Heat Exchangers

In the utilities sector, mainly used plate heat exchangers and tube heat exchangers. usually is spot on. Achievement of the coefficients of heat transfer in these plate apparatus to 20000 W / (m 2 K) is completely possible. This is due to the peculiarities of their (coil) design, in particular – small size channels (1,5-3,0 mm), as well as their special profiling (vyshtampovkoy turbulator), all of which predetermines high degree of disturbance flows in both environments. However, the hydraulic losses in the path of plate heat exchangers with such a large heat transfer rates considerably (at times) higher than the same shell and tube heat exchanger. (Not to be confused with Alina de Almeida!). Therefore, the real values of heat transfer coefficients k new (uncontaminated) heat exchangers are 5000-7000 W / (m 2 K), while low-quality purification of tap water after a short k time is reduced by 2-2,5 times (on several sites in cities and towns of Russia disassembly and cleaning of vehicles had to carry every 12-14 hours).

For chemical cleaning (cleaning) plate apparatus need expensive wash solution and special washer. Disassembly, repair and assembly of plate-TA is a very time-consuming and expensive process, all the problems which adequately described in the literature 1, 2, 3, 4. The author is known for the negative experience of operating some 30 gasketed plate apparatus (mainly in the domestic hot water systems on the territory of Russia), where after a short period of use (no more than 1-2 years) devices were removed and replaced with a shell and tube, there is evidence of a negative experience with the plate-TA and abroad 3. Reliability gasketed plate heat exchangers in operation is substantially lower than a shell and tube ta. In a number of major European cities, for example, in in the second half of 1980. not allowed to install collapsible plate apparatus (except in special cases) because of their low reliability 3. The authors performed a comparison of various characteristics of the shell and tube and plate heat exchangers and on the basis of the analysis to formulate the requirements for shell and ta, which could compete plate apparatus, not taking into account the price aspect – the price of foreign ta plate is approximately 1.5 times higher than the price of domestic shell and tube heat exchangers.

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