Pressure measuring method and device

A pressure measuring method which, by the connection to a pipe for feeding a gas or a liquid, measures the pressure in the said pipe, comprising

• a pressurizing and depressurizing step for pressurizing or depressurizing the inside of the pipe held in the closed state, and
• a step for measuring an amount of pressure change of the pipe in the standing state after completion of the said pressurizing and depressurizing step,
• wherein;
• before the said pressurizing and depressurizing step or after completion of the measurement of the amount of pressure change in the standing state, the said pipe is closed after adjusting the in-pipe pressure to the pressure outside the pipe, and the amount of pressure change in the pipe due to a temperature change is measured,
• an amount of pressurization and depressurization change of the in-pipe pressure by the said pressurizing and depressurizing step or an additional pressurizing and depressurizing step, and the flow rate of the gas or the liquid which is fed into, or discharged from the pipe during the pressurization or the depressurization, are measured,
• the volume of the pipe in the closed state is calculated on the basis of the said amount of pressurization and depressurization change, and the said flow rate of the gas or the liquid,
• the value of the said amount of pressure change in the standing state is amended in accordance with the said amount of pressure change due to the temperature change,
• and the amount of leakage of the gas or the liquid from the pipe is calculated on the basis of the said amended amount of the pressure change in the standing state and the said volume of the pipe.

A pressure measuring method which, by the connection to a pipe for feeding a gas or a liquid, measures pressure in said pipe, comprising

• a pressurizing and depressurizing step for pressurizing or depressurizing the inside of the pipe held in a closed state, and
• a measuring step for actually measuring an amount of pressure change of the pipe in a standing state after completion of said pressurizing and depressurizing step,
• wherein,
• before said pressurizing and depressurizing step, said pipe is closed after adjusting in-pipe pressure to match pressure outside the pipe, and an amount of pressure change in the pipe due to temperature change is measured,
• a predicted value of said amount of pressure change in the standing state is calculated in accordance with said amount of pressure change due to temperature change, and
• leakage condition of said pipe is judged by comparing said predicted value with the actually-measured amount of pressure change in the standing state.

A pressure measuring device performing a pressure measuring method which, by connection to a pipe for feeding a gas or a liquid, measures pressure in said pipe, comprising

• means for pressurizing or depressurizing the inside of the pipe held in a closed state, and
• means for measuring an amount of pressure change of the pipe in a standing state after completion of said pressurizing and depressurizing step, wherein,
• before said pressurizing and depressurizing step, said pipe is closed after adjusting in-pipe pressure to match pressure outside the pipe, and an amount of pressure change in the pipe due to temperature change is measured,
• and a value of said amount of pressure change in the standing state is amended in accordance with said amount of pressure change due to the temperature change, and influences of the temperature change on the pressure change in the standing state are eliminated.

A pressure measuring method which, by connection to a pipe for feeding a gas or a liquid, measures pressure in said pipe, comprising

• a pressurizing and depressurizing step for pressurizing or depressurizing the inside of the pipe held in a closed state, and
• a measuring step for measuring an amount of pressure change of the pipe in a standing state after completion of said pressurizing and depressurizing step, wherein,
• after completion of the measurement of the amount of pressure change in the standing state, said pipe is closed after adjusting in-pipe pressure to match pressure outside the pipe, and an amount of pressure change in the pipe due to temperature change is measured,
• and a value of said amount of pressure change in the standing state is amended in accordance with said amount of pressure change due to the temperature change, and influences of the temperature change on the pressure change in the standing state are eliminated.