JPH07305798A - Pressure vessel made of plastic - Google Patents

Abstract

PURPOSE:To reduce weight, to prevent the occurrence of potential different corrosion, and to perform a repeat use by a method wherein an outer line is formed in such a manner that a reinforced yarn made of aramide fibers impregnated with thermosetting resin is wound and laminated. CONSTITUTION:A pressure vessel made of plastic comprises a horizontal long cylindrical inner liner 1; and an outer liner 2 with which the outer surface of the inner liner 1 is covered. Partially spherical shell-form end walls 3 are formed at the right and left ends of the inner liner 1 and a mouthpiece 4 formed of an aluminum alloy is securely inserted in the central part thereof. The outer line 2 is formed in such a manner that a reinforced yarn 12 made of amide fibers impregnated with thermosetting resin is wound and laminated as it is wound around a pair of the mouthpieces 4 according to a filament winding method. The aramide fiber has specific gravity lower than that of glass fibers or carbon fibers, and by preparing FRP, a container made of plastic being more light is produced. Further, since electricity is not allowed to flow through the aramide fibers, even when the reinforced yarn 12 is laminated, potential different corrosion is prevented from occurring to a contact part between the mouthpiece 4 and the reinforced yarn 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic pressure vessel provided with a plastic inner liner having a die fixed to an insert and an outer liner made of a fiber reinforced plastic layer.

[0002]

2. Description of the Related Art A pressure vessel of this type is disclosed in JP-A-1-299.
It is publicly known in Japanese Patent Laid-Open No. 400 and Japanese Patent Laid-Open No. 3-89098. There, the inner liner is made of polyamide, polystyrene,
Alternatively, the outer liner is formed of a glass fiber reinforced plastic layer, which is formed of a plastic material having excellent gas barrier properties such as polyethylene. As the reinforcing fibers wound around the outer surface of the inner liner, it is known that organic fibers such as aramid fibers can be applied in addition to inorganic fibers such as glass fibers and carbon fibers (JP-A-4-249699). .

[0003]

A plastic pressure vessel having a mouthpiece inserted into the inner liner can reduce the weight of the vessel as compared with a pressure vessel having an all-metal inner liner. When carbon fiber is used as the reinforcing fiber of the fiber reinforced plastic layer (hereinafter simply referred to as FRP layer), the weight of the container can be further reduced as compared with the case of using glass fiber. However, since carbon fiber is a good electrical conductor, there is a risk of potential difference corrosion on the peripheral surface of the die around which the carbon fiber is wound, and there is concern about the durability of the die when the pressure vessel is repeatedly used.

Both glass fiber and carbon fiber have low shear strength, and the single fiber is broken at the stage of forming a reinforcing yarn (strand) of a predetermined size from the single fiber. In other words, the reinforcing yarn made of glass fiber and carbon fiber,
The tensile strength of the reinforcing yarn is reduced to less than half that of the single fiber state because it contains not a few defects.
This means that in order to impart a predetermined compressive strength to the FRP layer, it is necessary to use a larger amount of reinforcing yarn, and the thickness and weight of the FRP layer increase. When the thickness of the FRP layer is constant, the pressure vessel of the pressure vessel must have a small pressure resistance.

It is an object of the present invention to provide a plastic pressure vessel which is lighter in weight, does not cause potential difference corrosion and is suitable for repeated use. An object of the present invention is to provide a plastic pressure vessel capable of exhibiting a higher pressure resistance than a pressure vessel in which the FRP layer is formed of inorganic fibers when the thickness of the FRP layer is constant. . It is an object of the present invention to provide a plastic pressure vessel that can reduce the weight of the FRP layer when the pressure resistance of the FRP layer is constant, as compared to a pressure vessel in which the FRP layer is formed of inorganic fibers. The purpose of the present invention is to
An object of the present invention is to provide a plastic pressure container capable of preventing the base from collapsing inward of the container when a shock is applied to the base.

[0006]

The present invention has an inner liner 1 formed by plastic molding, and an outer liner 2 made of a fiber reinforced plastic layer covering the outer surface of the inner liner 1,
In a plastic pressure vessel in which a metal mouthpiece 4 is insert-fixed to an inner liner 1, an outer liner 2 comprises a reinforcing yarn 12 made of aramid fiber impregnated with a thermosetting resin,
It is characterized in that it is formed by being wound and laminated while being wound around the die 4 according to a filament winding method.
As the thermosetting resin impregnated in the reinforcing thread 12, any one of an epoxy resin, a phenol resin, and an unsaturated polyester resin can be used. Another plastic product pressure vessel of the present invention has a plastic-molded inner liner 1 and an outer liner 2 made of a fiber-reinforced plastic layer covering the outer surface of the inner liner 1, and the inner liner 1 is provided with a metal base. 4 is insert-fixed. The outer liner 2 is
The reinforcing yarn 12 impregnated with the thermosetting resin is wound and laminated while being wound around the die 4 according to the filament winding method. The base 4 has a flange 6 embedded in the inner liner 1 and a cylinder shaft 5 projecting to the outer surface of the inner liner 1, and a tapered wall having a small diameter end on the flange 6 side on the peripheral surface of the cylinder shaft 5. The constricted portion 10 is provided.

[0007]

Since the aramid fiber has a suppleness, no defect occurs when the reinforcing yarn 12 is formed from the single fiber, and the tensile strength of the reinforcing yarn 12 is
It is only slightly reduced from the tensile strength of single fiber and has a lower specific gravity than glass fiber or carbon fiber.
Therefore, a lighter plastic pressure vessel can be obtained by forming the FRP layer by making only the fibers forming the reinforcing yarn 12 different and keeping other conditions constant. Aramid fibers do not conduct electricity. Therefore, even if the reinforcing thread 12 is wound around the pair of caps 4 and laminated, potential difference corrosion does not occur at the contact portion of the cap 4 with the reinforcing thread 12.

[0008]

In the present invention, since the aramid fiber strand is used as the reinforcing yarn 12 for forming the FRP layer, the tensile strength is higher than that of the reinforcing yarn formed of glass fiber or carbon fiber of the same size. Can be improved. As a result, the container weight when the pressure resistance of the pressure container is kept constant can be sufficiently reduced as compared with the case where the FRP layer is formed of glass fiber or carbon fiber. Since there is no reduction in strength during formation, the weight of the container can be reduced by exceeding the difference in specific gravity between the carbon fiber and the aramid fiber. Since the reinforcing thread 12 is formed of aramid fiber, which is an electrically poor conductor, it eliminates potential difference corrosion on the peripheral surface of the base 4 that comes into contact with the reinforcing thread 12 and improves the durability of the base 4 during long-term use. Therefore, it can be safely applied to applications where the pressure vessel made of plastic having the mouthpiece 4 fixed with the insert is repeatedly used.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The pressure vessel of FIG. 1 is an on-vehicle cylinder of liquefied natural gas, and comprises a horizontal oblong inner liner 1 formed by a rotational forming device and an outer liner 2 covering the outer surface of the inner liner 1. Become. Partial spherical shell-shaped end walls 3 are provided at the left and right ends of the inner liner 1, and a cap 4 made of an aluminum alloy is insert-fixed to the center of the end walls 3. The inner liner 1 is formed by using a molding material such as polyamide, polyethylene, or polystyrene, which has excellent gas barrier properties.

In FIG. 2, a mouthpiece 4 has a circular flange 6 integrally projecting from the inner end of a cylinder shaft 5, and external accessories such as valves and meters are screwed into the inner peripheral surface of the cylinder shaft 5 on the outer end side. And a loading seat 8 for a seal ring. Through holes 9 are formed at six positions in the circumferential direction near the periphery of the flange 6 at equal intervals. On the outer peripheral surface of the cylinder shaft 5 near the flange 6, a constricted portion 10 formed of a tapered wall having a small diameter end on the flange 6 side is provided. As described above, the inner liner 1 is molded by the rotational molding method, and the ferrule 4 is inserted into the wall of the end wall 3 of the inner liner 1. At this time, the molding material does not easily flow into the gap between the flange 6 and the mold, but since the through hole 9 is formed in the flange 6, the molding material flows into the gap through the through hole 9. The insert of the die 4 can be surely performed without causing a molding defect. Furthermore, since the central axis of each through hole 9 is inclined toward the axial center of the cylinder shaft 5, the inflow of the molding material can be further promoted. The constricted portion 10 is formed in a tapered shape so that when an external force such as a drop impact acts on the mouthpiece 4, the outer force is transmitted to the outer liner 2 through the taper wall, and the mouthpiece 4 is prevented from being depressed inside the container. This is because.

The outer liner 2 is formed by winding and laminating a reinforcing yarn 12 made of aramid fiber impregnated with a thermosetting resin around a pair of caps 4 according to a filament winding method. As the thermosetting resin, epoxy,
Phenol, unsaturated polyester, etc. can be applied. The reinforcing yarn 12 is a strand of 400 to 7500 denier,
Select and use according to the pressure resistance of the pressure vessel.

(Comparative Test) The present inventor formed a pressure vessel using each fiber of aramid fiber, glass fiber and carbon fiber as the reinforcing yarn 12 of the outer liner 2 and compared the performance of each pressure vessel. The forming material of the inner liner 1 at this time was polyethylene, and the average thickness of the body was 5.0 mm. Its weight is 5.0
It was Kg. The inner volume of the pressure vessel was 50 liters, and its target pressure resistance strength (design strength) was 600 kg / cm ² .
An epoxy resin was used as the impregnating resin for each reinforcing yarn. As the glass fiber, 910 manufactured by Central Glass Co., Ltd.
0 denier E glass was used as the carbon fiber, 7200 denier T-300 manufactured by Toray Industries, Inc. As the aramid fiber, 7500 denier Technora (trademark) manufactured by Teijin Limited was used.

The total weight of each pressure vessel obtained was 20 kg for a glass fiber container, 18 kg for a carbon fiber container and 13 kg for an aramid fiber container.
The specific gravity of each fiber at this time was 2.25, 1.83, and 1.39 in the order of glass fiber, carbon fiber, and aramid fiber, respectively. That is, in the case of forming the FRP layer with the glass fiber and the carbon fiber, in order to obtain the pressure vessel having the same pressure resistance as compared with the case of forming the FRP layer with the aramid fiber,
It has been found that an extra reinforcing thread corresponding to a weight difference of 5 to 7 kg must be used. This is because when the reinforcing yarn is formed of glass fiber and carbon fiber, the tensile strength in the state of the reinforcing yarn is reduced to about half that in the state of the single fiber because it contains many defects such as breaking of the single fiber. Because it does. Note that there is no great difference in the tensile strength of each fiber in the single fiber state.

Since the reinforcing yarn 12 is wound around each of the spinnerets 4 and wound in reverse, the yarn surface directly contacts the spinnerets 4. Therefore, when the reinforcing yarn is formed of carbon fiber, potential difference corrosion occurs on the peripheral surface of the die 4. However, the reinforcing yarn 12 formed of aramid fiber does not cause the problem of potential difference corrosion because it is an electrically defective conductor.

The pressure vessel of the present invention can be applied to an air cylinder for an air bag and various pressure vessels for aircraft.
The inner liner 1 may be formed by a plastic molding method other than the rotational molding method. The base 4 can be provided only on one end wall 3 of the inner liner 1.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view of a pressure vessel.

FIG. 2 is a cross-sectional view of a mouthpiece portion.

[Explanation of sign]

 1 Inner liner 2 Outer liner 4 Clasp 12 Reinforcing yarn

Claims (3)

[Claims] 1. An inner liner 1 molded from plastic,
A plastic pressure vessel having an outer liner 2 made of a fiber reinforced plastic layer covering the outer surface of the inner liner 1, and a metal base 4 being insert-fixed to the inner liner 1, wherein the outer liner 2 is A plastic pressure vessel formed by winding and laminating a reinforcing yarn 12 made of aramid fiber impregnated with a thermosetting resin while being wound around a base 4 according to a filament winding method. 2. The plastic pressure vessel according to claim 1, wherein the thermosetting resin impregnated in the reinforcing yarn 12 is one of an epoxy resin, a phenol resin, and an unsaturated polyester resin. 3. An inner liner 1 molded from plastic,
A plastic pressure vessel having an outer liner 2 made of a fiber reinforced plastic layer covering the outer surface of the inner liner 1, and a metal base 4 being insert-fixed to the inner liner 1, wherein the outer liner 2 is Reinforcing yarn 12 impregnated with thermosetting resin
Is formed by being wound and laminated around the base 4 according to the filament winding method, and the base 4 includes a flange 6 embedded in the inner liner 1 and a cylindrical shaft 5 protruding to the outer surface of the inner liner 1. A plastic pressure vessel having a constricted portion 10 having a tapered wall having a small diameter end on the flange 6 side and provided on the peripheral surface of the cylindrical shaft 5.