JPH0354749B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a down pipe with excellent cold resistance.

[Conventional technology]

Traditionally, downpipes were made of polyvinyl chloride resin, aluminum, copper, iron, etc. in a cylindrical shape, but in cold regions such as Hokkaido, when these downpipes are installed outside the house, In the winter, rainwater flowing into the downpipes freezes and expands, destroying the downpipes. In an attempt to prevent this, insulation material was wrapped around the outer circumference of the downpipe, but
This was also ineffective on extremely cold days, resulting in freezing and destruction. Therefore, in cold regions, it was common not to install downpipes outside houses.

As a way to solve this problem,
As described in Publication No. 9614, an antifreeze heater is installed on the downpipe, and
As described in the above publication, in addition to antifreeze heaters, there is also known a structure in which a foamed synthetic resin outer pipe is laminated around the outer periphery of a downpipe.

[Problem that the invention seeks to solve]

However, the above-mentioned conventional downpipe has a complicated structure due to the use of a heater to prevent freezing, and
There was a problem in that electricity costs increased, and furthermore, in the event of a power outage, the antifreeze heater would not work and the downpipe would freeze and break.

The present invention has been made for the purpose of solving the above-mentioned problems of the conventional downpipe, and providing a downpipe that has a simple structure and is free from freeze damage.

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention has a structure of a vertical gutter in which a waterproof layer is provided on the inner circumferential surface of an elastic cylindrical foam and a protective layer is provided on the outer circumferential surface.

[Effect]

Rainwater flows along the waterproof layer on the inner circumference of the downpipe.
Even in winter, since the downpipe is made of foam, rainwater flowing through the downpipe is insulated and kept warm by the air inside the foam, making it difficult to freeze. Even if rainwater freezes inside the downpipe and expands in volume,
The elastic foam absorbs this volumetric expansion and does not destroy the downpipe. The protective layer on the outer circumferential surface of the trough prevents the trough from being damaged or deformed.

〔Example〕

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

FIG. 1 is a sectional view showing an embodiment of a downpipe according to the present invention.

1 is a downpipe, and a cylindrical foam body 2 has elasticity.
A waterproof layer 3 is provided on the inner peripheral surface, and a protective layer 4 is provided on the outer peripheral surface.

The cylindrical foam 2 has such elasticity that it can absorb rainwater when it freezes and expands within the downpipe 1. When water freezes and becomes ice, it expands in volume by about 9%, so the foam 2
It is preferable that the foam layer 21 and the waterproof layer 3 are compressed by 10% or more and shrink in volume. In particular, when considering the case where rainwater is trapped and freezes inside the vertical gutter, the direction perpendicular to the axis of the vertical gutter (thickness direction)
It is preferable that the material can be compressed by 5% or more. and,
The foam 2 has a compression set (JIS K 6767) so that it can withstand repeated freezing and thawing of rainwater.
is preferably 30% or less.

In addition, in order to prevent rainwater from freezing, the foam layer 21 should preferably have a high heat retention property, and if it is made of synthetic resin, the apparent density is 0.01 to 0.6.
A range of g/cm ³ is preferred. As for the cell structure of the foam layer 21, closed cells are preferable to open cells because they have better heat retention and rainwater does not penetrate into the foam layer 21 even if the waterproof layer 3 is damaged.

The waterproof layer 3 is formed inside the foam layer 21,
The membrane layer is such that rainwater does not penetrate into the foam layer 21 when it flows through the downpipe 1. The thickness of the waterproof layer 21 is preferably 100 μm or more in terms of strength, since garbage and the like flow together with rainwater in the downpipe 1.

The protective layer 4 has such hardness that the outer surface of the downspout 1 will not be damaged. The protective layer 4 preferably has a thickness of 200 μm or more in terms of strength, although it depends on the material used.

The wall thickness of the vertical trough 1 is preferably in the range of 2 mm to 25 mm, considering the above-mentioned freeze expansion absorption and heat retention properties.

To form this downpipe, for example, a synthetic resin such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyurethane, or rubber is formed into a cylindrical shape by extrusion foam molding to form an elastic foam. , a relatively thin skin layer may be formed on the inner peripheral surface, and a relatively thick skin layer may be formed on the outer peripheral surface. Then, the skin layer on the inner peripheral surface becomes the waterproof layer 3, and the skin layer on the outer peripheral surface becomes the protective layer 4.

Further, the waterproof layer 3 and the protective layer 4 may be separately formed by extrusion coating on the inner peripheral surface and the outer peripheral surface of the foam layer 21.

Next, we will explain the results of a freeze-fracture experiment conducted after fabricating a vertical trough.

Example 1 Low-density polyethylene was used as the main raw material, fed to an extruder, dichlorotetrafluoroethane was injected as a blowing agent midway through the extruder, extruded into a cylinder, and the inner surface was injected with air from the inside. and extrusion foaming was performed while cooling the outer surface in a cooling mold following the extruder to produce a cylindrical foam.

The cylindrical foam has a closed cell structure with an inner diameter of
It was 58 mm long and had a wall thickness of 10 mm, with a 200 μm skin layer as a waterproof layer formed on the inner peripheral surface, and a 500 μm skin layer as a protective layer on the outer peripheral surface. and,
It is possible to compress the foam in the thickness direction by more than 50%,
The compression set was 3% and the apparent density of the foam layer was 0.2 g/cm ³ . This cylindrical foam was used as a downpipe.

On the other hand, as Comparative Example 1, the outer diameter is 60 mm and the wall thickness is 1.1 mm.
As Comparative Example 2, an aluminum pipe with an outer diameter of 60 mm and a wall thickness of 1.0 mm was prepared.

Then, as shown in FIG. 2, these downpipes with a length of 1 m are placed in a container 5 containing water, and -
The water was left at 50°C for 2 hours to freeze the bottom 20cm of the downpipe. Next, a width of polyethylene foam (apparent density 0.04) was placed outside the center of the downpipe as an insulation material.
Approximately 8 turns of 40cm and approximately 3mm thick (approximately 24mm thick)
The tube was wrapped, the inside of the pipe was filled with water, and the tube was left in a -50°C freezer for 17 hours.

As a result, the water in the downpipe freezes starting from the top and ending with the insulation.
There was no escape for the volumetric expansion caused by freezing of the insulation material, and the hard PVC pipe of Comparative Example 1 burst into pieces, and the aluminum pipe of Comparative Example 2 burst at the part where the insulation material was wrapped. did. However, in the downpipe of Example 1, no abnormality was observed on the outer peripheral surface. When we tried to melt the ice inside the downspout of Example 1, no abnormality was found on the inner peripheral surface.

Therefore, the above-mentioned freezing and thawing experiment was repeated 30 times for the downpipe of Example 1.
No abnormalities were observed on the outer circumferential surface, and only a few dents were observed on the inner circumferential surface, which did not affect use.

Next, in Sapporo City, Hokkaido, when the down pipe of Example 1 and the down pipes of Comparative Example 1 and Comparative Example 2 were installed in a house, abnormalities were found in the down pipe of Example 1 during the winter of 1960. However, the pipes of Comparative Examples 1 and 2 burst due to freezing.

In the above example, a protective layer made of the same polyethylene was provided on the outer circumferential surface of the foam layer made of low-density polyethylene, but the protective layer may also be made of a metal such as copper for decorative purposes. good.

〔Effect of the invention〕

As described above, the downpipe of the present invention is formed by providing a waterproof layer on the inner circumferential surface of an elastic cylindrical foam body and a protective layer on the outer circumferential surface. The foam acts as a conventional downpipe, and its insulation and heat retention ability alleviates the freezing of rainwater flowing inside the downpipe, and the elasticity of the foam absorbs the volumetric expansion of frozen rainwater. itself cannot be destroyed.

Therefore, the downpipe of the present invention can be suitably used in cold regions such as Hokkaido.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of the down pipe of the present invention, and FIG. 2 is a cross-sectional view illustrating a freezing experiment of the down pipe of the present invention. 1... Downpipe, 2... Cylindrical foam, 21... Foam layer, 3... Waterproof layer, 4... Protective layer.

Claims (1)

[Scope of Claims] 1. A vertical gutter comprising an elastic cylindrical foam body provided with a waterproof layer on the inner circumferential surface and a protective layer on the outer circumferential surface. 2. The vertical gutter according to claim 1, wherein the foam is compressible by 5% or more in the thickness direction from the waterproof layer side. 3. The vertical gutter according to claim 1 or 2, wherein the foam has a compression set of 30% or less in the thickness direction from the waterproof layer side. 4. The downspout according to claim 1, 2 or 3, wherein the foam has a closed cell structure. 5. Claims 1, 2, 3, or 5, wherein the foam has a thickness in the range of 2 mm to 25 mm, the waterproof layer has a thickness of 100 μm or more, and the protective layer has a thickness of 200 μm or more. The downpipe described in Section 4.