Vympel CONG Prima 2M - Cp 2 M Provisions for Explosion Protection

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surface. As a result, the photo detector F2 receives two sets of reflected light rays, which are

slightly out of phase.

The light signal registered by the detection system produces a characteristic interference

pattern.

The intensity of the light received by the photo detector is directly dependent on the amount

of hydrocarbon condensation on the mirror’s surface. As more hydrocarbons precipitate onto

the mirror the film becomes thicker, this in turn means that the distance between the two

upper and lower boundary interfaces becomes greater. This increase in distance correlates

to a greater phase discrepancy between the two reflected rays that increases the signal

strength.

The registration of the hydrocarbon dew point temperature occurs as soon as the

condensation film reaches a thickness of 5 – 10nm (default setting).

In this way, these two separate modalities generate two separate signals: the signal from

photo detector F1 is used to establish the dpW and the signal from photo detector F2 to

establish the dpHC (Illus. 3.1 and 3.2).

Illustration 3.1

Illustration 3.2

Diagram of the light scatter from a hydrocarbon film (2) on a mirror with a reflection index of n2.

1 – chilled dielectric mirror;

2– hydrocarbon condensate;

3 – sample medium (ex. gas)

1.3 CP 2M provision for explosion protection

The CP2M is certified as compliant with the requirements of EN 60079-0:2009, EN 60079-

1:2007. It carries the explosion protection marking II 2G EEx d IIA + Н

T5.

This marking identifies the CP 2M as a “flameproof enclosure” as per the requirements

stated in EN 60079-1:2007.

Explosion protection is provided by encasing the electrical elements of the electronics unit in

an enclosure that is mechanically robust and meets the standards of EN 60079-0:2009. This

enclosure can withstand explosion pressures and prevent combustion from escaping into an

ambient explosive environment.

Integrity of the flameproof enclosure is maintained through the use of threaded and

cylindrical flameproof joints. A drawing of the explosion protection measures (Appendix С)