| 摘要 |
PURPOSE:To detect a gas leak by noticing that the temp. of a gas in a liquid state or a gas immediately after vaporization is low, and measuring a temp. decrease in a low-temp. insulating material covering piping, flanges, etc. of a plant. CONSTITUTION:A pipe 2, wherein a gas 1 in a liquid state (low-temp. fluid) such as liquefied propane flows, is surrounded with a low-temp. insulating material 3 such as urethane and thermally insulated to avoid the temp. increase due to external air. The outside thereof is mechanically protected by providing a cover 4 consisting of a steel plate, etc. When such a low-temp. insulating material is provided to the pipe, the temp. gradient on the cross section of the low-temp. insulating material 3 shows a pattern like a curve A represented with a solid line. Meanwhile, when leakage happens, the temp. gradient becomes a curve B as shown by an alternate long and short dash line and the temp. at a measuring point l=l1 in the low-temp. insulating material is decreased by DELTAT (50-60 deg.C) due to the leakage. Accordingly, a gas leak is detected by detecting the DELTAT. |
