Patent ID: 7621428
Filing Date: 2009-11-24
Classification: B05C,B65D,Y10T

Abstract:
1. A piston for venting air and dispensing liquid, the piston comprising: a piston shell having an opening to atmosphere formed therein; and a bleed plug having at least one bleed channel formed thereon, wherein the bleed plug is disposed within the piston shell for engagement with the liquid, and wherein the bleed plug is designed such that at a pre-determined pressure point the bleed plug moves by contact with the liquid into sealing engagement with the piston shell to form a seal; wherein the bleed plug has a sealing edge formed thereon, and the sealing edge moves into sealing engagement with the piston shell to form a seal at the pre-determined pressure point; and wherein the piston shell has a seal surface formed therein having at least one notch formed thereon and wherein the sealing edge moves into sealing engagement with the seal surface of the piston shell to form a seal at the pre-determined pressure point.