JPS59153916A - Exhaust pipe - Google Patents

Abstract

PURPOSE:To aim at enhancing the heat-insulating effect of an exhaust pipe, by using such a sandwich structure that an aluminum foil of 5-50mu on the exhaust pipe side and an aluminum foil of 30-70mu on the outside are applied onto the front and back surfaces of an asbestos cloth, respectively, with the use of a high polymer bonding agent which is burnt out at a temperature below 300 deg.C. CONSTITUTION:Around the outer peripheral surface of an exhaust pipe 1, an asbestos cloth 7 which is applied, on the exhaust pipe side, with an aluminum foil 6 of 5-50mu and, on the outside, with an aluminum foil 9 of 30-70mu through thin air layers D, E, respectively, is covered, with a thin air layer C being formed therebetween. The adhesion of the aluminum foils 6, 9 to the asbestos cloth 7 is made with the use of a high-polymer bonding agent such as, for example, a vinyl chloride group bonding agent which is burnt out at a temperature below 300 deg.C, so that the bonding agent is burnt out when the exhaust pipe is actually used, to form the aforementioned air layers D, E serving as heat-insulating air layers.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an insulated exhaust pipe that is easy to manufacture and has a high heat insulation effect.

As shown in Fig. 1, a conventional exhaust pipe is made by coating an asbestos paste 2 on an exhaust pipe 1 made of cast metal or sheet metal, and after drying, asbestos cloth 3 is wrapped around the asbestos cloth 3. The wire mesh 4 was wrapped completely and fixed with brass wire 5 for insulation. In FIG. 1, A and B indicate minute air layers, X indicates the inside of the exhaust pipe, and yVi indicates the outside atmosphere.

However, such conventional exhaust pipes have the following drawbacks.

(1) Many steps are required for manufacturing, resulting in high costs.

(2) During engine operation, heat and vibration cause the applied asbestos and asbestos cloth to age and turn into powder, scattering into the surrounding area and worsening the environment.

The present invention was made to eliminate all of these drawbacks, and has the following features: (11) It is easy to manufacture, low cost, and has the same insulation effect as the conventional exhaust pipe mentioned above; (2) Asbestos is The present invention provides an insulated exhaust pipe that satisfies the following requirements: Even if it becomes powdered due to aging, it will not be easily scattered around.

That is, the present invention has a sandwich structure in which aluminum foil is coated on the front and back sides of asbestos cloth with a polymeric adhesive that burns out at temperatures below 600°C. Aluminum foil is used to cover the exhaust pipe with a covering material having a thickness of 30 to 70μ.

The exhaust pipe of the present invention has a sandwich structure in which both sides of asbestos cloth are wrapped with aluminum foil to improve the heat insulation effect and prevent asbestos powder from scattering.

The aluminum foil on the inside, that is, on the exhaust pipe side, does not need to be too thick in order to prevent asbestos powder from scattering, and should have a thickness of 5 to 50 μm. The aluminum foil on the outside, that is, on the outside air side, needs to be slightly thicker for fixing the asbestos cloth and preventing external damage, and should be 30 to 70 μm thick. In addition, if the thickness is 70μ or more, the rigidity will be strong and it will be difficult to process the intricate parts.
If the thickness is less than μ, there is a possibility that tools, worker's fingernails, tightening wires, etc. may damage the aluminum foil when installing it to the exhaust pipe, causing the aluminum foil to break and expose the asbestos cloth. On the other hand, the aluminum foil on the exhaust pipe side may be slightly damaged during installation without any problem, and may be thinner than the aluminum foil on the outside air side. However, if it is less than 5μ, it cannot withstand the engine exhaust pipe temperature.

The adhesion between the above aluminum foil and asbestos cloth is 300
All polymer adhesives that burn out at temperatures below ℃ are used, such as vinyl chloride adhesives, so that they burn out when the exhaust pipe is used, and an extremely thin air layer is formed between the asbestos cloth and aluminum foil. K. The air layer acts to improve the heat insulation effect.

FIG. 2 is a diagram showing an embodiment of the exhaust pipe of the present invention.

In Figure 2, 1 is an exhaust pipe, 6 is an inner aluminum foil, and 7 is an exhaust pipe.
1 is an asbestos cloth, 9 is an outer aluminum foil, 5 is a brass wire for mounting, O and D are minute air spaces, and the other parts are the same as the conventional exhaust pipe shown in FIG. In addition, the exhaust pipe 1 of the covering material
Attachment to the exhaust pipe is carried out by making the entire covering material of the sandwich inch structure in advance, wrapping it around the exhaust pipe 1, and attaching it with the wire 5.

In the case of the conventional exhaust pipe shown in FIG. ), 5th paragraph (
It reaches the surface through five stages of heat transfer with the brass wire mesh 4), but in the exhaust pipe of the present invention, the first stage (micro air layer C), the second stage (aluminum foil 6), and the third stage (micro air layer D), the 4th stage (asbestos cloth 7), the 5th stage (micro air layer Z), the 6th stage (aluminum foil 9), and the heat transfer reaches the surface by one more stage, so it has a heat insulation effect. will improve.

Moreover, in the case of the one shown in FIG. 1, the minute space A.

The thickness of B is asbestos cloth, and the installation of brass wire may be loose depending on the direction of installation, so the insulation effect cannot be guaranteed, but according to the present invention, when the exhaust pipe is used after completion of the product, a minute air layer is formed, B is generated, ensuring a heat insulating effect.

Furthermore, the production time is approximately 1/3 to 5 times shorter than that of conventional methods.
This is a significant reduction of 1/2.

EXAMPLE A conventional exhaust pipe shown in FIG. 1 and an exhaust pipe of the present invention shown in FIG. 2 were manufactured in the manner shown in the table below and used as engine exhaust pipes.

In addition, the aluminum foils 6 and 9 and asbestos cloth 7 of the examples of the present invention
A vinyl chloride adhesive was used to bond the parts.

As is clear from the above table, the exhaust pipe of the present invention had a significantly reduced thickness of the heat insulating material compared to the conventional exhaust pipe, but it was confirmed that it exhibited a heat insulation effect close to that of the conventional exhaust pipe.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a conventional exhaust pipe, and FIG. 2 is a diagram showing an embodiment of the exhaust pipe of the present invention. Sub-agents 1) After-the-day agent Ryo Hagiwara -

Claims (1)

[Claims] Aluminum foil on the front and back sides of the asbestos cloth The polymer adhesive, which burns out at temperatures below 7500℃, has a sandwich inch structure with 9 µm, and the aluminum foil on the exhaust pipe side is 5 to 50μ, and the aluminum foil on the outside air side! An exhaust pipe whose outer periphery is covered with a covering material having a thickness of IO~70μ.