been described in language specific to structural features and/or methods, it is to be understood that the appended claims are not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed as examples of implementations for composite cylinder boss assembly 200.