NEEDLE-LESS INJECTOR OF MINIATURE TYPE

摘要

Needleless injectors for liquids are known from the art in a variety of designs that are adapted to different conditions of application. The inventi ve needleless injector is designed as a hand-held device. It comprises a lockab le tensioning system, an energy-storing spring (36), a hollow piston (37) displaceable within a cylinder (38), and a nozzle (39). The hollow piston is provided with a valve body on its one end. The storage container (44) for th e liquid is disposed within the housing. The lockable tensioning system is tensioned by counterrotating the two housing parts (31; 32), thereby withdrawing the hollow piston (37) from the cylinder (38). At the same time the amount of liquid required for the injection is withdrawn from the storag e container (44) and transported through the hollow piston to the pump chamber (34). When the lockable tensioning system is released, the amount of liquid is ejected from the pump chamber through the nozzle. The needleless injector is easy and reliable to handle also for unpracticed people. It is used for intracutaneous injections of a medical liquid into biological tissue, for injecting a liquid containing an active substance into a plant or for injecting a liquid through a membrane into the space behind said membrane.