PHOTOTUBESTYPE UV1 UV2/N UV3FLAME SENSORS FOR GAS BURNERSUV1UV2/N
INTRODUCTION
Flame detection in burners occurs by means of sensors
detecting the presence of flame through an electric signal
which can be used by ignition and control devices.
UV phototubes exploit the ultra-violet radiation emitted by thelight generated by the flame; they are especially suitable forapplications in which very dissimilar fuels (e.g. liquid andgaseous fuels) are used.

UV34068_r07

FEATURES
These sensors are used for flame detection in gas and mixedfuel (gas and oil) burners. UV phototubes consist of a glass
bulb filled with gas, containing two electrodes suitably
shaped. When supplying both electrodes with AC voltage, if
ultra-violet electromagnetic radiation (range from 190 to 290nm) hits the phototube, the electrons emitted by the negative
biased electrode, and captured by the positive biased one,start an ionization process leading to the generation of anelectric discharge and hence to the production of electric
current.
UV1, UV2/N and UV3 are the available phototube models;
their features and dimensions are described hereunder.

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PHOTOTUBE TYPE UV1Phototubes type UV1 are available with two differentsensitivity:
Standard sensitivity/H : high sensitivity
The standard cable length is 655 mm, but versions withlonger cables are available.

Ø22TECHNICAL DATA
Nominal life time:
Maximum distance from UV source:
UV1-3 sensor temperature range:
UV2/N sensor temperature range:

10.000 hours (*)
1m-20 ÷ +50 °C (*)-20 ÷ +60 °C(*) The UV1 and UV3 phototubes can operate also at atemperature higher than + 50°C, but in this case the sensor
life time will be shorter than the 10.000 hour nominal life.
DIRECTIVITY AND RELATIVE SENSITIVITY
In the graphs below you can see the characteristic graphs ofthe phototubes:

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UV1-UV3
Directivity
Figure 1

PHOTOTUBE TYPE UV2/N
Phototubes type UV2/N are smaller than type UV1 (thelength and the diameter of the housing are smaller).
The standard cable length is 655 mm, but versions withlonger cables are available.

Ø1776

Figure 2

PHOTOTUBE TYPE UV3The length and the superficial treatment of the housing andthe side windows are the differences between models UV3and UV1. The superficial treatment of the housing consists ofa chromium plating.
The UV3 phototube has no cable, which is supplied as anaccessory (see figure 1).
Phototubes type UV3 are available with two different
sensitivity:
Standard sensitivity/H: high sensitivity

Front and top view - Figure 5

Ø2280
Front view - Figure 6

Relative sensitivity

Figure 3

Figure 4 shows the UV1, UV2/N and UV3 drilling plane.
for UV1 and UV3

for UV222.518.517.5

1718.537

Figure 4
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Sensitivity - Figure 74068_r07

UV2/N
Directivity

Top view - Figure 8

Front view – Figure 9

DIRECTIONS FOR INSTALLATION
Respect the applicable national and Europeanstandards (EN 60335-1 and EN 60335-2-102) regarding
electrical safety;
Avoid placing the detection cable close to power orignition cables;
To avoid problems due to the ageing of the sensing
element, we recommend replacing it after about 10.000
operating hours. These flame sensors are not sensitiveto daylight and do not need any particular screening,
unless they are positioned close to gas-discharge lamps(neon lamps or similar) that might affect theirperformance.
Avoid subjecting the device to strong stress, impacts orfalls.
The sensing part of the bulb collects the light signal
through both the side and the top windows: take this into
account during installation and make sure that at least
one window is well illuminated by the flow of incident
light. It may be worth noting that the UV3 is provided
with one side window only and is therefore more
selective than the UV1 which has three.
REPLACING THE SENSING ELEMENT IN PHOTOTUBESTYPE UV1 AND UV3:
In these types of phototubes, the sensing element can be
replaced by simply pulling it out of the housing top opening.
The new sensing element must be inserted into the housingwith the orientation shown in the following figure:

Relative sensitivity

Phototube
orientation

UV2/N

WindowSUNLIGHTGAS
FLAME
Figure 12
Sensitivity - Figure 10CONNECTION
The blue wire is marked with number 8 because it must beconnected to terminal 8 in Brahma devices series MF2,MF2.4, SR3/TR and M300 (and to terminal 21 in Brahma
device type MPI); the brown wire must be connected to theearth.
In the Brahma device type RE3 the blue wire must beconnected to terminal n°3 and the brown wire to terminal
n°4.

NOTES ABOUT PRODUCT DISPOSAL
The device contains electronic components and cannot
therefore be disposed of as normal household waste. For thedisposal procedure, please refer to the local rules in force for
special waste.

ATTENTION  Company Brahma S.p.A. takes no responsibility for any damage resulting from Customer tampering with the device.

BRAHMA S.p.A
Via del Pontiere, 3137045 Legnago (VR)Tel. +39 0442 635211 - Telefax +39 0442 25683
http://www.brahma.it
E-mail : brahma@brahma.it

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17/01/2020 Subject to amendments without notice3/3