Abstract: In-line pressure balanced expansion joint for thermal expansion compensation of piping and ducting of circular cross section with the tie rods located inside the device consists of one large, central expansion joint and two smaller, mirror-symmetrical, side expansion joints (2a) and (2b). Three expansion joints are made of bellows (3) and (9) and of straight pipe spools and annular plates welded to each other. Tie rods (15a) and (15b) are placed on a circle at equal angular intervals which connect the sides of the expansion joints. The inner surfaces of the sides of the central expansion joint are reinforced with welded rectangular radial ribs and triangular ribs. The compactness and functionality allows expansion joints for all types of piping and ducting and is particularly suitable for making expansion joints for piping and ducting with a diameter greater than 2 meters.

Abstract: A method for producing heat exchanger tubes involves applying a surface coating to the tube through which a fluid medium flows and which has a number of cooling fins arranged on an outer wall. The method comprises applying a surface coating to an inner wall and the outer wall of the tube, the inner wall and the outer wall comprised of structural steel, the surface coating comprising copper, nickel, cobalt, chromium, a nickel alloy, a chromium alloy, a copper alloy, a cobalt alloy or stainless steel. The method further comprises soldering the number of cooling fins to the outer wall. The surface coating is configured to facilitate direct soldering of the number of cooling fins to the outer wall of the tube and to provide the inner wall with corrosion resistance to the fluid medium in the tube.