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JUNCTION BOX TERMINALS—
PIRVOL junction box terminals UL/CSA rated for 14 to
22 AWG wire; terminals DIN/VDE rated for 2.5 mm2
wire.
CERTIFICATION—
CSA:
Class I, Division 1, Groups B, C and D;
Class I, Division 2, Groups A, B, C
and D (T3C).
DIMENSIONS—
See Figure 3 for dimensions of the PIRVOL and Figure
4 for dimensions of the PIRVOL Junction Box.
SHIPPING WEIGHT (Approximate)—
Aluminum:
1.9 pounds (0.9 kilogram).
Stainless Steel: 5.0 pounds (2.3 kilograms).
3.2 (78)
2.75
(70)
4.1
DESCRIPTION
DETECTION METhOD
PIRVOL operates on the infrared absorption
principle. A beam of modulated light is projected
from an internal infrared source to a reflector, which
sends it back to a pair of infrared sensors. One of
the sensors is designated reference and the other
active, with different optical filters in front of the two
sensors to make them selective to different infrared
wavelengths. The reference wavelength is unaffected
by combustible gases, while the active wavelength
is absorbed by combustible gases. The ratio of the
active to the reference wavelength is computed within
the PIRVOL to determine the concentration of gas
present. This value is then converted into a 4 to 20
milliampere current output for connection to external
display and control systems.
CURRENT LOOP OUTPUT
During normal operation, the PIRVOL has a 4 to 20
milliampere current output that is proportional to gas
concentrations from 0 to 90% by volume methane. A
current output less than 4 milliamperes indicates a
fault condition (see Table 1).
5.8 (147)
Figure 3—PIRVOL Dimensions in Inches (mm)
4
6.1 (154)
4.6
(116)
B2029
95-8522
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