Thermal insulating bushing for piston first stages

A first stage pressure regulator comprising:

• a valve body having an inlet and an outlet and defining a pressure chamber between the inlet and the outlet, the valve body defining a pressure compensation chamber having an opening fluidly communicating the pressure compensation chamber with a surrounding water;
• a valve seat within the valve body;
• a valve member slidably carried within the valve body pressure chamber having a valve end and an expansion head connected to the valve end, the valve member slidable between an open state in which the valve end is spaced from the valve seat and that permits fluid flow between the inlet and outlet and a closed state in which the valve end is sealingly seated against the valve seat and that prevents fluid flow between the inlet and outlet, the expansion head being exposed to the pressure compensation chamber and being operably acted upon by the surrounding water within the pressure compensation chamber to bias the valve member toward the open state;
• an annular insulating bushing within the compensation chamber and covering a portion of the valve body defining a portion of the pressure compensation chamber;
• and
• a biasing member interposed between the annular insulating bushing and the expansion head to bias the valve member towards the open state.