JPS61240137A - Method for testing leakage of ammonia - Google Patents

Abstract

PURPOSE:To easily and certainly perform the inspection of leakage within a short time, by providing a small container filled with NH3 gas in a hermetically sealed state to the back surface of a membrane tank having a membrane welded thereto and discharging NH3 gas at the time of a leakage test by a proper method to detect the same by a detection solution. CONSTITUTION:When a membrane tank 2 is provided to the inside of an outside tank 3 comprising concrete, a recessed part 4 is provided to the bottom part of the tank 3 and a small container 1 made of thin glass is placed on the base material 5 attached to said recessed part 4 and an upper member 7 is engaged with a recessed part 6 so as not to move the container 1 and an interval (l) is provided so as to rupture the container 1 when the membrane tank 2 is struck by a hammer 8 while the container 1 is filled with NH3 gas or aqueous ammonia. The container 1 is ruptured at the time of a leakage test to discharge NH3 gas and, if the membrane tank 2 has a leaking place, said place can be detected by the coloration of a detection solution. By this method, a leakage test is performed inexpensively and simply.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an ammonia leak test method for testing the airtightness of a membrane tank formed by welding a thin film.

Conventional technology Conventional airtightness testing of membrane tanks involves installing a pipe such as a vinyl hose with a blowout hole between the membrane and the outer tank (concrete frame, heat insulation layer, etc.), and sending ammonia gas through the pipe. There is also a known method in which the ammonia detection solution is instructed to change color (Kokai No. 53-98510), but even with this method, there is a risk that incomplete diffusion may remain, and in order to prevent this from occurring, This had the disadvantage of requiring a considerable density of piping, etc., and was costly.

Problems to be Solved by the Invention The present invention attempts to solve the problem of preventing incomplete diffusion of ammonia gas, which can be installed at low cost, and which can be easily diffused.

Measures to solve the problem Install a small container filled with ammonia solution or ammonia gas on the back of the membrane of the membrane tank, and after welding the membrane and before the leak test, open the container appropriately to generate ammonia gas. It is detected using an ammonia detection liquid.

Example (D) A thin glass container (1) was filled with ammonia solution or ammonia gas and sealed, and the base material (5) was placed in the recess (4) formed in the outer tank (3) on the back of the membrane (2). Place the container (1) on the base material (5), insert the upper member (7) having a recess (6) into which the container (1) can fit without moving from above, and (7) is a container (1
) until it is damaged, maintain a slightly spaced apart distance (2) from the base material (5), and keep the upper surface flush with the outer tank (3).

The membrane (2) is then welded.

A plurality of such locations are formed at necessary locations on the membrane tank az.

After welding all the membranes, spray ammonia detection liquid onto the inspection area and tap the pre-marked insertion part of the container (1) with a wooden hammer (8) to make a thin glass container (1). Since the upper member (7) is press-fitted into the recess (4) by the distance U>, it will easily break and ammonia gas will enter between the membrane (2) and the outer tank (3), and if there is a leak, the ammonia detection liquid will be removed. This is indicated by changing color.

Example [■] (not shown) A container is provided with an appropriate opening, filled with ammonia solution or ammonia gas and sealed, and the opening is covered with a substance that melts when heated, such as wax. Recess (4
), and after welding the membrane (2), heat it from the top with a gas burner, or when inserting the container, heat it by energizing an electric heater, etc. installed near the opening of the container. By opening the opening, ammonia gas enters between the membrane (2) and the outer tank (3), and if there is a leak, the ammonia detection liquid changes color and indicates this.

Example (m) A glass or synthetic resin container (11) that can be broken relatively easily is filled with ammonia solution or ammonia gas and sealed, the container U is inserted into the recess (4), and the upper part is sealed. After inserting a metal rod (:I) having a high coefficient of thermal expansion into the metal rod (13), the membrane (2) or the bottom plate (11) is placed in contact with the metal rod (13) and welded.

When welding of the membrane (2) or the bottom plate (11) is completed, when it hits the upper part of the recess (4), it is heated with a filter gas burner or the like to expand the metal rod 0 and break the container (1B) to open it.

By releasing ammonia gas, the membrane (2)
Alternatively, if there is a leakage point between the bottom plate αυ and the outside +111 (3), the ammonia detection liquid changes color and indicates this.

Example [Container a, in which a hole aω having a small diameter taper on the outside is bored in the container 0, and a trapezoidal stopper that can be brought into close contact with the hole aω is provided.
→Insert the metal rod ui into the ammonia solution or ammonia station (4), arrange it so as to contact the membrane (2) or the bottom plate (11), and weld it.

When welding of the membrane (2) or the bottom plate I is completed, the upper part of the recess (4) is heated with a gas burner or the like to expand the metal rod ae and release the container I.

By releasing ammonia gas, the membrane (2)
Or, if there is a leakage point that has entered between the bottom plate aυ and the outer tank (3), the ammonia detection liquid changes color and indicates this.

Embodiment (Y) In addition, the present invention is not limited to the above embodiment, such as a method of opening the valve of a gas cylinder filled with ammonia gas by electrical control or fluid control.

Effects of the invention By opening the container and generating ammonia gas, gas can be easily supplied to areas where it is difficult to diffuse, and the gas diffusion time can be greatly shortened, making it even more reliable when used in combination with conventional methods. Leakage tests can be carried out.

Furthermore, the present invention is not limited to membrane tanks, but can also be used, for example, at the joint between the air color plate Qυ and the bottom plate Ql) of a normal vertical cylindrical tank (9) as shown in FIGS. 3 and 4. This can be applied when it is not possible to work from the back of the machine.

[Brief explanation of drawings]

Figure 1 is a sectional view of the membrane tank, Figure 2 is an enlarged view of part A in Figure 1, Figure 3 is a sectional view of the cylindrical tank, Figure 4 is an enlarged view of part B in Figure 3, and Figures 5 to 5. FIG. 8 is an enlarged cross-sectional view of the main part of the other embodiment.

Claims (1)

[Claims] (1) A small container filled with ammonia solution or ammonia gas is installed on the back side of the membrane of the membrane tank, and after welding the membrane, the container is appropriately opened during a leak test to generate ammonia gas. Ammonia leak test method.