The plate heat exchanger is a new efficient and compact heat exchanger that has developed and extensively used in recent decades. It consists of multiple parallel corrugated-surface thin metal sheets that overlap and are then fixed by lamp plates and bolts. The cold working fluid and the hot working fluid flow through the narrow and winding passage made of two neighboring plates alternately and realize cold and heat exchange through the plates separating the two working fluids.
The plate heat exchanger consists essentially of heat transfer plates, gaskets and a clamping device. Thanks to its structure and heat exchange principle, it is characterized by compact structure, small floor area, high heat transfer coefficient and operation flexibility, wide application range, small heat loss, easy installation and cleaning, etc. The two mediums have a mean temperature difference as small as 1ºC and heat recovery efficiency higher than 99 percent. Based on the same pressure loss, the plate heat exchanger has, compared with a tubular heat exchanger, a heat transfer coefficient two to four times higher, a one-third floor area and two-thirds metal consumption. It is therefore an efficient and energy, material and investment saving advanced heat exchanger. It is now widely used in industrial fields such as chemical industry, petrochemical, food, machinery, central heating, metallurgy, power, ships, paper-making, textile, pharmaceutical industry, nuclear industry, seawater desalination and combined heat and power generation to meet the requirements of processes such as cooling, heating, condensation, concentration, sterilization and residual heat recovery. It has become a highly competitive product in the heat exchanger field or evenly has replaced conventional tubular heat exchangers. With its development, it will be used in more and more fields.
Plate and gasket
Table 1 Plate Materials
| Material name |
Thickness (mm) |
Material grade |
Applicable place |
| Stainless steel |
0.5-0.8 |
304,321,316,316L |
Places with serious corrosion caused by acid or base mediums and places not suitable for chloride ions |
| Commercial pure titanium |
0.5-0.8 |
Ti |
Alkali or salt making places, sea water desalination places, low-temperature places, freezing places or places with chloride-ion corrosion |
| Nickel |
0.5-0.8 |
Ni |
Places resistant to corrosion, hot alkali liquor corrosion, neutral solutions or subacid solutions |
| Acid-resistant steel |
0.5-0.8 |
RS-2, SM0254, HC-276 |
Sulfuric acid field and the fields with acid corrosion |
Table 2 Gasket Materials
| Material name |
Code |
Applicable temperature |
Applicable place |
| NBR |
N |
-20~110ºC |
Water, non-polar oil, mineral oil, lubricating oil, silicon oil, etc. |
| EPDM |
E |
-20~150ºC |
Steam, water, ozone, polar chemical mediums, alcohol, weak acids, weak bases, salt solutions, etc. |
| Chloroprene rubber |
C |
-40~100ºC |
Ammonia, mineral roil, lubricant, freon, etc. |
| Fluororubber |
F |
0~180ºC |
Inorganic acids, bases, mineral oil, halohydrocarbon and oxidant |
| Silicon rubber |
Q |
-40~200ºC |
Food field, etc. |
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