Description; Notes On The Detected Gas - Tecno Control SE138E Series User Manual

IST-2138.EC01.01/C
EN

DESCRIPTION

The SE138E series are stand alone gas detectors able to detect toxic gases by employing an electrochemical sen-
sor calibrated to different gases and find their best application in centralized alarm systems for parking, laborato-
ries, manufacturing industries and environments to be protected from possible leakage of gas.
The instrument is flameproof certified and comprise of an enclosure in which the electronic circuit and the terminals
are mounted and a downward facing cylindrical sensor housing with inside a "Replaceable Cartridge Sensor".
The SE138E series have three alarm levels, with different set-up, depending on the models, as listed in
The outputs are solid state relays with tension free single pole contacts (SPST). The instrument has also a 4÷20mA
linear output (S) with F.S. of the detected gas, expressed in ppm (part per million). This output can be used to connect
a remote central unit and / or for Test and Calibration routine, code protected, by using the F1 and F2 keys, placed
on the electronic circuit, on which there are 5 Led that indicate:
rd
3 red Led "ALARM 3":
nd
2 red Led "ALARM 2":
st
1 red Led "ALARM 1":
Green Led "ON":
Yellow Led "FAULT":

NOTES ON THE DETECTED GAS

The above Gas value is on compliance with EN61779-1.
SE138EA has a sensor that can detect Ammonia (NH
pungent smell, lighter than air, (its density as to air is 0.6). His TWA is 25ppm (Time-Weighted Average) and STEL is
35ppm (Short Term Exposure Limit). His LEL (Lower Explosivity Limit) is 15% v/v (volume). This gas is irritating to the eyes
and mucous membranes (respiratory and digestive tracts). Ammonia is used in industrial refrigeration applications.
It is also used as fertilizers (either as its salts), as a component in paints, for the production of plastics and poly-
mers, such as solvent or as household cleaners.
SE138EA-H model is as previous, but it uses a sensor suitable for industry and polluted environments and with
presence of other toxic gases.
SE138EC-S has a sensor that can detect Carbon monoxide (CO) gas which is a poisonous, colourless, odour-
less, and tasteless. CO is a little lighter than air (its density as to air is 0.97) and his LEL (Lower Explosive Limit) is
10.9%v/v (%volume). His TWA is 25 ppm (Time-Weighted Average) and STEL is 35 ppm (Short Term Exposure Limit).
CO is produced by incomplete burning of carbon-based fuels, including gas, oil, wood and coal. Carbon-based
fuels are safe to use. It is only when the fuel does not burn properly that excess CO is produced, which is poison-
ous. When CO enters the body, it prevents the blood from bringing oxygen to cells, tissues, and organs.
SE138EC-H model is as previous, but it uses a sensor suitable for industry and polluted environments and with
presence of other toxic gases.
SE138ES has a sensor that can detect Sulphur dioxide (SO
ide) gas which is a toxic, colourless, with pungent odour, heavier than air (its density as to air is 2.25). His TWA (Time-
Weighted Average) is 2 ppm and STEL (Short Term Exposure Limit) is 5 ppm.
SO is a strong irritant to eyes and respiratory system. Inhalation may cause pulmonary edema and prolonged ex-
2
posure can lead to death and when it combines with water forms H
SE138EH has a sensor that can detect Hydrogen sulphide (H
toxic, flammable, colorless, with a characteristic odor of rotten eggs, heavier than air (its density as to air is 1.19). His
TWA is 5ppm (Time-Weighted Average) and STEL is 10 ppm (Short Term Exposure Limit). His LEL (Lower Explosive Limit) is
4% volume. The H S smell is perceived at concentrations above 0.2 ppm, to low levels (50÷100 ppm) already pro-
2
duces irritation to the eyes and throat, cough, fast breathing and training of fluid in the respiratory tract. This gas,
over 150 ppm, acts on the olfactory nerve, making it impossible for the perception of its odour, and higher concen-
trations can cause unconsciousness within a few minutes and can lead to death.
SE138EHCN has a sensor that can detect Hydrogen cyanide (HCN) (synonymous with Hydrocyanic acid, Prussic acid)
gas which is a toxic, extremely poisonous gas, colourless, with has an almond-like odour, a little lighter than air
(its density as to air is 0.94). His TWA (Time-Weighted Average) is 4.7 ppm and STEL (Short Term Exposure Limit) is 10 ppm.
The HCN is a strong irritant to eyes and respiratory system. Inhalation may cause effects on the cellular respira-
tion, resulting in convulsions and unconsciousness. Exposure to 300ppm for 2 minutes may result in death.
SE138EN has a sensor that can detect Nitric oxide (NO) gas which is a toxic and colourless, heavy as air (its den-
sity as to air is 1.04). His TWA (Time-Weighted Average) and STEL (Short Term Exposure Limit) are 25 ppm. NO is a strong
oxidant and reacts with combustible and reducing materials. On contact with the air turns it into nitrogen dioxide
(NO ). Nitric oxide is irritating to eyes and respiratory tract. Inhalation can cause pulmonary edema, may also have
2
effects on the blood, causing the formation of metaemoglobina. In more severe cases it can lead to death. Nitric ox-
ide is a pollutant that is generated in part in combustion processes, in part by natural emissions, fires or civil activi-
ties and industrial processes involving combustion, (diesel engine, gasoline, LPG, production of heat and electricity etc.).
SE138EN2 has a sensor that can detect Nitrogen dioxide (NO
characteristic sharp, biting odour, heavier than air (its density has to air is 1.58). His TWA (Time-Weighted Average) is 3
ppm and STEL (Short Term Exposure Limit) is 5 ppm. NO
NO is formed in most combustion processes using air as the oxidant. At elevated temperatures nitrogen combines
2
with oxygen to form nitrogen dioxide. The most important sources of NO
plants, heating and vehicles, especially diesel engines). NO
lungs, pulmonary edema and death as it is capable of combining with the haemoglobin by changing the chemical
TECNOCONTROL S.r.l. - Via Miglioli, 47 20090 SEGRATE (MI) ITALY
Istruzione / User's Manual / Manuel d'utilisation
rd
3 relay activation
nd
2 relay activation
st
1 relay activation
normal working condition
the sensor should be faulty, disconnected, out of scale or expired.
) gas which is a toxic, colourless and with a characteristic
3
combined with water turns into nitric acid and nitric oxide.
2
is toxic by inhalation, it can cause irreversible damage to the
2
) (also Sulphurous anhydride, Sulphurous oxide, Sulphur ox-
2
S (Hydrogen sulphide).
2
S) (synonymous with hydrogen sulphide) gas which is a
2
) gas which is a reddish-brown toxic gas with a
2
are internal combustion engines (power
2
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Tables 5÷11.