Industrial chiller cooling liquid evaporator classification
The cooling medium of the industrial chiller cooling liquid evaporator is mainly water, and it is mainly divided into shell tube evaporator and tank evaporator. The shell-and-tube evaporator is divided into a liquid-filled shell tube evaporator and a dry shell tube evaporator according to the flow of the refrigerant; the water tank-type evaporator is divided into an upright tube evaporator and a spiral tube evaporator according to the tube group. Snake evaporator.
1. Liquid-filled shell-tube evaporator: Its outer shell is a cylinder welded with steel plates. Tube plates are welded at both ends of the cylinder. The heat-exchange tubes are fixed on the tube plate by welding or expansion. Ammonia refrigerating system Heat exchangers for chiller evaporators are generally seamless steel tubes, Freon refrigeration systems chiller evaporators generally use copper tubes (using low ribs). The refrigerant vaporizes in the space outside the tube, and the refrigerant flows in the tube. In order to ensure that the coolant of the industrial chiller has a certain flow velocity in the pipe, a partition plate is cast in both ends of the cover, so that the coolant is passed through the evaporator in multiple passes.
In order to be able to observe the liquid level in the evaporator, a bypass pipe is arranged between the liquid separator and the housing, and the frost on the bypass pipe indicates the liquid level in the evaporator. Liquid-filled shell-and-tube evaporators are mostly used in chillers for land-based ammonia refrigeration systems. In marine chillers, the liquid may be sucked back by the compressor due to the swaying of the hull. In the Freon refrigeration system chiller, due to the large amount of liquid filled, the cost of the refrigerant is expensive, and the oil in the evaporator of the industrial chiller is difficult to return to the compressor, a dry shell-tube evaporator is preferred.
2. the dry shell tube evaporator: its shape and structure are basically the same with the liquid-filled shell tube evaporator, the main difference is: the refrigerant in the dry shell tube evaporator in the heat transfer tube vaporization absorption, refrigeration liquid The filling volume is very small, about 35% to 40% of the internal volume of the tube group. The liquid refrigerant flows outside the tube. In order to increase the flow rate of the refrigerant, a plurality of baffle plates are installed across the tube bundle in the barrel.
3. vertical tube evaporator: mainly used for ammonia system chiller. It is made of welded seamless steel tubes. The evaporator is a tube unit. According to the requirements of different capacities, it can be composed of hot-dry tube groups. The evaporator tube set is mounted in a rectangular metal box. At the upper end of the pipe group, the upper pipe is connected to the gas separator and the lower pipe is connected to the oil collector. Ammonia enters the evaporator from the middle inlet pipe.
The vertical tube evaporator has good heat transfer performance, large metal consumption, large area, and can only be applied to an industrial chiller of ammonia as a refrigerant, and is used in factories.
4. the spiral tube evaporator: The structure of the vertical tube evaporator is basically the same, the heat exchange tube adopts single-head spiral tube or double-head spiral tube to replace the vertical tube tube bundle, the height is smaller than the vertical tube bundle. It is suitable for use in industrial chillers of ammonia refrigeration systems, cooling water or brine. In addition to the advantages of the vertical tube evaporator, the spiral tube evaporator has better heat transfer performance and compact structure. Compared with the vertical tube evaporator, the spiral tube evaporator has smaller volume and saves metal materials. Replaces the trend of vertical tube evaporators.
5. Serpentine Evaporator: It is a common evaporator for the Freon refrigeration system's small chiller. It consists of one or more sets of copper tubes bent into serpentine coils. The evaporator is immersed in a water tank filled with a coolant (water or salt water, etc.), and an agitator is installed at one end of the tank. The industrial chiller freon liquid is supplied from the upper part of the evaporator and vaporized by absorbing the heat on the heat transfer surface of the coil, and the vapor is sucked by the refrigeration compressor from the lower part through the return air tube. The brine or salt water circulates in the tank under the agitation of the agitator and exchanges heat with the refrigerant flowing in the pipe.