A protective sleeve placed within the cylinder of a syringe, the sleeve protects a piston and a computer controlled device or human operator pushing the piston from material leaking past a piston assembly. The sleeve has lips or ridges at either end, one that is attached to the piston assembly at the output end of the syringe and a second lip that is attached with a retention plate at the far end of the syringe. The sleeve may have a bellows or accordion configuration that slides along the inner surface of the syringe cylinder without appreciably loading the drive mechanism.一種保護套筒安裝在一注射器之圓筒內,此套筒保護一活塞及一電腦控制裝置或人員操作者推動活塞免於材料洩漏通過一活塞組合。套筒在任一端具有唇部或突脊,一個被附著到在注射器之輸出端的活塞組合,且一第2唇部被附著於在注射器之遠端的一保持板。套筒可具有一風箱或手風琴式結構,其沿注射器圓筒之內表面滑動而不致給驅動機構施以重大負荷。2...注射器4...活塞6...軸8...出口10...空間12...注射器圓筒之內表面14...注射器圓筒20...保護套筒
