The present invention is concerned with a sealing cover with quick-plug interface, comprising: cover body, above which a through hole is arranged, and in which a communication hole is arranged, and said through hole is connected with said communication hole; an annular sealing member and an annular fixing sleeve are arranged in said through hole, and said sealing member is arranged at the bottom of said through hole, and said fixing sleeve is arranged above said sealing member; said sealing member and said fixing sleeve are both clipped to an inner wall of the through hole, and said sealing member is made of a flexible material. There is no metal material in contact with the fluid inside the sealing cover with quick-plug interface provided by the present invention, so there is no hidden danger of corrosion in long-term use, and the defect that the metal material is not resistant to corrosive fluids is avoided.

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.

[Problem] To provide a pipe joint allowing reliable connection to a pipe P without flaring.

[Means of solving problem] The pipe joint includes a flare joint body 1F, a cap nut 2, and a stop ring 3. A curved pressure-contacting slope surface 32 of the stop ring 3 contacts a slope surface 5 with reduced-diameter tip of the flare joint body 1F under pressure to establish sealing by means of mutual contact between metallic surfaces. The pipe P is grasped in a tightly pressure-contacting state using a back tooth and a front tooth formed at a tip head 37 of a substantially cylindrical thin part 35 of the stop ring 3.

[Problem] To provide a pipe joint allowing reliable connection to a pipe P without flaring.

[Means of solving problem] The pipe joint includes a flare joint body 1F, a cap nut 2, and a stop ring 3. A curved pressure-contacting slope surface 32 of the stop ring 3 contacts a slope surface 5 with reduced-diameter tip of the flare joint body 1F under pressure to establish sealing by means of mutual contact between metallic surfaces. The pipe P is grasped in a tightly pressure-contacting state using a back tooth and a front tooth formed at a tip head 37 of a substantially cylindrical thin part 35 of the stop ring 3.

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 fluid coupler including a ferrule adapter having a body with a receiving bore for receiving a fluid conduit, a stop axially spaced away from the body and configured to engage an end of the fluid conduit, and a connector configured to adjust the axial distance between the body and the stop.

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 pipe connecting system for first and second pipe pieces extending along a common longitudinal axis includes a clamp. The pipe pieces each have first end and first clamping surfaces. The clamp has first and second contact surfaces lying against respective clamping surfaces to prevent the clamping surfaces from moving away from one another, while leaving a space between the first and second end surfaces. A retaining ring has a sealing connection attachment to the second pipe piece, and on which a sealing ring is mounted, the sealing ring lying against a circumferential first sealing surface of the first pipe piece. An interior of the first and second pipe pieces between the two pipe pieces is sealed against the surrounding environment by the sealing connection. The two pipe pieces can move towards one another without the first sealing ring moving out of contact with the first sealing surface.

A pipe connecting system for first and second pipe pieces extending along a common longitudinal axis includes a clamp. The pipe pieces each have first end and first clamping surfaces. The clamp has first and second contact surfaces lying against respective clamping surfaces to prevent the clamping surfaces from moving away from one another, while leaving a space between the first and second end surfaces. A retaining ring has a sealing connection attachment to the second pipe piece, and on which a sealing ring is mounted, the sealing ring lying against a circumferential first sealing surface of the first pipe piece. An interior of the first and second pipe pieces between the two pipe pieces is sealed against the surrounding environment by the sealing connection. The two pipe pieces can move towards one another without the first sealing ring moving out of contact with the first sealing surface.

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.