Evacuation valve
An evacuation valve for a metering device or pump for a liquid medium is disclosed. The valve includes a seal holder having an annular groove formed therein and an O-ring seal. The O-ring seal is positioned within the annular groove and provides an evacuation valve seal surface.
1. An apparatus for metering a liquid medium, said apparatus comprising:
an evacuation valve for a liquid medium metering device having an O-ring seal and a seal holder, wherein the evacuation valve is in removable communication with a cylinder open end;
said seal holder comprising a unitary, one-piece construction;
said seal holder consists of a body having an outer surface;
said seal holder defining an annular groove formed in said outer surface; and
said O-ring seal being positioned within said annular groove; wherein said O-ring is biased against said annular groove by said liquid medium when said apparatus is pumping said liquid medium.
2. The apparatus of claim 1 , wherein said O-ring seal and said seal holder includes an external portion of said O-ring seal extending axially outwardly of said outer surface of said seal holder.
3. The apparatus of claim 1 , wherein said annular groove having an inner diameter being greater than an inner diameter of said O-ring seal.
4. The apparatus of claim 1 , wherein said O-ring seal has an outer diameter and said annular groove has an outer diameter; said outer diameter of said annular groove being the same as said outer diameter of said O-ring seal.
5. The apparatus of claim 1 , wherein said O-ring seal has a height and said annular groove has a depth, said O-ring seal height being greater than said annular groove depth.
6. The apparatus of claim 1 , wherein said seal holder is formed from hexagonal bar stock.
7. The apparatus of claim 6 , wherein said hexagonal bar stock has apices, each apex being substantially broken.