Manual

Chapter 1
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BE1085-14
1303 Multipoint Sampler and Doser LumaSense Technologies A/S
Page 9 of 60
1.1.1 The Sampler System
The pneumatic system of the 1303 is shown schematically in Fig. 1.1.
The sampler system is constructed of 316 stainless steel and PTFE (Poly
Tetra Fluoro Ethylene) tubing to minimize adsorption of samples. The
system has 6 inlet channels, each with a solenoid valve. Each inlet
channel has a tube-mounting stub on the front-plate of the 1303; 6
tubes of up to 50m length connect each channel to the respective sam-
pling point. The 6 inlet channels converge into one; a three-way valve
can then direct the gas sample to the Gas Monitor for analysis, or
through the pump to the waste-air outlet on the 1303’s back-plate. A
pressure transducer checks the efficiency of the sampling pump and al-
lows checks for blocked airways.
An air-filter is attached to the end of each sampling tube to keep the
samples free of particles.
1.1.2 The Doser System
The doser system has 6 outlet channels, see Fig. 1.1, each with a sole-
noid valve. Each channel has a nozzle which reduces the internal diam-
eter of the channel. The nozzles ensure that the rate of flow of tracer-
gas to the dosing points is dependent only upon the tracer-gas supply
pressure and temperature, and is unaffected by the pressure in the
dosing tubes or at the dosing point itself. Three different nozzle sizes
are used: four medium, one large and one small. Each size gives a dif-
ferent volume flow rate so that the amount of tracer-gas delivered to a
particular dosing point can be matched to the requirement at that point
by using the outlet channel which has the appropriate nozzle.
Each of the 6 dosing outlet channels has a tube-mounting stub on the
front plate of the 1303. 6 tubes of up to 50m length connect each stub
to the respective dosing point.
2 separate inlet channels mounted on the back plate of the 1303 serve
the dosing channels: the tracer-gas inlet, and the carrier-air inlet.
The doser-gas inlet channel is pressurized by the tracer-gas supply cyl-
inder, which is connected to the inlet on the 1303’s back plate by tub-
ing. A pressure and a temperature transducer give information on the
tracer-gas supply; a fine filter ensures that the dosing channels are
particle-free. The main valve on the tracer-gas inlet channel is used to
enclose a volume of tracer-gas between itself and the dosing valves.
This volume is used when calibrating the doser system.