Continuous manufacture of flat tubing for heat exchangers from aluminum strip, controls pressing duration and instant of cutting to length, in terms of measured strip delivery

摘要

Continuous strip (3) is taken from the storage unit (2) and conveyed along (A) the line. It is pressed (4), e.g. dimpled, between two counter-rotating rollers. The upper roller is raised periodically, leaving non-pressed sections, under control from the measured strip delivery. The strip is bent continuously to a tube having a longitudinal slot with facing edges. These are joined, preferably by welding. The tube length or velocity of advance is measured and it is cut to set lengths in a parting unit (8). To control the instant of cutting, the length of advance or a speed measurement is used. To control the instant of upper roller raising and the durations of its elevation and pressing, the foregoing measurements, the instant of cutting, the predetermined tube length and the spacing of the pressing unit (4) from the parting unit (8) in the direction of conveying (A), are used. The measurement unit (7) sends a length signal to the pressing unit controller (41) and to the parting unit controller (42) each time the tube has advanced over the predetermined cutting length. Alternatively a measured velocity value is sent at set intervals. The signal initiates cutting at a set instant. The action of cutting sends a corresponding signal to the pressing controller. Preferably the length tolerance of the pressed section is +-2 mm. Flat tubes, especially multichamber flat tubes, are produced. Preferred non-pressed lengths are 10-12 mm and the total length is 400-2000 mm. The tubes have non-pressed ends, the remaining intermediate region being continuously-pressed. Parallel grooves are produced in the strip; after bending, their bases face each other. Further mechanical details of the equipment are provided in accordance with the foregoing principles. An independent claim IS INCLUDED FOR corresponding equipment.