Valve seat and valve disc with cascaded geometries

A valve disc comprising:

• a substantially frusto-conical valve body having a radial axis;
• a first disc surface aligned at a first angle relative to the radial axis;
• and
• a second disc surface aligned at a second angle relative to the radial axis, wherein the second angle relative to the radial axis is smaller than the first angle relative to the radial axis.

A valve seat comprising:

• a valve seat with a substantially hollow seat interior, wherein the substantially hollow seat interior defines a substantially frusto-conical seat cavity having a radial axis, and the substantially hollow seat interior further comprises:
• a first wall section of the substantially hollow seat interior aligned at a first angle relative to the radial axis;
• and,
• a second wall section of the substantially hollow seat interior aligned at a second angle relative to the radial axis, wherein the second angle relative to the radial axis is smaller than the first angle relative to the radial axis;
• a third wall section aligned at a third angle relative to the radial axis, wherein the second wall section is positioned between the first wall section and the third wall section;
• an inlet transition section interposed between the third wall section and the second wall section, wherein the inlet transition section has an angle relative to the radial axis that is less than the third angle relative to the radial axis and greater than the second angle relative to the radial axis;
• and
• an outlet transition section interposed between the first wall section and the second wall section of the substantially hollow seat interior, wherein the outlet transition section has an angle relative to the radial axis that is less than the first angle relative to the radial axis and greater than the second angle relative to the radial axis.