A bending device for forming a product from a workpiece includes a shaft driven to rotate by a motor, an actuator including an extendable end configured to secure a portion of the workpiece, and a die coupled to the shaft and driven about an axis. The die includes a peripheral portion including a channel configured to receive the workpiece. The channel includes a first end and a second end offset from the first end in a direction parallel to the axis. Rotation of the die about the axis causes the workpiece to bend along the channel.

Tightly-coiled helical ducts for centrifugal air separators may be formed with the tools and methods disclosed herein. A helical coil toolset includes a helically grooved mandrel and an entry block. The helical groove of the mandrel has a small helix inside diameter relative to a width of the helical groove. The entry block has a guide channel to guide a tube to the helical groove and a mandrel channel to receive the mandrel. Methods include forming tubing into a tightly-coiled helical duct by filling a tube with fine particles, positioning the tube in the helical groove of a helically grooved mandrel, fixing the tube relative to the mandrel, assembling an entry block around the tube and around the mandrel, and bending the filled tube around the helically grooved mandrel into the tightly-coiled helical duct by rotating the mandrel relative to the entry block.

Methods for forming thin wall tubing into a tightly-coiled helical duct comprise selecting a thin wall tube with an outside tube diameter and a wall thickness that is less than 15% of the outside tube diameter; and bending the thin wall tube to form the tightly-coiled helical duct so that an outside duct diameter of the tightly-coiled helical duct is less than four times the outside tube diameter.

Methods for forming thin wall tubing into a tightly-coiled helical duct comprise selecting a thin wall tube with an outside tube diameter and a wall thickness that is less than 15% of the outside tube diameter; and bending the thin wall tube to form the tightly-coiled helical duct so that an outside duct diameter of the tightly-coiled helical duct is less than four times the outside tube diameter.

The objective of the present invention is to provide an apparatus for manufacturing an elbow-shaped duct, comprising: a main body obliquely provided at the upper part thereof; a duct movement guiding part provided to rotate and vertically move; a duct vane forming part including forming jigs symmetrically formed and respectively slid in the opposite directions to be coupled to and separated from each other; a duct vane coupling part including a duct fixing member for guiding the fixing of a duct and a duct vane pressing member for coupling upper and lower vanes of the duct; and a rotary driving part rotatably provided inside the main body, and including an eccentric rotary roller having, at the upper part thereof, a cutting roller for cutting the duct and a forming roller for forming the upper and lower vanes of the duct, thereby enabling the duct to be manufactured, by loading the cylindrical duct on the movement guiding part, as is, and simultaneously performing cutting and forming to correspond to an elbow shape, and thus remarkably reduces manufacturing time.

The objective of the present invention is to provide an apparatus for manufacturing an elbow-shaped duct, comprising: a main body obliquely provided at the upper part thereof; a duct movement guiding part provided to rotate and vertically move; a duct vane forming part including forming jigs symmetrically formed and respectively slid in the opposite directions to be coupled to and separated from each other; a duct vane coupling part including a duct fixing member for guiding the fixing of a duct and a duct vane pressing member for coupling upper and lower vanes of the duct; and a rotary driving part rotatably provided inside the main body, and including an eccentric rotary roller having, at the upper part thereof, a cutting roller for cutting the duct and a forming roller for forming the upper and lower vanes of the duct, thereby enabling the duct to be manufactured, by loading the cylindrical duct on the movement guiding part, as is, and simultaneously performing cutting and forming to correspond to an elbow shape, and thus remarkably reduces manufacturing time.

The present invention provides a mandrel tool and method for more efficiently and consistently forming various shapes of material. In one embodiment of the invention, a pair of pliers having mandrel jaws that are shaped with a uniform cross sectional area throughout a length of the mandrel jaw is used to replace the traditional tapered mandrel. Because the mandrel jaws have a uniform cross sectional area, the wire, for example, can be wrapped multiple times around the mandrel jaw when it is desired to produce multiples of the same shape. For added versatility, the pliers can have opposing mandrel jaws, with different size cross sectional area.

A counterflow heat transfer system comprises a heat exchanger and a flow controller arranged to convey a first fluid through the heat exchanger in a first flow direction and a second fluid through the heat exchanger in a second counterflow direction. The heat exchanger comprises at least one first thermally conductive tube conveying the first fluid and at least one second thermally conductive tube conveying the second fluid. The first and second tubes are wound around one another and in contact with one another in an entwined tubular arrangement.

A counterflow heat transfer system comprises a heat exchanger and a flow controller arranged to convey a first fluid through the heat exchanger in a first flow direction and a second fluid through the heat exchanger in a second counterflow direction. The heat exchanger comprises at least one first thermally conductive tube conveying the first fluid and at least one second thermally conductive tube conveying the second fluid. The first and second tubes are wound around one another and in contact with one another in an entwined tubular arrangement.

A method for obtaining a three-dimensional curve in a tubular product starting from a tube extending along a rectilinear longitudinal axis includes performing, by a first bending device, a first bending operation on a bending plane passing through the rectilinear longitudinal axis (x), so that the tube leaving the first bending device has a curved portion lying on the plane of curvature, and performing on the tube leaving the first bending device, by a second bending device, a second bending operation, so that the curved portion of the tube at the output of the second bending device has a first tangent and a second tangent (t1, t2) at its opposite ends lying on a cylindrical surface having generatrices orthogonal to two planes (A1, A2) respectively containing the first and second tangents (t1, t2). A method for manufacturing complex-curvature tubular products is also provided.