An adjustable duct start collar may include a base with a flange on a first end of the base and a plurality of tabs on a second end of the base. The base may be constructed of a material of substantially uniform thickness and include at least two slots in the base. The first of the slots may be positioned substantially parallel to a second of the at least two slots. Each of the slots of the at least two slots being able to independently receive the flange, whereby when the base is curved into a cylindrical shape with the flange positioned in the first of at least two slots, the curved base will form a cylindrical shape with a first diameter and when the flange is positioned in the second of the at least two slots, the curved base will form a cylindrical shape with a second diameter.

A connector assembly has a connector body to receive a spigot. The connector body includes a mechanism to retain the spigot in the connector body. A fluid transfer conduit is coupled with the connector body. A heating element extends through the fluid transfer conduit and into the connector body and spigot, when the spigot is retained by the connector body. The heating element heats the spigot and the connector body from the inside.

A connector assembly has a connector body to receive a spigot. The connector body includes a mechanism to retain the spigot in the connector body. A fluid transfer conduit is coupled with the connector body. A heating element extends through the fluid transfer conduit and into the connector body and spigot, when the spigot is retained by the connector body. The heating element heats the spigot and the connector body from the inside.

A metal pipe including a curved portion produced by bending in which a plurality of non-bending surfaces and a plurality of bent portions at which the non-bending surfaces are connected in a bending manner are provided on a circumferential surface on an inside of a center of a curvature side of the curved portion is provided.

In a sectional-type high wear-resistant double-layer straight tube and a method for preparing the same, the double-layer straight tube includes a protective outer tube and a sectional-type wear-resistant inner tube. The protective outer tube is nested outside of the sectional-type wear-resistant inner tube; the sectional-type wear-resistant inner tube includes at least two wear-resistant inner tube sections; and the wear-resistant inner tube sections are connected sequentially. The sectional-type wear-resistant inner tube at least includes a left inner tube section, a right inner tube section, and one or more middle inner tube section. The wear-resistant straight tube can greatly prolong the service life of the pipeline so that the cost performance of the pipeline is increased by more than a few times. It would also easily achieve mass production, the quality is stable and reliable, and the safety performance is high.

At least two spacers in an elongated shape is provided between an internal pipe and an external pipe along the center line of a double pipe. In the cross section of a bent portion as viewed in a direction along the center line of the double pipe, the first spacer is located inwardly relative to the center of the double pipe with reference to the radial direction of the bent portion. The second spacer is located outwardly relative to the center of the double pipe. When a straight line that passes through the center of the radius of the bent portion and through the center of the double pipe is taken as a reference line at least either one of the first spacer or the second spacer overlaps the reference line.

At least two spacers in an elongated shape is provided between an internal pipe and an external pipe along the center line of a double pipe. In the cross section of a bent portion as viewed in a direction along the center line of the double pipe, the first spacer is located inwardly relative to the center of the double pipe with reference to the radial direction of the bent portion. The second spacer is located outwardly relative to the center of the double pipe. When a straight line that passes through the center of the radius of the bent portion and through the center of the double pipe is taken as a reference line at least either one of the first spacer or the second spacer overlaps the reference line.

A water distribution pipe comprises an elbow formation along its length, an aperture-defining formation defining an aperture in a radially distal wall of the elbow formation along a radius of the curvature of the elbow, and an openable closure that is mounted or mountable to the aperture-defining formation and that closes the aperture.

A water distribution pipe comprises an elbow formation along its length, an aperture-defining formation defining an aperture in a radially distal wall of the elbow formation along a radius of the curvature of the elbow, and an openable closure that is mounted or mountable to the aperture-defining formation and that closes the aperture.

Provided herein is a liner that can be loosely inserted in process pipe to form a lined pipe and to decrease the rate of heat transfer between process fluids flowing through the liner and the process pipe. The liner provided herein can reduce applied thermal loading on the outer pipe resulting from, for example, turbulent mixing between fluids having different temperatures (with or without stratification), circumferential thermal gradients, and/or longitudinal thermal gradients. An annulus between the process pipe and liner can be at least partially filled by process fluids, thereby creating a thermal buffer to further decrease the rate of heat transfer between the fluids and the process pipe.