JP2003056729A - Check valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the strength of a check valve itself and to improve adhesion strength of an adhesion part with a bag body. SOLUTION: This check valve is so constituted that two films 11 are stacked to each other, their edges 12 are sealed by heat so as to form a lengthwise long opening part for passing gas in an approximate center of the film 11, and each of the two films 11 has a three-layer structure of a central layer 11b extending over the whole opening part, an inside layer 11a having the length equal to that of the central layer 11b in one end in the extending direction of the opening part and shorter than that of the central layer 11b in the other end, and an outside layer 11c having the length equal to those of the central layer 11b and the inside layer 11a in one end and having its tip position between the tip of the central layer 11b and the tip of the inside layer 11a in the other end.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a check valve used for filling a bag such as a cushioning material or a balloon with air, hydrogen or the like, and particularly to the adhesion strength between the check valve and the wind body. ,
And the one in which the strength of the check valve itself is improved.

[0002]

2. Description of the Related Art A check valve has hitherto been used for filling a plastic cushioning material used for boxing or a bag such as a balloon for decoration with air or hydrogen. This check valve is made by stacking two thin films made of polyethylene, etc., and heat-sealing the edges of the films to form a gas flow path inside, and install it inside the opening of the bag. The bag is filled with air using a gas cylinder or the like. When the bag is sufficiently filled with gas and the cylinder is removed, the film edges inside the bag are overlapped by the air pressure inside the bag, and after that, due to the blocking property of the film (the property that the films stick to each other). The outflow of air to the outside is blocked. When degassing, a straw or the like is inserted from the outer end of the bag to form an air outflow path.

FIG. 4 is a diagram showing the structure of a conventional check valve. The thick arrow indicates the direction of gas flow when the bag is filled with air or hydrogen. As shown in FIG. 4, the check valve 2
0 is, for example, two films 21 made of a material having a heat-sealing property such as polyethylene, which are overlapped,
(Dot portion in FIG. 4A) is heat-sealed and bonded together to form a gas flow path inside. The edges of the both ends 23, 24 of the gas flow passage are not heat-sealed for the convenience of inserting the cylinder. In addition,
In the example shown in FIG. 4, the polyethylene film forming the check valve 20 has a single-layer structure, but each film may have a double-layer structure.

The check valve 20 is fixed to the inner surface of the bag body by a heat fusion, an adhesive or the like at a portion indicated by reference numeral 25.
Therefore, the portion other than the end portion 23 on the side where the gas is injected is located inside the bag body such as the cushioning material. The edge portion of the end portion 23 is not heat-sealed, and this portion is opened and a gas cylinder or the like is inserted to feed gas into the bag body. Either of the ends 23 and 24 may be arranged inside.

[0005]

As described above, by using the check valve, the bag can be easily filled with gas or degassed, but the conventional check valve 2 described above is used.
0 indicates not only when the film forming the valve has a single-layer structure but also when it has a double-layer structure, the adhesive strength between the bag body and the check valve and the check valve are formed. The adhesion (heat seal) strength between the films
There is a problem that the gas filled in the bag is easily released. It is considered that this is because the strength of the film itself is small and it is difficult to control the heat sealing of the films because the films are thin. When the adhesive strength varies as described above, the gas from the bag easily flows out, and the air inside the bag cannot be maintained for a long period of time.

Further, in the conventional check valve as shown in FIG. 4, since the edge portion of the end portion 24 of the film located inside the bag is not heat-sealed, the end portion 24 is not opened when gas flows in. It will be in a floating state, and a gap will be formed between the films at the end portion 24 after filling. This gap is
Even if the air pressure inside the bag body does not allow them to be superposed, the gas may escape from this portion.

The present invention has been made to solve these problems, and the film forming the check valve is formed of a film having a three-layer structure to increase the strength of the film itself and further to form a bag body. The adhesive strength of the adhesive portion of was also improved. In addition, by making the size of each layer constituting each film different, the blocking property of the film front end portion inside the bag body was kept good, and a structure in which gas was difficult to escape was adopted.

[0008]

In order to solve the above-mentioned problems, the check valve of the present invention has a structure in which two films are superposed,
In a check valve provided with a vertically long opening portion for heat-sealing an edge portion of the film to allow gas to flow into substantially the center of the film, each of the two films extends over the entire opening portion. The center layer to be, and at one end in the extending direction of the opening portion, the center layer and its length are aligned, and at the other end, an inner layer having a shorter dimension than the center layer,
A three-layer structure having the same length as the center layer and the inner layer at one end and an outer layer having a tip position between the tip of the center layer and the tip of the inner layer at the other end is formed. Characterize.

Further, the check valve of the present invention is a check valve in which two films are superposed, the edges of the films are heat-sealed, and a vertically long opening portion for allowing gas to flow into substantially the center of the film is provided. In the valve, each of the two films, a center layer extending over the entire opening portion, at one end in the extending direction of the opening portion, the length is aligned with the center layer, at the other end. An outer layer having a shorter dimension than the central layer, the inner layer having the same length at the one end as the central layer and the outer layer, and the other end having a tip position between the center layer tip and the outer layer tip. It is characterized by forming a three-layer structure consisting of layers.

As described above, in the check valve of the present invention, the film constituting the valve has a three-layer structure to obtain the strength of the film itself and to extend only the central layer over the entire opening, that is, The tips of the layers constituting the film were aligned at one end in the extending direction of the opening, and the dimensions of the layers were made different at the other end, so that the film had a single-layer structure at the other end. Therefore, by positioning the other end inside the bag, the blocking property between the films can be enhanced. Further, the tip of the outer layer is located between the tip position of the center layer and the tip position of the inner layer at the other end, and the outer layer covers the step caused by the difference in the tip positions of the center layer and the inner layer. In this way, the gas is prevented from leaking from the tunnel-shaped gap generated in the step portion.

The check valve of the present invention is characterized in that, of the layers constituting the film, at least the inner layer and the outer layer are made of a material having a heat-sealing property.
With this configuration, the adhesive strength between the bag body and the check valve can be increased. Furthermore, it is preferable to use a material having a heat-sealing property also in the central layer. Particularly when the central layer extends over the entire opening portion, the blocking property can be enhanced by heat-sealing the edge portion on the other end side.

Further, in the check valve of the present invention, the portion where the films are heat-sealed is heat-sealed to the film front end at the other end in the extending direction of the opening portion, and the film front end at the one end. Is not heat-sealed. With this structure, the blocking property at the leading end of the film is kept good, and the operability such as the insertion of the cylinder at the rear end is secured.

Further, the check valve of the present invention includes at least a tip at the other end of the inner layer constituting each of the films, a tip at the other end of the center layer, and a tip at the other end of the inner layer. The heat-sealed portion projects inward toward the open portion in a step portion caused by the different positions of and.

As described above, in the check valve of the present invention, since the tip positions of the center layer and the inner layer are different, a tunnel-shaped cavity is likely to be generated at this step portion. By projecting inward toward the open part, this cavity was closed to prevent outflow of gas.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a diagram showing the configuration of the check valve of the present invention. As shown in FIG. 1, the check valve 10
Is a film in which two rectangular films 11 are superposed and both side edge portions 12 in the lateral direction (dot portions in FIG. 1A) are heat-sealed to form a gas distribution path in the longitudinal direction inside the film.

As shown in FIG. 1B, each film 11
Is a center layer 11b extending over the entire length of the valve in the longitudinal direction, an inner layer 11a having a tip located inside the center layer 11b, and tips of the inner layer 11a and the center layer 11b. It has a three-layer structure including an outer layer 11c located between them. For each layer constituting the film, a material having heat-sealing property such as polyethylene, polypropylene, polyester, polyethylene terephthalate, polyester, ethylene-vinyl alcohol copolymer is used.

Here, the outer layer 11c is preferably made of the same material as the bag body to which the check valve is attached.
For example, when the check valve is attached to a cushioning material made of polypropylene, the outer layer 11c is made of polypropylene. As the material of the center layer 11b, nylon, polyethylene terephthalate, and polypropylene having excellent blocking properties can be preferably used.
Furthermore, it is preferable to use polyethylene, which is excellent in heat sealability, for the inner layer 11a. Incidentally, the second
In the embodiment, it is preferable to use polypropylene having excellent heat-sealing property and blocking property for the inner layer 11a extending in the entire longitudinal direction.

As described above, by using a material having sufficient heat seal strength for at least the outer layer and the inner layer of the three-layer structure constituting the film, the adhesive strength between the films (inside) and the film The adhesive strength of the bag body (outside) can be enhanced.

The sizes of the respective layers are the same for the three layers in the lateral direction, and in the longitudinal direction, the tip positions of the three layers are aligned at one end 13 (air injection side) and the other end 14 (air outflow side). In, the central layer 11b is extended over the entire length in the longitudinal direction, and the tip of the inner layer 11a is made shorter than this. The check valve 10 is attached to the inside of a bag (not shown) at a portion indicated by reference numeral 15. The tip of the outer layer 11c was positioned between the tip of the center layer 11b and the tip of the inner layer 11a. The thinner the film, the higher the blocking property, so
A high blocking property can be realized by making the center layer 11b have a single layer structure at the tip.

Here, the tip of the outer layer 11c is connected to the inner layer 11
By locating it between the tip of a and the tip of the central layer 11b, it becomes difficult to form a tunnel-like void near the step portion between the inner layer 11a and the central layer 11b. Further, as shown in FIG. 1, even if a tunnel-shaped void is formed by the step, it is possible to eliminate the influence by projecting the heat seal portion inward of the gas flow path in the vicinity of the step portion 16. is there. In this embodiment,
Although the heat seal part is projected at the step,
As shown in FIG. 2, a heat seal portion may be further provided from this portion to the tip portion (tip located inside the bag body).

In the present embodiment, a material having a heat-sealing property is also used for the center layer 11b, and the edge portion of the center layer on the tip side is heat-sealed in the same manner as the other portions, so that the tip of the center layer is formed. Blocking is more likely to occur on the side and blocking properties are improved.

FIG. 3 is a diagram showing the configuration of the second embodiment of the present invention. In the second embodiment, the positions of one end of each layer constituting the film are aligned, and at the other end, the center layer 11b extends over the entire length of the gas flow path, and the end of the outer layer 11c is the tip of the inner layer 11a. Shorter dimensions. The point that the central layer 11b extends over the entire length of the gas flow path is the same as in the first embodiment. With this configuration, the same effect as that of the first embodiment can be obtained.

[0023]

As is apparent from the above description, according to the check valve of the present invention, the strength of the check valve itself can be improved by forming the film forming the check valve with a film having a three-layer structure. Moreover, the adhesive strength of the adhesive portion with the bag can be improved. Further, by making the size of each layer constituting each film different so that the leading end portion of the film inside the bag has a single structure, good blocking property can be maintained, so that gas is hard to escape. Also, since the center layer and the inner layer have different tip positions, a tunnel-shaped cavity is likely to occur in this step portion, but by projecting the heat seal portion in the step portion inward toward the opening portion, this cavity is formed. It is closed to prevent the outflow of gas.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a first embodiment of the present invention, FIG. 1 (a) is a plan view thereof, and FIG. 1 (b) is FIG.
It is sectional drawing in the XX line of (a).

2 is a diagram showing a modification of the check valve shown in FIG. 1, FIG. 2 (a) is a plan view thereof, and FIG. 2 (b) is FIG.
It is sectional drawing in the XX line of (a).

FIG. 3 is a diagram showing a configuration of a second exemplary embodiment of the present invention.

FIG. 4 is a diagram showing a configuration of a conventional check valve,
FIG. 4 (a) is a plan view thereof, and FIG. 4 (b) is X of FIG.
It is a sectional view taken along the line X-.

[Explanation of symbols]

10, 20 Check valve 11 films 11a inner layer 11b Central layer 11c outer layer 12, 22 Heat seal part 13, 23 Edge 14, 24 ends 15, 25 Adhesive points with bag 16 Projection

Claims (6)

[Claims] 1. A non-return valve provided with a vertically long open part for superimposing two films, heat-sealing an edge portion of the films, and allowing gas to flow into substantially the center of the films. Each of which has a center layer extending over the entire opening portion and one end in the extending direction of the opening portion, the length of the center layer is aligned with that of the center layer, and the other end has a shorter dimension inside the center layer. A three-layer structure comprising a layer and the center layer and the inner layer whose lengths are aligned at the one end, and the outer layer having a tip position between the center layer tip and the inner layer tip at the other end. Check valve characterized by eggplant. 2. A non-return valve provided with a vertically long open part for superimposing two films and heat-sealing an edge part of the films to allow gas to flow into substantially the center of the two films. Each of which has a length equal to that of the central layer at one end in the extending direction of the opening portion and the central layer extending over the entire opening portion, and the outside of a shorter dimension than the central layer at the other end. A three-layer structure comprising a layer and an inner layer having the same length as the center layer and the outer layer at the one end and a tip position between the center layer tip and the outer layer tip at the other end; Check valve characterized by eggplant. 3. The check valve according to claim 1, wherein at least the inner layer and the outer layer of the layers constituting the film are made of a material having a heat-sealing property. Stop valve. 4. The check valve according to claim 3, wherein the central layer is further made of a material having a heat-sealing property. 5. The check valve according to claim 1, wherein a portion where the films are heat-sealed is heat-sealed to the leading end of the film at the other end in the extending direction of the opening portion. The check valve is characterized in that the end of the film is not heat-sealed at one end. 6. The check valve according to claim 1, wherein at least a tip at the other end of the inner layer forming each of the films, a tip at the other end of the central layer, and A check valve, wherein the heat-sealed portion projects inward toward the open portion at a step portion generated by a position at which the tip of the other end of the inner layer is different from the tip.