A preassembly for a conduit fitting includes an annular fitting component and a conduit gripping device. The annular fitting component has an interior wall extending along a central axis from an inboard end to an outboard end. The interior wall includes an inboard surface having a first diameter, an outboard surface having a second diameter smaller than the first diameter, and an intermediate surface recessed from the inboard surface by an outward facing inboard radial wall and recessed from the outboard surface by an inward facing outboard radial wall. The conduit gripping device is retained within the annular fitting component and includes a projection extending radially outward of an outer circumferential surface of the conduit gripping device, and axially toward an inboard end of the conduit gripping device, with an end portion of the projection being axially captured between the inboard radial wall and the outboard radial wall.

In a method of assembling a conduit fitting, a conduit fitting is provided, including a first coupling member, a second coupling member, an internal conduit gripping device disposed between said first coupling member and said second coupling member, and an external deformable structure. The first coupling member is pulled up with the second coupling member on an end portion of a conduit to engage the external deformable structure with an external surface of one of the first and second coupling members. After engaging the external deformable structure with the external surface of one of the first and second coupling members, the first coupling member is further pulled up with the second coupling member to axially compress the external deformable structure, until an amount of torque required to continue pulling up the first coupling member increases to a predetermined torque. The predetermined torque corresponds to an initial pulled-up position in which the conduit gripping device grips and seals the conduit.

A conduit fitting of the type having first and second threaded fitting components and at least one conduit gripping device, further includes a stroke limiting member that allows the fitting to be pulled up by applying a predetermined torque. In one embodiment, the stroke limiting member may realized as an integral or integrated load bearing member that functions as a torque collar and deflects under load. The disclosure also presents a gauging structure and method for fittings that can be pulled up by turns, by torque or both.

Compression fittings for pipes having a range of diameters, including a support body with a central section between end sections, the central section having a smaller diameter than the end sections, with a transition surface between the central section and each end section. A gasket fits over a pipe and engages one of the support body end section end surfaces. A fitting nut is movable axially over the support body to draw the support body and the gasket together in the axial direction and bias the gasket radially inward against the pipe. A grip ring encircles the pipe at one gasket end and has a surface engaging the fitting nut whereby the fitting nut biases the grip ring radially inwardly toward the pipe. An insert adapter has a hub with a radially extending flange may block the other gasket end to load the gasket between its axial ends.

A fitting is provided that may optionally be pulled-up to its final assembled condition by torque rather than by turns. In one embodiment, at least one fitting component includes a structure that facilitates pull-up by torque. The structure may take a wide variety of different forms.

Disclosed herein is a back ferrule having a bellows-shaped elastic part. The back ferrule (40) is used, for pipe connection, along with: a connector body (10) having an external thread on an outer circumferential surface thereof; a drive nut (20) having an internal thread on an inner circumferential surface thereof; and a front ferrule (30). The back ferrule (40) includes: a nose part (41) having a front-end inclined surface (41b); a tail part (42) having a rear-end inclined surface (42b); and an outer circumferential surface (43) and an inner circumferential surface (44) connecting the nose part to the tail part. An outer circumferential corrugated surface (45) and an inner circumferential corrugated surface (46) are respectively formed on the outer circumferential surface and the inner circumferential surface between the nose part and the tail part.

The present application discloses methods and apparatus for installing fitting components, such as a conduit gripping device, on a conduit to form an assembly. The assembly is joinable with at least one other fitting component to form a fitting. The present application also discloses methods and apparatus for evaluating characteristics of components of a mechanically attached connection. Characteristics that may be evaluated include, but are not limited to, the position of a conduit gripping device on a conduit, an amount of axial compression or stroke of the conduit gripping device, an amount of clamping force applied to the conduit gripping device as the conduit gripping device is compressed, and an amount of torque applied to members that compresses the conduit gripping device.

This invention relates to a partially carbonitriding heat treated stainless steel ferrule, having a first region with a first hardness and a second region with a second hardness, wherein the first region includes a nitrogen layer having a nitrogen concentration higher than a carbon concentration, and a carbon layer formed under the nitrogen layer and having a carbon concentration higher than a nitrogen concentration, so that the first hardness is greater than the second hardness. Thereby, partial heat treatment is effective at preventing rotational torque of the region, except for the portion to be heat treated, from increasing due to the total hardening.

A fitting is provided that may optionally be pulled-up to its final assembled condition by torque rather than by turns. In one embodiment, at least one fitting component includes a structure that facilitates pull-up by torque. The structure may take a wide variety of different forms.

A fitting for a tube or pipe capable of functioning a high pressures having a first fitting component adapted to receive the conduit end; a conduit gripping device such as a ferrule or ferrules and a second fitting component that can be joined to the first fitting component to cause the conduit gripping device to grip the conduit and seal when assembled. In one aspect of the invention, the first fitting component is constructed from a material that is softer than the material used to construct the second fitting component. An additional aspect of the invention include a retaining portion on the second fitting component that constrains the tube gripping device against pressure. The retaining portion can also be configured to retain the tube gripping device to the second fitting component prior to installation and in a finger-tight condition. A further aspect of the invention includes a first fitting component in which an exterior portion of the component is work hardened radially outward from the tube gripping device. The fitting may optionally be provided with a structure to effect the pull-up by torque functionality.