A coupling connects a valve structure to a container for enclosing pure gas under high pressure. The neck of the container and the valve structure include cooperating contact surfaces. One of the contact surfaces is convexly curved, or alternatively is of frusto-conical shape. The other of the contact surfaces is of convex spherical shape. A sealing ring is compressed between those contact surfaces. The inner surface of the container is polished to achieve a high degree of smoothness. The container is formed of a top part, and a bottom portion welded to an intermediate mantle.

An anti-rotation arrangement for a detection device assembly used in a fire suppression system. The anti-rotation arrangement comprises an adapter secured to the housing of the detection device, a locking collar freely rotatable between the adapter and housing, and a union engageable to the locking collar and a T-fitting of a fluid conduit for connecting the detection device assembly to the T-fitting. Both the union adapter and union include radial teeth formed about the outer circumference of each component which interlock and mate when the union is securely, fully engaged to the locking collar during connection of the detection device assembly to the fluid conduit. The interaction of the radial teeth effectively prevents rotation of the detection device assembly once the assembly is engaged to the T-fitting of the fluid conduit.

Quick joint for rapid, tight-seal connection of pipes, in which from the end of the female hollow body an internal flaring with decreasing cross-section extends, suitable for getting engaged, with interference, with a corresponding external counter-flaring provided on the male hollow body in the neary of the overhanging shoulder of the latter which, on its one side, cooperates with the sleeve of the joint and, on its other side, cooperates with said end of said female hollow body; from the end of said male hollow body furthermore a second external flaring with decreasing cross-section extends, suitable for getting engaged, with interference, with a counter-flaring provided inside the interior of said female hollow body in the nearby of an internal shoulder for said male body. Also preferred embodiments are disclosed.

Disclosed is a connection stub and a housing, in particular a high-pressure fuel reservoir, for a fuel injection system for internal combustion engines with a welded connection stub, in which sealing faces between the housing and the connection stub are provided, spatially separately from the weld seam.

A heat exchanger unit has a case made of plastic or resin, and a heat exchanger is accommodated and fixed within the case. Within the case, first terminal ends of the inlet pipe and outlet pipe are connected to the heat exchanger, and second terminal ends of the pipes are fixed to a wall on the case by the external pipe connection portion. The external pipe connection portion has a flange portion formed integrally with the case itself on the wall, and a nut plate.