A pipe-fitting device capable of easily connecting pipes having different diameters includes a fitting body and a pair of fixing nuts. The fitting body includes a first channel portion having a first inner diameter formed in a first inner side of the fitting body, a second channel portion having a second inner diameter formed in a second inner side of the fitting body, the second inner diameter being smaller than the first inner diameter such that a step is formed inside the fitting body at the boundary between the first channel portion and the second channel portion. Each fixing nut is rotatably coupled to a corresponding open end of the fitting body and configured to fix the corresponding one of the first pipe and the second pipe through rotational tightening.

A resin tube fitting prevents backwaters between its body and inner ring. The fitting includes a body, an inner ring, and a union nut. The body has main, outer, and inner sleeves, and a groove. The inner ring has a cylinder, an insert, and outer and inner protrusions. The union nut has a body and a pressing member. The inner sleeve has a through hole serving as a channel. The inner protrusion extends from the cylinder to an axial direction to contact the inner sleeve. The inner protrusion has a through hole serving as another channel connected with the inner sleeve's channel. The tip of the inner protrusion has an inner diameter not less than the minimum inner diameter of the inner sleeve. An inner peripheral surface is located at the inner periphery of the inner protrusion and causes it to reduce in inner diameter toward another axial direction.

A leak-proof tube fitting assembly structure includes a liquid tube, a liquid tube fitting, and a nut for locking and connecting the liquid tube and the liquid tube fitting. The liquid tube fitting has a first connecting end, a first threaded connecting portion and a second connecting end that are axially arranged in sequence in a forward direction. The first threaded connecting portion has a first external thread. Thereby, the sealing performance of the connection of the liquid tube and the liquid tube fitting is improved to prevent leakage.

A leak-proof tube fitting assembly structure includes a liquid tube, a liquid tube fitting, and a nut for locking and connecting the liquid tube and the liquid tube fitting. The liquid tube fitting has a first connecting end, a first threaded connecting portion and a second connecting end that are axially arranged in sequence in a forward direction. The first threaded connecting portion has a first external thread. Thereby, the sealing performance of the connection of the liquid tube and the liquid tube fitting is improved to prevent leakage.

An inner ring 4 of a pipe joint 1 includes a bulge portion 6 formed at an axially outer end portion thereof so as to project toward a radially outer side, and to be press-fitted into an end portion of a tube 8, and has a fluid flow passage 4a formed on a radially inner side of the bulge portion 6. The bulge portion 6 is formed so as to be tapered from an axially inner side toward an axially outer end thereof in an axial cross-sectional view, and has a flat surface 6e formed at the axially outer end thereof and extending in a radial direction.

A fitting element, in particular for an HPLC application, is configured for providing a fluidic coupling of a tubing to a fluidic device. The fitting element comprises a gripping piece to exert—upon coupling of the tubing to the fluidic device—a grip force (G) between the fitting element and the tubing. The gripping piece comprises a hydraulic element configured to transform an axial force (S) into a hydraulic pressure (P) within the hydraulic element. The hydraulic pressure (P) in the hydraulic element causes the grip force (G).

A structure of a resin-made pipe joint includes a sleeve which is press-insertable from one axial side into one longitudinal end portion of a flexible tube to flare the one longitudinal end portion to hold the flared state, a joint body which is couplable to the sleeve, and a union nut which is fastenable to the joint body to hold a state where the sleeve press-inserted into the one longitudinal end portion is coupled to the joint body. The sleeve has a taper-like first outer circumferential surface, a second outer circumferential surface having an outer diameter that is smaller than a maximum outer diameter of the first outer circumferential surface, and an annular step portion which is an annular step portion that is disposed between the first outer circumferential surface and the second outer circumferential surface and comprises an edge portion on a side of the first outer circumferential surface.

A biocompatible tube and fitting system that can be used in a liquid chromatography system is described. The tube can have a polymer tip and can be used in conjunction with one or more fitting assembly.

A fitting assembly may seal a wire within a tube to inhibit ingress of fluid outside the tube into the tube and into contact with the wire. The fitting assembly may optionally include a body and a nut, with a part of the nut received within the body. The nut may be threadedly connected to the body, such that threading and/or unthreading the nut translates the part of the nut within the body. Optionally, the nut may include a ring extension that is received within a ring cavity of the body, and an interfacing between the ring extension and the ring cavity may create a seal to inhibit leaking of the fluid past the seal. A method of sealing a wire within a tube may comprise positioning a tube with a wire therein within such a fitting assembly.

A fitting includes a first and second threaded fitting component and a conduit gripping device receivable within the first threaded fitting component. A stroke resisting member is integral with the first threaded fitting component and includes a web having a first radial thickness and extending axially inward from the first threaded fitting component to a distal ring portion having a second radial thickness greater than the first radial thickness. A radially extending bearing surface of the distal ring portion axially engages a radially extending portion of the second fitting component when the first and second fitting components are joined together to the first relative axial position. The stroke resisting member resists additional axial stroke of the first and second fitting components, such that a tightening torque beyond the first relative axial position is increased by the axial engagement.