Plate Heat Exchangers were first produced in the 1920s and have since been widely used in a great number of sectors. Plate exchangers are composed of parallel plates that are stacked one on top of the other so that fluid can flow between them.Fluid flows between adjacent plates in the space between them.Through holes at the corners of the plates, hot and cold fluids can alternately flow through the exchanger, so that a plate is always in contact on one side with the hot fluid and on the other with the cold fluid. Plate sizes can range from a few square centimetres (100 mm x 300 mm side) to 2 or 3 square metres (1000 mm x 2500 mm side). From a few square centimetres (100 mm x 300 mm) to 2 or 3 square metres (1000 mm x 2500 mm).
Generally, these plates are corrugated to increase turbulence, the surface for thermal exchange and provide mechanical rigidity to the exchanger. Metal sheets of 0.3 mm to 1 mm thick can be cold forged into corrugated shapes by cold forging. Stainless steel (AISI 304, 316), titanium, and aluminium are the most commonly used materials for the plates. Corrugations on the plates cause the fluid to travel on a tortuous path, creating a space between two adjacent plates B of 1 to 5 millimetres. You can cross the channels in series (a less common solution) or in parallel by making counter-current or current configurations. This configuration is used when the flow rate for each fluid is small, but the heat jump is high; the greatest problem is with a high pressure drop and an imperfect counter-current. Parallel configurations with countercurrent channels are most common for high flow rates with moderate temperature drops. Anytime there is a large difference between the flow rates (or maximum permissible pressure drop) of the two fluids, the exchanger can be run twice by the lower flow fluid (or higher losses) to balance pressure drops or specific flow rates in the channels.