CZ298770B6 - Thin-walled liner for high-pressure cylinders - Google Patents

Abstract

In the present invention, there is disclosed a thin-walled liner of amorphous material for high-pressure cylinders of composite material such as fiberglass, containing a central cylinder part and two faces, with a socket in one of them wherein the invention is characterized in that the thickness of face and central-part walls and the height of the liner faces being in the proportion of 0.001 to 0.01 to 0.3 to 0.1 of the maximum diameter and the main part of the amorphous material being crystalline thermoplastic, with the crystallization temperature ranging from 100 to 280 degC as measured using differential scanner calorimetry (DSC), at the heating rate of 10 degC per minute and the surface shine of over 90 at the measuring angle of 20 degrees as measured according to DIN 67530.

Description

The present invention relates to high-pressure vessels, the body of which is a composite material and lined inside a hermetic liner.

BACKGROUND OF THE INVENTION

These containers are used for the storage and transport of the liquid medium, ie liquid or gas, under pressure and their body is made of composite material and lined inside with a hermetic layer - lining which, depending on the type and nature of the liquid medium contained in the container, made of thermoplastic, aluminum or stainless steel. The hermetic lining usually has a sleeve made of the same material from which the lining is made. This mouthpiece extends all the way into the throat channel of the throat located in the body of the container during manufacture, and a throat equipped with a shut-off fitting of any suitable type is located inside the throat.

Such containers are usually subjected to multiple cyclic high pressure stresses. Therefore, particular importance in containers of a similar type is placed on the hermetic casing material - liner and in particular on the hermeticization of the casing sleeve in the throat channel of the throat in order to prevent leakage of the liquid environment or failure of the hermetic container.

Attempts have been made to create pressure vessels using polyethylene and a device for hermetically sealing the sleeve in the channel of the neck of the high pressure vessel.

In particular, a high-pressure vessel with a body of composite material with an installed socket has been provided, which extends along the length of the throat channel and is in contact with its inner surface, with a centrally located throat, a sleeve pressure sleeve. to the inner surface of the throat channel having at least one outer circular or screw protrusion on the side of the container body cavity, which rests on the sleeve sleeve and interacts with it to seal the sleeve, see FIG. for example GB 1023011 A, 16.03.66, F 17 Cl / 16.

However, as it turns out, said means for hermetically sealing high pressure vessels is insufficient since the variations in the spacing of the outlet of the throat at high pressure are within the elastic deformation at the same time as the flowability of the lining material and its sleeve is significantly higher. in deformations, the underlying cause of non-hermeticity of the vessel at high pressure levels is high pressure.

[0005] EP 0300931 A1, F 17 Cl / 16, which discloses a high-pressure vessel having a composite material body with its own flange on the axle of the axle 45 channel and with an outlet threaded pin located in this channel all the way into the threaded pin of the inner hermetic sleeve sleeve - lining and installed in the sleeve coaxial throat channel centrally located sleeve with a closing fitting that presses the sleeve sleeve against the inner surface and which is threaded to a threaded spigot.

A similar solution is disclosed in WO 99/27293, WO 99/13263 and U.S. Pat. No. 4,925,044.

However, at high pressures of the liquid medium that fills the cavity of the container body, even in these cases, the reliable hermetic seal of the container-liner to the outlet

The nozzle, particularly at the points of contact thereof, with the inner surface of the throat channel and the outer surface of the throat, mostly due to the reasons given above.

In patent RU 2150634 a solution is described which largely removes the aforementioned shortcomings by providing a reliable device for sealing the sleeve of the inner packaging.

- linings in the neck of the container at significantly higher cyclic pressure of the high pressure.

This object is achieved by means of a device for hermetically sealing the inner sleeve - a liner in the neck of a high-pressure vessel with a body of composite material which is lined inside with a hermetic sleeve - a liner with a sleeve along the entire length of this channel, and a throat with a shut-off fitting located inside the sleeve coaxially with the throat channel. According to the disclosure, a circular cavity is formed between the sleeve mouth and the neck into which a sealing material is placed, which is compressed axially by the pressure of the fluid environment in the container body cavity and interacts radially outwardly on the inside surface of the sleeve mouth.

In the most preferred embodiment of the solution according to the patent RU 2150634, the neck has a flange at the end facing the cavity of the container body, and the neck at its free end emanating from the body of the container - exiting and adjacent to the neck surface. the side of the circular cavity in which the sealing material is placed.

In this way, the proposed solution of the task of patent RU 2150634 concludes that in the construction of the device according to this patent, the seal in the circular chamber is permanently tested by axial load on the side of the neck flange under pressure of the liquid environment. The material exerts a permanent radial outward force on the sleeve sleeve

the lining, pressing it tightly against the inner surface of the throat axial channel, thus ensuring its reliable sealing.

However, even in this case, the task of ensuring reliable hermetic packaging of the liner and throat is not entirely solved because the overall drawback of this design solution and of the prior art cylinder design solutions is that amorphous thermoplastics such as polyethylene are used as liner material. , which have high viscoelastic deformability, low gas permeability coefficients for virtually all technical gases and at high pressure have the main drawback of decompression loss, the so-called Keson's disease.

SUMMARY OF THE INVENTION

SUMMARY OF THE INVENTION It was an object of the invention to provide a more reliable solution for the construction of a hermetic casing - lining 40 and a solution for hermetizing the sleeve of the inner casing - lining in the neck of the container at substantially higher cyclic load.

This object was solved by the proposed construction of a hermetic lining made of amorphous thermoplastic material, comprising a central cylindrical portion and two fronts, in one of which a throat is installed.

According to the invention, the wall thickness of the face and the central part and the height of the end faces of the lining are in the ratio of 0.001 to 0.01 to 0.3 to 0.4 of its maximum diameter and contain as crystalline thermoplastic with crystallization temperature within 100 to 280 ° C measured by differential scanning calorimetry (DSC) at a heating rate of 10 ° C / min. and its surface gloss measured according to DIN 67530 at a measuring angle of 20 ° is more than 90.

The most reliable embodiment of the invention is one in which the crystalline thermoplastic has a crystallinity within the range of 5 to 15% by weight in the face wall and the central part of the lining.

-2GB 298770 B6

Also reliable is an embodiment in which the crystalline thermoplastic in the lining sleeve has a crystallinity in the range of 75 to 99% by weight.

In the most reliable embodiment of the invention, the crystalline thermoplastic is selected from the group consisting of polyethylene terephthalate, polybutadienterephthalate, a cycloolefin polymer and a cycloolefin copolymer.

In yet another embodiment of the invention used, the standard viscosity SV (DCE) of crystalline thermoplastic measured in accordance with DIN 53728 in a 50:50 mixture of phenol with 1.2 dichlorobenzole is in the range of 75 to 85%, whereas in dichloroacetic acid is between 800 and 1800.

Also suitable is an embodiment of the invention wherein the notched amorphous state of the material measured by the Izoda method in accordance with ISO 180 / 1A is 2 to 8 kJ / m ² .

In one exemplary variation of this solution, it is contemplated that polyethylene terephthalate having a post-crystallization temperature of between 120 ° C and 160 ° C is used as the crystalline thermoplastic.

In another exemplary variation of this solution, it is contemplated that the crystalline lining thermoplastic comprises at least one ultraviolet stabilizer selected from 2-hydroxybenzotriazole and triacin.

Desirably, a change in the notch toughness of the Sharp crystalline thermoplastic in accordance with ISO 179 / 1D does not create a crack.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in detail in the examples below with reference to the drawings. FIG. 1 is a longitudinal sectional view of a high pressure vessel with a hermetic throat solution. FIG. 2 is an enlarged longitudinal sectional view of one of the variations of FIG. 1 in accordance with the invention.

Examples

When analyzing the basic properties of some of the most commonly used thermoplastics listed in Table 1, it may be noted that based on the gas permeability and strength requirements for use as liner material, polyethylene terephthalate, related to the crystalline class, is the most appropriate material according to strength, deformation characteristics and gas permeability. thermoplastics.

-3 CZ 298770 B6

Name polymer State Limit Tension in turn MPa Relat. předl. at violation % Water vapor permeability g / m ² Oxygen, permeability g / m ² / per 24 hours Temperature mp ° C ΡΞΝΡ Amorphous 9-17 500 15 - 20 6500 - 8500 102-105 PEV? Amorphous 17 - 35 300 5 1600 - 2000 125-137 PP Amorphous 41 300 10 - 20 370 160-176 PVC, nep; astif Amorphous 45-55 120 30 - 40 150-350 150-220 PVIC Amorphous 48-137 20 - 40 1.5 - 5.0 8-25 220 OPS Amorphous 62-73 20 May 70-150 4500 - 6000 180 BYE Amorphous 69-97 250-400 40 - 80 500 225 FIVE Amorphous 150-180 70-110 25 - 30 40 - 50 250-260 FIVE Amorphous 190-260 20 - 30 2,5 - 15 2-20 250-260 PK Amorphous. 59 75 77-93 4500 220-270 AC Amorphous 49-83 15 - 45 100-320 2000 - 3000 Hydrate cellulose Amorphous 48-110 15 - 25 5-15 670

where

PENP - low density polyethylene;

PEVP - high density polyethylene;

PP - polypropylene;

PVC - polyvinyl chloride;

PVIC - polyvinylidene chloride

OPS - oriented polystyrene;

PA - polyamide;

PET - polyethylene terephthalate;

PK - polycarbonate;

AC - cellulose acetate

Usually, when designing cylinders, a certain amount of diffusing gas, ie diffusing gas, is permissible over a certain period of use. For example, the requirement of EN 12245 - 0.25 cm / l per hour.

The wall thickness of its faces and cylindrical part can be determined from the condition §> k * p * S * t / Δ V where Δ V - volume of spilled lace k - gas permeability coefficient of used material

P - working pressure of gas in the cylinder S - surface area over which the gas leaks t - time of using the gas cylinder δ - wall thickness of the cylinder liner

-4GB 298770 B6

It is apparent from the average reference characteristics of the various thermoplastics shown in the table that to meet the gas permeability requirements set by various standards such as EN 12245 or NGV-4, the wall thickness of the faces and the central part of the crystalline thermoplastic liner is between 0.001 and 0.01 the maximum lining diameter and is considerably smaller than the thickness of other types of thermoplastics, for example polyethylene 100 times. Due to the low wall thickness of the liner and the low gas permeability when using a crystalline thermoplastic, the loss of strength of the thermoplastic upon decompression of the liner is avoided.

Crystallization of the thermoplastic on the face and the cylindrical part of the lining with a volume of 5 to 15 parts by weight at a crystallization temperature in the range of 100 to 280 ° C measured by differential scanning calorimetry (DSC) with a heating rate of 10 ° C / min. gas permeability through the lining wall while retaining their deformation properties.

As shown in FIG. 1, in one embodiment of the high-pressure vessel, the composite material body also comprises a multilayer skeleton, the layers of which are obtained by winding cross-threads of glass or aluminum fiber soaked in a polymer bonded in one direction. A coaxial flange 2 and a flange 3 with the neck 4 are wound into the body 1 during its production in order to connect the body 5 to the surrounding space, the body and the container being lined inside with a hermetic lining 6 which is made of crystalline thermoplastic.

As shown in FIG. 2 in one embodiment of the filler neck device of the invention, the lining 6 covering the inside of the body 1 has a sleeve 7 disposed along the entire length of the axial channel 8 of the neck 4 and associated with its inner surface 9. and a neck 10 is provided with a centrally located neck 10, which has a flange 11 at the inverted end into the cavity 5 of the container 1, which fits on its surface 12 with its circular surface 12 to the inner surface 13 of the sleeve 7. sleeve 7 linings 6.

Subsequently, the neck 4 is provided at its free outlet end from the body 1 with an inlet flange 14 adjacent its circular surface 15 to the outside surface 16 of the neck 10.

As a result, it is obtained that a circular concentrically positioned cavity 17 is formed between the sleeve 7 of the lining 6 and the neck 10, which is covered from the front parts by the neck flange 11 and the neck flange 14.

Inside the cavity 17 there is a gasket 18 which fills its entire volume, which during axial movement of the neck 10 is compressed in its axial direction by pressure on its fluid flange 11 in the cavity 5 and acting radially outwardly on the inner surface 13 of the sleeve 7 and presses it firmly against the inner surface 9 of the axial channel 8 of the neck 4 and thus seals the sleeve 7 in the channel 8 of the neck 4.

At high pressure in the cavity of the body and the container in the circular cavity Γ7, a pressure of 3 to 5 times the pressure in the cavity 5 is generated.

Accordingly, in the zone of contact of the seal 18 with the sleeve 7, increased thermo45 strength of the plastic as well as its low creep are required. This is solved by crystallization of the lining of the lining. Crystallization of the thermoplastic in a volume of 75 to 99 parts by weight in the zone of the filler neck allows to increase the strength of the thermoplastic in the zone and to reduce the creep characteristics of the crystalline thermoplastic several times. This in turn causes an increase in the operational characteristics of the junction node.

When the cylinder is subjected to pressure on the surface, a frictional stress occurs between the composite and the liner which depends on the degree of cleanliness of the liner surface, which can then be determined by gloss according to DIN 67530. For the lining variant using crystalline thermoplastic DIN 67530 more than 90.

-5GB 298770 B6

In order to achieve the above characteristics of crystalline thermoplastics, it is most useful to use thermoplastics with a standard viscosity measured in accordance with DIN 53728 in a 50:50 mixture of phenol with 1,2 dichlorobenzenol, ranging from 75 to 85%.

In order to avoid local damage in stress concentration and deformation zones, the use of thermoplastics in which the notched toughness of the material in the amorphous state measured according to ISO 180 / 1A is more than 2 to 8 kJ / m ² and is desirable Sharp change of notch toughness of crystalline thermoplastic in accordance with ISO 179 / 1D did not result in a crack.

Due to the general availability, the most widely used among known thermoplastics and well-tuned processing technologies are one of the practical variants of lining construction where polyethylene terephthalate with an additional, i.e., cold crystallization temperature of 120 to 160 ° C is required as a crystalline thermoplastic. Aging in the natural sub-15s comprises at least one ultraviolet stabilizer selected from 2-hydroxybenzotriazole and triacin.

In order to ensure the strength of the composite cylinder, the profile of the cylinder faces must be selected according to the uniform stress of the reinforcing fibers of the composite along its meridian length. To provide such a solution using a thin-walled deformable liner, it is necessary that the maximum profile depth of the liner fronts be within the range of 0.3 to 0.4 of the maximum liner diameter. In the present case, when the reinforcing fibers are wound up and the liner is subsequently overfilled, the fronts of the cylinder assume the shape of an optimum profile ensuring uniform stress of all reinforcing fibers of the composite used.

The functionality of a high pressure vessel is to fill it with a liquid medium, i.e. liquid or gas, to the required pressure level, to store, transport, discharge, then refill and consume the liquid medium, i.e., repeat operations and operations with multiple cyclic loads.

The function of the solution according to the invention has been described in describing variants of construction and is obvious to those skilled in the art, and therefore does not require any special explanation.

The invention is not limited to the above embodiments, given merely to illustrate the invention, and may be varied within the scope of the claimed invention.

Industrial applicability

With the creation of the proposed solution, there was a real possibility to use high-pressure vessels made of composite material and hermetic inner lining. The production and testing of high-pressure vessels with designed liner for their hermetization confirmed their high reliability and efficiency.

-6GB 298770 B6

PATENT CLAIMS

Claims (9)

PATENT CLAIMS A thin-walled lining of a high-pressure amorphous material container for composite material cylinders, for example fiberglass, comprising a central cylindrical portion and two end faces, one of which has a neck, characterized in that the wall thickness of the faces and the central portion and the height of the faces the lining (6) is in a ratio of 0.001 to 0.01 to 0.3 to 0.1 of maximum diameter and the main component of the amorphous material is a crystalline thermoplastic having a crystallization temperature in the range of 100 to 280 ° C measured by differential scanning calorimetry at speed heating at 10 ° C / min, and a surface gloss of 20 ° above 90 °. Lining according to claim 1, characterized in that the crystalline thermoplastic in the wall The 15 faces and the central part of the lining (6) is crystalline in the range of 5 to 15 wt. Lining according to claims 1 and 2, characterized in that the crystalline thermoplastic in the wall of the sleeve (7) of the lining faces (6) is crystalline in the range of 75 to 99% by weight. 20 May The lining according to claims 1 to 3, characterized in that the standard viscosity of the crystalline thermoplastic in the 50:50 mixture of phenol and 1,2 dichlorobenzole is between 75 and 85%. The lining according to claims 1 to 4, characterized in that the crystalline thermoplastic is 25 is selected from the group consisting of polyethylene terephthalate, polybutadienterephthalate, cycloolefin polymers and cycloolefin copolymers. The lining according to claims 1 to 5, characterized in that the crystalline thermoplastic does not show cracks in the Sharp notched impact test. The lining according to claims 1 to 6, characterized in that the notch toughness of the material in the amorphous state measured by the Izoda method is 2 to 8 kJ / m ² . The lining according to claims 1 to 7, characterized in that the crystalline thermoplastic 35 is a polyethylene terephthalate with an additional, i.e., cold crystallization, temperature in the range of 120 ° C 160 ° C. The lining according to claims 1 to 8, characterized in that the crystalline thermoplastic of the lining (6) comprises at least one ultraviolet stabilizer selected from 2-hydroxybenzotriazole. 40 and triacin. 45 2 drawings -7EN 298770 B6