CP Test Equipments

There are several test equipments available in the market, Himoya Corrosion Technolgy (P) Ltd. supplies all types of test equipment and accessories for CP system installation, survey and monitoring purpose. The test equipment used for obtaining cathodic protection data should be of an appropriate type. Instruments and related equipment should be maintained in good operating condition and checked periodically for accuracy.

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Reference Electrode

A reference electrode is an electrode which has a stable and well-known electrode potential. The high stability of the electrode potential is usually reached by employing a redox system with constant (buffered or saturated) concentrations of each participants of the redox reaction. There are many ways reference electrodes are used. The simplest is when the reference electrode is used as a half cell to build an electrochemical cell. This allows the potential of the other half cell to be determined.

There are many types of reference electrodes: Aqueous reference electrodes, Non-aqueous reference electrodes, Pseudo-reference electrodes etc. Mostly the aqueous reference electrodes are in use for potential measurement.

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Current Interrupter

Current Interrupters are the key instrument to obtain IR free potential (instant Off potential) for the protected structure. Now advance and  portable, flexible, rugged, fully-programmable GPS synchronized current interrupter that is designed specifically for cathodic protection (CP) surveys. These interrupters  helps operators to ensure corrosion mitigation effectiveness and meet regulatory requirements.

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Pin Brazing

Pin brazing is an easy, metallurgically safe method of making electrical connections to steel and ductile iron pipelines as well as other metallic structures, which are to be cathodically protected or electrically earthed. The pin brazing technique is based primarily upon Electric-arc silver soldering using a specially designed portable pin brazing unit, a hollow brazing pin containing silver solder and flux.

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The brazing process is initiated by depressing a trigger on the brazing gun. This, as with most forms of electrical welding, simply completes a circuit through which a DC current is passed. The pin tip is the point of highest resistance at which point an arc is drawn, melting the solder flux whilst simultaneously heating the lug material and the surface of the structure or pipeline to the required soldering temperature. After approximately 1.5 seconds the circuit is mechanically or electronically broken, the solenoid is de-energized and the brazing pin is pushed forward into the molten pool of brazing alloy. The pin tip, brazing alloy, flux and lug cool into a homogenous unit.

Thermite Welding (TW)

Also known as exothermic welding, and thermit welding, is a welding that employs molten metal to permanently join the conductors. The process employs an exothermic reaction of a thermite composition to heat the metal, and requires no external source of heat or current. The chemical reaction that produces the heat is an aluminothermic reaction between aluminium powder and a metal oxide.

In exothermic welding, aluminium dust reduces the oxide of another metal, most commonly iron oxide, because aluminium is highly reactive. 3   C u 2 O + 2 A l ⟶ 6   C u + A l 2 O 3 {\displaystyle \mathrm {3\ Cu_{2}O+2Al\longrightarrow 6\ Cu+Al_{2}O_{3}} } Thermite welding is widely used to weld railway rails. Thermite welding is also use to making electrical connections to steel and ductile iron pipelines as well as other metallic structures, which are to be cathodically protected or electrically earthed.

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Data Logger

In a modern cathodic protection system it is essential to monitor and / or record continuously and precisely the Potential Difference (P.D.) between the protected structure and the environment surrounding it. Data loggers are computerized instruments into which data, control points, and other information can be entered. Some of them are so small they can fit into a ground level test station. After use, data loggers are connected to a computer and the information is downloaded. The computer can also create graphs of data.

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Many new instruments have recently been added to the armoury of those providing cathodic protection. Several of these are given here, which is also concerned with the resistivity of electrolytes and its measurement and the complementary use of insulating coatings and cathodic protection.

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