A heating, ventilation, and air-conditioning (HVAC) duct system which includes, at least in part, one or more modular, uniform, pre-manufactured duct elbow elements having two faces of two sizes. Each elbow provides a twenty-two and a half degree (22.5°) bend in a duct system. When combined, the elbow sections can provide forty-five (45°) degree bends or ninety (90°) degree bends, or even offsets within a duct system. Due to the size and shape of the elbows, multiple elbows can be nested within one another for easy packing and shipping.

A ventilation duct for a fire rated ventilation duct wall penetration has one or more metal sheets forming said duct, wherein said metal sheet duct is covered on the outside by a heat insulating material, and said duct includes elongated stiffening members located on the outside of the duct and attached to said metal sheets. The stiffening members each comprises a metal profile and at least one non-combustible bar of inorganic material. The metal profile is fixed to the metal sheet of the duct and retains the non-combustible bar by at least partly encircling the bar.

A carrier for seam formation and sealing comprising a roller assembly having at least one roller; a housing for holding the roller assembly; a fastening member for mounting the roller to the housing; and the fastening member is an interchangeable mechanism.

An axial flow baffle for a shell and tube heat exchanger includes a substantially planar body configured for transverse arrangement in a longitudinally elongated shell of the shell and tube heat exchanger, a plurality of axial flow tube apertures each comprising a central tube hole configured to receive a tube of the heat exchanger, and an array of peripheral primary flow holes circumferentially spaced apart around the tube hole. The primary flow holes each interrupt the central tube hole and formed a radially inward projecting tube support protrusions between the primary flow holes which engage a single tube. Each primary flow hole has a non-polygonal configuration, which may be semicircular in some embodiments. The primary flow holes create axial flow around the periphery of the tubes through the baffles. In another aspect, a hybrid cross-flow baffle includes a combination of axial flow tube apertures and circular tube support holes.

A flanged duct blank has a male part defined by lead notches formed at each side of a leading end and has a female part defined by trail notches formed at each side of a trailing end. The male part includes a lock tab. The female part includes a leg part and a Z-bend. The Z-bend includes a leg part and a gap. The duct blank is repeatedly clamped and bent by a pivoting wiper to form a duct portion. The pivoting wiper includes a clench tool that has a retractable rib and a retractable roller. With the lock tab inserted into the Z-bend and the retractable rib engaged with the Z-bend, the retractable roller clenches the leg part over the lock tab to lock the male and female parts together in a duct seam.

A panel clip formed from a clip pre-form and configured for use with insulated, reinforced duct is provided. The panel clip includes a first plurality of gripping teeth formed in a first panel section. A second plurality of gripping teeth is formed adjacent the first plurality of gripping teeth. A first bending zone is positioned adjacent the second plurality of gripping teeth and opposite the first plurality of gripping teeth. A second bending zone is positioned spaced apart from the first bending zone and opposite the second plurality of gripping teeth. A third bending zone positioned spaced apart from the second bending zone and opposite the first bending zone. A distance formed from the first bending zone to the second bending zone is defined by a thickness of a layer of rigid insulation.

A double pipe includes an outer pipe in which an inner pipe is placed, and a spacer that maintains a clearance between the inner pipe and the outer pipe. At least a part of the spacer is press-fitted by an inner circumferential surface of the outer pipe and an outer circumferential surface of the inner pipe. More specifically, the outer pipe includes a diameter-reduced portion having undergone diameter reduction by plasticity processing. An inner circumferential surface of the diameter-reduced portion is present across the entire circumference other than the opening of the spacer, and presses an outer circumferential surface of the spacer inwardly in the radial direction.

A hot and cold composite formed square and rectangular steel tube and a production method for the same are provided. The radius of an outer corner of the square and rectangular steel tube meets the following conditions: when t is less than or equal to 6 mm, R is greater than 0 and less than 2.0 t; when t is greater than 6 mm and less than or equal to 10 mm, R is greater than 0 and less than 2.5 t; when t is greater than 10 mm, R is greater than 0 and less than 3.0 t, wherein t is the wall thickness of a straight tube part of the square and rectangular steel tube; R is the radius of each of the outer corners of the four corners of the square and rectangular steel tube; and the wall thickness of each corner of the square and rectangular steel tube is between 1.0 t and 1.8 t.

A forming device which expands a metal pipe material to form a metal pipe having a pipe portion and a flange portion includes first and second dies paired with each other and including pipe forming surfaces for forming the pipe portion and flange forming surfaces for forming the flange portion, a drive unit that drives at least one of the first and second dies, and a controller that controls the drive unit, in which, on at least one of the flange forming surfaces of the first and second dies, a protrusion portion protruding by an amount not to abut against the other flange forming surface when the dies are closed is formed and the controller controls the drive unit to form a thin wall portion at which a thickness of the flange portion becomes partially small at the flange portion by the protrusion portion pressing the flange portion.

A joint seal system and method may include a seal and a band. The seal may be positioned between abutting flanges of two adjacent duct sections. A band may be positioned over the two flanges and the flange interface. The joint seal system and method may be configured to mitigate and/or eliminate leakage of pressure, flue gases, condensate, and/or any other fluid, gas, and/or vapor between abutting flanges of duct sections at a flange interface.