A heat exchanger (4) has fluid flow channels (6) with at least one heat exchanging surface (10) which has an undulating surface section for which the surface profile varies along a predetermined direction such that at a first edge (E1) the surface profile follows a first transverse wave (20), at a second edge (E)2 the surface profile follows a second transverse wave (22) and at an intermediate point I between the edges the surface profile follows a third transverse wave (24). The third transverse wave (24) has a different phase, frequency or amplitude to the first and second transverse waves so that chevron-shaped ridges and valleys are formed. This improves the mixing of fluid passing through the channel and hence the heat exchange efficiency.

A heat exchanger (4) has fluid flow channels (6) with at least one heat exchanging surface (10) which has an undulating surface section for which the surface profile varies along a predetermined direction such that at a first edge (E1) the surface profile follows a first transverse wave (20), at a second edge (E)2 the surface profile follows a second transverse wave (22) and at an intermediate point I between the edges the surface profile follows a third transverse wave (24). The third transverse wave (24) has a different phase, frequency or amplitude to the first and second transverse waves so that chevron-shaped ridges and valleys are formed. This improves the mixing of fluid passing through the channel and hence the heat exchange efficiency.

An outer finned tube includes a tube body, an outer wall of the tube body is provided with outer fins spirally arranged in an extension direction of the tube body; grid fins are arranged between two adjacent spiral parts of the outer fins correspondingly; two ends of each grid fin are connected to the two adjacent spiral parts of the corresponding outer fin respectively; a gap is kept between each grid fin and the outer wall of the tube body; and the plurality of grid fins are spaced in the extension direction of the tube body. An enhancing cavity is formed in an area defined by the outer wall of the tube body, inner walls of the grid fins and the outer fins in an encircling way, which can form a larger degree of superheat, provides a nucleation point for a boiling/condensation process and improves a heat exchange performance.

An outer finned tube includes a tube body, an outer wall of the tube body is provided with outer fins spirally arranged in an extension direction of the tube body; grid fins are arranged between two adjacent spiral parts of the outer fins correspondingly; two ends of each grid fin are connected to the two adjacent spiral parts of the corresponding outer fin respectively; a gap is kept between each grid fin and the outer wall of the tube body; and the plurality of grid fins are spaced in the extension direction of the tube body. An enhancing cavity is formed in an area defined by the outer wall of the tube body, inner walls of the grid fins and the outer fins in an encircling way, which can form a larger degree of superheat, provides a nucleation point for a boiling/condensation process and improves a heat exchange performance.

An alignment device for aligning a tube panel with a plurality of pipes system and a method of performing the alignment is provided. The alignment device is used in a panel comprising a plurality of tubes having an inner diameter and an outer diameter. The alignment device includes a cylindrical first portion sized to fit within the tube inner diameter. A tapered second portion is provided opposite the cylindrical first portion, the tapered second end having a first end diameter that is substantially the same size as the outer diameter.

An alignment device for aligning a tube panel with a plurality of pipes system and a method of performing the alignment is provided. The alignment device is used in a panel comprising a plurality of tubes having an inner diameter and an outer diameter. The alignment device includes a cylindrical first portion sized to fit within the tube inner diameter. A tapered second portion is provided opposite the cylindrical first portion, the tapered second end having a first end diameter that is substantially the same size as the outer diameter.

A method of manufacturing a recuperator segment uses metal tubes deformed into air cells in a waved configuration. The air cells are stacked one to another to form a double skinned recuperator segment providing cold air passages through the respective air cells and hot gas passages through spaces between adjacent air cells.

A method of manufacturing a recuperator segment uses metal tubes deformed into air cells in a waved configuration. The air cells are stacked one to another to form a double skinned recuperator segment providing cold air passages through the respective air cells and hot gas passages through spaces between adjacent air cells.

A heat exchanger for heating a liquid is provided, in particular, for high-pressure cleaners, including an inner and an outer heating coil which each have a plurality of turns, and including spacers which are arranged between the inner heating coil and the outer heating coil and are distributed over the circumference of the inner heating coil. To develop the heat exchanger in such a way that it can be manufactured more cost-effectively and is highly efficient, at least one turn of the outer heating coil includes between two spacers immediately adjacent to each other a first turn section in which the radial spacing from the inner heating coil is smaller or larger than in the region of the spacers. Two methods for manufacturing such a heat exchanger are also provided.

A heat exchanger for heating a liquid is provided, in particular, for high-pressure cleaners, including an inner and an outer heating coil which each have a plurality of turns, and including spacers which are arranged between the inner heating coil and the outer heating coil and are distributed over the circumference of the inner heating coil. To develop the heat exchanger in such a way that it can be manufactured more cost-effectively and is highly efficient, at least one turn of the outer heating coil includes between two spacers immediately adjacent to each other a first turn section in which the radial spacing from the inner heating coil is smaller or larger than in the region of the spacers. Two methods for manufacturing such a heat exchanger are also provided.