Details for Patent: 5,964,416

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)
Assignee:	Boehringer Ingelheim GmbH (DE)
Filing Date:	Oct 04, 1996
Application Number:	08/726,219
Claims:	1. A device for atomizing fluid, comprising: a housing having an upper housing part and a lower housing part; a pump housing disposed in said upper housing part; a nozzle disposed at one end of said pump housing; a cylinder disposed in said pump housing, said cylinder defining a pressure chamber; a hollow piston having a piston axis disposed in said cylinder; a valve member having a valve axis, said valve member configured for axial movement with said piston wherein the valve axis remains parallel to the piston axis, said valve member movable between an open position and a closed position, wherein fluid flows into said pressure chamber when said valve member is in the open position; a spring housing rotatably mounted on said upper housing part; a spring disposed in said spring housing; and a blocking mechanism for retaining said spring in a biased state, wherein release of said spring from the biased state causes said valve member to move to the closed position and causes said hollow piston to pressurize fluid in said pressure chamber to form pressurized fluid that is atomized by said nozzle as it exits the device. 2. A device according to claim 1, further comprising: an annular land coupled to an outlet end of said hollow piston, wherein a diameter of said annular land is less than a diameter of said hollow piston; a groove formed between said annular land and the outlet end of said hollow piston, wherein the diameter of said annular land is greater than a diameter of said groove; and wherein said valve member comprises an undercut snap hook movable in said groove so that an inner edge of said undercut snap hook abuts on said annular land when said valve member is in the open position. 3. A device according to claim 1, further comprising: an inwardly shaped edge disposed at an outlet end of said hollow piston; and wherein said valve member comprises an undercut peg having a longitudinal axis coaxial with said valve axis, said undercut peg including a projecting end, wherein said inwardly shaped edge defines a bore through which said undercut peg is received so that said projecting end is engaged by said inwardly shaped edge to limit axial movement of said valve member. 4. A device according to claim 1, wherein said hollow piston comprises a widened portion at one end of said hollow piston and a remainder portion, wherein an inner diameter of said widened portion is greater than an inner diameter of said remainder portion, and wherein said valve member is mounted in said widened portion so that said valve member is axially movable in said widened portion. 5. A device according to claim 1, further comprising: an inwardly shaped edge disposed at one end of said hollow piston, wherein said hollow piston includes an encircling constriction spaced apart from said inwardly shaped edge, wherein said valve member is mounted in a portion of said hollow piston between said inwardly shaped edge and said encircling constriction so that said valve member is axially movable in said portion. 6. A device according to claim 1, further comprising: a closure member, wherein said hollow piston comprises a widened portion at an inlet end of said hollow piston and a remainder portion, said closure member coupled to said widened portion, wherein said closure member defines a depression in which said valve member is mounted, said valve member being axially movable in said depression. 7. A device according to claim 1, further comprising: an actuating button releasing said spring from the biased state. 8. A device according to claim 1, further comprising: a counter coupled to said spring housing, said counter including a spindle and a slide. 9. A device according to claim 1, wherein said nozzle comprises two plates joined together, at least one plate having a channel that connects a nozzle inlet end to a nozzle outlet end, wherein said nozzle outlet end has a nozzle opening that has a hydraulic diameter less than or equal to 10 .mu.m. 10. A device according to claim 1, wherein said nozzle comprises at least two nozzle outlet openings each having a direction of spray, wherein the direction of spray of one nozzle outlet opening is inclined relative to the direction of spray of the other nozzle outlet opening. 11. A device according to claim 1, wherein said hollow piston exerts a pressure of about 50 to 600 bar on the fluid in said pressure chamber when said spring is released from the biased state. 12. A device according to claim 1, wherein said hollow piston exerts a pressure of about 100 to 600 bar on the fluid in said pressure chamber when said spring is released from the biased state. 13. A device according to claim 1, further comprising: a replaceable storage container for fluid to be atomized disposed in said lower housing part. 14. An atomizer for spraying pressurized liquid, comprising: an atomizing nozzle; a pump for pressurizing a predetermined volume of liquid and discharging it through said atomizing nozzle, said pump comprising a cylinder, a tubular piston reciprocable in said cylinder, wherein said piston provides an inlet flow path to said cylinder beyond a first end of said piston; a valve member movable with said piston; a liquid reservoir; a cap for said liquid reservoir, wherein said cap is penetrated by a second end of said piston remote from said first end to permit liquid to flow from said liquid reservoir through said piston into said cylinder on an induction stroke of said pump, wherein said piston and said liquid reservoir are fixed relative to each other during operation of said pump; and pump reciprocating means for providing relative movement between said piston and said cylinder. 15. An atomizer according to claim 14, wherein said second end of said piston is pointed to enable penetration of said cap. 16. An atomizer according to claim 14, wherein said pump reciprocating means comprises: a spring for operating said pump in a compression stroke; and means for tensioning said spring for operating said pump in the induction stroke. 17. An atomizer according to claim 16, wherein said pump reciprocating means further comprises: a manually operable latch for holding said spring in a biased state. 18. An atomizer according to claim 14, wherein said pump pressurizes liquid to a pressure of at least 50 bar. 19. An atomizer according to claim 14, wherein said liquid reservoir comprises liquid medicament for inhalation into the lungs, said atomizing nozzle atomizing the liquid medicament into droplet having a mass mean size of not more than 12 .mu.m. 20. A reciprocating pump device for pressurizing fluid, comprising: a cylinder; a hollow cylindrical piston having a piston axis reciprocable in said cylinder, said piston providing a path for fluid to flow therethrough, wherein a portion of said piston defines a valve seat; a pressure chamber disposed in said cylinder, wherein fluid flows through said piston into said pressure chamber; a valve member movable by said piston between a closed position in contact with said valve seat and an open position spaced apart from said valve seat, said valve member comprising a surface that engages said valve seat, wherein said valve member is configured so that it cannot rotate about an axis transverse to the piston axis. 21. A reciprocating pump device according to claim 20, wherein said valve member is cylindrical. 22. A reciprocating pump device according to claim 20, wherein said valve seat is frustoconical.