[Dezhou + nano photocatalyst + air purifier] what are the advantages of high and low temperature test box products?
Source: website release time: November 6, 2019 14:55:00 reading: 462 [Dezhou + nano photocatalyst + air purifier] high and low temperature test chamber The product has the law of temperature change in simulated atmospheric environment. It is mainly used for the adaptability test of electrical and electronic products, components and other materials in high temperature and low temperature environment. For product design, improvement, identification and inspection.
Temperature fluctuation This index is also called temperature stability. After the temperature is stabilized, it can be controlled within any given time interval, The difference between the maximum and minimum temperatures at any point in the workspace. There is a small difference here. The "workspace" is not a "studio", but a space about 1 / 10 of the length of each side of the chamber from the wall. This indicator evaluates the control technology of the product. [Dezhou + nano photocatalyst + air purifier] temperature range It refers to the limit temperature that can be tolerated and / or reached by the product working room. Generally, it contains the concept of constant control, which should be the extreme value that can operate stably for a relatively long time. The general temperature range includes extreme high temperature and extreme low temperature. The general standard requirements are ≤ 1 ℃ or ± 0.5 ℃. Temperature uniformity The old standard is called uniformity, and the new standard is called gradient. After the temperature is stable, the maximum value of the difference between the average temperature values of any two points in the working space in any time interval. This index can evaluate the core technology of products more than the following temperature deviation index, so many companies' samples and schemes deliberately hide this item. The general standard requirement index is ≤ 2 ℃ Temperature deviation After the temperature is stable, the difference between the average value of the center temperature of the working space and the average temperature value of other points in the working space in any time interval. Although the new and old standards have the same definition and title of this indicator, the test has changed. The new standard is more practical and more demanding, but the assessment time is shorter. General standard requirement index is ± 2 ℃, pure high temperature test chamber above 200 ℃ can be used according to the actual use temperature (℃) ± 2%. Category editing [Dezhou + nano photocatalyst + air purifier] high and low temperature test chamber can be divided into alternating test and constant temperature test according to the test methods and industry standards. Both test methods are upgraded and expanded on the basis of high and low temperature test chamber. The alternating test chamber can set the required high temperature, low temperature and required temperature time in the instrument parameters at one time, and the test chamber will press According to the set procedure, the high and low temperature test chamber is making a fixed temperature to make the test effect closer to the natural climate and simulate the worse natural climate, so as to improve the reliability of the tested samples.
High and low temperature test chambers include lrhs-101b-ljs 450 × 450 × 500 1160 × 1000 × 1610;  lrhs-225b-ljs 500 × 600 × 750 1210 × 1150 × 1870 ; lrhs-504b-ljs 700 × 800 × 900 1260 × 1340 × 2070 ; lrhs-800b-ljs 800 × 1000 × 1000 1370 × 1550 × 2170 ; lrhs-1000b-ljs 1000 × 1000 × 1000 1560 × 1550 × 2170. 
System editor Refrigeration cycle of two single-stage refrigeration system Two stage cascade refrigeration system Three element cascade refrigeration cycle In order to obtain the low temperature below - 20 ℃, the cascade refrigeration system is adopted 1. Limitation of thermophysical properties of refrigerants In the single-stage refrigeration cycle of [Dezhou + nano photocatalyst + air purifier] constant temperature and humidity testing machine, the medium temperature refrigerant is basically R404A. At one atmospheric pressure, its evaporation temperature is - 46.5 ℃ (R22 / - 40.7 ℃), but the heat transfer temperature difference of air-cooled condenser is usually about 10 ℃ (under the forced air cooling cycle, the temperature difference between evaporator and inner box) can only be prepared in the box -Low temperature of 36.5 ℃. Of course, the lowest evaporation temperature of R404A refrigerant can be reduced to - 50 ℃ by lowering the evaporation pressure of compressor. Therefore, to obtain the low temperature of - 50 ℃ and below, the cascade refrigeration cycle of medium temperature refrigerant and low temperature refrigerant must be adopted to make the low temperature of - 50 ℃ ~ - 80 ℃. R23 is generally selected as the low temperature refrigerant, and its evaporation temperature under one atmospheric pressure is generally selected The temperature is - 81.7 ℃. 2. Limitation of pressure ratio of single stage compression steam refrigeration cycle The minimum evaporation temperature of a single-stage vapor compression refrigerator mainly depends on its condensing pressure and compression ratio. The condensing pressure of refrigerant is determined by the type of refrigerant and the temperature of environmental medium (such as air or water). Under normal circumstances, it is in the range of 0.7 ~ 1.8MPa, and the compression ratio is related to the condensation pressure and evaporation pressure. When the condensation pressure is constant, the condensation pressure of the refrigerant is determined, With the decrease of evaporation temperature, the evaporation pressure also decreases correspondingly, which makes the compression ratio rise. It will cause the compressor exhaust temperature to rise, the lubricating oil will become thinner, and the lubrication conditions will deteriorate, and even the phenomenon of coking and cylinder pulling will occur in serious cases, With the increase of compression ratio, the gas transmission coefficient and cooling capacity of the compressor will decrease. The farther the actual compression process deviates from the isentropic process, the power consumption of the compressor will increase, the refrigeration coefficient will decrease and the economy will decrease. 3. For any refrigerant, the lower the evaporation temperature, the lower the evaporation pressure. The lower the evaporation pressure, sometimes it may make it difficult for the compressor to inhale, or make the outside air enter the refrigeration system 4. When the evaporation temperature is too low, some commonly used refrigerants have reached the freezing temperature, so the flow and circulation of refrigerants cannot be realized 5. In order to obtain the required cooling capacity, the suction volume must be increased to make the compressor volume too large 6. Limitation of heat dissipation of compressor coil [Dezhou + nano photocatalyst + air purifier] when the single-stage compressor is working, it is about - 35 ℃, because the coil of the compressor is in the middle of the compressor, which causes a problem. At - 35 ℃, the low pressure of the compressor is negative, that is to say, a vacuum degree is generated, so the heat at the top of the coil can not be dissipated, so the surface of the compressor is very cool It's actually inside, and its temperature is very high (because vacuum is the best insulation medium). It can be seen from the above: the constant temperature and humidity test can adopt single-stage refrigeration cycle or cascade refrigeration cycle system for - 40 ℃ model, but the single-stage refrigeration cycle can reduce the evaporation pressure (about 0.7 atmospheric pressure) by reducing the expansion valve opening of the compressor and reducing the refrigerant flow limit, so as to obtain lower evaporation temperature. This design is based on the system The cooling capacity is only about 0.7-0.8 of the standard), which leads to low refrigeration efficiency and increases the load of the compressor. Moreover, it is easy to cause overheating of the compressor coil and affect the service life of the compressor. Principle selection [Dezhou + nano photocatalyst + air purifier] environmental and reliability test equipment selection should follow the following five basic principles: 1. Reproducibility of environmental conditions It is impossible to reproduce the environmental conditions of nature completely and accurately in laboratory. However, within a certain tolerance range, people can accurately and approximately simulate the external environmental conditions experienced by engineering products in the process of use, storage, transportation, etc., which is summarized in engineering language, that is, "the environmental conditions around the tested products (including platform environment) created by the test equipment should meet the environmental conditions specified in the product test specifications Parts and their tolerance requirements ". For example, the temperature box used for military product test should not only meet the test value and time of high temperature and low temperature specified in national military standards gjb150.3-86 and gjb150.4-86 according to different types of products, but also meet the requirements of temperature field uniformity and temperature control accuracy in test specifications. Only in this way can the reproducibility of environmental conditions be guaranteed in the environmental test. 2. Repeatability of environmental conditions An environmental test equipment may be used for multiple tests of the same type of product, and a tested engineering product may also be tested in different environmental test equipment. In order to ensure the comparability of the test results of the same product under the environmental test conditions specified in the same test specification, the environmental conditions provided by the environmental test equipment must be repeatable 。 In other words, the stress levels (such as thermal stress, vibration stress, electrical stress, etc.) applied by environmental test equipment to the tested products are consistent with the requirements of the same test specification. The repeatability of environmental conditions provided by the environmental test equipment is guaranteed by the national metrological verification department according to the verification regulations formulated by the national technical supervision organization. Therefore, the environmental test equipment must be able to meet the requirements of various technical indexes and accuracy indexes in the verification regulation, and the use time shall not exceed the time limit specified in the verification cycle. For example, in addition to meeting the technical indexes of exciting force, frequency range and load capacity, the widely used electric vibration table must also meet the requirements of accuracy indexes such as transverse vibration ratio, table acceleration uniformity, harmonic distortion, etc. in addition, the service cycle after each verification is two years, and it can only be put into use after passing the re verification for more than two years. 3. Measurement and control of environmental parameters The environmental conditions provided by any environmental test equipment must be observable and controllable. This is not only to limit the environmental parameters within a certain tolerance range and ensure the reproducibility and repeatability of the test conditions, but also necessary for the safety of product test, so as to prevent the damage of the tested product caused by the out of control environmental conditions, which may bring unnecessary The loss. It is generally required in various test specifications that the accuracy of parameter test should not be less than one third of the allowable error of test conditions. 4. Exclusivity of environmental test conditions In each environmental or reliability test, the category, quantity and tolerance of environmental factors are strictly specified, and the penetration of environmental factors not required by the test is excluded, so as to provide accurate basis for judging and analyzing product failure and failure mode during or after the test. Therefore, the environmental test equipment is not allowed to provide the specified environmental conditions Other environmental stress interferences were added to the tested products. Such as table magnetic flux leakage, acceleration signal-to-noise ratio and total root mean square value ratio of in band and out of band acceleration specified in verification regulation of electric vibration table. The accuracy indexes such as random signal inspection and harmonic distortion are all verification items to ensure the uniqueness of environmental test conditions. 5. Safety and reliability of test equipment Environmental test, especially reliability test, has a long test cycle. Sometimes, the test object is military products with high value. During the test process, testers often operate or test around the site. Therefore, the environmental test equipment must have the characteristics of safe operation, convenient operation, reliable use and long service life, so as to ensure the normal operation of the test itself 。 All kinds of protection, alarm measures and safety interlock devices of test equipment should be perfect and reliable to ensure the safety and reliability of test personnel, test products and test equipment itself. Maintenance editor High and low temperature box 1. [Dezhou + nano photocatalyst + air purifier] the temperature and humidity of the high and low temperature laboratory are important factors affecting the device performance, which may cause corrosion of mechanical parts, metal mirror Xiajiang, high and low temperature mechanical parts leading to error or performance end degradation; In the case of high and low temperature, the grating of optical elements such as Shiyan is corroded in the constant temperature electron microscope, focusing lens, aluminum, etc., stray light, noise and even equipment stop working due to insufficient light, thus affecting high and low temperature. Maintenance life should be corrected regularly. 2. When the high and low temperature are used for a period of time, the Ministry of interior will accumulate the guidance of engineers, dust, the best electric constant temperature drying oven, or through regular maintenance engineers, a certain amount of work will be converted to dust jacket within the high and low temperature range, while the radiator will re tighten the heating elements, clean the sealed optical frame window, calibrate if necessary, clean the mechanical parts and necessary lubrication After that, restore the original state, and then carry out the necessary inspection, adjustment and record. 3. High and low temperature working environment, dust and corrosive gas can also affect the flexibility of mechanical system, reduce limit switches and buttons. The reliability of optical coupling is one of the reasons for the corrosion of aluminum parts. Temperature is high, low temperature is fast, usually it is best not to add water, in order to avoid the impact on the machine. Maintenance of constant temperature and humidity box 1. Replace the bulb with wet cloth in the laboratory When the test is not clean cloth or hard surface, or complete the temperature control, continue to do the temperature and humidity control of the ball, you must change the cloth before the test. Cloth about 3 months of testing to replace 1, change the temperature when the body is clean cloth [i.e., temperature sensor, replace with a new test application first clean cloth. 2. Test room and water adjustment level of wet bulb temperature and humidity The water level of the water pipe is not too high, the water overflow pipe or the water absorption rate is low, so that the wet cloth ball test is abnormal, affecting the accuracy of the wet bulb, and maintaining about 6 can be sufficient water level. The water level of water pipe can be adjusted, and the high and low water tanks can be adjusted. Two or three times, almost every test needs to be done to check and replenish water. 3. Inspection of over temperature protection device in laboratory Laboratory operation, set the maximum value of over temperature protection plus 20 ℃ ~ 30 ℃. When the internal test temperature rises to the set value of the over temperature protection, the heater of the power supply stops, and the "overheat" overheat warning light is on, but the fan is still running. If it is operated for a long time and unattended, it is necessary to check the real over temperature protection before operation, whether it is correct [the wet bulb temperature protection device should be set at 120 ℃. 4. Dust removal test chamber condenser The condenser should be maintained regularly every month. The dust attached to the condenser net should be inhaled and cleaned by vacuum cooling or sprayed with high-pressure air. 5. External cabinet for laboratory cleaning and maintenance 1) The impurities in the operation of the laboratory should be moved by before. 2) The distribution room should be cleaned more than once a year. The cleaning and vacuum cleaner can be used for indoor dust and can be inhaled. 3) The external fuel tank must be cleaned once, for a year or more, and can be cleaned with soap and water. 6. Inspection and maintenance laboratory of humidifier The water in the humidifier should be changed to once a month to ensure clean water. The water pan of the humidifier should be cleaned once a month to ensure smooth water flow. Many laboratories use water, but still hope that the relevant monthly cleaning of glass is actually very simple. Maintenance editor Here we talk about the high and low temperature series of test equipment, including: high and low temperature test chamber, high and low temperature alternating test chamber, constant temperature and humidity test chamber, high and low temperature humidity and heat test chamber, temperature impact test chamber, etc., the same refrigeration core of these equipment compressor. The quality of equipment test system is directly related to the control performance of compressor. As the core part of temperature testing machine, the maintenance of refrigeration compressor is particularly important. Below, still measure on high and low temperature series of test equipment compressor maintenance, summed up the following experience. First of all, in the laboratory environment, we need to choose a good installation site, which means that the compressor of high and low temperature series test equipment can use the air system correctly. If the test environment of the test equipment has not been planned in advance, it is not known that such a hasty result will lead to compressor failure and maintenance difficulties and poor quality of compressed air in the future. 1. Since the compressor has an air circulation system, if there is much dust in the air around the equipment, it is necessary to add a filter device. At the same time, the air is absolutely not allowed to contain combustible gas and corrosive gas, so as to avoid explosion or internal corrosion. Overall, to ensure that the relative humidity of the air is low, often a small amount of ash, good ventilation. 2. The compression performance should not be subjected to high temperature, and the ambient temperature should be lower than 30 ℃. If the temperature is too high, the output air volume of the compressor will be reduced. 3. The equipment should be placed in a spacious place, and the space is narrow, which is not conducive to the later repair and maintenance. In particular, the radiator (condenser) of the cryocooler of the compressor should be regularly maintained and kept clean. 4. If the working site voltage of the test box should be stable, the current will be too large or too small, and the compressor will be damaged if it works under this condition. 5. The test box shall be built on a hard floor, and the foundation plane shall be leveled before installation to avoid noise caused by vibration of compressor. In the process of high and low temperature test equipment, correct operation and reasonable troubleshooting are conducive to the maintenance and extension of service life of compressor. 1. During the test, the compressor should not be started frequently, and the interval time of compressor starting is 15 minutes. 2. During the commissioning of the equipment, the running direction of the compressor shall be strictly checked. In case of reverse rotation, the machine shall be shut down immediately, the power supply shall be cut off, any two of the three-phase lines shall be switched on again, otherwise the compressor will be damaged. 3. During the operation of the test equipment, the compressor safety valve and other protection systems are regularly inspected to ensure its sensitivity and reliability. Using editing 1. During the environmental test of high and low temperature test chamber, it is necessary to be familiar with the sample performance, test conditions / test procedures and test technology, the technical performance of the test equipment used, and the structure of the equipment, especially 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, resulting in the damage of the test sample and the incorrect test data. 2. Reasonable selection of high and low temperature test chamber test equipment. In order to ensure the normal operation of the test, the appropriate test equipment should be selected according to the different conditions of the test sample, and a reasonable proportion should be maintained between the test sample and the effective volume of the test chamber. For the test of heating test sample, its volume shall not be greater than one tenth of the effective volume of the test chamber. For non heating test samples, the volume shall not be greater than one fifth of the effective volume of the test chamber. For example, when a 21 'color TV is used for temperature storage test, a test box with a cubic volume can meet the requirements, but when it is powered on, it can't meet the requirements. A larger test box should be replaced, because the TV will radiate heat when it works. 3. Place the test sample correctly. The test samples of high and low temperature test chamber should be placed more than 10 cm away from the box wall, and multiple samples should be placed on the same plane as far as possible. The sample should not block the air outlet and return air outlet, and a certain distance should be left for the temperature and humidity sensor. To ensure the correct test temperature. 4. Use of damp heat test chamber. There are certain requirements for wet bulb gauze (wet bulb paper) used in the damp heat test chamber. Not any gauze can replace it, because the reading of relative humidity is the root distance and the difference between temperature and humidity. Strictly speaking, it is also related to the local atmospheric pressure and wind speed at that time. The indication value of wet bulb temperature is related to the amount of water absorbed by gauze and the surface evaporation. These are directly related to the quality of the gauze, so the meteorological provisions, wet ball gauze must be flax woven into a special "wet ball gauze.". Otherwise, it is difficult to ensure the accuracy of the indication of the wet bulb thermometer, that is, the accuracy of the humidity. In addition, the placement of wet ball gauze is also clearly specified. The length of gauze is 100 mm, tightly wind the sensor probe, and the probe is 20-30mm 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. 5. For the environmental test of adding medium in the test, it should be added correctly according to the test requirements of high and low temperature test chamber. If there are certain requirements for the water used in the damp heat test chamber, the water and electricity resistance of the test box shall not be lower than 500 ohm, the resistivity of tap water shall be 10-100 ohm, the resistance of distilled water shall be 100-10000 ohm, and the resistance of deionized water shall be 10000-100000 ohm. Therefore, distilled water or deionized water shall be used, and fresh water shall be used, because water is easy to be exposed to oxygen after contacting with air Carbon and dust pollution, water can dissolve a variety of substances, after a long time, the resistivity will decline. There is a kind of pure water on the market, which is more economical and convenient. Its resistivity is equivalent to distilled water. Differential editing The difference between high and low temperature test chamber and high and low temperature alternating test chamber mainly lies in control part and refrigeration part. The control part of the high and low temperature test box is mainly controlled by digital display instrument, while the high and low temperature alternating test box is controlled by programmable controller. The digital display instrument is generally controlled manually, and the command that can be executed is generally single time, while the programmable controller is fully automatic control. The parameters to be set and the number of tests can be set in advance, and then according to the settings Set the program to work. The refrigeration part of high and low temperature test chamber is relatively simple, as long as it can be kept constant at a certain temperature. The high and low temperature alternating test chamber needs to measure a certain amount of cooling capacity, so as to output different cooling capacity at different temperature points to realize alternating. Their box structure and technical parameters are basically the same. Digital display instrument Digital display instrument Safety knowledge editor 1、 When the test box is installed, the enclosure must be grounded. If the test box is not grounded, once there is leakage, there will be a risk of electric shock;  2、 Do not run the equipment before it is installed, and make sure that it can be installed to the side before conducting the test;  3、 If the heating sample is placed in the box, please use the external power supply instead of the local power supply directly;  4、 The operation of the cabinet will produce dangerous current, and non professionals are not allowed to open the cover plate of the electric control cabinet;  5、 If the high and low temperature test chamber is not equipped with humidification function, pay attention to the differences in use and requirements when reading the instructions;  6、 When the machine is running, all kinds of motors and fans are started according to the instructions under the control of the controller. Do not touch the components that are temporarily in static state by hand to prevent the components from starting suddenly and causing personal injury. If it is necessary to work close to the rotating parts, please cut off the main power switch and ensure that the protective devices are in good condition;  7、 It is forbidden to move the test box when there is a sample inside, otherwise the sample may reverse or fall;  8、 Before use, make sure that the high and low temperature test box has been fixed, that is, the caster is off the ground and the feet are on the ground. Otherwise, the test box will move accidentally under external force.  Note editor Danger and personal safety information 1. High temperature scald The temperature in the high and low temperature test chamber is very high during the high temperature test. During the test or at the end of the test, special care should be taken to open the door to avoid scalding. When the refrigerator works, the temperature of the exhaust copper pipe is very high. Do not touch it during operation to avoid scalding. 2. Hypothermia and frostbite The temperature in the high and low temperature test chamber is very low during the low temperature test. During the test or at the end of the test, special care should be taken to open the door to avoid frostbite. 3. Electric shock Although the equipment has sound anti electric shock measures, but still need to pay attention, especially the electrical control system, do not touch the electrical parts under working conditions. Installation safety information 1. Power supply The power supply of high and low temperature test box uses three-phase five wire system, and the equipment cable is four core wire, three phase wire and one zero wire. Please make sure the zero line is distinguished. Due to partial load of the equipment and single-phase control system, wrong connection of zero line will lead to equipment failure and damage. The grounding wire of the equipment is equipped with grounding pole. Ensure that the equipment is well grounded to make the equipment safe and reliable. Wrong connection of zero line and ground wire will lead to abnormal operation of equipment. The cable needs to be extended due to the user's site and other factors. Please ensure that the rated parameters of the extension cord and power supply can meet the power supply requirements of the product. 2. Venue This equipment will produce a lot of heat during use. Please install the equipment in a well ventilated place. Do not use the equipment near flammable materials or explosive environment. Do not use in strong magnetic field and strong vibration environment. Use safety information Do not connect the power supply of the test object into the power supply of the equipment, otherwise the power load of the equipment will be increased. Unless the equipment has a power interface for the test object. It is strictly forbidden to test inflammable, explosive, highly corrosive and strong radiation articles. Do not carry or overhaul the equipment when it is powered on or during operation. Measurement items, methods and calculation of high and low temperature test chamber High and low temperature test chamber is the necessary environmental test equipment in various industries. It is mainly used to test and determine the parameters and performance of electronic electricians, materials and other products after high temperature, low temperature or constant test. In measurement, customers should pay attention to the following matters: A. Metrological characteristics Temperature and humidity deviation, temperature and humidity fluctuation, temperature and humidity uniformity. B. Explanation of terms 1. Uniformity: the difference between the test points (temperature and humidity) at a certain time in the working space when the environmental test equipment is in a stable state. (simply defined as the temperature difference between points). 2. Fluctuation: the variation of the parameters of the center point of the working space with time under the stable state of the environmental test equipment. (it is simply defined as the runout value of a point). 3. Deviation: the upper and lower deviation between the measured maximum value and the measured minimum value of each measuring point in the working space and the nominal value under the stable state of the equipment. C. Measurement method 1. The measurement is carried out under no-load condition. If there is a load, the load shall be stated in the certificate. 2. Generally, the upper limit, lower limit and central point of equipment application range should be selected for measuring turbidity and humidity points, and the commonly used temperature and humidity points can also be selected according to the user's needs. 3. Location of measuring points: when the equipment volume is less than 2m3, there are 9 temperature points, 3 Humidity points, and the equipment volume is greater than 2m3, 15 temperature points and 4 humidity points. Processing method editing The high and low temperature test chamber is the product placed at the specified temperature and humidity, to see the high temperature, low temperature and humidity resistance of the product, then the constant temperature and humidity machine has the ability of heating, cooling, humidifying and dehumidification at the same time. [Dezhou + nano photocatalyst + air purifier] temperature system is divided into humidification and dehumidification. In general, humidifying steam is used to humidify the space. This humidification method has the advantages of quick humidification, sensitive humidification control, and easy to realize forced humidification in cooling. There are two dehumidification methods: mechanical refrigeration dehumidification and drying dehumidification. The dehumidification principle of mechanical refrigeration dehumidification is to cool the air below the dew point temperature to condense and precipitate water vapor greater than the saturated moisture content, thus reducing the humidity. Desiccator dehumidification is to use the air pump to draw out the air in the test chamber, and inject the dry air. At the same time, the wet air is sent to the recyclable drying for drying. After drying, it is sent to the test chamber again and again, so that the dehumidification can be carried out repeatedly. The former dehumidification method and the latter dehumidification method can make the dew point temperature below 0 ℃. It is suitable for occasions with special requirements, but the cost is relatively high. The heating device is used to control the constant temperature and humidity machine [Dezhou + nano photocatalyst + air purifier] high and low temperature test box. It is the key link of temperature rising. When the controller gets the temperature rising command, the controller will output voltage to the relay, and about 3-12v DC will be added to the solid-state relay. Its AC end is equivalent to the wire connection. The contactor is also pulled in, and the two ends of the heater have voltage Its heating, driven by the circulating fan, brings the heat to the box, so that the temperature of the constant temperature and humidity machine will rise, and the temperature will quickly reach your set value; the controller can adjust the heat by adding on-off of the solid-state relay; we can adjust the calorific value by looking at the heating output on the screen of the constant temperature and humidity machine; this is the temperature control above 89 degrees; how to control the temperature stability below 89 degrees? Constant temperature and humidity machine is through solid-state relay heating output on one side; on the other hand, it achieves dynamic balance through refrigeration cycle of compressor; the temperature is constant. Cooling is an important part of high and low temperature test chamber, and it is an important parameter to judge the performance of a constant temperature and humidity machine. It consists of compressor, condenser, throttling device and evaporator. The compressor is the heart of the refrigeration system. It inhales low-temperature and low-pressure gas, turns into high-temperature and high-pressure gas, condenses into liquid to release heat, and takes away heat through the fan. Therefore, under the constant temperature and humidity machine, there is hot air under it, and then it becomes low-pressure liquid by throttling, then it becomes low-temperature and low-pressure gas through evaporator, and finally returns to the compressor; the refrigerant absorbs heat in the evaporator The gasification process is heavy and absorbs heat to achieve the purpose of refrigeration and complete the cooling process of constant temperature and humidity machine. [Dezhou + nano photocatalyst + air purifier] the relative humidity of high and low temperature test chamber is the ratio between absolute humidity and maximum humidity. Its value shows how high the water vapor saturation is, and its unit is%. The relative humidity of the air is 100%. A relative humidity of 50% of the air contains water vapor up to half of the saturation point of the air at the same temperature. Water vapor in air with relative humidity over 100% generally condenses. With the increase of temperature, the more water can be contained in the air, that is to say, with the same amount of water vapor, the higher the temperature, the lower the relative humidity. Therefore, it is necessary to provide temperature data as well as relative humidity. The dew point can also be calculated from relative humidity and temperature. The humidification system is roughly the same as the heating system; the high and low temperature test box generator is the process of heating water into steam by the heater; the purpose of humidification of constant temperature and humidity machine is completed. The dehumidification system is also completed by the refrigeration system, and the evaporator is placed in the constant temperature and humidity test chamber; when it is relatively cold, the high humidity gas in the constant temperature and humidity machine will condense into liquid when meeting with cold objects; in this way, the high humidity gas in the box will be very few, so as to achieve the purpose of dehumidification.