The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 12, 1978
Filed:
Apr. 01, 1977
Wolfgang Hein, 3354 Dassel, DE;
Peter Grundmann, 5330 Konigswinter, DE;
Claus Cosack, 3354 Dassel, DE;
Other;
Abstract
A syringe of the slide piston pump type is adapted to overcome a pressure resistance at its outlet as may be provided, for instance, by a filter in communication with the outlet and through which the syringe is to pump a medium, particularly a liquid medium, for filtration. The syringe comprises a cylinder containing a piston, and a piston rod. The piston rod is fixed to a second piston sliding within a longitudinal bore in the first-mentioned piston. The bore and the second piston cooperate to define an air-filled pressure chamber connected to a cylinder chamber, defined by the first piston and the cylinder, by a valve. Inward movement of the piston rod produces an over-pressure (e.g. 16 atmospheres) in the pressure chamber to open the valve to apply the over-pressure to the liquid or other medium in the cylinder chamber to overcome the pressure resistance of the filter and enable the liquid to be forced through the filter. A safety pressure release is provided to prevent bursting or inadvertent release of the liquid medium.