Abstract: A tyre has a tread pattern comprising at least one circumferential sipe (10), having, in radial section, a profile comprising: a first zone (Z1) close to the radially outer surface (S), having side walls (11) mutually spaced apart according to a minimum width W1; a second zone (Z2), having a portion (Pt) in which the side walls (11) diverge from one another, and a portion of maximum width (Pmax) having a maximum section width W2; and a third zone (Z3) having a maximum width W3, less than W2, radially inner with respect to the second zone (Z2). In the third zone (Z3) the side walls (11) join with a bottom portion (Pf) defining a total depth (H10) of the sipe (10). The ratio between W2 and W1 is greater than 1 and equal to or less than 2. A geometric centre (G2) of the portion of maximum width (Pmax) lies at a depth (PG) comprised between 40% and 60% of the total depth (H10).

Abstract: The water heater (2) or steam generator comprises a chamber (4) in two sections (5, 6) formed in particular by stamping. Inside this chamber a heating element (8) is arranged, which has a spiral-shaped main section (10) and two end sections (11, 12) passing through two circular openings of the chamber. The two end sections are welded to the chamber by a laser beam such that the weld obtained is continuous and ensures a good mechanical fixture of the heating element and an adequate tightness for the water heater or steam generator. For this purpose, a flange (18) is arranged at the periphery of each opening. Moreover, the two sections of the chamber have a widened edge (28) to allow them to be welded effectively.

Abstract: The water heater (2) or steam generator comprises a chamber (4) in two sections (5, 6) formed in particular by stamping. Inside this chamber a heating element (8) is arranged, which has a spiral-shaped main section (10) and two end sections (11, 12) passing through two circular openings of the chamber. The two end sections are welded to the chamber by a laser beam such that the weld obtained is continuous and ensures a good mechanical fixture of the heating element and an adequate tightness for the water heater or steam generator. For this purpose, a flange (18) is arranged at the periphery of each opening. Moreover, the two sections of the chamber have a widened edge (28) to allow them to be welded effectively.

Abstract: The water heater (2) or steam generator comprises a chamber (4) in two sections (5, 6) formed in particular by stamping. Inside this chamber a heating element (8) is arranged, which has a spiral-shaped main section (10) and two end sections (11, 12) passing through two circular openings of the chamber. The two end sections are welded to the chamber by a laser beam such that the weld obtained is continuous and ensures a good mechanical fixture of the heating element and an adequate tightness for the water heater or steam generator. For this purpose, a flange (18) is arranged at the periphery of each opening. Moreover, the two sections of the chamber have a widened edge (28) to allow them to be welded effectively.