Expansion valve

A spool assembly configured for use in a two-stage proportional control valve in a fluid system comprising:

• a sleeve, wherein the sleeve is substantially cylindrical and includes an axially extending sleeve bore formed therein and extending from an open first end to an open second end of the sleeve;
• and
• a spool including a spool bore extending axially from an open first axial end to a closed second axial end and slidably mounted within the sleeve bore, the spool further including:
• a first circumferentially extending groove formed on an outside surface thereof and defining a fluid flow path;
• a second circumferentially extending groove formed on an outside surface of the spool near the first axial end thereof;
• a third circumferentially extending groove formed on an outside surface of the spool near the second axial end thereof;
• a circumferentially extending pressure groove formed on an outside surface of the spool between the second axial end and the third circumferentially extending groove;
• a first transverse fluid passageway formed through a side wall of the spool between the spool bore and the second circumferentially extending groove;
• a second transverse fluid passageway formed through a side wall of the spool between the spool bore and the third circumferentially extending groove;
• and
• a third transverse fluid passageway formed through a side wall of the spool between the spool bore and the circumferentially extending pressure groove.