Which factors are related to the performance of the constant temperature and humidity machine

Time:2021/10/19 13:57:47

The constant temperature and humidity machine is suitable for testing the humidity resistance of electronic and electrical products, components, parts and materials under various temperature and humidity conditions. It can also be used for storage, transportation and use at high and low temperatures. Any factors that appear in the experiment will affect the test results of the product. So what factors are related to the performance of the constant temperature and humidity machine? Next, let the editor of the constant temperature and humidity machine explain it, I hope it can be helpful to everyone.

1. Sensor

You can use a solid-state sensor that is not affected by condensation to measure relative humidity, or use a fast-acting dry and wet bulb or dew point meter to measure relative humidity. Do not use sensors that are sensitive to condensation, such as lithium oxide sensors. The test conditions require the data acquisition system to perform measurements, and the measurement system must be equipped with appropriate recording equipment. During the test, the data acquisition system is independent. When using scale printing paper, the accuracy is ±0.6°C. If the wet ball test method is used, the wet ball and container should be kept clean before each test, and a new wet ball gauze should be replaced every 30 days. The wet paper towel used should be as thin as possible to promote evaporation and maintain moisture on the sensor surface. The water used in the wet bulb system is of the same quality as the wet water. During the test, whenever possible, the wet ball gauze, water container, sensor, and other components of the RH system should be checked every 24 hours to ensure the expected performance.

2. Wind speed

The wind speed should not be less than 4.6m/s, and a wet ball should be placed on the suction side of the fan to prevent heat from acting on the fan. The wind speed of any part of the test piece should be between 0.5-1.7 m/s.

3. Methods of moisturizing

Wet the air around the sample and spray it with steam or water. The resistivity is 1500～2500 Ohm·m at 25°C, and the pH of wet water is 6.5-7.2. Check the water quality frequently (less than 15 days) to ensure that the water quality is correct. After wetting, the water temperature should be adjusted before spraying to avoid violating the test conditions, and the water should not be sprayed directly into the test area. The condensed water generated during the test of the constant temperature and humidity machine should be excluded from the constant temperature and humidity machine.

4. Prevent pollution

In order to prevent the sample from deteriorating or affecting the test results, no direct contact with the sample except water is allowed, and no corrosive substances are allowed to enter the test room. Drying, humidifying, heating and cooling samples cannot change the composition of air, water or steam in the sample chamber.

5. The control sample must meet the following requirements:

(1) The test room is to be equipped with a measuring and recording device separate from the control of the test room.

(2) During the test, unless otherwise specified, the simulated values of temperature and relative humidity should be continuously measured.

(3) The tools and test box used should meet the tolerance requirements of relevant standards.

The above five points are all about the five factors that affect the performance of the constant temperature and humidity machine. Thank you for your understanding and support!