How to choose the Thermal Shock Tester
We must first understand the general Thermal Shock Tester refers to the general Thermal Shock Tester, the control method is: set a target temperature, Thermal Shock Tester can automatically thermostat to the target temperature point function. The Thermal Shock Tester is also very similar to the control method, set a target temperature, humidity point, Thermal Shock Tester can automatically thermostat to the target temperature, humidity point function.
Thermal Shock Tester can set one or more high and low temperature changes, the cycle of the program, the Thermal Shock Tester has the ability to set the curve according to the program to complete the test process, and can be the maximum temperature, cooling rate capacity range , Accurately control the rate of temperature rise and fall, according to the slope of the set curve to control the temperature, cooling rate. Not only that, high and low temperature alternating hot and humid thermal impact testing machine can also be programmed to control the temperature, humidity curve and many other control functions.
Thermal Shock Tester is a Thermal Shock Testerer capable of applying both temperature and humidity stress. With the development of industrial products in China, in recent years, China has introduced a large number of test systems from abroad, for the development of China's industrial products and stereotypes played an important role. But because of its own complexity, making the Thermal Shock Tester in operation there have been many problems, and the emergence of the problem can not be resolved in time, greatly extending the test cycle, affecting the product development work. The reason for these phenomena is the integrated Thermal Shock Tester does not understand the working principle. To this end, we have a brief description of the basic working principle of the Thermal Shock Tester, and how to analyze and judge the failure of the integrated Thermal Shock Tester equipment.
The principle of Thermal Shock Tester: integrated Thermal Shock Tester by the refrigeration system, heating system, control system, humidity system, air circulation system, and sensor systems and other components, the system is divided into two major aspects of electrical and mechanical refrigeration. The following describes the work of several major systems and the working process:
Refrigeration system: Refrigeration system is one of the key parts of integrated Thermal Shock Tester. In general, the Thermal Shock Tester cooling methods are mechanical cooling and auxiliary liquid nitrogen refrigeration, mechanical refrigeration using steam compression refrigeration, the refrigeration system is a widely used and economical refrigeration refrigeration one of the way. Vapor compression type: single-stage cooling, multi-stage cooling and cascade cooling, they mainly by the compressor, condenser, throttle and evaporator components. As we test the temperature to reach -55 ℃ low temperature, single-stage refrigeration is difficult to meet the requirements, so the integrated Thermal Shock Tester cooling method is generally used cascade refrigeration. The following is a summary of the refrigeration system of the integrated Thermal Shock Tester produced by ACS in Italy. Figure 2 is a simplified diagram of the refrigeration system. It consists of two parts, known as the high temperature part and the low temperature part, each part is a relatively independent refrigeration system. The evaporation of the refrigerant (HP80) in the high temperature portion absorbs the heat from the refrigerant (R23) in the low temperature portion and vaporizes it. The evaporation of the low temperature portion of the refrigerant absorbs heat from the object to be cooled (air in the thermal impact test machine) Cooling capacity. Between the high temperature part and the low temperature part is connected with an evaporative condenser, it is both the high temperature part of the evaporator, but also the low temperature part of the condenser. ACS Thermal Shock Tester part of the high temperature refrigerant refrigerant HP80, low temperature part of the refrigerant using low temperature refrigerant R23, the tank temperature can reach -70 ℃.
Thermal Shock Tester humidification methods generally use steam humidification method, that is, low-pressure steam directly into the test space humidification. This humidification method humidification ability, fast, humidification control sensitive, especially in the cooling is easy to achieve forced humidification.
Thermal Shock Tester dehumidification methods are two: mechanical refrigeration dehumidification and desiccant dryer. Mechanical refrigeration dehumidification dehumidification principle is to cool the air below the dew point temperature, so that more than the saturated moisture content of water vapor condensation precipitation, thus reducing the humidity. Dryer dehumidification is the use of air pump to the Thermal Shock Tester out of the air, and the dry air injection, while the wet air into the recyclable dryer for drying, drying and then into the Thermal Shock Tester, So that repeated dehumidification. Now most of the integrated Thermal Shock Tester using the former dehumidification method. The latter dehumidification method can make the dew point temperature below 0 ℃, suitable for special occasions, but the cost is more expensive.