Claims for Patent: 7,284,474

Summary for Patent: 7,284,474

Title:	Piston-pumping system having o-ring seal properties
Abstract:	The present invention relates to a piston pumping system for substantially gas-free measurement and/or pumping of predetermined quantities of liquids, preferably pharmaceutical liquids containing oxidation-prone ingredients. Preferably, the system is used as a micropump or as a component thereof in medical devices such as transdermal therapeutic systems, for example.
Inventor(s):	Eigemann; Jutta (Dortmund, DE), Geser; Johannes (Ingelheim, DE)
Assignee:	Boehringer Ingelheim International GmbH (Ingelheim, DE)
Application Number:	10/727,286
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for patent 7,284,474
Patent Claims:	1. A piston pumping system comprising a piston guided within a guide tube and capable of performing a stroke movement along its longitudinal axis, opening into a pumping chamber, the pumping chamber being connected via a liquid-conveying connection with valve to a storage vessel and from the pumping chamber a liquid conveying connection leads to a device for delivering the liquid, wherein within the guide tube is formed an O-ring seal held by a groove which seals off the piston, has a gas permeation coefficient of 100 to 500 N*cm.sup.3*mm/(m.sup.2*h*bar) for nitrogen (N.sub.2) and a radial compression of less than 30% and the seal fills the groove with a groove filling level of more than 90%. 2. A piston pumping system according to claim 1, wherein the groove filling level is more than 95%. 3. A piston pumping system according to claim 1, wherein the valve is a non-return valve. 4. A piston pumping system according to claim 1, wherein a non-return valve is formed in the connection to a device for delivering the liquid. 5. A piston pumping system according to claim 1, wherein the piston has a diameter of 0.25 to 4 mm. 6. A piston pumping system according to claim 1, wherein the piston has a length of 5 mm to 10 cm. 7. A piston pumping system according to claim 1, wherein the stroke movement of the piston along its longitudinal axis covers a length from 1 mm to 5 cm. 8. A piston pumping system according to claim 1, wherein the O-ring seal consists of silicon. 9. A piston pumping system according to claim 1, wherein the piston is a hollow piston in which the liquid-conveying connection with a valve, which connects the pumping chamber to a storage vessel, is integrated. 10. A piston pumping system according to claim 1, wherein the movement of the piston is mechanically controlled. 11. A piston pumping system according to claim 10, wherein the piston is moved by a helical spring. 12. A piston pumping system according to claim 1, wherein the movement of the piston is electronically controlled. 13. A piston pumping system according to claim 12, wherein the piston is controlled by a microchip. 14. A piston pumping system according to claim 12, wherein the piston is moved by a piezoelectric element. 15. A piston pumping system according to claim 1, wherein the pump volume is from 1 microliter to 1 ml. 16. A piston pumping system according to claim 1, wherein the device for delivering the liquid is at least one nozzle, at least one micro-pin or at least one microcutter along which the liquid is guided, at least one canula and/or at least one outlet. 17. A piston pumping system according to claim 1, wherein the cord thickness of the O-ring is from 0.3 to 3 mm.