JPH06265464A - Corrosion tester - Google Patents

Abstract

PURPOSE:To make pressure and steam pressure in a test tank controllable simply and accurately by interconnecting a saturated water tank, forcing air into saturated steam pressure by way of making water and inflow air at the preset temperature contact with each other, with this test tank. CONSTITUTION:A desired flow rate of air is fed to a saturated tank 1 from its lower part. This air passes through a filter 2 and comes to fine bubbles, passing through a water current 3 at the preset temperature in the underwater, and finally it is reached to an upper space of the saturated tank 1. This air passes through a pipe 5, joining with a corrosive gas from a pipe 6, coming into a test tank 8. Here, a temperature in the saturated tank 1 is kept constant by a constant tenperature water tank, while the air run past the saturated tank 1 has constant steam pressure to be determined by the temperature of the saturated tank 1, therefore it comes 9.206mmHg, 92.596mmHg each at temperatures of 10 deg.C and 50 deg.C, by way of example. As for the air, if it is preset so as to be saturated at the maximum flow rate and temperature, it is fully saturated with water vapor, and a fact that temperature control over the water tank 4 is set to + or -0.1 deg. is not so hard to be done. With this constitution, temperature and steam pressure in the test tank 8 can be controlled simply and accurately.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus which enables a corrosion test based on corrosive gas, temperature and water vapor pressure for a certain object.

[0002]

2. Description of the Related Art Various materials, especially metals, are used as H in the environment.
_The surface is corroded by trace elements such as ₂ S, SO ₂ , etc.,
The performance of the electronic part and the like using such a material gradually deteriorates. Recently, the exhaust gas has been increasing, and the environment in which it is used is becoming more and more severe. In response to this, new materials and products have been developed, but it is important to evaluate whether or not they have sufficient performance in a short time.

Corrosion of metals is controlled not only by the concentration of corrosive gases such as H ₂ S, SO ₂ , etc., but also by the temperature and humidity of the atmosphere, so a constant temperature and humidity can be set to a desired temperature and humidity. It has been conventionally practiced to introduce a corrosive gas into a tank, place a sample therein, and examine a change in its characteristics. And what is generally called a constant temperature and humidity tank has a water tank for humidification in it, but since corrosive gas often dissolves well in water, the test time is long and the gas becomes water when the gas concentration becomes high. It will be occluded.

On the contrary, when it is desired to reduce the gas concentration, water becomes a source of gas generation, which is an obstacle to lowering the gas concentration. Therefore, in order to keep the gas concentration in the tank constant, it is necessary to measure the gas concentration to adjust the amount of gas replenishment and to replace the water in the humidifying water tank. In addition, a wet and dry bulb is often used for measuring and controlling the humidity in a constant temperature and humidity chamber. However, since the wet bulb is always wet with water and absorbs gas, its water vapor does not show the correct relative temperature unlike pure water.

In order to solve the above-mentioned problems, there is a so-called method in which the air conditioner 10 is placed outside the test tank 20 containing the sample as shown in FIG. 1 and a gas having a constant relative humidity gas concentration is inserted into the test tank. It is used as a "constant flow rate method".
That is, in the constant flow rate system, air is previously passed through a humidity control water tank (not particularly shown in FIG. 1) to have a constant relative humidity, and conversely, air that has passed through the humidity control water tank recirculates on the water surface or It is characterized by a structure that does not backflow. However, actually, the accuracy of the humidity of the air that has passed through the humidity control tank and the air conditioner is at most 3% RH.

Further, if there is a difference in temperature between the air conditioner 10 and the test tank 20, the relative humidity of the test tank will have different values, so even if the air conditioner has a constant humidity, it will be useless.

As described above, in the constant flow rate system shown in FIG. 1, it is difficult to maintain constant humidity, but originally, the cause of the progress of corrosion in the corrosion test is that water adsorbed on the surface of the material. Corrosion gas, not relative humidity in the test chamber.

On the other hand, the amount of water adsorbed on the sample surface is determined by the temperature of the sample itself and the water vapor pressure in the atmosphere.

That is, the reliability of the corrosion test depends on how correctly and stably the water vapor pressure in the atmosphere and the temperature of the sample can be set with good reproducibility. Considering that it is not essential, it must be said that setting the relative humidity to a constant value in the constant flow method itself is out of the requirement of the corrosion test problem.

Further, when water is stored in the air conditioner shown in FIG. 1, the above-mentioned action cannot avoid the same phenomenon as that of providing a constant temperature and constant humidity tank in the test tank and a defect based on this phenomenon.

[0011]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a corrosion test apparatus which overcomes the above-mentioned drawbacks of the prior art and the temperature and water vapor pressure in a test tank easily and accurately. It is a thing.

[0012]

In order to solve the above-mentioned problems, the structure of the present invention is a saturated water tank in which water having a preset temperature is brought into contact with inflowing air or the like to bring the air to a saturated vapor pressure. And a corrosion test device by connecting the saturation tank and the test tank.

According to the means for solving the above problems,
To explain the principle of the present invention, as long as the saturated water tank and the test tank are in communication with each other, the water vapor pressures of both are equal, and eventually the water vapor pressure of the test tank is equal to the saturated water vapor pressure of the saturated water tank. Depends exclusively on the temperature of the saturated water bath and not on other external conditions.

That is, there is a characteristic feature of the principle of the present invention in that the condition of the corrosion test can be set only by two parameters of the temperature of the sample in the test tank and the temperature of the saturated water tank.

[0015]

EXAMPLE 1 FIG. 2 shows an example in which a gas obtained by passing gas through water and saturating water vapor into the gas merges with a corrosive gas and then flows into the test tank in the saturation tank.

Here, a desired flow rate of air is sent from the lower part of the saturation tank 1 to the saturation tank.

The air passes through the filter 2 to form fine bubbles, passes through the water 3 to reach the upper space of the saturation tank, and is sent to the test tank through the external conduits 5 and 7.

The air that has passed through the saturation tank has a constant water vapor pressure determined by the temperature of the saturation tank.

For example, the water vapor pressures at 10.degree. C., 30.degree. C. and 50.degree. C. are 9.206 mmHg and 31.839 mmH, respectively.
g, 92.596 mmHg.

In order to keep the temperature of the saturation tank constant, the saturation tank is generally contained in a constant temperature water tank.

The air must be completely saturated with water vapor, but if it is set so as to be sufficiently saturated at the maximum flow rate and maximum temperature used, no problems will occur at flow rates and temperatures below that.

The temperature of the constant temperature water tank is controlled to ± 0.
It is not difficult to set the temperature to 1 ° C.

On the other hand, the air conditioner 1 as shown in FIG.
When trying to obtain a gas with constant humidity by 0,
First, the temperature of the gas inside the air conditioner must be kept constant, and the humidity inside the air conditioner must be measured by a humidity sensor such as a wet and dry bulb to humidify or dehumidify the air to the desired humidity.

However, as described above, the control of humidification / dehumidification as described above is complicated, and the accuracy is at most ± 3% RH.

For example, when the temperature of the test tank is set to 50 ° C. and the relative humidity is set to 75%, the accuracy of the water vapor pressure in the test tank is compared between Example 1 and the case of the air conditioner shown in FIG. In Example 1, 75% humidity is 69.427 mmHg
(92.596 × 0.75), which is 44.3 ° C.
Since it corresponds to the saturated water vapor pressure in, the saturation tank (and constant temperature water tank) should be set to 44.3 ° C.

As described above, even if the error range of the temperature of the saturation tank is ± 0.1 ° C., it is 44.4 ° C. (44.3 ° C. + 0.1).
Saturation water vapor pressure in the case of (° C) is 69.741 mmHg, and considering that the saturated water vapor pressure at 44.2 ° C (44.3 ° C-0.1 ° C) is 69.024 mmHg, the error of Range is at best ± 69.4mmHg
It is 0.4 mmHg.

On the other hand, when the air conditioner shown in FIG. 1 is used, there is an error range of ± 3% RH.
The accuracy is 69.4 ± 2.8 mmHg, and the difference from the case of Example 1 is clear.

[0028]

[Embodiment 2] FIG. 3 shows an embodiment in which the saturated water vapor pressure is obtained by filling the water surface with air instead of passing the air through the water in the saturated tank as in Embodiment 1.

In this case, it is necessary to design the water surface wider and design the time for the air to stay on the water surface longer than in the first embodiment.

The fact that the humidity of the test tank can be easily controlled and the accuracy is high is the same as that of the first embodiment.

[0031]

[Third Embodiment] In the first and second embodiments, a gas having a saturated water vapor pressure and a corrosive gas are merged through the pipes 5 and 6 and flowed into the test tank. Reference numeral 3 shows a configuration in which both of them flow into each other by the pipes 5 and 6.

In the third embodiment as well, it is needless to reiterate that the humidity of the test tank can be easily controlled and its accuracy is high.

[0033]

According to the present invention having the above-described structure, a highly reliable gas test can be performed under desired temperature and humidity with simple control and accuracy without using a humidity sensor in a test tank. it can.

Further, since the amount of water vapor (humidity) in the test tank can be controlled by changing the temperature of the constant temperature tank, the range of humidity that can be set is wide.

Further, since the corrosive gas does not contaminate the saturated tank which is the humidifier, it is possible to obtain a test environment having a desired gas concentration and water vapor pressure.

As described above, the present invention has various advantages as compared with the conventional device and its value is enormous.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a test device using a conventional air conditioner.

[Fig. 2]

[Fig. 3]

FIG. 4 is a block diagram showing a corrosion test apparatus of the present invention.

[Explanation of sign]

1: Saturation tank 2: Filter 3: Water 4: Constant temperature water tank 5, 6, 7: Pipe 8: Test tank 9: Air inflow pipe 10: Air conditioner in conventional technology 20: Test tank in conventional technology 30, 40, 50 : Pipe in the prior art (however, 3
(0 is a pipe into which air flows in, 40 is a pipe into which corrosive gas flows in)

Claims (5)

[Claims] 1. A corrosion test apparatus by providing a saturated water tank in which water having a preset temperature is brought into contact with inflowing air to bring the air to a saturated vapor pressure, and the saturated tank and the test tank are communicated with each other. 2. The corrosion test apparatus according to claim 1, wherein the air flowing into the saturation tank passes through water. 3. A corrosion test apparatus for storing air flowing into a saturated tank on the surface of water. 4. The corrosion test apparatus according to claim 1, wherein a pipe connecting the saturated tank and the test tank is joined with a pipe into which a corrosive gas flows. 5. The corrosion test apparatus according to claim 1, wherein a pipe for inflowing a corrosive gas and a pipe for connecting the saturated tank to the test tank are provided side by side.