| 摘要 |
A spring-actuated infusion syringe includes a housing having an open distal end, with a spring-loaded piston disposed for axial translation in the housing. The piston is biased toward the distal end of the housing. The syringe also includes a barrel for containing a liquid medicament, the barrel having a distal end having a fluid passage therethrough and an open proximal end. A plunger is disposed in the barrel for axial translation therein. The proximal end of the barrel is axially insertable into the distal end of the housing, whereby the piston enters the proximal end of the barrel and engages the plunger. In use, the barrel is filled with a medicament through the fluid flow passage, and the flow of medicament from the syringe is obstructed. The proximal end of the barrel is inserted into the distal end of the housing, whereby the piston enters the proximal end of the barrel. The plunger, immobilized by the hydrostatic pressure of the liquid in the barrel, pushes the piston proximally against its biasing force. An engagement between an annular barrel flange and an internal housing thread retains the barrel at the desired axial position within the housing. To deliver the liquid from the syringe, the obstruction is removed. The hydrostatic pressure in the barrel being relieved, the biasing force of the piston pushes the plunger distally into the barrel, displacing the liquid therefrom through the fluid flow passage.
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