Market status of environmental test equipment such as high and low temperature test chamber, constant temperature and humidity test chamber

[Overview] Environmental test equipment, including high and low temperature test chamber, constant temperature and humidity test chamber, thermal shock test chamber, constant temperature box, drop machine, high temperature box, ultraviolet aging test box and other varieties. At present, the performance of domestic environmental testing equipment is still a certain gap compared with foreign brands, but from the perspective of cost performance, domestic environmental testing equipment has been occupying an advantage of low temperature in the international market.

Dongguan Qinzhuo Environmental Testing Technology Co., Ltd. specializes in the production of high and low temperature test chambers, constant temperature and humidity test chambers, thermal shock test chambers, constant temperature chambers, simulated vibration test benches and other environmental testing equipment. Welcome to visit. Or consult 0769-82205656

One. Current status of environmental testing equipment Currently, most domestic environmental testing equipment is produced to meet the national standard GB2423 "Basic Test Regulations for Electrical and Electronic Products". These environmental testing equipment now have corresponding national standards for products, such as GB10586-89 "Technical Conditions for Humidity Test Chamber "GB10589-89" Technical conditions for low temperature test chamber "GB10591-89" Technical conditions for high / low temperature test chamber "GB10591-89" Technical conditions for high / low temperature test chamber "etc.

Before the 1980s, most of the environmental test equipment used in China was imported from Western countries, and the price was relatively expensive. Nowadays, with the development of electronic technology, especially the development of control technology, from analog control to current digital control ; The display mode is from pointer to digital to the current touch screen display; the control accuracy is increased from ± 1 ℃ to 0.1 ℃ or even within 0.01 ℃; the volume of the equipment is from a small box to a room (room) of hundreds of cubic meters. , China's environmental test equipment manufacturers have been able to produce equipment that meets the test requirements. Performance can be comparable to imported equipment, and the price is only about half of imported equipment. However, some special equipment, such as temperature shock equipment, rapid temperature change (15 ℃ / min) can not be localized or production equipment can not meet the requirements.

two. Proper use of environmental testing equipment Despite this, environmental testing equipment is still a sophisticated and valuable equipment. Proper use and operation of environmental testing equipment can not only provide an accurate basis for inspectors, but also enable the environmental testing equipment to operate normally for a long time and extend the service life of its equipment.

First of all, when doing environmental tests, you should be familiar with the required sample performance, test conditions, test procedures and test techniques, the technical performance of the test equipment used, and the structure of the equipment, especially Be familiar with the operation and performance of the controller. Also read the operation manual of the test equipment carefully, so as to avoid the abnormal operation of the test equipment caused by the operation error and damage the test sample, and the test data is incorrect.

Second, choose the test equipment reasonably. In order to ensure the normal operation of the test, appropriate test equipment should be selected according to the different conditions of the test sample, and a reasonable ratio between the test sample and the effective volume of the test box should also be maintained. For the test of the fever test sample, its volume shall not be greater than one tenth of the effective volume of the test chamber. For the non-heat test sample, the volume should not be greater than one-fifth of the effective volume of the test chamber. For example, when a 21` color TV is used in a temperature storage test, a test box with a cubic volume can be used to meet the requirements. When the power is turned on, it cannot meet the requirements. A larger test box should be replaced. Because the TV set must emit heat during operation.

Third, place the test sample correctly. The location of the test samples should be more than 10cm away from the wall of the box, and multiple samples should be placed on the same plane as much as possible. The sample should be placed so as not to block the air outlet and return air outlet, and leave a certain distance for the temperature and humidity sensor. To ensure the correct test temperature.

Fourth, for the environmental test of the medium required for the test, it should be added correctly according to the test requirements. If the water used in the hot and humid test chamber has certain requirements, the water resistance of the test chamber should not be less than 500 ohms. The general resistance of tap water is 10--100 ohms. The resistance of distilled water is 100-10000 ohms. Deionized water The resistivity is 10000-100000 ohm.m, so the water used in the damp heat test should use distilled or deionized water, and it must be fresh. Because the water is in contact with the air, it is susceptible to carbon dioxide and dust pollution. Nature, after a long time, the resistivity will drop. There is a kind of pure water on the market that is more economical and convenient, and its resistivity is equivalent to distilled water.

fifth. Use of damp heat test chamber. The wet ball gauze (wet ball paper) used in the damp heat test chamber has certain requirements, not any gauze can be substituted, because the relative humidity reading is the root distance is the difference between temperature and humidity, strictly speaking, it is also related to the local atmospheric pressure and wind speed at the time . The wet bulb temperature indication is related to the amount of water absorbed by the gauze and the evaporation of the surface. These are directly related to the quality of the gauze, so the weather stipulates that the wet ball gauze must be a special "wet ball gauze" woven from linen. Otherwise, it is difficult to ensure the correctness of the indication of the wet bulb thermometer, that is, the correct humidity. In addition, the placement of the wet ball gauze is also clearly stipulated. The length of the gauze is 100mm. The sensor probe is tightly wound. The probe is 25-30mm away from the humidity cup. The gauze is immersed in the cup.

three. Maintenance of environmental test equipment There are many types of environmental test equipment, but the most widely used environmental test equipment is high temperature, low temperature, and humid heat test chambers. Nowadays, it is more popular to combine high temperature, low temperature, and humid heat test boxes-high and low temperature damp heat test It is more difficult to repair than other environmental test equipment, and it is representative. The following is an example of high and low temperature damp heat test box, to talk about the structure of high and low temperature damp heat test box and some common faults and troubleshooting methods.

(1) The construction testers of the common high and low temperature damp heat test chambers should not only operate in accordance with the operating procedures correctly, but also understand their structure. The high and low temperature damp 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 a structure that can adjust the direction of air supply; the humidification system has two types: boiler humidification and surface evaporation; the cooling and dehumidification system uses air-conditioning working structure cooling structure; the heating system uses electric fin heating and electric furnace wire direct heating Two kinds of structure; temperature and humidity test method adopts dry and wet bulb test method, and also has direct measurement method with humidity sensor; control and display operation interface adopt temperature and humidity separate and temperature and humidity combined controller and other methods.

(2) Some common faults and troubleshooting methods of the high and low temperature damp 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 to eliminate the fault one by one. If the temperature rises very slowly, it is necessary to check the wind circulation system to see if the adjustment baffle of the wind circulation is opened normally, otherwise, check whether the motor of the wind circulation is operating normally. If the temperature overshoot is severe, the PID setting parameters need to be adjusted. If the temperature rises directly and the over-temperature protection, then the controller fails, the control instrument must be replaced.

2. The low temperature can not reach the test index, then you should observe the temperature change, whether the temperature drops slowly, or the temperature has a tendency to rise after the temperature reaches a certain value, the former should check whether the temperature Drying in the studio, keep the studio dry, and then put the test samples into the work room for testing. Whether the test samples in the work room are placed too much, the wind in the work room cannot be fully circulated. It is necessary to consider whether it is a fault in the refrigeration system. In this case, the professional personnel of the manufacturer must be repaired. The latter phenomenon is caused by the poor use environment of the equipment. The ambient temperature of the equipment and the location (the distance between the back of the box and the wall) must meet the requirements (as specified in the equipment operation instructions).

3. In the humid heat test, the actual humidity will reach 100% or the actual humidity is very different from the target humidity, the value is much lower, the former phenomenon: it may be caused by the dry gauze on the wet ball sensor, then check the humidity Whether the water tank of the ball sensor is short of water, the water level in the water tank is automatically controlled by a water level controller, check whether the water supply system of the water level controller is normal, and whether the water level controller works normally. It may be that the wet ball gauze will harden the gauze due to the long use time or the purity of the water quality of the water supply, so that the gauze can not absorb the water and dry. Just replace or clean the gauze to eliminate the above phenomenon. The latter phenomenon is mainly because 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 to control the water level of the humidification boiler is normal, and whether the water level in the humidification boiler is normal. If all of the above is normal, then check the electrical control system, which requires professional maintenance personnel to carry out maintenance.

4. When the equipment suddenly fails during the test operation, the corresponding fault display prompt and an audible alarm prompt appear on the control instrument. The operator can quickly check which type of fault belongs to the chapter of troubleshooting in the operation and use of the device, and then you can ask a professional to quickly troubleshoot to ensure that the test is carried out normally. There will be other phenomena in the use of other environmental test equipment, then specific phenomena, specific analysis and elimination are required.

The environmental test equipment should also be regularly maintained, the condenser of the refrigeration system should be cleaned regularly, the moving parts should be lubricated and lubricated according to the instructions, and the electrical control system should be regularly maintained and inspected. These tasks are indispensable.