Patent ID: 7762961

Claim:
A pressure generating unit for a biopsy apparatus carrying a biopsy needle unit, comprising: a cylinder having an interior cylinder wall, a first cylinder space, a second cylinder space, a connector, and a connecting path, the connector being located at a first end of the cylinder adjacent the first cylinder space and configured for connection to the biopsy needle unit, the connecting path being configured to facilitate selective connection between the first cylinder space and the second cylinder space; a piston arrangement including a piston connected to a piston spindle, the piston being movably positioned in the cylinder, a vacuum being generated in the first cylinder space by retracting the piston and the vacuum being released when the piston is positioned adjacent the connecting path; and an absorbent element carried by the piston, the absorbent element being located in contact against the interior cylinder wall, wherein the piston separates the first cylinder space from the second cylinder space, and the absorbent element filters air prior to entry into the first cylinder space via the connecting path when the piston is positioned over the connecting path to release the vacuum.