WO2023144597A1

WO2023144597A1 - Boss part assembly for composite cylinder and method of manufacture thereof

Info

Publication number: WO2023144597A1
Application number: PCT/IB2022/056092
Authority: WO
Inventors: Barun Kumar Bhoumik
Original assignee: Barun Kumar Bhoumik
Priority date: 2022-01-28
Filing date: 2022-06-30
Publication date: 2023-08-03

Abstract

The present embodiment herein provides a boss part assembly for composite cylinder. The assembly consist of a single cylindrical hollow metallic part 111 which has a hexagonal shaped head 120 on top of the metallic part followed by depressing contours 126,130 cut in steps, the depressing contours is having multiple slotted indentations 134, 136, 140 with v-grooves 138, 142; a circular disc 122 with multiple holes 124 is connected to the depressing contour 130; another depressing contour 126 joins a cylindrical section 127 with the circular disc 122; and a hollow portion 144 formed starting from top to bottom within the metallic body having a step cut in between the hollow portion; a plastic subassembly part 112 blow molded onto the metal subassembly part 110, filling the indentations, the contours, the v-grooves and the multiple holes 124, 128 with HDPE and filling the holes such that they join together; and a threaded plug 114 having a head 153 with a threaded portion 154 which securely connects the threaded plug 114 with the metallic subassembly part 110 and the plug also has multiple holes 158 at bottom of the plug for passage of gas to and from the composite gas cylinder.

Description

“BOSS PART ASSEMBLY FOR COMPOSITE CYLINDER AND METHOD OF

MANUFACTURE THEREOF”

BACKGROUND

Technical Field

The embodiments herein generally relate to a composite gas cylinders and more particularly to, but not limited to, an improved boss part assembly for the composite cylinder to prevent gradual leakage of any type of gases such as liquefied petroleum gas, compressed natural gas, oxygen, etc. from high or low pressure composite cylinders. The present embodiment also describes method of manufacturing the boss part assembly.

Description of the Related Art

Traditional steel cylinders are heavy and difficult to handle, and they generate high logistical and maintenance costs. Unaesthetic as they are, they are easily damaged and therefore steel cylinders can be explosive under certain circumstances. Steel cylinders are corrosive devices and many gas distributors have issues regarding this. Also, with thieves who steal them for scrap. From the consumers point of view, steel cylinders are unsafe if they are not well managed. The gas level cannot be checked and users can be affected by the weight and the risk of explosion.

Disadvantages of gas cylinders are as follows Difficult to handle - Heavy in weight, Corrosive, Explosion risk - Spark susceptible, Unfavorable environmental effects, unable to check the level of gas, Easily damaged, Metal thefts, Aesthetically unappealing, High logistic and maintenance cost, very old technology.

To overcome this disadvantages, new age composite cylinder has been developed. Composite cylinder is a three-layer cylinder made up of a blow-molded HDPE inner liner, covered with composite layer of polymer-wrapped fiber glass and fitted with a HDPE outer jacket. The second layer is a composite layer of polymer-wrapped fibre glass. And the third and last layer to the LPG composite cylinder is an HDPE outer jacket. These new-age composite cylinders have multiple advantages over the existing steel cylinders. These cylinders are lightweight. The weight of a composite cylinder is half of its steel counterpart. Moreover, these cylinders have a translucent body that helps customers to accurately check the LPG level against light. This will help customers plan their next refill easily. These cylinders are also rust-free and do not corrode and reduces the chances of leaving stains and marks on surfaces. Designed in such a way that these cylinders make them visually appealing and ideal for the modem kitchens of today. You can replace the existing LPG steel cylinders with composite cylinders.

However, composite gas cylinders may suffer from gradual leakage from Boss part integration over a period of time. This may be due to poor integration of the boss part into neck of the composite cylinder. Many a times while refilling the cylinder, the valve system or the regulator installation into the boss part may result in some minor gaps left between the Boss part and the cylinder. Also, long-term damage (ageing) and failure mechanisms of composites may result in gas leakage especially from the Boss part of the cylinder. Wherein the plastic and metal part of the Boss assembly gets detached or peel off from each other over a period of time due to continuous use, exposure to high temperature, handling, refilling of gas, etc. resulting in gradual leakage of gas from the composite cylinder where the Boss part is connected. Such percentage of gas leakage through the Boss part is beyond standard norms and is not acceptable by Industry standards. Accordingly, there remains a need for an improved Boss part assembly which will keep the metal and the plastic part of the assembly intact over a longer period of time without leaking any gas and thereby providing ideal sealing of the integration between the cylinder body and the Boss part with almost zero leakage of the gas from the composite cylinder. SUMMARY

The present embodiment herein discloses an improved boss part assembly for the composite cylinders, the boss part assembly comprises of a metal subassembly part having a single cylindrical hollow metallic part characterized in that having a machined outer metallic body forming a hexagonal shaped head on top of the metallic part, followed by a depressing contours cut in steps, wherein the depressing contours consist of multiple slotted indentations each having an angled v-grooves cut within the indentations such that each of the v-grooves is forming a depressing angle between 50 and 70 degrees normal to the slotted indentations; a circular disc connected to the depressing contour, wherein the disc is having multiple holes throughout the disc; a depressing contour cut in steps connecting the disc, joins a cylindrical section having multiple holes with the circular disc; and a hollow portion machined from top to bottom from within the metallic body having a step cut in between the hollow portion, wherein the hollow portion has a larger threaded portion on upper side of the metallic body and a smaller threaded portion on the lower side of the metallic body; a plastic subassembly part blow molded onto the metal subassembly part, filling the indentations, the contours, the v-grooves and the multiple holes of the metallic part with High-density polyethylene (HDPE) material leaving partially the hollow portion unfilled, wherein the multiple holes is filled with plastic material within the holes such that the HDPE material joins together through the holes and locks the plastic subassembly part with the metallic subassembly part, thus forming an inseparable linking with the metallic part ; and a threaded plug consisting of a head having a threaded portion to securely connect the threaded plug with the metallic subassembly part, wherein the plug consist of a hexagonal shaped hole starting from top of the plug, passing through body from within and touching a multiple holes at bottom of the plug for safe passage of gas to and from the composite gas cylinder. In an embodiment, the circular disc may be tapered on upper surface at an angle of 95 degrees from normal of the depressing contour. In one embodiment, the boss part assembly may be fused to a fiber glass composite at one of the depression.

In an example embodiment, the larger threaded portion which is located on the upper side of the metallic body may help secure any type of adaptors or connectors with the assembly for connecting gas regulator on to the composite cylinder.

In another example embodiment, the smaller threaded portion which may be located on the lower portion of the metallic body help secure the threaded plug with the metallic subassembly part.

A method of manufacturing a boss part assembly, is described with steps such as below:

Step a. machining a cylindrical metallic block to obtain a single cylindrical hollow metallic part characterized in that a machined outer metallic body forms a hexagonal shaped head on top of the metallic part, followed by a depressing contours cut in steps, wherein the depressing contours consist of multiple slotted indentations; and a circular disc connected to the depressing contour, wherein the disc is having multiple holes throughout the disc; a depressing contour cut in steps connecting the disc, joins a cylindrical section having multiple holes with the circular disc; and a hollow portion machined from top to bottom from within the metallic body having a step cut in between the hollow portion, wherein the hollow portion has a larger threaded portion on upper side of the metallic body and a smaller threaded portion on the lower side of the metallic body;

Step b. creating an angled v-grooves which is cut within the indentations such that each of the v-grooves forms a depressing angle between 50 and 70 degrees normal to the slotted indentations; Step c. blow molding a plastic subassembly part onto the metal subassembly part, which fills the indentations, the contours, the v-grooves and the multiple holes of the metallic part with High-density polyethylene (HDPE) material leaving partially the hollow portion unfilled, wherein the multiple holes is filled with plastic material within the holes such that the HDPE material joins together through the holes and locks the plastic subassembly part with the metallic subassembly part, thus forming an inseparable linking with the metallic part;

Step d. machining another cylindrical metal part to obtain a threaded plug which includes a head having a threaded portion, a body and a hexagonal shaped hole starting from top of the plug, passing through body from within and touching multiple holes at bottom of the plug for safe passage of gas to and from the composite gas cylinder; and

Step e. fastening the threaded plug onto the single cylindrical hollow metallic part, preferably on the smaller threaded portion located on the lower side of the metallic body, making the assembly complete.

In one embodiment, the larger threaded portion located on the upper side of the metallic body secures any type of adaptors or connectors with the assembly for connecting gas regulator onto the composite cylinder, the metallic body has a treaded notch on top of the metallic part within the hexagonal shaped head.

In an example embodiment, the metal subassembly part may be made from any non- corrosive metal preferably high grade stainless steel or brass. In another example embodiment, the threaded plug may be made from any non-corrosive metal preferably high grade stainless steel or brass.

These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference will be made to embodiments of the invention, examples of which may be illustrated in the accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in the context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments:

The embodiments herein will be better understood from the following detailed description with reference to the drawings, in which:

FIG. 1 illustrates a front schematic view of a typical composite cylinder having various layers with a Boss part integrated into the composite cylinder according to an embodiment mentioned herein;

FIG. 2 illustrates a perspective view of a Boss part assembly according to an embodiment mentioned herein;

FIG. 3 illustrates a front schematic sectional view of the Boss part assembly detailing metal and plastic subassembly parts and threaded plug according to an embodiment mentioned herein;

FIG. 4 illustrates a front schematic view of outer metallic part of the metal subassembly part according to an embodiment mentioned herein;

FIG. 5 illustrates a front schematic view of the metal subassembly part detailing various contours and grooves located on outer surface of the metallic body of the metallic subassembly part according to an embodiment mentioned herein;

FIG. 6 illustrates a front schematic view of a plastic subassembly part integrated on to the metallic body of the metal subassembly part according to an embodiment mentioned herein; and

FIG. 7 illustrates a perspective view of a threaded plug which is part of the Boss part assembly according to an embodiment mentioned herein; and

FIG. 7A illustrates a front schematic view of a threaded plug which is part of the Boss part assembly according to an embodiment mentioned herein.

Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example, the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure.

Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Although specific terms are used in the following description for the sake of clarity, these terms are intended to refer only to the particular structure of the invention selected for illustration in the drawings, and are not intended to define or limit the scope of the invention.

References in the specification to “one embodiment” or “an embodiment” member that a particular feature, structure, characteristics, or function described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment.

In the following description, for purposes of explanation and not limitation, specific details are set forth such as particular architectures, interfaces, techniques, etc. in order to provide a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. That is, those skilled in the art will be able to devise various arrangements which, although not explicitly described or shown herein, embody the principles of the invention and are included within its spirit and scope. In some instances, detailed descriptions of well-known devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail. All statements herein reciting principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future, i.e., any elements developed that perform the same function, regardless of structure.

Accordingly, there remains a need for an improved Boss part assembly which will keep the metal and the plastic part of the assembly intact over a longer period of time without leakage of any gas thereby providing ideal sealing of the integration between the cylinder and Boss part with almost zero leakage of the gas from the composite cylinder.

The present embodiments herein provides an improved boss part assembly for the composite cylinder to prevent gradual leakage of any type of gases such as liquefied petroleum gas, compressed natural gas, oxygen, etc. from high or low pressure composite cylinders. The present embodiment also describes method of manufacturing the boss part assembly. Referring now to the figures, more particularly from FIG. 1 to FIG. 7A, where similar reference characters denote corresponding features consistently throughout the figures, preferred embodiments are shown.

FIG. 1 illustrates a front schematic view of a typical composite cylinder 100 having various layers with a Boss part integrated into the composite cylinder according to an embodiment mentioned herein. The composite cylinder 100 has a gas tight inliner 102, a fiber glass composite layer 106, an outer casing 108 and a Boss part 104.

In an embodiment, an inner container which is a gas tight inliner 102 may be made of polyethylene (PE) and is treated with special chemicals and resins to provide excellent anti-permeation property. The fiber glass composite layer 106 is made from composite material of fiber which is helically woven and combined with resins to provide combination of high tensile strength, light weight and UV resistance.

In an embodiment, the outer casing 108 may be a heavy duty PE casing to suit rough handling and logistics. Usually the outer casing 108 has attractive design to provide space for branding unlike metal cylinders. These casing may be customized with different colour combinations as per client needs. In an embodiment, the boss part 104 which may also be termed as universal boss is made of steel so that the boss part is insulated from regular wear and tear on any number of screwing/ unscrewing operations of brass valve. The boss part 104 is suitable to operate at a temperature range -60° C to 200° C.

In an example embodiment, a composite cylinder body may consist of the gas tight inliner 102, the fiber glass composite layer 106 and the outer casing 108 without the boss part.

FIG. 2 illustrates a perspective view of a Boss part assembly 104 according to an embodiment mentioned herein. The boss part assembly 104 includes metal subassembly part 110, a plastic subassembly part 112 and a threaded plug 114. The metal subassembly part 110 is fabricated or machined to form a specific shape and size which is then blow molded with High-density polyethylene (HDPE) material over the metal subassembly part 110. The threaded plug 114 is then bolted or fastened to the metal subassembly part 110.

In an example embodiment, the metal subassembly part 110 and the threaded plug 114 may be made from any non-corrosive metal preferably high grade stainless steel or brass.

FIG. 3 illustrates a front schematic sectional view of the Boss part assembly 104 detailing the metal subassembly part 110, the plastic subassembly part 112 and the threaded plug 114 according to an embodiment mentioned herein. In an embodiment, the metal subassembly part 110 has a larger threaded portion 116 which is located on within upper side of the metallic body, which may secure any type of adaptors or connectors with the assembly 104 for connecting gas regulator on to the composite cylinder 100.

In another embodiment, the metal subassembly part 110 may also include a smaller threaded portion 118 on the lower side of the metallic body. The smaller threaded portion 118 helps to safely secure or bolt the threaded plug 114 with the metallic subassembly part 110.

In an embodiment, the boss part assembly 104 may be fused to the composite cylinder body 101 at a depression 113 joining the plastic part subassembly 112 with the composite cylinder body 101.

Referring now to FIG. 4 which illustrates a front schematic view of the outer metallic part or body 109 of the metal subassembly part 110 and FIG. 5 illustrates a front schematic view of the metal subassembly part 110 detailing various contours and grooves located on outer surface of the metallic body 109 of the metallic subassembly part according to an embodiment mentioned herein.

In an embodiment, the metal subassembly part 110 consist of a single cylindrical hollow metallic part 111 which is having a machined outer metallic body 109.

In an embodiment, the outer metallic body 109 has a hexagonal shaped head 120 on top of the metallic part 111 which is followed by a depressing contours 126,130 cut in steps. In an embodiment, the depressing contours may consist of multiple slotted indentations 134, 136, 140. In an example embodiment, the slotted indentations 136 and 140 is having an angled v-grooves 138, 142 cut within the indentations such that each of the v-grooves is forming a depressing angle between 50 and 70 degrees normal to the slotted indentations.

The metal body 109 also includes a circular disc 122 connected to the depressing contour 130, wherein the disc is having multiple holes 124 throughout the disc. In an embodiment, a depressing contour 126 cut in steps is connecting the disc from below which joins a cylindrical section 127 with multiple holes 128. In an embodiment, the circular disc 122 may be tapered on upper surface 123 at an angle of 95 degrees from normal of the depressing contour 130. In an embodiment, a hollow portion 144 is machined from top to bottom from within the metallic body may be having a step cut within the hollow portion. In an example embodiment, the hollow portion 144 has a larger threaded portion 116 which may be located on upper side of the metallic body 109 and a smaller threaded portion 118 which may be located on the lower side of the metallic body 109.

FIG. 6 illustrates a front schematic view of the plastic subassembly part 112 integrated on to the metallic body 109 of the metal subassembly part 110 according to an embodiment mentioned herein. In an example embodiment, the plastic subassembly part 112 blow molded onto the metal subassembly part 110. The blow molding operation may fill the indentations 134, 136, 140, the contours 126, 130, the v-grooves 138, 142 and the multiple holes 124, 128 of the metallic part 111 with High-density polyethylene (HDPE) material. In an embodiment, the hollow portion 144 may or may not be filled with HDPE. The metallic body 109 has a treaded notch 121 on top of the metallic part within the hexagonal shaped head 120.

In one embodiment, the multiple holes 124, 128 is filled with plastic material within the holes such that the HDPE material 150, 152 joins together through the holes 124, 128 and locks the plastic subassembly part 112 with the metallic subassembly part 110 such that they form an inseparable linking with the metallic part 110. Thus a very strong bond is created between the metal subassembly part 110 and the plastic subassembly part 112.

FIG. 7 and 7A illustrates a perspective and schematic view of the threaded plug 114 which is part of the Boss part assembly 104 according to an embodiment mentioned herein. In an embodiment, the threaded plug 114 includes a head 153 which is having a threaded portion 154 for securely connecting the threaded plug 114 with the metallic subassembly part 110. In an additional embodiment, the plug 114 may have a hexagonal shaped hole 156 starting from top of the plug 114, passing through body 160 from within the plug and touching a multiple holes 158 at bottom of the plug 114 for safe passage of gas to and from the composite gas cylinder. This hexagonal shape is provided for bolting or securing the threaded plug 114 with the metallic subassembly part 110 using hexagonal shaped tools.

In an embodiment of the present disclosure also provides a method for manufacturing a boss part assembly 104. The method includes steps as below:

Step a. machining a cylindrical metallic block to obtain a single cylindrical hollow metallic part 111 characterized in that a machined outer metallic body 109 forms a hexagonal shaped head 120 on top of the metallic part, followed by a depressing contours 126,130 cut in steps, wherein the depressing contours consist of multiple slotted indentations 134, 136, 140; and a circular disc 122 connected to the depressing contour 130, wherein the disc is having multiple holes 124 throughout the disc; a depressing contour 126 cut in steps connecting the disc, joins a cylindrical section 127 having multiple holes 128 with the circular disc 122; and a hollow portion 144 machined from top to bottom from within the metallic body having a step cut in between the hollow portion, wherein the hollow portion 144 has a larger threaded portion 116 within upper side of the metallic body and a smaller threaded portion 118 within the lower side of the metallic body;

Step b. creating an angled v-grooves 138, 142 which is cut within the indentations such that each of the v-grooves forms a depressing angle between 50 and 70 degrees normal to the slotted indentations;

Step c. blow molding a plastic subassembly part 112 onto the metal subassembly part 110, which fills the indentations 134, 136, 140, the contours 126, 130, the v-grooves 138, 142 and the multiple holes 124, 128 of the metallic part 111 with High-density polyethylene (HDPE) material leaving partially the hollow portion 144 unfilled, wherein the multiple holes 124, 128 is filled with plastic material within the holes such that the HDPE material 150, 152 joins together through the holes 124, 128 and locks the plastic subassembly part 112 with the metallic subassembly part 110, thus forming an inseparable linking with the metallic part 110; Step d. machining another cylindrical metal part to obtain a threaded plug 114 which includes a head 153 having a threaded portion 154, a body 160 and a hexagonal shaped hole 156 starting from top of the plug, passing through body 160 from within and touching multiple holes 158 at bottom of the plug for safe passage of gas to and from the composite gas cylinder; and Step e. fastening the threaded plug 114 onto the single cylindrical hollow metallic part 111, preferably on the smaller threaded portion 118 located on the lower side of the metallic body 109, making the assembly complete.

In an advantageous embodiment, the boss part assembly provides below advantages: a) Simple process of assembly without damaging of critical parts without requiring any highly skilled person. b) Time saving assembly due to less number of child parts. c) Cost saving due to simple design and less number of assembly parts etc. no possibility of rejection during assembly.

Thus, the present embodiment tries to achieve optimum integration of the metal and the plastic part which will keep the assembly intact over a longer period of time without leakage of any gas, thereby providing ideal sealing of the integration between the cylinder body and the Boss part with almost zero leakage of the gas from the composite cylinder. The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope.

Claims

CLAIMS WE CLAIM:

1. A boss part assembly 104 for composite cylinder comprising: a metal subassembly part 110 consisting of - a single cylindrical hollow metallic part 111 characterized in that having a machined outer metallic body 109 forming a hexagonal shaped head 120 on top of the metallic part, followed by a depressing contours 126,130 cut in steps, wherein the depressing contours consist of multiple slotted indentations 134, 136, 140 each having an angled v- grooves 138, 142 cut within the indentations such that each of the v- grooves is forming a depressing angle between 50 and 70 degrees normal to the slotted indentations; a circular disc 122 connected to the depressing contour 130, wherein the disc is having multiple holes 124 throughout the disc; a depressing contour 126 cut in steps connecting the disc 122, joins a cylindrical section 127 with multiple holes 128 with the circular disc 122; and a hollow portion 144 machined from top to bottom from within the metallic body having a step cut within the hollow portion, wherein the hollow portion 144 has a larger threaded portion 116 on upper side of the metallic body and a smaller threaded portion 118 on the lower side of the metallic body; a plastic subassembly part 112 blow molded onto the metal subassembly part 110, filling the indentations 134, 136, 140, the contours 126, 130, the v-grooves 138, 142 and the multiple holes 124, 128 of the metallic part 111 with High-density polyethylene (HOPE) material leaving partially the hollow portion 144 unfilled, wherein the multiple holes 124, 128 is filled with plastic material within the holes such that the HOPE material 150, 152 joins together through the holes 124, 128 and locks the plastic subassembly part 112 with the metallic subassembly part 110, thus forming an inseparable linking with the metallic part 110; and a threaded plug 114 consisting of a head 153 having a threaded portion 154 to securely connect the threaded plug 114 with the metallic subassembly part 110, wherein the plug consist of a hexagonal shaped hole 156 starting from top of the plug, passing through body 160 from within and touching a multiple holes 158 at bottom of the plug for safe passage of gas to and from the composite gas cylinder.

2. The assembly as claimed in claim 1, wherein the circular disc 122 is tapered on upper surface 123 at an angle of 95 degrees from normal of the depressing contour 130.

3. The assembly as claimed in claim 1, wherein the boss part assembly 104 is fused to a composite cylinder body 101 at a depression 113 joining the plastic part subassembly 112 with the composite cylinder body 101.

4. The assembly as claimed in claim 1, wherein the metallic body 109 has a treaded notch 121 on top of the metallic part within the hexagonal shaped head 120.

5. The assembly as claimed in claim 1, wherein the larger threaded portion 116 located on the upper side of the metallic body secures any type of adaptors or connectors with the assembly 104 for connecting gas regulator on to the composite cylinder 100.

6. The assembly as claimed in claim 1, wherein the smaller threaded portion 118 located on the lower portion of the metallic body secures the threaded plug 114 with the metallic subassembly part 110.

7. A method of manufacturing a boss part assembly 104, said method comprising steps as below: a. machining a cylindrical metallic block to obtain a single cylindrical hollow metallic part 111 characterized in that a machined outer metallic body 109 forms a hexagonal shaped head 120 on top of the metallic part, followed by a depressing contours 126,130 cut in steps, wherein the depressing contours consist of multiple slotted indentations 134, 136, 140; and a circular disc 122 connected to the depressing contour 130, wherein the disc is having multiple holes 124 throughout the disc; a depressing contour 126 cut in steps connecting the disc, joins a cylindrical section 127 having multiple holes 128 with the circular disc 122; and a hollow portion 144 machined from top to bottom from within the metallic body having a step cut in between the hollow portion, wherein the hollow portion 144 has a larger threaded portion 116 within upper side of the metallic body and a smaller threaded portion 118 within the lower side of the metallic body; b. creating an angled v-grooves 138, 142 which is cut within the indentations such that each of the v-grooves forms a depressing angle between 50 and 70 degrees normal to the slotted indentations; c. blow molding a plastic subassembly part 112 onto the metal subassembly part 110, which fills the indentations 134, 136, 140, the contours 126, 130, the v-grooves 138, 142 and the multiple holes 124, 128 of the metallic part 111 with High-density polyethylene (HDPE) material leaving partially the hollow portion 144 unfilled, wherein the multiple holes 124, 128 is filled with plastic material within the holes such that the HDPE material 150, 152 joins together through the holes 124, 128 and locks the plastic subassembly part 112 with the metallic subassembly part 110, thus forming an inseparable linking with the metallic part 110; d. machining another cylindrical metal part to obtain a threaded plug 114 which includes a head 153 having a threaded portion 154, a body 160 and a hexagonal shaped hole 156 starting from top of the plug, passing through body 160 from within and touching multiple holes 158 at bottom of the plug for safe passage of gas to and from the composite gas cylinder; and e. fastening the threaded plug 114 onto the single cylindrical hollow metallic part 111, preferably on the smaller threaded portion 118 located on the lower side of the metallic body 109, making the assembly complete.

8. The method as claimed in claim 7, wherein the larger threaded portion 116 on the upper side of the metallic body secures any type of adaptors or connectors with the assembly 104 for connecting gas regulator onto the composite cylinder 100.

9. The method as claimed in claim 7, wherein the metal subassembly part 110 is made from any non-corrosive metal preferably high grade stainless steel or brass.

10. The method as claimed in claim 7, wherein the threaded plug 114 is made from any non-corrosive metal preferably high grade stainless steel or brass.