The first roller dies will perforate, puncture the metal strip after the strip goes through the front guide. After the perforation the metal strip can then be corrugated. This is an improvement over punching the metal strip. Punching the metal, rotary punch, requires and extra step and leaves metal scrap, which is why punching metal for the first rolls would clog the machine and cause damage to the machine. The results of these tiny holes in the cylindrical duct help muffle the vibration and other noises from the motorized fan down the ductwork. The cylindrical perforated duct acts like a muffler. Air conditioning, bathroom exhaust fans, kitchen exhaust fans noise can me great reduced cheaply and efficiently. This perforated duct will be used with a vapor barrier and/or insulation.

A production method provides for punching holes in a metal strip, cold-forming the metal strip to form a guide tube, and joining the lengthwise edges of the metal strip to each other by a seam or teeth so as to create a uniform material. Subsequently, a piston-like striker is inserted into the guide tube.

The present invention provides a method and an apparatus for manufacturing an interlocking pipe obtained by easily and precisely shaping a pipe with a circular cross section or with the edges of the cross section nearly forming a circle in a non-loose manner, so as to provide excellent machining performance when the interlocking pipe is cut off and provide excellent operation efficiency for the apparatus itself. A metal band plate is helically wound onto a core member with a circular cross section or with the edges of the cross section nearly forming a circle. Clamping device is freely assembled at a front end of the code member in a detachable and switchable manner, and synchronously rotate in accordance with instructions from a main computing-controlling member, so as to prevent the metal band plate from being loosened, thereby to manufacture the interlocking pipe efficiently.

A method for manufacturing a refrigerant guide tube of a heat exchanger and a refrigerant guide tube manufactured using the method and a heat exchanger with the refrigerant guide tube are disclosed. The refrigerant guide tube includes tube body and channels extending through a wall of the tube body. The tube body is formed by a butt joint of side edges of more than one bar-shaped plate materials along the length direction. The method allows forming the refrigerant channels of the guide tube before or during forming the tube body when the method is used to manufacture the guide tube, so as to avoid directly forming the channels on the tube body and make the process of manufacture the guide tube simpler and more convenient.

A single piece stent construction having a plurality of commissure posts, each of which extends upwardly from a solid ring along a bend line and generally along a central longitudinal axis of the stent.

A single piece stent construction having a plurality of commissure posts, each of which extends upwardly from a solid ring along a bend line and generally along a central longitudinal axis of the stent.

Apparatus (10) for forming a spirally wound conduit (14) from a flat strip (2) comprising: a forming device (6) comprising a bending section (7) configured to spiralling bend the strip (2) and a joining section (8) configured to join opposite longitudinal sides (2A,2B) of the strip (2) each other; a feeding device (11) of the strip (2) along a feeding direction (F) parallel to the longitudinal edges (9) of the strip (2); a cutting device (1) arranged upstream the forming device (6) comprising a cutting head (3) for cutting the strip (2) and moving means configured to move said cutting head (3) along a plurality of moving axes (X,Y,Z) orthogonal to each other; a control unit (18) configured to command said moving means according to diameter (D) of the conduit (14) to be realized and to the width (B) of the strip (2) so that said cutting head (3) realizes on the strip (2) a plurality of arrays (12) of holes (13) each one tilted with respect to one of the longitudinal edges (9) of the strip (2) by an angle () function of the width (B) of the strip (2) and of the diameter (D) of the spiral conduit (14) to be realized. The present invention relates also to a air conduit (14), a perforated strip (2) and a coil (19) of a perforated strip (2) comprising a plurality of said arrays (12) of holes (13) wherein said holes (13) comprise at least two different shapes.

A helically wound tubular structure formed from helically wound sheet metals is disclosed. The tubular structure has a first sheet metal helically wound about a longitudinal axis. A second sheet metal having voids disposed therein is helically wound about the longitudinal axis and coaxially about the first sheet metal. A third sheet metal is helically wound about the longitudinal axis and coaxially about the first sheet metal and the second sheet metal.