A roll body for a hydrostatic rolling tool includes a center, an axis of rotation running through the center, and a machining zone for rolling a workpiece. The roll body is rotatable about the axis of rotation and the machining zone has a working profile line formed in a cross-section of the roll body. The working profile line has a first working arc extending around a first machining center and a second working arc extending around a second machining center. The first machining center is arranged offset to the center, and the second machining center is arranged offset to the center and offset to the first machining center. In an example embodiment, the roll body has a parallel to the axis of rotation, the first machining center lies in the cross-section on the parallel, and the second machining center lies in the cross-section on the parallel.

A tube for a heat exchanger includes a tube outer body enclosing a tube inner volume, and a corrugated insert received within the tube inner volume. The tube outer body has a pair of broad planar walls joined by arcuate end walls. The corrugated insert defines flow channels through the tube, with opening in flanks of the insert allowing for flow communication between adjacent flow channels. Bypass channels adjacent the arcuate end walls are fluidly isolated from the adjacent flow channels by the absence of such openings in the end flanks. Flow through the bypass channels is obstructed by flow blocks at one or both ends of the bypass channels.

A brazed plate heat exchanger (100) for exchanging heat between at least two fluids comprises several elongate heat exchanger plates (110) provided with a pressed pattern comprising depressions and elevations adapted to keep the plates on a distance from one another by contact points between the elevations and depressions of neighboring plates under formation of interplate flow channels for media to exchange heat. At least four port openings are placed in corner regions of the elongate heat exchanger plates and have selective fluid communication with the interplate flow channels such that the fluids to exchange heat will flow between port openings parallel to long sides of the elongate heat exchanger plates. A circumferential seal sealing off the interplate flow channels from communication with the surroundings is provided, and the heat exchanger plates are joined by brazing. The circumferential seal results partly from contact between skirts of neighboring plates contacting one another, said skirts extending at least partly along two sides of each heat exchanger plates, and partly from contact between flat areas extending along two other sides of the heat exchanger plates.

An elongate profile having a first portion and a second portion, the first and second portions being joined together at a first joining portion, the first and second portions being non collinear, the joining portion comprising an array of raised or rebated formations, each formation extending across the joining portion in a direction which is non-parallel to the principal axis of the profile and flat lands being provided between successive formations in an array and the pitch between successive formations in an array being from 2 to 20 times, for example from 5 to 15 times, the thickness of the flatlands.

An elongate profile having a first portion and a second portion, the first and second portions being joined together at a first joining portion, the first and second portions being non collinear, the joining portion comprising an array of raised or rebated formations, each formation extending across the joining portion in a direction which is non-parallel to the principal axis of the profile and flat lands being provided between successive formations in an array and the pitch between successive formations in an array being from 2 to 20 times, for example from 5 to 15 times, the thickness of the flatlands.

An air fin for a heat exchanger has air channels defined by corrugations, the corrugations having generally planar flanks joined by alternating crests and troughs. Perforations extend through portions of at least some of the flanks and are aligned within two spaced apart planes. A rectangular aperture extends through at least two consecutive ones of the corrugations, and is bounded by the two planes. A method of making the air fin includes forming perforations into a continuous strip of metal sheet at regular intervals, corrugating the strip to form crests and troughs between the perforations, and punching out a portion of the strip at regular intervals. The punching out includes shearing webs between the perforations, and results in the formation of the rectangular aperture.

An air fin for a heat exchanger has air channels defined by corrugations, the corrugations having generally planar flanks joined by alternating crests and troughs. Perforations extend through portions of at least some of the flanks and are aligned within two spaced apart planes. A rectangular aperture extends through at least two consecutive ones of the corrugations, and is bounded by the two planes. A method of making the air fin includes forming perforations into a continuous strip of metal sheet at regular intervals, corrugating the strip to form crests and troughs between the perforations, and punching out a portion of the strip at regular intervals. The punching out includes shearing webs between the perforations, and results in the formation of the rectangular aperture.

Electrochemical systems, separator plates and methods for production thereof, the separator plate comprising: an active region and at least one first through-opening for supplying a reaction medium to flow channels, and one second through-opening for conducting the reaction medium away from flow channels. At least one through-opening enclosed by a roller-embossed sealing bead. Roller embossing a first layer in a first transportation direction and roller embossing a second layer in a second transportation direction, and arranging the two metal layers opposite one another relative to the respective transportation directions. Two roller-embossed sealing beads are arranged one above the other.

Among a plurality of layers of metal rings, an inner circumferential projection is formed on an inner circumferential surface of at least one metal ring, and an outer circumferential projection is formed on an outer circumferential surface of the outermost metal ring. Thus, cracks extending from a surface of the metal ring can be arrested by the inner circumferential projection and the outer circumferential projection. Moreover, the outer circumferential projection of the outermost metal ring that does not abut against any other members is set to have a smaller projection height than the inner circumferential projection that abuts against other members. Thus, even if the inner circumferential projection wears by abutting against the other members, the inner circumferential projection can remain and arrest extension of the cracks; also, the projection height of the outer circumferential projection is reduced to enhance flatness of the outer circumferential surface of the metal ring.

A heat recovery wheel for a heat exchanger includes a wheel rim defining an outer perimeter of the heat recovery wheel, and a plurality of wheel passages located between the wheel rim and the wheel axis, the plurality of wheel passages arranged in a plurality of layers relative to a wheel central axis. One or more parting elements are located between adjacent layers of the plurality of layers, each of parting elements a strip having a strip width less than an axial length of the plurality of layers. The plurality of wheel passages are configured for flow of a first airflow and a second airflow therethrough for thermal energy exchange between the first airflow and the second airflow.