Cap for syringe needle and device for dialysis circuit priming

A dialysis circuit priming device comprising:

• a first needle cap and a second needle cap, the first and second needle caps each having a tip end part and a base part, the base part having a needle connecting part, the needle connecting part being arranged with a needle;
• a joint member having two ends and two locking parts, one locking part of the two locking parts arranged at each end of the two ends;
• and
• a flow path connected to the needle connecting parts of the first needle cap and the second needle cap,
• wherein each tip end part of the first and second needle caps has an opening,
• wherein each tip end part of the first and second needle caps has a shape which locks with the locking parts of the joint member,
• wherein the joint member locks the tip end part of the first needle cap at one of the locking parts and the tip end part of the second needle cap at the other locking part of the two locking parts,
• wherein the needle includes a tip, a frustoconical part and a cylindrical part sequentially arranged,
• wherein the cylindrical part has a diameter larger than a diameter of the tip,
• wherein a diameter of the frustoconical part expands radially outward from the tip toward the cylindrical part,
• wherein each of the first and second needle caps has a cylindrical inner surface at the needle connecting part and a frustoconical inner surface connecting to the cylindrical inner surface,
• wherein a diameter of the frustoconical inner surface contracts radially inward from the cylindrical inner surface toward the tip end part, and
• wherein each needle connecting part of the first and second needle caps covers the cylindrical part of the needle.

A needle cap comprising:

• two ends;
• a needle connecting part arranged at one end of the two ends, the needle connecting part having a diameter larger than a diameter of the other end of the two ends, and the needle connecting part being capable of connecting a needle;
• a cylindrical inner surface at the needle connecting part;
• a frustoconical inner surface connecting to the cylindrical inner surface;
• an opening arranged at the other end of the two ends;
• a flow path connected to the opening;
• and
• a threaded part arranged at the other end of the two ends,
• wherein the needle includes a tip, a frustoconical part and a cylindrical part sequentially arranged,
• wherein a diameter of the frustoconical part expands radially outward from the tip toward the cylindrical part,
• wherein a diameter of the frustoconical inner surface contracts radially inward from the cylindrical inner surface toward the opening, and
• wherein the needle connecting part is capable of covering the cylindrical part of the needle.