JPS608206B2 - On-site foam insulation method - Google Patents

Description

[Detailed Description of the Invention] The present invention involves spraying and foaming a foamable resin material such as polyurethane multiple times on the surface of a metal object, which is the outer wall of a container or pipe that needs to be kept cold or warm. This invention relates to an in-situ foam insulation construction method that forms a heat insulation layer of a required thickness by using the following method.

In this type of in-situ foam insulation method, in the layer portion that comes into direct contact with the metal covering, the reaction heat during foaming is absorbed by the highly thermally conductive metal covering, and the outside air passes through this metal covering. It is inevitable that the foaming rate will decrease due to the heat dissipated to the metal object, which means that there will be loss in the raw material, and this foaming rate and loss rate will be greatly affected by changes in the ambient temperature around the metal object. It changes.

In the conventional method, the amount of spray per unit time from the first to the final spray was the same for each spray, and was constant regardless of the ambient temperature, so the temperature conditions In some cases, there have been disadvantages such as a significant increase in raw material loss and non-uniformity of each layer. In other words, in the past, no consideration was given to the phenomenon that the foaming rate decreases due to heat absorption and radiation by the metal object, or that the rate of decrease in the foaming rate changes depending on the ambient temperature. As a result, the above-mentioned inconvenience occurred. The present invention takes the above-mentioned phenomenon into consideration and proposes an in-situ foam insulation construction method that can eliminate the above-mentioned conventional disadvantages.

In the in-situ foam insulation method according to the present invention, first, a preliminary insulation layer is formed by spraying on the surface of a metal object at a small spray amount per unit time, and then the unit time during which the preliminary insulation layer is formed is It is characterized by being able to repeat spraying a required number of times with a spray amount larger than the hit spray amount.

That is, first, a preliminary heat insulating layer is intentionally formed, and this preliminary heat insulating layer can be used to thermally isolate subsequent spray foam layers from the metal object. can be sufficiently foamed at a high foaming rate regardless of the ambient temperature, and can be formed into a mutually uniform structure, and the amount of spray for forming the preliminary insulation layer is smaller than that of the general spray. Since it is made as small as possible according to the ambient temperature in each case, it has become possible to minimize the loss of raw materials due to heat absorption and heat radiation during the formation of this preliminary insulation layer. .
The method of the present invention is particularly effective when the temperature of the metal object is low.

Hereinafter, embodiments of the construction method of the present invention will be described based on the drawings.

As shown in FIG. 1, in order to form a foamed heat insulating layer 2 made of a foamable resin material such as polyurethane on the surface of a metal object 1 to a desired thickness, first, as shown in FIG. The spray gun 3 sprays the surface of the metal object 1 with a small amount of spray per unit time to form the preliminary heat insulating layer 2A.

After that, by repeating spraying on the surface of the preliminary heat insulating layer 2A a required number of times at a spray amount larger than the spray amount per unit time when forming the preliminary heat insulating layer 2A,
The main first insulation layer 2b, the second insulation layer 2c, the third insulation layer 2d, etc. are sequentially laminated.

When forming the first heat insulating layer 2b, the preliminary heat insulating layer 2
Since A ensures thermal isolation from the metal object 1, foaming is performed at a sufficiently high foaming rate.

The same applies to the second heat insulating layer 2c and subsequent layers. Each layer 2
b, 2c, 2d......If the spray amount per unit time for formation is made equal to each other, each layer 2b, 2c, 2d, .・・・． ... have the same (or almost the same) thickness and a mutually uniform structure.

Also, for example, if the spray amount per unit time is increased as one goes to the upper layer, each layer 2b, 2c, 2 as shown in FIG.
The thickness of d...... gradually increases, and the parentheses also have a mutually uniform structure. However, the former is preferable in terms of workability. An example of a method for increasing the spray amount per unit time when forming the preliminary heat insulating layer 2A to 4 times more than the subsequent ones is as follows. Reduce the jet speed or
Alternatively, the spraying speed from the spray gun 3 may be kept constant and the moving speed of the spray gun 3 may be increased.

This also applies to the case shown in FIG. 4 above. The amount of spray per unit time for forming the preliminary heat insulating layer 2A is adjusted according to the ambient temperature around the metal object 1, but in any case, the preliminary heat insulating layer 2A is the first heat insulating layer. When forming the layer 2b, the layer 2b should be able to exhibit a heat insulating effect sufficient to reliably thermally isolate the layer 2b from the metal object 1.

Ideally, the amount of spray should be the minimum amount necessary within that range.

[Brief explanation of the drawing]

The drawings illustrate embodiments of the in-situ foam insulation method according to the present invention, with FIG. 1 being a cross-sectional view of the completed state, FIG. 2 being a cross-sectional view of the preliminary insulation layer formed, and FIG. FIG. 4 is a sectional view corresponding to FIG. 3 showing another implementation method. 1...Metal object 2...Insulating layer, 2A
...Preliminary insulation layer. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1 This is an on-site foaming insulation method in which a heat insulating layer 2 of a required thickness is formed by spraying and foaming a foamable resin raw material in multiple layers on the surface of a metal covering 1. First, the metal covering is After forming a preliminary heat insulating layer 2A by spraying on the surface of the projectile 1 at a small spray amount per unit time, a spray amount larger than the spray amount per unit time when forming the preliminary heat insulating layer 2A is formed. An in-situ foam insulation method that allows spraying to be repeated as many times as required.