Abstract: A heat exchanger device and method of making same disclosed has a heat exchanger core and a stack of inner plates with alternating hot and cold flow fluid passages producing diagonal flow therethrough. One embodiment adds a pair of core retaining plates with end portions extending beyond the core with apertures at precise locations to connect with connectors of equipment to which it is coupled and the other embodiment has end connectors that weld to the core to provide straight in line fluid flow.

Abstract: A heat exchanger apparatus (which can be a boiler) includes a plurality of tanks assembled together. Each of the tanks is a separate structural member that provides opposed parallel surfaces. The surfaces carry a plurality of parallel longitudinally extending U-shaped grooves that are correspondingly placed. When the grooves are aligned, they form a first plurality of channels for holding a first fluid system. A load-carrying portion of each plate-like tank extends between the opposed surfaces. A second plurality of fluid conveying channels carries a second fluid system through the load carrying portion of the tank. Fluid inlets and outlets are provided for each fluid system. The design of the present invention provides an improved plate-like tank structure that allows the separate fluid systems to be maintained at substantial pressure differentials such as, for example, between about 1,000-3,200 p.s.i.

Abstract: In a welded plate heat exchanger the edge portion of each heat transferring plate (2) is welded together with the edge portions of a first adjacent heat transferring plate (3) along an outer line (10B) and with the edge portion of a second adjacent heat transferring plate (1) along an inner line (11B). In order to ensure, in connection with welding together of the heat transferring plates from only one direction, that contact is maintained between the plates along said outer line (10B) each heat transferring plate is formed with a stiffening crease (18) outside said outer line. The stiffening crease (18) extends along the edge of plate outside said outer line (10B).