Disposable positive and negative pressure injector

Abstract

A disposable positive and negative pressure injector comprises a needle cylinder, a needle head, a piston and a push rod, and the needle cylinder and the piston are in interference fit and are of an oval structure with a rotation stopping function; a nut is coaxially embedded and fixedly installed on the inner side of the axial rear end of the piston body, a plurality of expansion seams are formedin the nut in the axial direction, the nut is provided with an axial inner hole, the inner hole is of a cone structure with the small front portion and the large rear portion, and internal threads are formed in the inner wall of the inner hole. The nut is screwed to be matched with the axial front end of the expansion bolt of the cylinder structure through internal threads, and the axial rear endof the expansion bolt and the axial front end of the push rod are coaxially and fixedly connected into a whole. According to the principle of the expansion bolt, the expansion bolt is screwed into the nut by rotating the push rod, so that the nut continuously expands to expand the piston, displacement of the piston is prevented, and a stable negative-pressure suction effect is achieved to suck thick liquid; both positive pressure and negative pressure can be generated; the injector is simple in structure, convenient to use and suitable for popularization.

Description

technical field [0001] The invention belongs to the technical field of medical equipment and relates to an intravenous syringe, in particular to a disposable positive and negative pressure syringe. Background technique [0002] The syringe is usually composed of a cylindrical hollow syringe, a piston push rod installed in the hollow syringe, a fixed stroke piston fitted at the front end of the piston push rod, and a needle at the front end of the syringe. When in use, the piston is in interference fit with the inner wall of the syringe to form a closed space, and the liquid is sucked or pushed out. Under the existing technology, in the daily diagnosis and treatment activities, when performing vascular puncture, puncture of pleural and peritoneal effusion, and tumor cytology biopsy, ordinary syringes are usually used, and both hands are required to pull the piston push rod to make the inner wall of the syringe barrel and the piston Interference fit, forming a closed space to...

AI Technical Summary

Problems solved by technology

In this process, ordinary syringes are likely to cause the position of the syringe and needle to move, the stability of negative pressure suction is poor, and the effect of negative pressure suction is unstable, which affects the suction effect

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