Pipeline, pipeline connector, and liquid chromatography system

A pipeline, comprising:

• a pipeline body;
• a sealing member;
• and
• a sleeve;
• wherein:
• the pipeline body comprises a connection end;
• the connection end comprises a first section and a second section adjacent to the first section;
• and the first section comprises an end face perpendicular to an axis of the pipeline body;
• the sealing member comprises a first annular part and a second annular part;
• the first annular part and the second annular part are disposed coaxially;
• the second annular part comprises a first surface oriented toward the first annular part;
• an axial projection of the first annular part falls within the first surface;
• the first surface comprises a first region and a second region;
• the first region is enclosed by the axial projection of the first annular part, and the second region surrounds the axial projection of the first annular part;
• the first annular part sleeves an outer wall of the first section;
• and the end face of the first section abuts against the first region;
• the sleeve sleeves the second section and the first annular part;
• and the sleeve comprises an end face abutting against the second region;
• and
• an outer diameter of the second annular part repeats a pattern of increasing and then decreasing along the axial direction multiple times.

A pipeline connector, comprising a screw;

• wherein:
• the screw comprises a first through hole;
• the first through hole comprises a first hole part and a second hole part disposed adjacent to the first hole part;
• the first hole part has a greater diameter than the second hole part;
• and a junction of the first hole part and the second hole part forms a first step structure;
• a sidewall of the screw further comprises a first slot communicating with the first through hole;
• the first slot extends axially through the sidewall of the screw;
• a width of the first slot, measured in a direction perpendicular to an axis of the first through hole, is smaller than a diameter of the first hole part but equal to or larger than a diameter of the second hole part;
• the pipeline connector further comprises a cap detachably connected to the screw;
• the cap comprises a second through hole and a protrusion;
• and the protrusion extends axially along the second through hole;
• the second through hole and the first through hole are coaxially disposed;
• and the protrusion is at least partially inserted into the first slot.