Structure and Working Principle of Plate Heat Exchangers

A plate heat exchanger is constructed by stacking thin metal heat transfer plates that have been pressed into shape. These plates create narrow rectangular flow channels, through which heat is exchanged between fluids in alternating channels. The four corner holes in the plates and sealing gaskets form manifolds for distributing and collecting the fluids, simultaneously separating the hot and cold streams. The working fluids flow through the narrow, winding channels between each pair of plates.

Hot and cold fluids pass through the flow channels in turn, separated by a layer of plate through which heat exchange occurs. Sealing gaskets between the plates ensure fluid tightness and direct the flow, creating separate channels for the hot and cold fluids. Heat is exchanged with the adjacent plates to achieve the desired temperature for the user. The two heat transfer media flow into their respective channels, forming counter-current or co-current flow to exchange heat through each plate.

Each heat transfer plate has holes at its four corners. When assembled into a plate pack, these holes form fluid distribution and collection manifolds. After heat exchange, the hot and cold media return through their respective manifolds for recycling. The heat transfer plates are stamped with various corrugated patterns, most commonly V-shaped grooves, to prevent fouling on the plate surfaces.

The main components of a plate heat exchanger include heat transfer plates, sealing gaskets, pressure plates, guide rails, and clamping bolts.

· Heat transfer plates: The primary components for heat exchange, typically embossed with a herringbone pattern. Their materials vary according to the fluid medium, with stainless steel and titanium being commonly used.

· End pressure plates: Clamp and secure all heat transfer plates to prevent fluid leakage.

· Sealing gaskets: Provide a seal between the plates; most leaks in plate heat exchangers are caused by gasket misalignment or aging.

· Clamping bolts: Secure the end plates and heat transfer plates together.