JP2000291841A - Refractory double-layer tube with inner and outer tubes fixed thereto, and method for fixing inner and outer tubes of the refractory double-layer tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refractory double-layer tube in which inner and outer tubes of the refractory double-layer tube are fixed to each other, and the inner and outer tubes to be easily released are fixed to each other. SOLUTION: A tapered portion 22 is formed on an end portion of an outer tube 20. This tapered portion 22 is formed on the whole circumference of the inside diameter of the outer tube 20. On the other hand, in an inner tube 30, an elastic body projection 32 is formed on an outer circumferential surface of the inner tube 30. In this condition, when the outer tube 20 is moved in the direction of the arrow, and the inner tube 30 is moved under the force at the arrow, the tapered portion 22 is brought into contact with the projection 32. Since this projection 32 is formed of an elastic body, the projection is bitten inside the tapered portion 22. Detachment of the outer tube 20 is prevented by the friction force between the tapered portion 22 and the projection 32.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-layered tube in which a synthetic resin inner tube is inserted into a non-combustible outer tube so that the inner tube and the outer tube are not easily separated. The present invention relates to a fire-resistant double-layered pipe in which an inner pipe and an outer pipe are fixed, and a method of fixing an inner pipe and an outer pipe of the fire-resistant double-layered pipe.

[0002]

2. Description of the Related Art Conventionally, synthetic resin pipes such as vinyl chloride have excellent properties such as chemical resistance, corrosion resistance, inner surface smoothness, workability, etc. as compared with metal pipes, so that water supply and drainage of buildings. Widely used for pipes and ventilation pipes. However, synthetic resin pipes such as vinyl chloride pipes are inferior in fire resistance and easily burned out in the event of a fire, and have the disadvantage of spreading fire and generating toxic gas. In particular, in apartment buildings such as condominiums, there is a risk that fire may be transferred to other sections through the synthetic resin pipe, which has been a major problem in disaster prevention.

Therefore, in order to cover such a drawback, a fire-resistant double-layer pipe (also referred to as a composite pipe / double-layer pipe) in which the outer peripheral surface of a synthetic resin pipe is coated with a nonflammable material, for example, fiber-reinforced mortar A vinyl chloride tube or a double-layered asbestos vinyl tube coated with a resin is generally widely used. In such a fire-resistant double-layer tube, the difference in the degree of thermal expansion and contraction between the inner and outer tubes is caused by shrinkage of the outer tube (coating material) due to drying or thermal expansion of the inner tube (synthetic resin tube) caused by passage of hot water. The resulting stresses on the inner and outer tubes may cause cracks in the inner and outer tubes.

As a countermeasure, a method for absorbing these stresses has been taken. For example, a projection is provided on the outer side of the inner tube to form a gap between the inner tube and the outer tube (Japanese Patent Publication No. 50-7770). Intervening a layered body
Japanese Patent Publication No. 57-177871), in which the inner circle of the outer tube is made elliptical to hold the inner tube on the shorter diameter side and form a gap with the inner tube on the longer diameter side. I have.
In both cases, a gap is formed between the inner tube and the outer tube to absorb the stress generated in the inner and outer tubes. The simplest way to create a gap between the inner and outer tubes is to combine them with an outer tube having an inner diameter that is larger than the outer diameter of the inner tube.

Incidentally, a fire-resistant double-layer pipe which forms a gap between the inner pipe and the outer pipe causes an accident in which the inner pipe falls off during storage or transportation during use and construction, and the like. Must be fixed so that they do not easily come off,
Further, it is desirable that these fixing means can be easily released on site at the time of construction. Therefore, as a method for preventing the detachment of the inner tube, a method of interposing a layered material such as expanded polystyrene in the longitudinal direction between the inner tube and the outer tube as disclosed in Japanese Patent Application Laid-Open No. Sho 51-12813 is disclosed. A method of fitting a rubber band near the outer tube end of the inner tube exposed from the part, enclosing the inner tube and part of the outer tube exposed from the outer tube end with a heat shrink film and heating (JP-A-59-106785 and JP-A-59-106786), a method of forming a string-like member near the outer tube end of the inner tube exposed from the outer tube end. (Japanese Patent Application Laid-Open No. Sho 59-2462) and a method of driving a wedge-shaped stopper from the end of the outer tube into the gap between the inner tube and the outer tube (Japanese Utility Model Laid-Open No. 57-175892). , Including the inner tube and part of the outer tube exposed from the outer tube end How to siege by expanding Zhang adhered film (JP-A-8-3005
No. 04).

[0006]

However, the method of providing protrusions on the outside of the inner tube and the method of interposing a layered body of expanded polystyrene or the like in the longitudinal direction in the gap between the inner tube and the outer tube have not been developed. It is difficult to insert the tube, and simultaneously inserting the layered body is even more difficult, complicating work and inducing damage to the outer tube at the time of insertion, and reducing productivity. Further, in the method of fixing the inner tube with the rubber band, the rubber band may come off and come into contact with the end of the outer tube, and the inner tube is easily detached. In order to prevent this detachment, it was necessary to fix the rubber band quite firmly. The fixing method using a heat shrink film requires a heating device and a heating operation, which is complicated, and even if the inner tube or the outer tube shrinks slightly due to a change in the environment after the heating and fixing, the tightening by the heat shrink film. The force is released and the inner tube and the outer tube may come off.

[0007] In the method of winding a string-like body near the end of the outer tube of the inner tube exposed from the end of the outer tube and fixing it with an adhesive tape, and the method of fixing it with a self-stretch adhesive film, the adhesive tape is changed over time. In addition, the self-stretch adhesive film may be loosened, or the fastening force may be weakened, and the inner tube and the outer tube may be insufficiently fixed. In addition, there is a problem that it takes time and effort to remove the above-mentioned fixing material at the time of piping construction of the fire-resistant double-layer pipe, and the waste material of the fixed material such as the removed film increases. Therefore, a fire-resistant double-layer pipe in which the inner pipe and the outer pipe of the fire-resistant double-layer pipe are easily fixed with a simple device and material has been urgently desired.

Accordingly, a first object of the present invention is to provide a fire-resistant double-layered tube in which an inner tube and an outer tube are fixed to each other so that the inner tube and the outer tube of the fire-resistant double-layer tube can be securely fixed and easily released. Is to provide a tube. A second object of the present invention is to provide a method for fixing an inner tube and an outer tube which can securely fix the inner tube and the outer tube of a fire-resistant double-layer tube and can easily release the fixing.

[0009]

According to the first aspect of the present invention, a synthetic resin inner pipe having an outer diameter slightly longer than the outer pipe and smaller than the inner diameter of the outer pipe is provided on the non-combustible outer pipe. In the inserted fire-resistant double-layer pipe, both ends of the inner pipe are exposed from both ends of the outer pipe, and the inner pipe is exposed at one or both of the exposed portions of the inner pipe at a position close to the end of the outer pipe. Forming an elastic projection higher than the gap between the outer diameter of the pipe and the inner diameter of the outer pipe, wherein the inner pipe is characterized in that the inner diameter side end angle of the outer pipe in contact with the elastic projection is tapered. The first object is achieved by fixing the outer tube.

According to a second aspect of the present invention, in the first or second aspect of the invention, the elastic projection is an elastic body made of a synthetic adhesive or a polymer resin, and the elastic projection is formed in an outer circumferential direction of the elastic projection. The total length is の of the outer circumference of the inner tube
With the above, the first object is achieved. In the invention according to claim 3, in the invention according to claim 1,
The height of the elastic projection formed on the outer peripheral surface of the inner tube is 0.5 to
5.0 mm, and the tapered shape of the inner tube side end corner of the outer tube has a height of 30% to 100% with respect to the outer tube end thickness,
The first object is achieved by the fact that the depth from the outer tube end is 0.5 to 20.0 mm.

According to a fourth aspect of the present invention, there is provided a fire-resistant secondary pipe comprising a non-combustible outer pipe inserted with a synthetic resin inner pipe having an outer diameter slightly longer than the outer pipe and smaller than the inner diameter of the outer pipe. In the layered pipe, both ends of the inner pipe are exposed from both ends of the outer pipe, and the outer diameter of the inner pipe is set at a position close to the end of the outer pipe on one or both outer peripheral surfaces of the exposed portion of the inner pipe. And forming an elastic projection higher than the gap between the inner diameter of the outer tube and a tapered portion at an inner diameter side end corner of the outer tube in contact with the elastic projection, and a protrusion formed on the inner tube. The second object is achieved by preventing the inner tube from being detached from the outer tube by engaging a tapered portion formed on the outer tube.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to FIGS. FIG.
FIG. 2 is a side view of a fire-resistant double-layer tube 10 including an incombustible outer tube 20 and a synthetic resin inner tube 30 according to the embodiment.
A slight gap is formed between the outer tube 20 and the inner tube 30 to absorb the stress generated when the inner tube 30 expands with hot water or the like. Because of the gap between the two, the inner tube 30 may come off the outer tube 20 in some cases.

In this example, the outer tube 20 has a tapered portion 22 formed at an end thereof. This tapered part 2
2 is formed over the entire inner circumference of the outer tube 20, as shown in FIG. That is, the inner diameter angle of the end of the outer tube 20 is
It is cut off in a taper shape concentrically with the center of. On the other hand, an elastic projection 32 is provided on the outer peripheral surface of the inner tube 30. In this state, as shown in FIG.
When the inner tube 30 moves in the direction of the arrow or when the inner tube 30 is moved by the force of the arrow, the tapered portion 22 and the projection 32 come into contact with each other. Since the projection 32 is an elastic body, the tapered portion 22
It becomes a state that bites into the inside of the. The friction between the tapered portion 22 and the projection 32 at this time causes the outer tube 2
Departure of 0 is prevented. As described above, since the projections 32 bite into the tapered portion 22, the projections 32 are not separated from the inner tube 30 by the force of the outer tube 20 and come off. In other words, the force applied from the outer tube 20 to the projection 32 is changed obliquely inward of the inner tube 30 by the tapered portion 22, and the projection 32 is less likely to be pushed outward.

As a result, the inner tube 30 of the projection 32 acting as a stopper is smaller than when the tapered portion 22 is not provided.
Adhesive strength to the surface is weak. Therefore, when performing the construction on site, the protrusions 32 can be easily removed. In FIG. 3, reference numeral 40 denotes the outer tube 20 and the inner tube 3.
2 shows a gap formed between the gap and the zero. 1A shows the height of the tapered portion 22, B shows the depth of the tapered portion 22, and C shows the height of the projection 32. In FIG. 2, D indicates the outer diameter of the tapered portion 22, and E indicates the outer diameter of the outer tube 20.

The protrusion 32 is an elastic body made of a synthetic adhesive or a polymer resin. For example, ethylene propylene rubber, natural rubber, synthetic rubber, SBS, priurethane,
Teflon, etc. are used. It is formed on the outer peripheral surface of the inner tube 30 at least 以上 or more, preferably over the entire circumference. The height C of the projection 32 ranges from 0.5 mm to 5.
0 mm is desirable and must be at least larger than the gap 40. The height A of the tapered portion 22 is
0 to 30% of the thickness. In this example, since the thickness of the outer tube 20 is 7 mm, the height A of the tapered portion 22 is
Is from 2.1 mm to 7 mm. The height A of the tapered portion 22 is preferably higher than the height C of the projection 32. This is because when it comes into contact with the projection 32, it enters the inside of the tapered portion 22 and generates a large frictional force. The depth B of the tapered portion 22 is 5 mm,
0.5 mm to 10.0 mm is desirable. The outer diameter of the outer tube 20 in this example is 104 mm, and the outer diameter of the inner tube is 89 mm.
mm, and the gap 40 is 1 mm.

FIG. 4 is a table showing the results of the fixing test of the outer tube 20. If the tapered portion is provided as in Examples 3 to 23, the fixing of the outer tube 20 and the inner tube 30 is stable. The protrusion 32 and the tapered portion 22 according to this embodiment may be provided only at one end of the fire-resistant double-layer pipe 10, but are preferably provided at both ends in order to surely prevent falling off.

[0017]

According to the invention described in each claim, an elastic projection higher than the gap between the outer diameter of the inner pipe and the inner diameter of the outer pipe is formed at a position near the end of the outer pipe on the outer peripheral surface. And, by making the inner diameter side end angle of the outer tube in contact with the elastic projection tapered, the elastic projection will bite into the tapered portion when both come into contact, and the inner tube and the outer tube Separation can be reliably prevented. In addition, since the force applied from the outer tube to the elastic projection is changed to the center (inward) direction of the inner tube because of the tapered portion, the elastic projection is less likely to be detached from the inner tube.

[Brief description of the drawings]

FIG. 1 is a side view of a fire-resistant double-layer pipe according to the present embodiment.

FIG. 2 is a diagram illustrating a tapered portion formed on the outer tube of the fire-resistant double-layer tube according to the present embodiment.

FIG. 3 is a diagram illustrating a contact state between an outer tube and an inner tube.

FIG. 4 is a table showing the results of an outer tube fixing test.

[Explanation of symbols]

 Reference Signs List 20 outer tube 22 tapered portion 30 inner tube 32 protrusion 40 gap

Continuation of the front page (72) Inventor Kunio Meguro 2-12-10 Shiba-Daimon, Minato-ku, Tokyo Asano Slate Co., Ltd. F-term (reference) 3H036 AA01 AB14 AB16 AB24 AB26 AB32 AC01 AD01 AE01 AE07 3H111 AA01 BA15 BA37 CB03 CB14 CB24 CB29 DA11 DB03 DB11 EA14

Claims (4)

[Claims] 1. A fire-resistant double-layer pipe in which a synthetic resin inner pipe having a slightly longer outer diameter than the inner diameter of the outer pipe is inserted into a non-combustible outer pipe. A gap between the outer diameter of the inner pipe and the inner diameter of the outer pipe is provided at both ends of the inner pipe by exposing both ends thereof, at one or both of the exposed portions of the outer pipe close to the end of the outer pipe. A fire-resistant double-layer pipe in which an inner pipe and an outer pipe are fixed, wherein a higher elastic projection is formed, and an inner end of the outer pipe in contact with the elastic projection is tapered. 2. The elastic projection is an elastic body made of a synthetic adhesive or a polymer resin, and the total length of the elastic projection in the outer peripheral direction is at least の of the outer periphery of the inner tube. A fire-resistant double-layered pipe in which the inner pipe and the outer pipe according to claim 1 are fixed. 3. The height of the elastic projection formed on the outer peripheral surface of the inner tube is 0.5 to 5.0 mm, and the tapered shape of the inner tube side end angle of the outer tube is smaller than the outer tube end thickness. The inner tube and the outer tube according to claim 1 or 2, wherein the height is 30% to 100% and the depth from the end of the outer tube is 0.5 to 20.0 mm. Fixed fire-resistant double-layer pipe. 4. A fire-resistant double-layer pipe comprising a non-combustible outer pipe inserted with a synthetic resin inner pipe having an outer diameter slightly longer than the outer pipe and smaller than the inner diameter of the outer pipe. Both ends of the inner tube are exposed from both ends of the tube, and the outer diameter of the inner tube and the inner diameter of the outer tube are located at a position close to the end of the outer tube on one or both outer peripheral surfaces of the exposed portion of the inner tube. An elastic projection higher than the gap is formed, and a tapered portion is formed at an inner diameter side end corner of the outer tube in contact with the elastic projection, and the projection formed on the inner tube and the outer tube are formed on the outer tube. A method for fixing an inner tube and an outer tube of a fire-resistant double-layer tube, wherein the inner tube is prevented from detaching from the outer tube by engaging a tapered portion.