Brazed heat exchanger is an evolution of detachable heat exchanger, the sealing material is changed from rubber pad to copper, and all the plates are combined together by copper solder. Brazed plate heat exchanger is one of the new equipment in the field of heating and cooling. Brazed heat exchanger does not have sealant pad, all the plates are made of high temperature melted and welded copper foil, the plate has a unique herringbone corrugated design, can make the fluid in low flow rate also achieve the effect of turbulence, heat transfer efficiency is high, brazed plate heat exchanger sizing is usually small, mainly used in high temperature and high pressure, rubber pad can not adapt to the working conditions. It also has certain disadvantages, brazed heat exchanger can not be separated to clean, can not be repaired, the price is slightly higher.
Tubular exchanger is the most widely used heat exchanger on chemical and alcohol production. It is mainly composed of shell, tube plate, heat exchange tube, head, baffle and so on. Required material, can be made of ordinary carbon steel, copper, or stainless steel.
During heat exchange, a fluid enters through the connecting pipe of the head, flows in the pipe, and flows out through the outlet pipe at the other end of the head. Another fluid enters by the nozzle of the shell and flows out from another nozzle on the shell. This is called the shell process.
The structure of the tube heat exchanger is simple, compact and cheap, but the outside of the tube can not be cleaned mechanically. The heat exchanger tube bundle is connected to the tube plate, which is welded to both ends of the shell respectively, and is connected to the top cover. The top cover and the shell are provided with a fluid inlet and outlet pipe.
A series of baffles perpendicular to the tube bundle are usually arranged outside the tube. At the same time, the connection between tube and tubesheet and shell is rigid, while outside the tube are two kinds of fluid with different temperature. Therefore, when the temperature difference between the tube wall and the shell wall is large, due to the thermal expansion of the two are different, a large thermal stress is generated, so that the tube twists or loosens the tube from the tube plate, or even destroys the heat exchanger.
Murphy plate finned tube heat exchanger has some obvious advantages in operation, especially in the field of air to air heat transfer, especially in the field of ultra-high temperature air to air heat transfer. To a certain extent, it has become the upgrading product of the tube, heat pipe and finned tube heat exchanger.
The main characteristics of Murphy plate finned tube heat exchanger: the finned tube heat exchanger can be designed with elastic structure, which can effectively solve the problem of its thermal expansion; there are rich test and actual operation data as support, through constant correction of the calculation formula, the calculation error is within 5%, and more than 95% of the equipment operation can reach the design parameters.
The plate heat exchanger is composed of a set of corrugated metal plates with four corner holes for the passage of two liquids for heat transfer. The metal sheet is mounted in a frame having a fixed plate and a movable pressing plate on one side and clamped by a clamp bolt. A gasket is placed over the plate to seal the fluid passages and direct fluid flow alternately into the respective passages to form a heat exchange.
The flow, physical properties, pressure drop and temperature difference of the fluid determine the number and size of the plates. The corrugation of the plate not only increases the degree of turbulence but also forms a number of support points sufficient to withstand the pressure difference between the media.
The metal plate and the movable compression plate are suspended on the upper guide bar and positioned by the lower guide bar, while the rod end is fixed on the support. On the column, but if one or both of the liquids pass through the heat exchanger more than once, the interface should be on the fixed plate and the movable compression plate. In most cases, one-way is used, and all the pipes are connected to the fixed platen. On, check the shoes to open the heat exchanger without disassembling the pipe.
