JPH0422213B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial field of the present invention] The present invention is a method for applying compressed air or the like into structures that require airtightness or watertightness, such as ship hulls, various tanks, pressure vessels, and piping, and applying a foaming liquid to the surface of the structure. The present invention relates to a gas leakage detection agent for detecting gas leakage based on the presence or absence of foaming, that is, a leakage detection agent for atmospheric pressure testing. [Prior art] Conventionally, in this field, soaps or synthetic detergents, often using various surfactants such as alkylbenzene sulfonates, fatty acid ethanolamides, alkylphenol polyoxyethylene ethers, and higher alcohol polyoxyethylene ethers, are used as foaming agents. In order to prevent corrosion of the specimen, a suitable amount of nitrite, phosphate, borate, benzoate, sebacate, etc. is added. [Disadvantages of the above conventional techniques] However, when these detection agents are used, the surfactants, polymer agents, and inorganic salts contained in them become sticky or sticky due to evaporation of water after the detection operation.
It remains as a white precipitate. The exterior surfaces of equipment subjected to barometric pressure tests are usually painted;
If paint is applied directly without removing these residues, the adhesion of the paint to the metal surface will be significantly impaired, leading to peeling, discoloration, etc., which not only impairs the aesthetics but also poses a major quality control problem. . Therefore, the residue of the detection agent must be removed, but new problems arise as the object becomes larger. That is, it is removed by brushing under running water or jet water in ships, tanks, etc., but since rust has already formed during washing with water, it is necessary to use a saunder, wire brush, etc. to remove rust after removal. The expenses and construction period required for these are one of the obstacles to cost reduction. [Object of the present invention] The present invention eliminates the residue that occurs when applying a conventional leak detection agent, thereby saving costs and shortening the construction period by omitting the work, and eliminating rusting accidents. The purpose is to provide a leak detection agent for atmospheric pressure tests. That is, in the present invention, after the detection work,
To provide a leak detection agent for atmospheric pressure tests that does not require work to remove residues and does not impede the adhesion of the paint film even if it is applied as is. [Structure of the present invention] In order to achieve the above object, the present invention uses a surfactant at a low concentration as a foaming agent, and
It is formulated with ammonium carbonate salt as an anticorrosion agent. That is, the present invention is a leak detection agent for atmospheric pressure tests characterized by comprising a mixed aqueous solution of 0.05 to 2% by weight of an ammonium salt of carbonate and 0.01 to 0.05% by weight of a surfactant. In order to generate foam and obtain stability, it is possible to select any surfactant that has foaming power, but it is especially desirable to use a surfactant that exhibits good performance at low concentrations. Of course. Therefore,
The surfactant that can be used in the present invention may be any surfactant as long as it has good foaming properties, but particularly preferred ones include nonylphenol polyethylene ether (addition of 10 to 20 moles of ethylene oxide), lauryl alcohol polyethylene ether, Oxyethylene ether (8 to 16 moles of ethylene oxide added)
It has excellent foaming properties and stability. These surfactants can be used in amounts ranging from 0.01 to 0.05% by weight. If it exceeds 0.05% by weight, it will affect the adhesion of the paint, and if it is less than 0.01% by weight, it will lack foaming properties and stability, which will lower the detection ability, which is not preferable. On the other hand, in the present invention, when the ammonium salt of carbonate added as a corrosion inhibitor is applied as a solution to the iron surface, it forms a passivation film on the iron surface and completely vaporizes and volatilizes, leaving no residue. It has the property that it never gets wet. As the ammonium salt of carbonic acid, ammonium carbonate, ammonium hydrogen carbonate, or a carbonate having any degree of neutralization between ammonium carbonate and ammonium hydrogen carbonate can be used. The concentration used can range from 0.05 to 2% by weight. Use of more than 2% by weight is unnecessary as it will result in excessive rust prevention. In addition, it takes time for it to volatilize, making it unsuitable for painting within a short period of time after detection. Further, if it is less than 0.05% by weight, the rust preventive power will be insufficient, which is not preferable. In the present invention, by using a low concentration of a surfactant with excellent foaming power and adding ammonium carbonate to this, it is applied to the steel surface to be detected and no residue remains even when the water evaporates. It does not rust and has good rust prevention properties, and as a result, it eliminates the need for washing with water, brushing, etc., which were conventionally used for removal, and can be painted immediately. It is. Hereinafter, specific examples of the present invention will be cited as invention products, and comparisons will be made with two conventional detection agents (conventional products A and B). The type of detection agent, test items, and results are shown in the table below.

【table】

[Effects of the present invention]

As detailed above, in the present invention, the amount of residual substances is extremely small compared to the conventional technology, and as a result, even if the residue is painted without being removed after inspection, there is no problem with the paint film. It produces a remarkable effect that does not give any effect.

Claims (1)

[Claims] 1. A leak detection agent for atmospheric pressure tests, comprising an aqueous mixed solution of 0.05 to 2% by weight of an ammonium salt of carbonate and 0.01 to 0.05% by weight of a surfactant.