In a method of producing a tubular structure for a gas generator, a tubular body is positioned relative to a forming device having inner and outer tools, which are moved relative to an end portion of the tubular body until an inner circumferential surface of a neck of the end portion rests against a support surface of the inner tool to reduce a diameter of the end portion by a tool contour of the outer tool and thereby form a shoulder. The outer tool is held in position upon the end portion and the neck inner circumferential surface is calibrated by a calibrating surface on a calibrating member of the inner tool while an outer circumferential surface of the neck is supported by the outer tool, as the inner tool is removed from the end portion. The outer tool is then removed from the end portion of the tubular body.

A wire harness and an electric wire protecting pipe that can prevent holes from being formed by flying gravel while the vehicle is moving and includes a bending pipe portion that can be bent easily. The electric wire protecting pipe is a resin pipe into which electric wires are insertable, and includes a bending pipe portion that is easily bent and is provided with protruding portions and recessed portions that are alternately continuous with each other in an axial direction, and a straight pipe portion that is flat and is not easily bent in the axial direction. A thickness of a lower wall portion that is disposed on a lower side when the electric wire protecting pipe is attached to a vehicle is greater than a thickness of a left wall portion and a right wall portion.

A method of improving the life expectancy of piping has steps of determining a circumferential position in the piping having a highest expected rate of wall thickness reduction; determining a circumferential section of a pipe length having a greatest wall thickness; and installing the pipe length in the piping by rotating the pipe length to align the circumferential section of the pipe length having the greatest wall thickness with the circumferential position of the piping having the highest expected rate of wall thickness reduction.

A single piece structural connector is provided that includes a single machined aluminum piece having first and second circular ends including a plurality of bolt holes and a center hole. The connector also includes an alignment dowel positioned on the center hole. The alignment dowel is configured to tightly fit into a center hole of a pipe plate.

Vacuum cleaner, comprising a tube having a first diameter, a hose having a second diameter exceeding the first diameter by at least 15%, and a transition piece (T) having a first end (1) arranged for being connected to the tube, and a second end (2) arranged for being connected to the hose, wherein the transition piece (T) has a curved part that has a non- circular cross-section, the curved part having a first part (I) in which in a direction from the first end (1) to the second end (2), a first dimension (R1) of the cross-section increases to a diameter exceeding the first diameter by 15%, the first dimension (R1) being in a radial direction of the curved part, while a second dimension (R2) of the cross-section, perpendicular to the first dimension (R1), does not exceed the first diameter by more than 10%. Preferably, the transition piece (T) has a second part (II), between the first part (I) and the second end (2), the second part (II) having a non-circular cross-section where the second part (II) meets the first part (I), and a circular cross-section where the second part meets the second end (2). Advantageously, in the first part (I), in a direction from the first end (1) to the second end (2), the first dimension (R1) of the cross-section increases to a diameter exceeding the second diameter, while the second dimension (R2) stays below the second diameter.

A tube arrangement for the transport of temperature control medium, comprising a base body (2) made of polymeric material and produced by means of blow molding, wherein at least one functional element (3) is arranged in the base body (2), which element is in operative connection with the temperature control medium.

A water delivery pipe made from PVC or PVCO and having an inner surface which is rifled. The inner surface of the pipe preferably includes a graphene material. The pipe has improved anti-bacterial properties such that the formation of bacterial biofilms is eliminated or reduced.

Methods of making the pipe are also disclosed.

Disclosed herein is a double tube for heat exchange. The double tube for heat exchange includes: a spiral pipe having ridges and valleys alternately formed on a circumferential surface thereof along a spiral track thereof and guiding a first fluid to flow therethrough; an outer pipe receiving the spiral pipe axially inserted thereinto and guiding a second fluid to flow along the circumferential surface of the spiral pipe in an axial direction such that the second fluid exchanges heat with the first fluid; and a resistance member protruding from the spiral pipe or the valleys to increase residence time of the second fluid in the valleys on the circumferential surface of the spiral pipe and to support the ridges adjacent thereto. Unlike typical double tubes, the double tube for heat exchange can improve heat exchange efficiency between a second fluid flowing inside an outer pipe and a fluid flowing inside a spiral pipe axially inserted into the outer pipe to increase residence time of the second fluid inside the outer pipe by virtue of a spiral shape of the spiral pipe; can improve flow directionality of the second fluid through formation of the grooves in valleys of the spiral pipe along a spiral track of the valleys; can reduce flow-induced noise through expansion of a space defined between an end joint of the outer pipe and the inner pipe to reduce the pressure of the second fluid; and further improve heat exchange efficiency through resistance members protruding from the valleys to increase residence time of the second fluid.

A guiding pipe for a water sprayer, and the water sprayer has a handle with an intake end configured to connect to a water source and another end connected a spray head through a guiding pipe. The guiding pipe has a spiral main tube provided with a respective circular connecting section at each end, and the circular connecting sections are respectively connected to the handle and the spray head.

A ducting system includes an elongate duct section or length and formed flange connectors at each end of the duct. Both the duct section and the flange connectors are elliptical in cross section, defined by a major axis and a minor axis. The elliptical cross section has the advantage of reducing the overall height of the duct system along minor axis, as well as defining a rigid structure due to there being no flat surface about the circumference of the duct, while also capable of transporting a significant volume of air relative to a circular duct system of the same size perimeter.