A plate heat exchanger is a type of heat exchanger, also known as a heat transfer device. In this process, heat is transferred from one medium to another without mixing. The plate heat exchanger consists of corrugated plates that are assembled in a specific way and have gaps between them.

Within these intermediate dimensions, two media circulate alternately: the heat absorption medium and the heat diffusion medium. The device is sealed externally and internally to the media, which is achieved in various ways. There are heat exchangers with screw plates, which are expandable and transfer flow differently.

Various types of plate heat exchangers are available. Plate heat exchangers characterized by welded plates are preferred.