A low temperature fluid dual structure pipe includes: an inner pipe through which a low temperature fluid flows; and an outer pipe externally fitted to the inner pipe with a sealed tubular space therebetween. An inactive gas having a melting point and a boiling point each of which is equal to or higher than a temperature of the low temperature fluid is filled in the tubular space between the inner pipe and the outer pipe. When the low temperature fluid flows through the inner pipe, the inactive gas is liquefied or solidified, and therefore, at least one of a liquefied inactive gas layer and a solidified inactive gas layer is formed on an outer peripheral surface of the inner pipe. As a result, a pseudo vacuum layer that is in a substantially vacuum state is formed in the tubular space.

In one embodiment, the present invention provides a central core element for a reverse osmosis separator assembly, the central core element comprising a pair of central core element components, each of said core element components comprising at least one porous exhaust conduit and at least one friction coupling, the friction couplings being configured to join said core element components to form a central core element defining a cavity configured to accommodate a first portion of a membrane stack assembly; wherein each core element component comprises a first section defining an exhaust cavity and a second section comprising a porous exhaust conduit, wherein said porous exhaust conduit comprises a removable wall member configured to form a substantial portion of a porous exhaust conduit wall.

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 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 method of sealing a hole in a wall of a hollow structure comprises providing a sealed chamber that is external to the structure and that is in fluid communication with an internal space of the structure via the hole. The structure may be a pipe-in-pipe structure and the internal space may be an annulus between outer and inner pipes. Fluid flows through the hole into or out of the chamber as the pressure and/or composition of fluid in the internal space is adjusted. Then, a plug is spun and friction-welded into the hole. The plug is inserted into the hole from within the chamber.

A tubular flow module includes at least two concentric tubes with spiral features, wherein first tube is coaxially arranged inside a second tube and each tube has a maximum diameter and a minimum diameter, wherein the maximum diameter of first tube is larger than the minimum diameter of second tube, defining a flow path for fluids between first and second tubes. A tubular flow module system and use of the tubular flow module is also disclosed.

Described herein is an autonomous fluid spill containment device for a pipeline which has a carrier conduit for transporting a fluid and a containment conduit located around the carrier conduit to define an interstitial space for receiving fluid spilled from the carrier conduit. The device includes a spilled fluid barrier for stopping spilled fluid flow. The fluid barrier is located in the interstitial space and extending between the carrier conduit and the containment conduit. A cable sensor is associated with the containment conduit for detecting spilled fluid flowing in the containment conduit.

Described herein is an autonomous fluid spill containment device for a pipeline which has a carrier conduit for transporting a fluid and a containment conduit located around the carrier conduit to define an interstitial space for receiving fluid spilled from the carrier conduit. The device includes a spilled fluid barrier for stopping spilled fluid flow. The fluid barrier is located in the interstitial space and extending between the carrier conduit and the containment conduit. A cable sensor is associated with the containment conduit for detecting spilled fluid flowing in the containment conduit.

A method of fabricating a conduit comprises steps of attaching a first first-tubular-outboard-ply-end of a first tubular outboard ply to a first inner collar portion of a first collar with a second weld and attaching a second first-tubular-outboard-ply end of the first tubular outboard ply to a second inner collar portion of a second collar with a fourth weld. The method also comprises steps of inserting a second tubular outboard ply into the first tubular outboard ply and inserting a tubular inboard ply into the second tubular outboard ply, so that the second tubular outboard ply is interposed between the tubular inboard ply and the first tubular outboard ply. The method further comprises steps of threadably interconnecting the first inner collar portion and a first outer collar portion of the first collar and threadably interconnecting the second inner collar portion and a second outer collar portion of the second collar.

A double-walled tube section for constructing a double-walled tube segment suitable for underpressure applications such as an evacuated tube transport system.