A brief introduction to the types and advantages and disadvantages of tubular heat exchangers

Tube heat exchanger structure is relatively simple, compact, inexpensive, but outside the tube can not be mechanically cleaned. This type of heat exchanger tube bundle connected to the tube plate, the tube plate were welded to the ends of the shell, and connected to its top cover, the top cover and shell with fluid import and export receiver. Usually outside the tube device a series of baffles perpendicular to the tube bundle. At the same time both the tube and the tube plate are connected to the shell rigidly, while inside and outside the tube are two different temperatures of the fluid. Therefore, when the tube wall and shell wall temperature difference is large, due to the difference in thermal expansion between the two, resulting in a large temperature difference stress, so that the tube twist and bend or make the tube loose from the tube plate, or even destroy the heat exchanger. In order to overcome the temperature difference stress must have temperature compensation device, generally in the tube wall and shell wall temperature difference of more than 50 ℃, for safety reasons, the heat exchanger should be temperature compensation device. But the compensation device (expansion joint) can only be used in the shell wall and tube wall temperature difference of less than 60 ~ 70 ℃ and the shell process fluid pressure is not high. General shell pressure of more than 0.6Mpa due to the compensation ring is too thick, difficult to expand, lose the role of temperature compensation, should consider other structures.

2 floating head type
Heat exchanger of a tube plate with a flange connected to the shell, another tube plate is not connected to the shell, in order to make the tube heat or cooling can be freely expanded, but in this tube plate connected to a top cover, called the "floating head", so this heat exchanger called Floating Head Heat Exchanger. Its advantages are: the tube bundle can be pulled out in order to clean; the expansion of the tube bundle does not change the shell restraint, so when the temperature difference between the two heat exchanger media, not due to the difference in the amount of thermal expansion of the tube bundle and shell and temperature stress. The disadvantage is the complex structure, high cost.
3 stuffing box type
This type of heat exchanger tube bundle can be free to expand one end, the structure is simpler than the floating head type, the cost is also lower than the floating head type. But the shell process of media leakage may be, the shell process should not deal with volatile, flammable, explosive and toxic media.
4 U-tube type
U-shaped tube heat exchanger, each tube is bent into a U-shaped, fixed at both ends of the same tube plate, each tube are free to expand and contract, thereby solving the problem of thermal compensation. The tube range is at least two courses, the tube bundle can be withdrawn for cleaning, and the tubes can be freely expanded. The disadvantage is that it is difficult to clean the inner wall of the tubes, difficult to replace the tubes, and few tubes are arranged on the tube plate. The advantages are simple structure, light weight, and suitability for high temperature and pressure conditions.
configured so that they do not collide with each other, which not only overcomes the problem of damage caused by mutual collision between floating coil Heat Exchangers, but also avoids the problem of easy scaling of ordinary shell and tube heat exchangers.

Vortex hot film heat exchanger performance characteristics.
1. energy efficient, the heat exchanger heat transfer coefficient of 6000-8000W/m2.0C.
2. All stainless steel production, long service life, up to 20 years, free replacement of heat exchanger quality problems within ten years.
3. change the laminar flow for turbulent flow, improve the heat transfer efficiency, reduce the thermal resistance.
4. Fast heat transfer, high temperature resistance (400 ℃), high pressure resistance (2.5Mpa);
5. compact structure, small footprint, light weight, easy installation, saving civil construction investment.
6. flexible design, complete specifications, practical relevance, saving money.
7. Wide range of application conditions, applicable to a wide range of pressure, temperature and a variety of media heat exchange.
8. Low maintenance cost, easy to operate, long scale cleaning cycle, easy to clean.
9. Using nano thermal film technology, significantly increase the heat transfer coefficient.
10. Broad application fields, can be widely used in thermoelectric power, factories and mines, petrochemical industry, urban central heating, food and medicine, energy and electronics, machinery and light industry, etc.

6 Folded baffle
In order to improve the shell process fluid flow rate, often installed in the shell of a certain number of baffles with the tube bundle perpendicular to each other. Folded baffle not only can prevent fluid short circuit, increase the fluid flow rate, but also force the fluid according to the prescribed path of multiple misflux through the tube bundle, so that the degree of turbulence is greatly increased. Commonly used folded baffle has a circular-shaped and disc-shaped two, the former is more commonly used.
7 multi-shell process
Tube heat exchanger must be considered from the structure of the impact of thermal expansion, to take a variety of compensation methods to eliminate or reduce thermal stress, according to the temperature difference compensation measures taken.