Cc Technologies Systems, Inc.

Gas Research Institute

Other

Cc Technologies Laboratories, Inc.

Neil G Thompson

George T Ruck

Kurt M Lawson

John R Birchmeier

Steven B Helton

Kenneth J Walcott

John A Beavers

Mark Yunovich

Dan L Caudill

Thomas J Barlo

An automated, remote control/monitoring system for a cathodic protection system for a buried metallic object based on monitoring multiple coupon test stations, buried next to the metal object, by a central processor, which can individually control multiple cathodic protection rectifiers. Preferably, the reference for potential measurements is a buried coupon having a metallurgy substantially the same as the metallurgy of the buried object.

Automated cathodic protection monitor and control system

An automated coupon monitor for detecting the electrical parameters associated with a pipe, a coupon and a reference electrode utilized with a cathodic protection system. A voltage detector circuit has its output applied to a pair of sample and hold circuits, one for recording E.sub.OFF and the other for recording E.sub.ON. Series connected between the coupon and the pipe is a zero resistance current detector circuit and an interrupter switch for measuring the pipe-coupon current and periodically interrupting that current to permit measurement, sampling and storing of E.sub.OFF. The sample and hold circuits and the interrupter switch are controlled by a microprocessor controller. The circuit provides DC level outputs which can be easily read by a digital multimeter or stored in a data logger for subsequent reading or transmission to another location.

Coupon monitor for cathodic protection system

A test station for measuring the effectiveness of cathodic protection including a cylindrical plastic reference tube extending downwardly through the soil to near the protected structure, such as a pipe. Two plastic coupon tubes extend within the chamber of the reference tube attaching to opposite sides of its interior sidewalls. First and second circular cylindrical rod-shaped coupons attach to, and sealingly engage, the bottom ends of the coupon tubes. Insulated conductors extend from attachment to each coupon upwardly through the coupon tubes. A first coupon is electrically connected to the pipe, and the second coupon is used to measure a free-corrosion (native) potential.

Coupon test station for monitoring the effectiveness of cathodic

A method for detecting the presence or absence of corrosion of cathodically protected steel structures in soil and concrete in which the cathodic protection circuit is subjected to an electrochemical impedance spectroscopic analysis and the presence of corrosion is indicated by the presence of a Warburg impedance.

Method for detecting the presence or absence of corrosion of

A corrosion monitoring apparatus and method for determining the corrosive effects of a chemical environment, having an environmental pressure, on a vessel containing the chemical environment. A probe is exposed to the environment and is made of a material substantially similar to that of which the vessel is made. The probe has a sealed internal chamber which contains a pressurized fluid which is monitored. A pressure transducer is in communication with the sealed internal chamber of the first probe for translating any pressure change within the chamber into a (preferably electrical) signal which is indicated by an electrical meter or similar device. Stress corrosion cracking of the probe causes fluid leakage and, therefore, a pressure change.

Monitoring of stress corrosion cracking

A method for detecting the polarized potential of a buried pipe which is cathodically protected by rectified alternating current impressed upon the pipe. Each rectified protection current is periodically pulsed to an off state for a precise pulse duration and pulse period which are integral multiples of the period of the alternating current. The potential between the pipe and a reference electrode at the test site is sampled and analyzed to detect the polarized potential. It is analyzed to find the area under the portion of the waveform during which no off pulses are present and to use that area to detect the on potential. The area within the off pulses, after reactive spikes are eliminated, is substracted from the on potential area to determine the IR drop potential. The IR drop potential is then subtracted from the on potential and the difference is displayed as the polarized potential.

Measurement of the polarized potential of buried pipeline having

The polarized potential at the boundary between a submerged pipe and a medium is measured unaffected by the presence of a distributed IR drop in the medium due to an impressed current from a corrosion protection system. The voltage between the pipe and a reference electrode in the medium is measured when the protection system current is zero. This is accomplished with a sample-and-hold circuit controlled by a trigger signal derived from the input signal and having a variable phase for controlling the phase angle at which the sample is taken.

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Dublin, OH, United States of America

Neil G Thompson