Pressure vessel arrangement providing piston position feedback, pressure vessel, and method for providing piston position feedback in a pressure vessel

A pressure vessel comprising:

• a cylinder construction having a cylinder wall extending from a cylinder wall first end to a cylinder wall second end, and having an internal surface forming an interior region;
• a first end cap closing the cylinder wall first end and having an optical window located therein to permit passage of light therethough and into the interior region, wherein the optical window comprises a first surface and a second, opposite, surface, wherein:
• (i) the first end cap comprises:
• (A) a cap structure having an optical window receiving region;
• and
• (B) an optical window attachment construction for holding the optical window in place within the optical window receiving region;
• (C) a first seal gasket located between the optical window first surface and a surface of the cap structure to prevent the optical window first surface from contacting the surface of the cap structure;
• and
• (D) a second seal gasket located between the optical window second surface and the optical window attachment construction;
• a second end cap closing the cylinder wall second end;
• and
• a piston constructed to slide within the cylinder construction interior region along a direction between the cylinder all first end and the cylinder wall second end and along the cylinder construction internal surface to separate the interior region into a first end interior region and a second end interior region.

A method for providing piston position feedback in a pressure vessel comprising:

• (a) emitting light through an optical window located in an end cap of the pressure vessel, wherein the optical window comprises a first surface and a second, opposite, surface, the pressure vessel including:
• a cylinder construction having a cylinder wall extending from a cylinder wall first end to a cylinder wall second end, and having an internal surface forming an interior region;
• a first end cap closing the cylinder wall first end and having the optical window located therein to permit passage of light therethough and into the interior region, wherein:
• (i) the first end cap comprises:
• (A) a cap structure having an optical window receiving region;
• and
• (B) an optical window attachment construction for holding the optical window in place within the optical window receiving region;
• (C) a first seal gasket located between the optical window first surface and a surface of the cap structure to prevent the optical window first surface from contacting the surface of the cap structure;
• and
• (D) a second seal gasket located between the optical window second surface and the optical window attachment construction;
• a second end cap closing the cylinder wall second end;
• and
• a piston constructed to slide within the cylinder construction interior region along a direction between the cylinder all first end and the cylinder wall second end and along the cylinder construction internal surface to separate the interior region into a first end interior region and a second end interior region;
• (b) receiving light reflected from the piston;
• and
• (c) determining the position of the piston in the cylinder construction based on information about the light emitted and the light received.