Application of Dawosi chiller in vacuum furnace industry

vacuum furnaceIt is a type of inert gas (mainly nitrogen and helium) environment,Melting polycrystalline materials such as polycrystalline silicon using graphite heaters.Equipment for growing dislocation free single crystals using the Czochralski method.Vacuum furnaces have extremely strict temperature requirements.For example:furnace bodyprocessingtemperatureIf the temperature of the furnace cannot be effectively controlled,The furnace body will deform due to high temperature.It will inevitably affect the size changes of the equipment, resulting in the appearance of unqualified products; At the same time, long-term high-temperature operation of the furnace material, uneven heating and cooling, will reduce the service life of the furnace and cause losses.

This requires a professional and stable cooling water system to meetvacuum furnaceThe cooling and cooling requirements are necessary to maintain the normal operation of the furnace equipment, so as not to cause equipment deformation and affect the growth of silicon crystals due to high temperature of the furnace equipment.

ShenzhenDavosi provides valuable refrigeration system engineering solutions and offers multiple sets of refrigeration solutions-The core solution provider series of chillers is suitable for sintering furnaces, annealing furnaces, diffusion welding furnaces, hot pressing furnaces, gas quenching furnaces, brazing furnaces, single crystal furnaces, isostatic presses, quenching furnaces, electric arc furnaces, melting furnaces, suspension furnaces, plasma sintering furnaces, etc. The cooling capacity is10KW-300KWThe chiller can be either an all-in-one machine or a customized split type chiller.

vacuum furnaceThe system often adopts an open loop system. The system consists of a circulating water tank, a cooling water circulating pump, an emergency cooling water tank, plate heat exchangers, etc. A crucial aspect of the system is the need to install a circulating water tank with a large effective volume. This tank is only used as a water pump suction tank during normal operation of the system. In emergency situations such as power outages, the chiller or cooling tower will stop running and cannot be used forvacuum furnaceWhen the system provides refrigerant, the cooling water circulation pump is equipped with emergency electricity to continue working, circulating the water in the pipe network and water tank. As the specific heat of water is greater than that of silicon, the heat of high-temperature silicon in the ingot furnace is absorbed by the water in the circulating water tank, thereby reducing the temperature of the ingot furnace and ensuring that the furnace body is not damaged or even exploded during power outages. The determination of the water storage capacity of the circulating water tank is based on cooling all the silicon materials in the furnace to a safe temperature, so that the temperature of the water in the tank does not rise to a level that the cooling water system pipeline and equipment cannot tolerate. The cooling water system must bevacuum furnaceThe circulating water pump is equipped with an emergency power supply, which generally uses a diesel generator. In order to ensure that there is still cooling water flowing through the furnace before the diesel generator is started, it is generally necessary tovacuum furnaceA high-level emergency cooling water tank is installed in the system. In the event of a power outage, the water in this tank flows through the furnace body by gravity to cool the furnace body. The circulation system process is shown in the diagram1.

　　 The above is about the ingot furnacevacuum furnaceA general description of the system. Due to the different geographical locations of the project, different methods will be adoptedvacuum furnaceThe refrigerant of the system is used to save operating costs, and the inlet temperature of the cooling water for the ingot furnace is generally required≤30℃, so when the wet bulb temperature in the summer of the project location is low, only the cooling tower can be used as the refrigerant to meet the requirements of the inlet water temperature of the ingot furnace cooling water; When the wet bulb temperature in the project area is high in summer, a chiller unit is needed to provide refrigerant to meet the requirements of the cooling water inlet temperature for the ingot furnace. Below, the author will introduce these two systems.

　 System 1: Regions with lower summer wet bulb temperatures such as the northwest. The summer wet bulb temperature in such areas can≤24℃, the outlet temperature of the cooling tower in summer can be ≤28If the temperature is ℃, the effluent from the cooling tower can be used as the refrigerant, and it can be cooled by a plate heat exchangervacuum furnaceThe water temperature drops to≤30℃, thus meeting the requirements of the ingot furnacevacuum furnaceinlet water temperature≤30The requirement of ℃. However, it should be noted that in areas with strong sandstorms and harsh weather conditions, ordinary open towers are easily affected by sandstorms, and closed cooling towers are more suitable. This system is more energy-efficient.

System 2: In areas with high wet bulb temperatures during summer such as central and southern regions, two-stage plate heat exchangers can be used to provide cooling water for ingots. The primary side cooling source of the first stage plate heat exchanger uses cooling water (produced by a cooling tower), while the primary side cooling source of the second stage plate heat exchanger uses chilled water (produced by a chiller). In winter and transitional seasons, the chiller is not turned on, only the cooling tower is turned on, and the effluent from the cooling tower is used as the refrigerant. During summer and transitional seasons, the cooling water from the ingot furnace first passes through the first stage plate heat exchanger for heat exchange, and then enters the second stage plate heat exchanger after the water temperature drops by a certain degree. The chilled water is used as the refrigerant tovacuum furnaceCool to the required inlet temperature of the ingot furnace.