Jerry teaches you how to use environmental test equipment correctly and how to remove common faults!

Environmental experimental equipment is a kind of combined experimental equipment which imitates one or more severe environments by artificial means in the laboratory It is an environmental experimental equipment for developing new commodities and checking the quality function of commodities It's the necessary equipment for our inspection and experiment So it is very important to use and protect the environment and reliability experimental equipment correctly According to the environmental factors imitated by the experimental equipment, the environmental experimental equipment can be roughly divided into: climatic environmental equipment (including biological environmental experimental equipment), mechanical environmental experimental equipment, climatic mechanical inductive environmental experimental equipment and other environmental experimental equipment We have dozens of environmental experimental equipment Environmental experimental equipment provides necessary information and data for the research and development of modern high-tech commodities and the regular inspection and inspection of commodities I current situation of environmental experimental equipment At present, most of the domestic environmental experimental equipment are produced to satisfy the national standard GB2423 basic experimental procedures for electrical and electronic goods These environmental experimental equipment now have corresponding national standards for goods, such as gb10586-89 technical conditions for damp heat test box gb10589-89 technical conditions for low temperature test box gb10591-89 technical conditions for high / low temperature test box gb10591-89 technical conditions for high / low temperature test box Conditions, etc In the 1980s, most of the environmental experimental equipment used in China was introduced from western countries, and the quotation is relatively precious Now, with the development of electronic skills, especially the development of control skills, from imitation control to digital control, the display methods are from the finger to the digital to the touch screen display; The control accuracy is increased from ± 1 ℃ to 0.1 ℃ or even within 0.01 ℃; the equipment volume is from a small box to a room (room) of several hundred cubic meters, and the Chinese environmental experiment equipment manufacturers can now produce the equipment that meets the experiment requirements The function can be compared with the imported equipment, and the quotation only needs about half of the imported equipment However, some special equipment, such as temperature shock equipment and rapid temperature change (15 ℃ / min), can not be localized or the equipment produced can not meet the demand Second, the correct use of environmental experimental equipment However, environmental experimental equipment is still a kind of fine and valuable equipment The correct use and operation of environmental test equipment can not only provide the basis for the testing personnel, but also enable the environmental test equipment to operate normally for a long time and extend its service life First of all, when doing environmental experiments, we need to know the sample function, experimental conditions, experimental procedures and experimental skills of the required experiments, the skill function of the applied experimental equipment, and the layout of the equipment, especially the operation and function of the controller Also read the operation manual of the experimental equipment carefully, so as to prevent the abnormal operation of the experimental equipment caused by the operation error and then the damage of the experimental sample and the incorrect experimental data Secondly, the reasonable selection of experimental equipment In order to ensure the normal operation of the experiment, the appropriate equipment should be selected according to the different conditions of the experimental samples, and a reasonable share should be maintained between the experimental samples and the useful volume of the experimental box The volume of the heating sample should not be more than one tenth of the useful volume of the chamber As for the non heating test sample, its volume shall not be more than one fifth of the useful volume of the test box For example, when a 21 'color TV is doing the temperature storage experiment, it can satisfy the demand by choosing a cube of experimental box, but when it is powered on, it can't satisfy the demand Maybe it needs to change to a larger experimental box, because the TV will radiate heat during the operation Third, place the test sample correctly The experimental samples should be placed 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 shall not block the air outlet and return air outlet, and a certain interval shall be reserved for the temperature and humidity sensor In order to ensure the correctness of the experimental temperature Fourthly, the environmental experiment of the medium needed in the experiment should be increased correctly according to the experimental demand If there is a certain demand for water for the damp heat test box, the water resistance for the test box shall not be less than 500 ohm M, usually the water resistivity is 10-100 ohm M, the distilled water resistance is 100-10000 ohm M, and the deionized water resistance is 10000-100000 ohm M, so the water for the damp heat test must be distilled water or deionized water, and it must be fresh, because after touching the water and air, it is easy to encounter two problems Carbon dioxide and dust pollution, water has the nature of dissolving a variety of substances, after a long time, the resistivity should be reduced Nowadays, there is a kind of pure water on the market which is economical and convenient Its resistivity is equivalent to distilled water Fifth, the use of the hot and humid experimental box The wet ball gauze (wet ball paper) used in the damp heat test box is a certain demand, not any gauze can be substituted Because the reading of relative humidity is the difference between the root distance and the temperature and humidity, it is strictly related to the local atmospheric pressure and wind speed at that time The wet bulb temperature is related to the amount of water inhaled by gauze and the external transpiration These are directly related to the quality of gauze, so it is necessary for the wet ball gauze to be a special "wet ball gauze" woven from flax according to the climatic rules Otherwise, it is difficult to guarantee the correctness of the indication of the wet bulb thermometer, that is, the correctness of the humidity There are also clear rules for the placement of other wet ball gauze The length of gauze is 100mm The probe is tightly around the sensor probe The probe is 25-30mm away from the humidity water cup, and the gauze is immersed in the water cup, so as to ensure the correctness of equipment control and humidity 3 There are many kinds of environmental protection experimental equipment, but Zui widely used environmental experimental equipment is high temperature, low temperature and damp heat experimental box Now, the contrast is that the high temperature, low temperature and damp heat experimental box, which integrates high temperature, low temperature and damp heat, is more difficult to repair than other environmental experimental equipment, and has representativeness The following is an example of the high and low temperature humidity and heat test box, talking about the layout of the high and low temperature humidity and heat test box and some common problems and cleaning methods (I) the layout of common high and low temperature humidity and heat test boxes In addition to correctly operating according to the operating procedures, the experimenters also have some knowledge about the layout The high and low temperature damp heat experiment box is composed of box, air circulation system, refrigeration system, heating system and humidity control system The air circulation system usually adopts the layout that can adjust the direction of air supply; the humidification system includes two types: the boiler humidification and the external transpiration; the cooling and dehumidification system adopts the refrigeration layout under the air conditioning condition; the heating system adopts two layouts: the electric heating fin heating and the direct heating of the electric furnace wire; the temperature and humidity test method adopts the dry and wet bulb test method and also uses the direct measurement method of the humidity sensor; The control and display operation interface adopts the methods of temperature and humidity separation independent and temperature and humidity combination controller (II) some common problems and cleaning methods of high and low temperature damp heat test box: 1 In high temperature experiment, if the temperature change can not reach the experimental temperature value, you can check the electrical system and remove the problems one by one If the temperature rises slowly, check the air circulation system to see if the conditioning damper of the air circulation is open normally, otherwise, check whether the motor operation of the air circulation is normal If the temperature overshoot is fierce, the setting parameters of PID need to be set If the temperature rises directly, the over temperature protection, then, the controller is faulty, must replace the control surface   2 If the low temperature can not reach the experimental policy, then you need to investigate the change of temperature It is the slow temperature drop, or the rising trend of temperature after the temperature reaches a certain value The former needs to check whether the operating room is dried before the low temperature experiment, so that the operating room insists on being dry, and then put the experimental samples into the operating room for further experiment, and whether the experimental samples in the operating room are placed Too much, so that the air in the operating room can not be fully circulated After removing the above reasons, we need to think about whether it is the fault in the refrigeration system, so we need to ask the professional personnel of the manufacturer to repair it The appearance of the latter is caused by the poor operation environment of the equipment The environment temperature and the placement direction (the space between the back of the box and the wall) of the equipment shall meet the requirements (there are rules in the operation instructions of the equipment)   3 In the wet and hot experiment, it is shown that the practical humidity will reach 100%, maybe the practical humidity is quite different from the policy humidity, and the value is much lower The appearance of the former is that the gauze on the wet ball sensor is dry, so it is necessary to check whether the water in the water tank of the wet ball sensor is short of water The water level in the water tank is automatically controlled by a water level controller, and check the water supply system of the water level controller Is the water supply normal? Is the operation of water level controller normal It can be that the wet ball gauze will harden due to the long use time, or the pure degree of water supply quality, which will make the gauze unable to absorb water and dry, and only need to replace or clean the gauze to remove the above appearance The appearance of the latter is mainly that the humidification system does not work Check the water supply system of the humidification system to see whether there is a certain amount of water in the water supply system, whether the water level control of the humidification boiler is normal, and whether the water level in the humidification boiler is normal If all of the above are normal, check the electrical control system, which requires professional repair personnel to repair 4 When the equipment suddenly presents faults during the experiment, the corresponding fault display prompt and audible alarm prompt shall be displayed on the control surface The operator can quickly check the type of fault according to the chapter of fault elimination in the operation and application of the equipment, and then ask the professional to eliminate the fault quickly to ensure the normal operation of the experiment There will be other appearances in the use of other environmental experimental equipment, that is, detailed representation, detailed analysis and cleaning The environmental experimental equipment shall be protected and maintained regularly, the condenser of the refrigeration system shall be arranged regularly, the movable parts shall be oiled smoothly according to the instructions, the electrical control system shall be protected and checked regularly, and so on These operations are essential.