JPS6342158B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a fire-resistant pipe joint in which an outer pipe made of an inorganic coagulated material is disposed on the outer peripheral surface of an inner pipe made of synthetic resin, and at least two openings are formed with a large diameter. The thickness of the cross section of each of the inner and outer tubes is made approximately uniform, a substantially ring-shaped gap is provided between the inner tube and the outer tube, and both the inner and outer tubes are disposed loosely, and the large diameter opening is This invention relates to a fire-resistant pipe joint in which the shoulder on the outer surface of the inner tube and the enlarged inner surface of the outer tube are in contact with each other, and the expansion of the inner tube is absorbed by the substantially ring-shaped gap, thereby preventing cracks from occurring in the outer tube. .

Conventionally, a compressible layer made of cotton, synthetic fiber, asbestos, or foamed material was attached to the outer periphery of a synthetic resin pipe, and mortar was applied on top to prevent cracks that would occur when the mortar dried. There is.

This method can prevent cracks in the mortar that occur when the mortar dries, but in order to attach the layered body, it is necessary to attach the layered body to the synthetic resin pipe in advance, which requires extra steps and materials, and reduces productivity. This significantly impedes economic efficiency.

In addition, if an asbestos cement layer is directly coated on the outer surface of a synthetic resin pipe fitting at room temperature, if hot water passes through the inner surface of the pipe joint during use, or if it is exposed to direct sunlight in the summer, The disadvantage is that the tube expands, causing cracks in the outer tube and impairing its fire resistance.

The present invention eliminates the above-mentioned drawbacks, and will now be described with reference to the drawings.

FIG. 1 is a longitudinal cross-sectional view of the fire-resistant pipe joint of the present invention, and FIG. 2 is a cross-sectional end view taken along the line A--A.

In FIGS. 1 and 2, 1 is an inner pipe of a synthetic resin pipe joint, and 2 is an outer pipe formed from a mixture of asbestos and cement.

In this example, the outer tube is made of asbestos and cement, but instead of cement, other materials that set, such as gypsum, plaster, lime, etc., may be used.

In addition, although it is possible to form the outer tube using only the above-mentioned coagulating material, reinforcing materials such as inorganic fibers, organic fibers, silica sand, etc.
There is no problem even if filler is mixed in. Reference numeral 3 denotes a gap provided between the inner tube 1 and the outer tube 2, and a substantially ring-shaped gap is formed at the transverse end surface of the fire-resistant pipe joint. (See Fig. 2) The outer surface of the shoulder provided in connection with each large diameter opening of the inner tube 1 made of synthetic resin is brought into contact with the enlarged inner surface of the outer tube 4, and the inner tube and outer tube are connected. Even if a substantially ring-shaped gap is formed between them, the inner tube is prevented from falling out. In this example, the inner surface enlarged portion of the outer tube is formed as a stepped portion, but it may also be formed as a gradually enlarged portion.

FIG. 3 is an external view showing another embodiment of the fire-resistant pipe joint of the present invention. FIG. 4 is a diagram showing that the fire-resistant pipe joint of the present invention can be manufactured by other manufacturing methods.

An example of the method for manufacturing the fire-resistant pipe joint of the present invention will be described here, but it may be manufactured using other manufacturing methods.

First, an asbestos cement layer is directly coated on the outer peripheral surface of a synthetic resin pipe joint, and then heated and cured to perform initial hardening. In this embodiment, the fire-resistant pipe joint is heated after molding, but the synthetic resin pipe joint may be heated before or during molding of the fire-resistant pipe joint.

The finished product is then cured at room temperature or in an autoclave. The molded product, especially the inner tube, may be heated by an electric heater or may be stored in a heating curing chamber.Furthermore, the end of the inner tube may be sealed with a rubber plug or the like, and the inner tube may be filled with boiling water. Good too.

The heating temperature of the inner tube is preferably 65 to 80°C,
Depending on the material of the inner tube, the temperature can be 30 to 100°C.

In addition, when the molded product is returned to room temperature after initial hardening by the heat curing, the inner tube will shrink more due to the difference in expansion coefficient between the inner tube and the outer tube, so there will be a gap between the inner tube and the outer tube. A ring-shaped void begins to appear.
This approximately ring-shaped gap is approximately 0.3 to 0.5 mm in the circumferential direction for small diameter pipe fittings, but can be as large as 2 to 5 mm for large diameter pipe fittings, and varies depending on the heating temperature and the diameter of the inner pipe. It is something.

Furthermore, if an expandable setting agent such as gypsum or expanded cement is used as the setting agent, a substantially ring-shaped gap will be created between the inner tube and the outer tube.

In addition, as shown in Figure 4, each part of the pipe is molded using a mold using a mixture of asbestos and cement into a shape that looks like a longitudinal section of the pipe joint from the center, that is, in two halves. It can also be manufactured by attaching a piece molded into a split shape from the outside along the outer peripheral surface of a synthetic resin pipe joint, and joining the joint portion 5 with an adhesive or the like.

Incidentally, depending on the shape of the pipe joint, a split mold of three or more parts may be used as the outer mold for molding.

Divide the outer tube into multiple parts using a split mold,
When molding each part, by making the inner diameter of the outer tube larger than the outer diameter of the inner tube, a substantially ring-shaped gap is created between the outer tube and the synthetic resin inner tube.

Since the present invention has the above-described configuration, even if hot water is passed through the piped fire-resistant pipe joint, no cracks or cracks will occur in the outer pipe of the fire-resistant pipe joint.

Since the present invention uses a synthetic resin pipe for the inner pipe, the water flow efficiency is superior to that of a cast iron pipe, and the inner pipe does not rust or accumulate water scale like cast iron pipes or steel pipes.
It never gets clogged.

Furthermore, synthetic resin pipes have the disadvantage of melting and burning due to the heat of a fire, generating toxic gas and causing loss of life, but the fire-resistant pipe joint of the present invention prevents the inner pipe from burning due to the fire resistance of the outer pipe. , ideal for building water supply and drainage pipes.

In addition, the present invention allows the use of conventional commercially available general products as the inner tube, and does not require any members between the inner tube and the outer tube, so the strength in the circumferential direction is uniform and the manufacturing process is simplified. It becomes simpler, lowers the cost of the product, and greatly improves productivity and economy.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of the fire-resistant pipe joint of the present invention, FIG. 2 is a cross-sectional end view thereof, and FIG. 3 is a diagram showing another embodiment of the fire-resistant pipe joint of the present invention. FIG. 4 is a diagram showing a fire-resistant pipe joint manufactured by another manufacturing method. 1...Synthetic resin pipe joint inner pipe, 2...Asbestos cement outer pipe, 3...Substantially ring-shaped gap, 4...Abutment between the shoulder on the outer surface of the inner pipe of the large diameter opening and the enlarged inner surface of the outer pipe Department,
5...Joint part.

Claims (1)

[Scope of Claims] 1. In a fire-resistant pipe joint in which an outer pipe made of an inorganic coagulant is disposed on the outer peripheral surface of an inner pipe made of synthetic resin, and at least two openings are formed with a large diameter, each of the inner and outer pipes The thickness of the cross section of the inner tube and the outer tube are made substantially uniform, a substantially ring-shaped gap is provided between the inner tube and the outer tube, and both the inner tube and the outer tube are disposed loosely, and the outer surface shoulder of the inner tube of the large diameter opening is A fire-resistant pipe joint in which the outer tube is brought into contact with the enlarged inner surface of the outer tube, the expansion of the inner tube is absorbed by the substantially ring-shaped gap, and cracks do not occur in the outer tube. 2. The fire-resistant pipe joint according to claim 1, wherein the outer pipe is made of reinforcing fibers and an inorganic coagulated material.