Dimpled heat exchange tube

A heat exchange tube comprising

• an S-shaped tube provided with an inlet end and an opposite outlet end,
• a first segment of said tube provided adjacent said inlet end,
• a first series of opposing and inwardly extending dimple pairs being provided in the wall of said tube along a second segment of said tube,
• said first series of opposing and inwardly extending dimple pairs being graduated in depth so that a first dimple pair of the first series which is located adjacent to said first segment of the tube has a smaller depth than a depth of a last dimple pair of the first series which is located adjacent to a third segment of said tube.

A heat exchange tube comprising

• a tube provided with an inlet end and an opposite outlet end,
• a first segment of said tube provided adjacent said inlet end,
• two pair of opposing and inwardly extending entry dimples being provided in a wall of said tube adjacent said inlet end, said two pairs of opposing and inwardly extending entry dimples being provided approximately perpendicular to each other in a single plane and said plane being approximately perpendicular to a longitudinal axis of a first segment of the tube,
• a first series of opposing and inwardly extending dimple pairs being provided in the wall of said tube along a second segment of said tube,
• said first series of opposing and inwardly extending dimple pairs being graduated in depth so that a first dimple pair of the first series which is located adjacent to said first segment of the tube has a smaller depth than a depth of a last dimple pair of the first series which is located adjacent to a third segment of said tube.