Patent ID: 7267166

Claim:
A grooved metal tube comprising: an arrangement having a groove-bottom thickness T f and an outside diameter De, for manufacture of heat exchangers which use one of a single-phase refrigerant and a coolant fluid, internally grooved by N helical ribs with an apex angle α, height H, base width L N , and helix angle β, two consecutive ribs being separated by a groove, one of flat-bottomed and non-flat bottomed, having a width L R , and a pitch P equal to L R +L N , wherein: a) the value of thickness T f of the tube is such that T f /De is equal to 0.023±0.005, wherein the values of T f and De are expressed in mm, with the value of De ranging between 4 and 14.5 mm; b) the ribs have the value of height H such that H/De is equal to 0.028±0.005, wherein the values of H and De are expressed in mm; c) the number N of ribs is such that N/De is equal to 2.1±0.4, and the value of the corresponding pitch P is equal to π·Di/N, with Di equal to De−2·T f , and the value of De being expressed in mm; d) the base widths L N and L R are such that L N /L R is between 0.20 and 0.80; e) the apex angle α ranges from 10° to 50°; and f) the helix angle β ranges from 20° to 50°; so that a single-phase fluid, including one of water and glycol water, are used as one of a refrigerant and coolant fluid to ensure simultaneously a high heat exchange coefficient during heating and cooling, a low level of head loss and a low weight/meter.