Plate & frame type heat exchanger is a fully welded plate and frame heat exchanger, which consists of a fully welded plate group and removable covers. Four covers can be opened from four directions for the inspection, maintenance and cleaning of the plate group. By adjusting the flow structure and the installation position of the partition, it is suitable for different working conditions. Plate corrugation will match with medium properties. With compact structure, this kind of heat exchanger has high heat transfer efficiency.