There are many kinds of environmental test equipment, but the most widely used environmental test equipment is high temperature, low temperature, wet and hot test chamber, and today is more popular is a collection of high temperature, low temperature, wet and hot as one of the test chamber high and low temperature wet and hot test chamber, it is more difficult to repair than other environmental test equipment, and representative. The following high and low temperature humidity and heat test chamber as an example, talk about the structure of high and low temperature humidity and heat test chamber and some common faults and elimination methods.

(a) the structure of the common high and low temperature humidity and heat test chamber

In addition to correct operation according to the operating procedures, the test personnel should also have an understanding of its structure. The high and low temperature humidity and heat test chamber is composed of a box body, an air circulation system, a refrigeration system, a heating system and a humidity control system. The air circulation system generally adopts the structure of adjustable air supply direction; The humidification system has two kinds: boiler humidification and surface evaporation. The cooling and dehumidification system adopts the refrigeration structure of air conditioning condition. The heating system adopts two structures: electric fin heating and electric furnace wire direct heating. Temperature and humidity test method using dry and wet ball test method, also useful humidity sensor direct measurement method; The control and display operation interface adopts independent temperature and humidity and combined temperature and humidity controller, etc.

(2) some common faults and troubleshooting methods of the high and low temperature humidity and heat test chamber:

1. In the high temperature test, if the temperature change does not reach the test temperature value, you can check the electrical system and eliminate the fault one by one. If the temperature rises slowly, it is necessary to check the wind circulation system to see whether the regulating baffle of the wind circulation is opened normally, otherwise, it is necessary to check whether the motor of the wind circulation is running normally. If the temperature is too high, the PID setting parameters need to be adjusted. If the temperature rises directly, overtemperature protection, then, the controller is out of order, the control instrument must be replaced.

2. Low temperature reach test indicators, then you have to observe the change of temperature, the temperature drop is slow, or temperature has a tendency to pick up after the temperature to a certain value, the former shall check and do the low temperature test whether the studio before drying, to keep the studio after drying and then test samples into the studio to do test, high low temperature test chamber indoor test sample is placed too much work, make work indoor wind is not fully cycle, after excluding the reasons, and consider whether in the refrigerating system failure, it will please manufacturers of professional personnel for maintenance. The latter phenomenon is caused by the bad use environment of the equipment. The ambient temperature and location of the equipment (the distance between the back of the box and the wall) should meet the requirements (as stipulated in the equipment operation instructions).

3. The high low temperature test chamber in hot and humid test, an actual humidity 100% humidity vary widely, with the target or actual humidity value low a lot, the former phenomenon: may be caused the dry gauze on the wet bulb sensor, that is about to check whether the wet bulb sensor in the sink water shortage, water level in tank is composed of a water level controller of automatic control, check whether water supply water supply the normal water level controller, level controller working is normal. Another possibility is that the wet bulb gauze will become hard due to its long use time or the purity of water supply, so that the gauze can not absorb water and become dry. The above phenomenon can be eliminated as long as the gauze is replaced or cleaned. The latter phenomenon is mainly the humidification system does not work, check the water supply system of the humidification system, whether there is a certain amount of water in the water supply system, whether the water level control of the humidification boiler is normal, whether the water level in the humidification boiler is normal. If all the above is normal, it is necessary to check the electrical control system, which should be repaired by professional maintenance personnel.

4. When the high and low temperature humidity and heat test chamber suddenly fails in the process of test operation, the corresponding fault display prompt and sound alarm prompt will appear on the control instrument. Operators can refer to the operation of the equipment in the use of the troubleshooting chapter to quickly check out which kind of fault, you can ask professionals to quickly troubleshoot, to ensure the normal test. Other environmental test equipment in use there will be other phenomena, that is to specific phenomenon, specific analysis and exclusion.

The high and low temperature humidity and heat test chamber should be maintained regularly, the condenser of the refrigeration system should be cleaned regularly, the moving parts should be lubricated according to the instruction, the electrical control system should be regularly maintained and checked, and so on. These works are essential.