Definition of heat exchanger

　　A heat exchanger is a device that transfers some of the heat from a hot fluid to a cold fluid, i.e., a large closed vessel filled with water or other media, while having pipes running through it. The hot water is allowed to flow through the pipe.

　　Due to the temperature difference between the hot water in the pipe and the hot and cold water in the container, a heat exchange will be formed, that is, the physical heat balance of the junior high school, the heat of the high temperature object is always transferred to the low temperature object, so that the heat of the water in the pipe is exchanged to the cold water in the container, the heat exchanger is also known as a heat exchanger.

　　Heat exchanger classification and structure

　　Heat exchangers can be classified by use as.

　　Cooler, condenser, heater, heat exchanger, reboiler, steam generator, waste heat (or waste heat) boiler.

　　According to the heat exchange method can be divided into.

　　Direct contact heat exchanger (also called hybrid heat exchanger), heat storage heat exchanger and inter-wall heat exchanger.

　　The following is a description of the heat exchanger classified according to the heat transfer mode.

　　1) Direct contact heat exchanger

　　Direct contact exchanger is dependent on direct contact between cold and hot fluids and heat transfer, this heat transfer method to avoid heat transfer between the wall and its two sides of the dirt heat resistance, as long as the contact between the fluid is good, there is a large heat transfer rate.

　　Therefore, wherever fluids are allowed to mix with each other, mixed heat exchangers can be used, such as gas washing and cooling, cooling of circulating water, mixed heating between steam and water, steam condensation, etc.. It is applied throughout the chemical and metallurgical enterprises, power engineering, air conditioning engineering and many other production sectors.

　　Commonly used mixed heat exchanger are: cooling tower, gas scrubber tower, jet heat exchanger and mixed condenser.

　　2) Heat storage heat exchanger

　　Accumulator heat exchanger is used to carry out heat storage type heat exchange equipment. Solid filler is installed inside to store heat.

　　Generally with refractory bricks and other fire lattice (sometimes with metal waveform belt, etc.).

　　Heat exchange is carried out in two stages.

　　In the first stage, the hot gas passes through the fire lattice, and the heat is transferred to the fire lattice and stored up.

　　In the second stage, the cold gas passes through the fire lattice and receives the heat stored in the fire lattice and is heated.

　　These two stages alternate. Usually two heat accumulators are used alternately, i.e., when the hot gas enters one vessel, the cold gas enters the other. Commonly used in the metallurgical industry, such as the heat storage chamber of steelmaking flat furnaces.

　　Also used in the chemical industry, such as gas furnaces in the air preheater or combustion chamber, artificial oil plants in the thermal storage cracking furnace.

　　3) Inter-wall heat exchanger

　　This type of heat exchanger, hot and cold between the two fluids separated by a metal, so that the two fluids do not mix and heat transfer.

　　In chemical production, hot and cold fluids often can not be in direct contact, so the wall heat exchanger is commonly used as a heat exchanger.