Two-stage pressure regulator for compressed gas

A two-stage pressure regulator, comprising:

• a body defining an inlet, an outlet, and a chamber extending between the inlet and the outlet, wherein the chamber includes an inlet section, an intermediate section, and an outlet section, and wherein the body includes an upstream valve seat adjacent the inlet;
• an upstream piston slidably positioned in the chamber adjacent the inlet to separate the inlet section and the intermediate section of the chamber, wherein the upstream piston includes a first plug that is configured to engage the upstream valve seat in a first closed position, and wherein the first plug is configured to be disengaged from the upstream valve seat in a first open position to enable compressed gas to flow from the inlet section and to the intermediate section;
• a seat assembly partially nested in the upstream piston and comprising a downstream valve seat;
• and
• a downstream piston partially nested in the seat assembly and slidably positioned adjacent the outlet to separate the intermediate section and the outlet section of the chamber, wherein the downstream piston includes a second plug that is configured to engage the downstream valve seat in a second closed position, and wherein the second plug is configured to be disengaged from the downstream valve seat in a second open position to enable the compressed gas to flow from the intermediate section and to the outlet section.