Patent ID: 11892375
Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. A method for inspecting an interior of a conduit and for determining abnormality associated with the conduit, comprising:
supplying water from a tank to an interior of the conduit through a hose connected to the conduit at a first end of the conduit;
while the supplying of the water continues:
releasing air at a second end of the conduit from the interior of the conduit to an outside of the conduit through an air vent tube of an air vent portion placed at the second end of the conduit, wherein the second end is distinct from the first end, wherein the releasing of air continues until water is released through the air vent tube;
determining whether water that does not contain air is drained from the air vent tube placed at the second end of the conduit; and
when it is determined in the determining that water that does not contain air is drained from the air vent tube, stopping the supplying of the water to the interior of the conduit, closing an air vent valve of the air vent portion, and, when the air vent valve is closed, the closed air vent valve of the air vent portion prevents the air from being released to outside the conduit;

resume supplying the water into the interior of the conduit at the first end of the conduit while both the first and second ends of the conduit are blocked, thereby increasing a pressure of the interior of the conduit whose interior is filled with water; and
when the pressure of the interior of the conduit reaches a predetermined pressure value, stopping the resumed supplying of the water;
measuring a pressure value of the interior of the conduit when a predetermined period of time elapses since stopping the resumed supplying of the water, wherein the predetermined period of time elapses while the conduit is blocked at the first end and the second end and without receiving further supply of the water; and
determine, based on a change in the measured pressure value of the interior of the conduit, the abnormality associated with the conduit.