JPH0314613Y2 - - Google Patents

Description

[Detailed description of the invention] A. Field of industrial application The present invention relates to a film valve with backflow prevention properties for blowing gas, which is installed in a flexible film airtight bag that becomes an inflatable body when gas is injected, such as an air cushion or a balloon. .

B. Conventional technology When air, helium, or other gas is pressurized into an airtight bag made of film such as rubber or plastic to create an inflatable body such as an air cushion or balloon, a vent pipe for blowing gas is provided in the airtight bag. It is very common practice to provide a backflow prevention function to the inflatable body to prevent gas leakage from the inflatable body.

As a ventilation pipe with backflow prevention properties, a flat ventilation pipe with flexible films layered and glued on both sides is used.
It is widely used because it has an extremely simple structure, and the internal air pressure of the airtight bag allows the films on both sides of the airtight bag that form the ventilation path to come into close contact and automatically seal, preventing backflow.

C. Problems to be solved by the invention The backflow prevention sealing effect of the above-mentioned flat vent tube made of flexible film is caused by the internal pressure of the airtight bag, but when the internal pressure is low, the sealing performance is weak and air leakage is completely prevented. In addition, if even a small amount of foreign matter such as water or dust enters the ventilation pipe, air leakage will easily occur, and once air leakage occurs, the automatic sealing effect will almost disappear, resulting in backflow. There is a problem that the prevention performance is unstable, and in order to solve this problem, two more films are sandwiched within the flat ventilation pipe made of the flexible film to form a narrow internal ventilation passage. A method has been proposed in which the middle part of the internal narrow air passage is made free from the external flat air passage (Japanese Utility Model Publication No. 47-4468).
(see publication).

According to the above-mentioned means, although the tight closing valve action of the middle part of the internal narrow air passage is performed well due to the pressure deviation effect of the flat ventilation pipe due to the internal pressure of the bag, it is difficult to actively prevent air leakage from occurring. It cannot have a sealing effect, and is still insufficient as a means for solving the above-mentioned problem.

D. Means for Solving the Problems The present invention includes two film valve bodies spaced apart inside the flat vent pipe made of flexible film to actively seal against leakage backflow. In addition, the above-mentioned problem is solved by providing each sealing surface on each of the two film surfaces constituting the flat ventilation pipe.

That is, in the present invention, two films are overlapped and the edges on both sides are bonded to each other in the air passage on the front end side of the air outlet of the flat air pipe. The first film valve body is bonded to the adhesive edges on both sides and the front edge is a free end, and the rear edge is attached to the entire inner width of the other film of the vent pipe, and the adhesive edges on both sides of the vent pipe are bonded on both sides. The second film valve body is provided with a second film valve body whose front end edge is a free end, and each rear end edge and each front end edge are positioned at intervals in the direction of the ventilation flow path. The gist is a stop film valve.

E. Effect The non-return film valve of the present invention having the above-mentioned configuration has a front end side air passage provided with two film valve elements inserted into an airtight bag, and the other end of the air outlet side protruding outside the bag. It is used by being installed closely to the bag so that the inside and outside of the bag are communicated only through the ventilation pipe, and gas is introduced from the inlet of this ventilation pipe.
Due to the flow of gas, the two film valve bodies are brought into close contact with the film surface of the vent tube to which the rear edges are bonded, allowing smooth gas filling without creating resistance to the gas flow, allowing gas to be fed. If it stops,
Due to the internal pressure of the bag, the double-sided film of the ventilation pipe comes into close contact with the part of the ventilation pipe where the bag body is attached, sealing the ventilation passage and preventing gas leakage.

If the above-mentioned sealed state is broken for some reason and the internal gas leaks out, the backflow airflow will move the free end of the film valve body near the air outlet and the rear end. Even if the film is pressed against the film surface of the vent pipe film to which it is adhered, creating a sealing action, and even if the sealing action is still insufficient to prevent air leakage, The leakage air flow causes the next film valve element to move in the opposite direction to the film valve element, producing a sealing effect, so that leakage backflow is completely prevented.

When the gas inside the airtight bag is to be discharged, a rod-shaped body or a tubular body is inserted into the ventilation pipe and the sealing action is released, and the gas flows through the ventilation pipe and flows out of the bag.

During the above gas supply and discharge process, the rear edge of the film valve body and both sides are adhered to the inner surface of the vent pipe and held in a stable state, and the free front edge of the film valve body is prevented from curling up or wrinkling. Since there is no dripping, it is possible to maintain a good backflow prevention effect at all times.

Note that if the vent pipe and the film valve body are made of a heat-bondable synthetic resin film such as polyethylene, polypropylene, or polyvinyl chloride, the molding process is easy and the product can be obtained at a low cost.
In this case, it is preferable that the film for the vent pipe be slightly thicker to provide shape retention, and the film valve body be slightly thinner to improve the sealing effect.

Example Embodiments of the present invention will be described with reference to the drawings.

Figure 1 is a plan view of the non-return film valve, Figure 2
The figure is a somewhat explanatory sectional view taken along line AA in FIG. 1, and FIG. 3 is an enlarged sectional view of the film valve body portion of FIG. 2.

In the drawing, 1 is a ventilation pipe, and 2 is rectangular.
Two sheets of polyethylene films 2 and 3 are stacked one on top of the other, and both edges are thermally bonded to form a flat cylindrical shape.The front end serves as the air outlet 22, and the rear end can be expanded without adhesive, allowing gas blowing operations. Easy-to-use air outlet 2
1.

Reference numerals 10 and 15 are film valve bodies made of thin polyethylene film provided in the air passage on the outlet side of the ventilation pipe 1, and the rear end edge 11 of the first valve body 10 is connected to the inner surface of one of the films 3 of the ventilation pipe 1. It is bonded over its entire width, and its both sides are sandwiched between the films 2 and 3 of the ventilation pipe 1 and heat bonded integrally therewith, and its front edge 12 is provided as a free end. . Further, the second valve body 15 has a rear end edge 1
The first valve body 10 is provided in the same manner as the first valve body 10, except that the second valve body 6 is thermally bonded to the other film 2 surface of the ventilation pipe 1. At this time, the rear edge 11 of the first valve body 10 and the second
Although the front edge 17 of the second valve body 15 is separated from the front edge 17 of the second valve body 15 as shown in the figure, even if the front edge of the second valve body 15 overlaps the surface of the first valve body 10, Therefore, both valve bodies 10 and 15 may have the same or different lengths in the direction of the air passage. Also, the adhesive rear edge 11, 1 of each valve body
6 are positioned at intervals in the direction of the ventilation flow path so that they can perform their respective sealing actions.

Reference numeral 20 denotes a thermal adhesion inhibiting surface provided on the inner surface of one film 2 of the vent pipe 1, and is formed by cellulose ink printing, aluminum vapor deposition, corona discharge treatment, etc., as shown by the dashed line in FIG. , the opening 31 of the airtight bag 30 having a heat-adhesive surface
Insert this non-return film valve into the vent pipe 1.
When the opening 31 is thermally bonded and sealed on the outer surface of the vent pipe 1, a ventilation passage is formed inside the vent pipe 1.

After installing this non-return film valve in an airtight bag and injecting gas under pressure, the gas in the airtight bag will flow into the ventilation pipe 1.
When the air leaks inside, the leaking airflow brings the front edge 12 of the first film valve body 10 into close contact with the opposing film 2 surface as shown by the arrow in FIG. The airflow presses the front edge 17 of the second film valve body 15 against the other film 3 surface, producing a positive sealing effect and achieving sufficient backflow prevention.

G. Effects of the invention As explained above, the non-return film valve of the present invention has a sufficient backflow prevention effect with an extremely simple structure, and the film valve body is maintained in a stable form. It exhibits excellent practical effects, such as being able to be manufactured easily and at low cost without causing any deterioration in its functionality even after multiple gas blowing and discharging operations.

[Brief explanation of drawings]

1 is a plan view, FIG. 2 is a sectional view taken along the line AA in FIG. 1, and FIG. 3 is an enlarged sectional view of the film valve body portion of FIG. 2. 1...Vent pipe, 2,3...Film, 10,1
5... Film valve body, 11, 16... Rear end edge, 1
2, 17...front edge, 21...inlet, 22...
Air outlet.

Claims (1)

[Scope of utility model registration request] In the air passage on the front end side of the flat air vent pipe 1, which is made by stacking two films 2 and 3 and bonding both sides, The first film valve body 10, which is bonded to the adhesive edges on both sides of the ventilation pipe 1 and whose front end edge 12 is a free end, and the rear end edge 16 are attached to the entire inner width of the other film 2 of the ventilation pipe, and both sides are attached to the ventilation pipe 1. The second film valve body 15, which is bonded to the adhesive edges on both sides and whose front edge 17 is a free edge, is attached to the respective rear edges 11 and 16.
and a non-return film valve characterized in that the front edges 12 and 17 are spaced apart from each other in the direction of the ventilation flow path.