Abstract: A needle-free injection device in which a gas cartridge or other source of pressurized gas is used to advance a piston and forcibly expel injectable fluid out through an injection orifice. When a gas cartridge is used, the gas cartridge may be moveable from an initial position to an actuating position in which gas is released to drive the injection, and a recoil inhibiter may be employed to prevent the gas cartridge from moving back to the initial position. A gas cartridge seal may be disposed on the gas cartridge and moveable with the gas cartridge to seal the gas cartridge against an interior wall of a gas cartridge housing. The needle-free injection device may also be configured so that sealing is compromised upon full advancement of the piston, so as to de-pressurize the device after delivery of an injection.

Abstract: A valve for a printing apparatus that uses liquid ink includes a valve seat, a valve stop and a valve member interposed between the valve seat and the valve stop.

Abstract: A system for injecting DNA-based medications into humans is provided by the present invention. The system includes a needle-free injector with an injection orifice of approximately 0.004 inches for supplying DNA-based medication at an initial pressure of from 3900 to 4300 psi, and then immediately declining to a level of about 2800 to 3800 psi, and then immediately cutting off pressure to terminate the injection. The injector includes an annular adapter for spacing the injection orifice from the skin of the patient. The adapter includes an abutment against which the injector is disposed so that the orifice is spaced approximately 0.76-1.0 inch from the skin of the patient, the adapter having an inner diameter at the distal end of approximately 0.50-0.70 inches.