Details for Patent: 6,402,055

Title:	Device for producing high pressure in a fluid in miniature
Abstract:	A miniaturized device for pressurizing fluid. The device includes a hollow piston that provides a fluid path and a valve member. The valve member is configured for axial movement so that the valve axis remains parallel to the piston axis. The valve member is arranged at one end of the hollow piston. The valve member may be partially or completely disposed within the hollow piston. The device is particularly adapted for use in a mechanically operated atomizer to produce an inhalable aerosol of a liquid medicament without the use of propellant gas.
Inventor(s):	Jaeger; Joachim (Bruchsal, DE), Cirillo; Pasquale (Dortmund, DE), Eicher; Joachim (Dortmund, DE), Geser; Johannes (Dortmund, DE), Freund; Bernhard (Gau-Algesheim, DE), Zierenberg; Bernd (Bingen am Rhein, DE)
Assignee:	Boehringer Ingelheim GmbH (DE)
Filing Date:	Jul 16, 1999
Application Number:	09/354,663
Claims:	1. A device for pressurizing fluid, comprising: a cylinder; a cylindrical hollow piston movable in said cylinder and providing a path for fluid therethrough, wherein an inlet end or an outlet end of said hollow piston includes a widened portion, an inner diameter of said widened portion being greater than the inner diameter of the remainder of said hollow piston, and wherein said inlet end or said outlet end includes an inwardly shaped edge; a valve seal provided by said piston; a high pressure chamber inside said cylinder; and a valve operating without any auxiliary force, said valve including, a uniaxially rotationally symmetrical valve member including a sealing surface at an inlet end of said valve member to cooperate with said valve seal, said valve member being guided inside said widened portion of said hollow piston, wherein the diameter of said valve member is less than said inner diameter of said widened portion and is greater than said inner diameter of the remainder of said hollow piston, such that said valve member does not extend into the remainder of said hollow piston, stop means provided at an outlet end of said widened portion to hold said valve member inside said hollow piston, a recess in said stop means or a recess or radially extending indentation in said valve member at an outlet end thereof, wherein said valve is closed when said valve member abuts said valve seal and said valve is open when said valve member abuts said stop means. 2. A device according to claim 1, wherein said sealing surface is an end surface of said valve member. 3. A device according to claim 1, wherein said high pressure chamber is located in front of said hollow piston. 4. A device according to claim 1, wherein said valve member is mounted in an axially movable manner. 5. A device according to claim 1, wherein at least a major part of said valve member is cylindrical. 6. A device according to claim 1, wherein said valve member is cylindrical. 7. A device according to claim 1, wherein said widened portion is disposed at said outlet end of said cylindrical hollow piston and said inwardly shaped edge is disposed at said outlet end of said hollow piston and comprises said stop means. 8. A device according to claim 1, wherein said widened portion is disposed at said inlet end of said hollow piston, said inwardly shaped edge is disposed at said outlet end of said hollow piston and comprises said stop means. 9. A device according to claim 1, further comprising: an encircling constriction near said inwardly shaped edge of said hollow piston, wherein said valve member is guided and mounted in axially movable manner inside said hollow piston between said inwardly shaped edge and said encircling constriction; and a recess in the region of said outlet end of said valve member. 10. A device according to claim 9, wherein said inwardly shaped edge is disposed at said inlet end of said hollow piston and comprises said valve seal; and said encircling constriction is provided in the vicinity of said inwardly shaped edge at said inlet end of said hollow piston and comprises said stop means. 11. A device according to claim 9, wherein said inwardly shaped edge is disposed at said outlet end of said hollow piston and comprises said stop means. 12. A device according to claim 1, wherein said cylindrical hollow piston includes a first encircling constriction spaced apart from said outlet end of said hollow piston, said first encircling said constriction comprising said stop means, and a second encircling constriction between said first construction and said inlet end of said hollow piston, said second encircling constriction comprising said valve seal; and wherein said valve member is guided and mounted in axially movable manner between said first and second constrictions. 13. A device according to claim 12, further comprising a displacement body disposed at said inlet end of said hollow piston, said displacement body having an axially extending channel and being arranged in and fixedly connected to said hollow piston, said displacement body extending as far as said second encircling constriction. 14. A device according to claim 12, further comprising a displacement body disposed at said outlet end of said hollow piston, said displacement body having an axially extending channel and being mounted in and fixedly connected to said hollow piston, said displacement body extending as far as said first encircling constriction. 15. A device according to claim 1, wherein a said widened portion is disposed at said inlet end of said hollow piston and the device further comprises: a tube disposed in the remainder of said hollow piston, a closure member disposed at said widened portion, said closure member connected to and containing a flat or conical depression with a bore, and a slot provided at said outlet end of said valve member as a recess or a notch.