CN201441705U - Low-resistance syringe plunger - Google Patents

Abstract

The utility model relates to a low-resistance syringe plunger, which belongs to the technical field of medical appliances. The syringe plunger has the following characteristics: the thickness of the conical top of the plunger is radially gradually increased from the center out, the inner cavity of the plunger consists of a plurality of cavities which are communicated with one another, and moreover, the diameter of the cavity at the open end is larger than or equal to the diameters of the other cavities at the rear end. A small interference fit can be adopted between the diameters of seal rings of the plunger with the shape and the inner wall of an outer sleeve of a syringe, so the push-pull resistance is low. When the syringe sucks or pushes liquid, the sizes of the front and the rear seal rings can be increased due to the deformation of the plunger, the higher the differential pressure is, the heavier deformation is, and as a result, leakage is prevented. Consequently, the syringe can be easily pushed and pulled during operation, and the sealing property is good.

Description

A kind of injection with low resistance piston

Affiliated technical field

This utility model relates to a kind of injection with low resistance piston, belongs to technical field of medical instruments.

Background technology

For guaranteeing the sealing of piston and overcoat, adopt tight slightly interference fit between the sealing ring of conventional syringe piston and the outer casing inner wall, cause in the use push-and-pull syringe core rod resistance big, increased medical worker's working strength greatly.

Summary of the invention

This utility model provides a kind of injection with low resistance piston, it has, and the magnitude of interference is little between the piston packing and outer casing inner wall in the use, resistance is low, with the good again performance of syringe jacket fitted seal, make clinical manipulation light, flexible.

The technical scheme that its technical problem that solves this utility model adopts is: the thickness of piston conical top is radially by outwards thickening gradually of center, when promoting core bar, because the big too pressure of rear end of the pressure of syringe piston front end, the conical top of piston caves in and the outside circumferencial direction stretching, extension of sealing ring before making, and the magnitude of interference before the piston between sealing ring and the outer casing inner wall and active force strengthen with the increase of internal syringe compression.During the pull core bar, because the inside of piston is communicated with by a plurality of difform cavitys and forms, and the diameter of opening cavity is more than or equal to the diameter of other cavity of rear end, so distance is not more than the distance between other sealing ring edge and each cavity inner wall between sealing ring edge, back and the opening cavity inner wall, when the pressure of syringe piston opening cavity syringe pressure inside greatly too, the outside circumferencial direction upset of the back sealing ring of piston, the magnitude of interference behind the piston between sealing ring and the outer casing inner wall and active force strengthen with the reduction of internal syringe compression.

So, when syringe uses the described piston of this patent, just can adopt the less magnitude of interference between piston packing and the outer casing inner wall, push-and-pull syringe feel is light when operating, resistance is low, the purpose of good airproof performance thereby reach.

This utility model is simple in structure, material consumption is lower in the production process, realize easily producing in batches, because that it has is good with the syringe jacket fitted seal, resistance is low in the use, this utility model has improved medical worker's work efficiency, has reduced working strength.

Description of drawings

Fig. 1 is the structural representation of embodiment;

Among Fig. 1: 1. conical top, 2. before sealing ring, 3. back sealing ring, 4. other cavity of rear end, 5. opening cavity

The specific embodiment

Below, accompanying drawings performance of the present utility model:

The thickness of piston conical top (1) is radially by outwards thickening gradually of center, when promoting core bar, the big too pressure of rear end of the pressure of syringe piston front end, the conical top of piston (1) caves in and makes outwards circumferencial direction stretching, extension of preceding sealing ring (2), and the magnitude of interference before the piston between sealing ring (2) and the outer casing inner wall and active force strengthen with the increase of internal syringe compression.

When the pull core bar, the pressure of syringe piston opening cavity (5) is the syringe pressure inside greatly too, sealing ring behind the piston (3) is upset outwards, and the magnitude of interference between sealing ring behind the piston (3) and the outer casing inner wall and active force strengthen with the reduction of internal syringe compression.

Claims (2)

1. injection with low resistance piston, the thickness that it is characterized in that the conical top (1) of piston is radially by outwards thickening gradually of center, when producing pressure in the syringe cavity, the conical top of piston (1) caves in and makes outwards circumferencial direction stretching, extension of preceding sealing ring (2).

2. injection with low resistance piston according to claim 1 is characterized in that: the inside of piston is communicated with by a plurality of difform cavitys and forms, and the diameter of opening cavity (5) is more than or equal to the diameter of other cavity of rear end (4).

Images