Welded plate heat exchangers include semi-welded plate heat exchangers, fully welded block type heat exchanger, fully welded disk and shell heat exchanger, plate coils heat exchanger, platular heat exchanger, and brazed or soldering heat exchanger. This type of heat exchanger works well in high temperature, high pressure, and corrosive fluid applications, which is a weak point in the gasket plate heat exchangers. This type of heat exchanger is usually cleaned by CIP method.