MEASURING METHOD OF LENGTH OF CONDUIT

摘要

PURPOSE:To obtain a method for measuring the length of a buried conduit quickly beforehand on the occasion when a cable is laid in the conduit. CONSTITUTION:A method for measuring the length of a conduit by sending air into the conduit 3 and inserting a filament body 1 therethrough by an air flow. The filament body 1 is formed of a light and flexible wire 1-2 and lightweight and elastic members 1-1 of large diameters fitted to the fore end of the wire and intermediate parts thereof. The diameters of the members 1-1 of large diameters are made larger toward the fore end, or intervals of the members 1-1 of large diameters being adjacent mutually are made narrower toward the fore end, and the filament body thus formed is inserted through quickly to a manhole 4 of an exit.