Structure and troubleshooting of high and low temperature boxes

Structure and troubleshooting of high and low temperature boxes

There are many types of environmental testing equipment, but the widely used environmental testing equipment is high-temperature, low-temperature, and humid and heat test chambers. Nowadays, it is a test chamber that integrates high-temperature, low-temperature, and humid and heat. The high and low temperature humidity and heat test chamber consists of a box, air circulation system, refrigeration system, heating system and humidity control system.

The air circulation system generally adopts a structure that can adjust the air supply direction; the humidification system includes boiler humidification and surface evaporation; the cooling and dehumidification system adopts a refrigeration structure in air conditioning conditions; the heating system adopts two structures: electric heating fin heating and electric furnace wire direct heating; the temperature and humidity testing method adopts dry and wet ball testing method, and there are also direct measurement methods using humidity sensors; the control and display operation interface adopts independent temperature and humidity separation and temperature and humidity combination controller.

1. In high-temperature tests, if the temperature change does not reach the test temperature value, you can check the electrical system and troubleshoot the fault one by one. If the temperature rises very slowly, check the air circulation system to see if the air circulation adjustment baffle is turned on normally. Otherwise, check whether the air circulation motor is running normally. If the temperature rises directly and is protected by overtemperature, if the controller fails, the control instrument must be replaced.

2. In the humid and heat test, the actual humidity will reach 100% or the actual humidity will be very different from the target humidity, and the value is much lower. The former phenomenon: it may be caused by the dry gauze on the wet bulb sensor. Then check whether the water in the wet bulb sensor is lacking in water. The water level in the water tank is automatically controlled by a water level controller. Check whether the water level controller water supply system is normal and whether the water level controller is working normally. Another possibility is that the wet-ball gauze will harden due to the long use time or the purity of the water supply, making the gauze hard, making it unable to absorb water and dry. As long as the gauze is replaced or cleaned, the above phenomena can be eliminated. The latter phenomenon is mainly because the humidification system is not working. Check the water supply system of the humidification system, whether there is a certain amount of water in the water supply system, control whether the water level control of the humidification boiler is normal, and whether the water level in the humidification boiler is normal. If all the above is normal, then you need to check the electrical control system, and you need to ask professional maintenance personnel to perform maintenance.

3. If the low temperature does not meet the test indicators, you must observe the change of temperature. Whether the temperature drops very slowly or the temperature tends to rebound after the temperature reaches a certain value. The former must check whether the studio is dried before performing a low temperature test, so that the studio is kept dry and then put the test sample into the studio before performing the test. Whether the test samples in the studio are placed too much so that the air in the studio cannot be fully circulated. After eliminating the above reasons, you must consider whether it is a fault in the refrigeration system.