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HEAT EXCHANGERS

The world is full of different kinds of heat exchangers. At its simplest, a heat exchanger is a wall-mounted hot-water radiator which heats the air in the room. Heat exchange can be divided into three methods: radiation, conduction and convection.

Radiation

Conduction

Convection

Heat exchangers are based on the transfer of heat via convection, wherein the transfer of heat through the interface is improved by the flow of fluids. This results in forced convection, which is dependent on the physical properties of the fluids (density, viscosity and thermal conductivity) and the flow (shape of flow channel, flow speed and viscosity). The interface (heat exchange surface) keeps the fluids separate, but also simultaneously reduces the transfer of heat from hot to cold.

Forced-convection heat exchangers can be divided into plate and shell-and-tube heat exchangers based on their heat exchange surface and the shape of their flow channel. Heat pipe heat exchanger is a two-phase closed thermosyphon, which operation model can be found here (linkki heat pipe).

Plate heat exchangers are further divided into groups by their type of gasket:

  • Gasketed
  • Semi-welded (every other plate is welded and every other is gasketed)
  • Fully welded (no gaskets at all)
  • Brazed, wherein all gaskets are replaced with soldered joints.

Shell-and-tube heat exchangers are divided into different types in accordance with the TEMA standard. The type of tube (smooth, finned or corrugated ) can improve heat exchange if the fluids so permit:

air and gases => finned tube
dirty liquid => corrugated

For heat exchange, it is essential to achieve a turbulent flow in the flow channel. Plate heat exchangers usually have better heat exchange than tube heat exchangers, but the requirements of the application, such as pressure, temperature, and the properties of the fluids will determine the type of heat exchanger required.

Our current product portfolio includes:

PHE = gasketed heat exchangers
SEMI = semi-welded heat exchangers
DOUBLE GASKET = double-gasketed high-pressure plate heat exchangers
SHELL & TUBE = shell-and-tube heat exchangers
AIR COIL = steam to air or water to air heaters/coolers
HPHE = heat pipe heat exchanger

FOR MORE INFORMATION,
PLEASE CONTACT

Arto Kettunen

Sales