Purpose

Corrosion speed indicator-plate block is designed for determination of corrosion hazard and efficiency of electrochemical protection of underground metal constructions against corrosion.

The meaning of the method is as follows. Indicator-plates of different widths serve to additionally estimate general corrosion and the range of its average speed at the electrochemical protection of pipelines in the place of block installation since the moment of installation till the loss of linear conduction of plates as a result of corrosion.
Features

Block is a single-use product; it is not to be rebuilt and repaired during operation period.
Operating conditions

Block ensures reliable and stable operation in all microclimate regions under the following climatic conditions:,
- the upper value of ambient temperature + 100°С;
- the lower value of ambient temperature - 40°С;
- the upper value of relative humidity 100% at 35°С.

Category of distribution: 5, according to GOST 15150-69.
Technical data

Parameter	Standard
1. Section of routing track thread, mm2	0,5...1,5*
2. Height of the block, mm	80
3. Width of the block, mm	62
4. Thickness of the block, mm	12
5. Weight (without weight of a wire), g	40
6. Length of conducting wires, mm	2500*

*The length of wires can be changed on customer's order.
Construction

Indicator-plate block consists of three plates of 2 mm width, 0.3 mm, 0.4 mm, and 0.5 mm thickness, connected with the common plate of 1.5 mm thickness. Control wire is connected to each plate. Block case is made from glass-filled polyamide. The case provides ensures the contact of plate working surface with the ground and protects backside and lateral sides against corrosion.
Principle of operation

Corrosion hazard and electrochemical protection efficiency is controlled by measuring electric resistance between wire output connected to one of the control plates and wire output connected to the common plate. Measurement is to start with the plate №1 of 0.3 mm thickness. Resistance measurement switch is to be set within the range 0-200 ohm. Resistance value is registered against the scale. Resistance value more than 10 ohm indicates destruction of the plate of 0.3 mm thickness. Analogous measurements are carried out on the plates of 0.4 and 0.5 mm thickness. If the plate of 0.4 mm thickness is destructed, the measurements are to be continued on the plate of 0.5 mm thickness. Measurements are to begin on the day of block mounting.

Measurements on the pipelines without electrochemical protection system are to be held every six months until the first plate has been destroyed, than every two months. Measurements are to be held not less than every six months since electrochemical protection has been started.

Order of magnitude of general corrosion speed (K) after fixation of indicator-plate corrosion destruction is estimated by formula:
К=365δ/t, mm/year,
δ - Thickness of plate, mm.
t - Number of days from the moment of block mounting till the first destruction of indicator-plate, days.
Note: By actuation of more than one plate, it is the plate with a greater thickness δ to be taken into account.

Attention! At operating conditions, wire from the common plate should be connected with the pipeline.
Block can be delivered mounted on the case of non-polarizable reference electrode ENES-1 (ENES-MS-2). In this case, beside the main function block also functions as a potential sensor (auxiliary electrode).
Scheme of block mounting on the pipeline

1 - Indicator-plate block; 2 - Hook-up clamp; 3 - Connecting cable; 4 - Terminal block; 5 - Control wires from pipeline, block common plate, indicator-plates.

Manufacturer’s guarantees

The manufacturer guarantees reliable operation of BPI-2 within 1 year from the date of commissioning under consumer’s observance of the conditions of mounting, transportation and storage. The guarantee covers the period not more than three years from the date of shipment to the consumer.

Service life of the block is 5 years.

The manufacturer undertakes an obligation of replacing the block in case of its breakdown during guarantee period.
Installation order
Attention! Before installation, remove oiled paper and clean the indicator surface with petrol.

Before block installation, measure indicator-plate resistance relative to the common plate. Resistance should be less than 10 ohm. If it exceeds the given value, the block is rejected and not subject to installation. The block is installed on the surface of protected structure with the outgoing indicators and fixed by the lugs situated on the block case lateral surface by means of rubber band included into delivery set (indicator-plate block is to be installed only on the return pipeline in case of heat-supply system protection).

Wires from the block, pipeline, and reference electrode (if the block is delivered fixed on the reference electrode) are connected to the terminal block situated in measuring column, metal case on building wall, and cabinet of cathodic protection station.