Residual gas volume measuring device and residual gas volume measuring method

A residual gas volume measuring method for introducing residual gas in a container to be tested into an airtight container filled with a basic carbon dioxide absorbing liquid and measuring the volume of the residual gas, comprising:

• an opening step of opening a valve provided in a first pipe through which a first reservoir retaining the carbon dioxide absorbing liquid and the airtight container are in communication with each other and that is filled with the carbon dioxide absorbing liquid;
• a preparing step of sending pressurization water retained in a second pipe through which a second reservoir retaining the pressurization water and the airtight container are in communication with each other, a section closer to the airtight container of which is filled with the carbon dioxide absorbing liquid, and a section closer to the second reservoir of which is filled with the pressurization water, toward the second reservoir, using a pump provided in the section of the second pipe that is filled with the pressurization water;
• an introducing step of introducing the residual gas from the container to be tested into the airtight container;
• a closing step of closing the valve;
• a first measuring step of measuring pressure in the airtight container;
• a pressurizing step of sending the pressurization water in the second pipe toward the second reservoir using the pump;
• a second measuring step of, after the end of the sending of the pressurization water in the second pipe in the pressurizing step, measuring pressure in the airtight container;
• and
• a calculating step of calculating the volume of the residual gas, based on the pressure measured in the first measuring step and the pressure measured in the second measuring step.