A resin joint includes a joint body having a flow path, sleeves, and union nuts that fix tubes to the joint body. The joint body has a body portion with a curved inner peripheral surface and a straight portion protruding from an end portion of the body portion. The straight portion has outer and inner cylindrical portions radially arranged inside the outer cylindrical portion. An end portion of the inner cylindrical portion is positioned closer to the body portion than is an end portion of the outer cylindrical portion. A groove portion extending parallel with the outer and inner cylindrical portions in an axial direction is formed between an inner peripheral surface of the outer cylindrical portion and an outer peripheral surface of the inner cylindrical portion. The tube is fixed to the joint body such that a press-fit portion of the sleeve is press-fitted in the groove portion.

A resin joint includes a joint body having a flow path, sleeves, and union nuts that fix tubes to the joint body. The joint body has a body portion with a curved inner peripheral surface and a straight portion protruding from an end portion of the body portion. The straight portion has outer and inner cylindrical portions radially arranged inside the outer cylindrical portion. An end portion of the inner cylindrical portion is positioned closer to the body portion than is an end portion of the outer cylindrical portion. A groove portion extending parallel with the outer and inner cylindrical portions in an axial direction is formed between an inner peripheral surface of the outer cylindrical portion and an outer peripheral surface of the inner cylindrical portion. The tube is fixed to the joint body such that a press-fit portion of the sleeve is press-fitted in the groove portion.

A fitting body includes a tubular end whose outer periphery has an external thread and whose inner periphery has an annular groove or protrusion. A sleeve connects a tube to the tubular end of the fitting body. A union nut includes a first axial end that receives the tube therein and a second axial end to be screwed onto the external thread of the fitting body. The fitting body includes first and second regulating portions extending in directions that intersect an axial direction of the fitting body to contact the union nut being screwed onto the external thread and then sharply raise torque to be transmitted through the union nut to a hand of a worker. When being screwed onto the external thread, the union nut contacts the first regulating portion and subsequently the second regulating portion.

A method and apparatus for assembling a high purity liquid distribution system is described. A distal end portion of the tube is heated then pushed over a sleeve so that the distal end portion can have a shrink seal fit over the sleeve to mitigate accidental or inadvertent pull out of the tube from a fitting. Other benefits are also achieved such as minimal flow restriction of the liquid flowing through the joint and the tube.

A dual containment fitting may include a primary tubing, a secondary tubing, and a dual containment body. The secondary tubing may surround and be concentric with a first portion of the primary tubing forming a first leak containment space between the primary tubing and the secondary tubing. The dual containment body may include a flare fitting portion and a primary containment nut portion. The flare fitting portion may surround and be concentric with the primary tubing forming a second leak containment space between the primary tubing and the flare fitting portion. The primary containment nut portion may surround and be concentric with the flared end of the primary tubing forming a third leak containment space between the primary tubing and the primary containment nut portion. The primary containment nut portion may include at least one leak passage hole connecting the third leak containment space with the second leak containment space.

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.

An inner ring of a pipe joint includes a first tapered surface formed at one axial end portion of an inner circumferential surface such that a diameter thereof gradually increases from another axial side toward one axial end thereof in a state before a bulge portion is press-fitted into an end portion of a tube. A diameter increase starting point of the first tapered surface is located in a range from a deformation starting point, which serves as a starting point from which an inner circumferential surface is deformed due to the bulge portion receiving external force from the tube when the bulge portion is press-fitted into the end portion of the tube, to a position, on the inner circumferential surface, corresponding to one axial end of an outer circumferential surface of a body portion.

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.

Disclosed is a structure for preventing a leak at a synthetic resin tube joint, which includes a synthetic resin tube including a tapered portion at an end portion; a ferrule inserted into the end portion of the synthetic resin tube and including a tapered portion corresponding to the tapered portion of the synthetic resin tube; a fitting which accommodates the synthetic resin tube and the ferrule, and includes a tapered portion corresponding to the tapered portion of the synthetic resin tube and a protrusion formed on the tapered portion of the fitting, and a nut which engages with the fitting.

A fluid circuit includes a plurality of tubing segments and a plurality of operative components. Each tubing segment includes i) a non-conductive polymer portion defining a fluid passageway and ii) one or more interior conductive fluoropolymer stripes extending axially to the ends of each of the respective tubing segments. Each operative component includes a conductive fluoropolymer that extends between a plurality of tubing connector fittings forming a part of the fluid circuit, wherein each of the tubing connector fittings conductively connect the respective conductor of the operative component to the interior conductive fluoropolymer stripes of the tubing segment to provide a path to ground that extends through each operative component and each tubing segment.