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 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.

A method of using a pipe cap assembly for a normally-sealed system includes attaching the base portion of a pipe cap to a pipe of a normally sealed system. A transition cap having internal threads is releasably coupled to an externally-threaded cylindrical connector portion of the pipe cap for sealing the same during normal operation. When access to the normally sealed system is required, the transition cap is unthreaded from the pipe cap, and a transition fitting is installed instead. A drain hose, vent hose, or the like, may be coupled to an access port of the transition fitting and fastened thereto for passing fluids to or from the normally sealed system. Alternatively, a test instrument may be coupled to the access port. Thereafter, the transition fitting is removed, and the transition cap is re-installed.

Two conduit gripping devices that are to be used together in a conduit fitting assembly are interconnected or held together as a cartridge or subassembly prior to assembly with fitting components to form a fitting assembly. In a more specific embodiment, one or both of the conduit gripping devices comprises a retaining structure by which the devices are mechanically connected together as a subassembly. For example, in one embodiment a front ferrule and a back ferrule for a tube fitting may be snapped together.

A ferrule and associated method characterized by an outer layer having a hardness; an intermediate layer below the outer layer, the intermediate layer having a hardness that is less than the hardness of the outer layer; and a core below the intermediate layer, the core having a hardness that is less than the hardness of the intermediate portion.

A fitting includes first and second fitting components adapted to be joined on a conduit to a first relative axial position to effect a seal between the conduit and a sealing element, sealing the conduit from a non-wetted fitting interior volume at least partially defined by the first and second fitting components. When the first and second fitting components are joined to the first relative axial position, first and second annular surfaces of the fitting axially engage, resulting in resistance to additional axial stroke of the first and second fitting components. At least one of the first and second annular surfaces includes a recess extending from an inner diameter to an outer diameter of the corresponding annular surface, and defining a leak detection port in fluid communication with the fitting interior volume when the first annular surface is in engagement with the second annular surface.

A fitting for a fluid conduit includes a coupling body, a coupling nut, a conduit gripping device that is axially driven by the coupling body and the coupling nut to provide grip and seal against a conduit, and a strain sensor unit disposed on a neck portion of the coupling body, the strain sensor unit including at least a first axially extending strain sensor positioned and oriented for strain sensor unit measurement of a first strain of the neck portion corresponding with a first fitting assembly condition, and a second strain of the neck portion corresponding with a second fitting assembly condition different from the first fitting assembly condition.

A fitting assembly includes a tube, a fitting body, a threaded drive nut, and at least one ferrule. An engagement indicator member is adapted to engage a corresponding engagement indicator member for indicating a correct installation of the fitting assembly, the engagement indicator member having a body having a geometry adapted to be rotatably received or non-rotatably received by one of the fitting body or the drive nut.

A subassembly for a conduit fitting includes a first ferrule and a second ferrule alignable relative to an axis. The first ferrule includes a camming surface at a back portion thereof, and the second ferrule includes a surface that contacts the camming surface when the first ferrule and the second ferrule are axially moved together along the axis. A retaining structure retains the first ferrule and the second ferrule together as a subassembly, and includes a flange extending radially outward and axially rearward from the back portion of the first ferrule to define an outer diameter recess. The flange includes an end portion that extends radially inward to define an inner diameter recess retaining a forward portion of the second ferrule. The outer diameter recess and the inner diameter recess together define a hinge portion of the flange.