Liquid fuel system and method

A method of protecting a flow of liquid fuel in a fuel line from the heat produced by a combustor of a gas turbine engine when the fuel line is not in use, comprising:

• positioning a purge air inlet about the fuel line upstream of the combustor
• positioning a check valve on the fuel line upstream of the purge air inlet;
• positioning a drain valve about the fuel line downstream of the check valve and at an elevation that is less than the combustor;
• forcing a flow of purge air through the purge air inlet and into the fuel line;
• opening the drain valve;
• and
• flowing the liquid fuel through the drain valve.

A purge air drain system for use with a flow of a liquid in a liquid line, comprising:

• a purge air inlet, in communication with a source of purge air, positioned about the liquid line;
• a check valve positioned on the liquid line upstream of the purge air inlet;
• a drain line in communication with the liquid line downstream of the check valve;
• and
• a drain valve in communication with the drain line and configured to allow so as to drain the flow of liquid in the liquid line downstream of the check valve to drain via a flow of purge air through the purge air inlet and opening the drain valve.