Corrosion is the enemy of all who have to do with underground pipe lines. Technical knowledge and experimentation have brought forth various coatings and wrappings for buried pipe. To determine the effectiveness of the pipe covering in combating corrosion without the necessity of uncovering the pipe, is the object of an electrical device invented and developed by A. L. Smith of Houston, Tex.
Mr. Smith in conjunction with Crutcher-Rolfs-Cummings, Inc. has been conducting a series of practical tests with the device, results of which have been marked with success.
The apparatus consists of a high frequency transmitter and a receiving instrument for measuring electrical flux density, both of which are portable.
The transmitter, one terminal of which contacts the pipe and the other connects with a ground rod located some distance to the side of the line, charges the pipe. The receiving instrument is carried along the line and, through a ground contact made at desired intervals, reacts to current discharges from the pipe in proportion to the current density in the soil around the pipe. The instrument has many possibilities.
It may be used, by utilizing the principle of two ground rods, for determining, in advance of pipe laying, the corrosive areas on proposed rights of way. Similarly in consideration of cathodic protection for sections of pipe lines, it will serve to check conditions of coating with respect to conductance.
Oil leaks or "collar sweats" on bare lines not visible on the surface also can be located by the instrument. Experiments now are being made to prove possible utilization of this new principle of measuring flux density in determining the geological nature of strata in drilling wells. R. H. 0.
"Was it not Dr. Johnson who even reproached Benjamin Franklin with collecting electricity in a bottle while such trifles as wars and political fortunes of the nations were left to pass unnoticed?"-J.
M. Clarke.