Product description
4.5.3
Leakage in the Measuring Gas Supply Line
A technically permanently leak-tight pipe is used. This is achieved by using a durable plastic tube or
stainless-steel pipe and corrosion resistant screw connections with resistant sealing. Components like
condensate traps that might be included in the measuring gas pipe also have screw connections. The
pipes are technically permanently leak tight up to the first valve, which can be used to shut off the pipe.
4.5.4
Gas volume
The pipes (< 5m) and sensors inside the gas analysis system contain less than 0.05 l of gas. No risk of
explosion results from this.
4.5.5
Leaks in the Gas Analysis System
Despite the slow reaction of methane with oxygen compared to other gases(55 bar*m/s compared
to 550 or 1.415 bar*m/s with hydrogen and acetylene) at a similar maximum pressure (7.1 bar under
normal conditions), the danger for persons at a control box volume of 60 l cannot be completely
eliminated if only due to a deflagration, in the event that an explosive mixture would form inside due to
a potentially occurring tightness error and a subsequent ignition due to unfavourable conditions or an
escape of the gas from the gas analysis system.
The pipes inside are considered to be technically leak-tight. Due to the way they are constructed,
some sensors can only be used with plug connections which are secured with spring terminals. As
an additional safety measure, the high-quality methane sensor that is integrated in the gas analysis
system is used to track down possible leaks. In case of a leakage, the first valve will cut off the supply
of measuring gas. Each measuring channel is filled for a maximum of 120 s with measuring gas and
is subsequently flushed with air for at least 60 s . As the air for flushing is sucked out of the inside of
the gas analysis system, the composition of the air inside the device casing can be measured every
2 minutes . Fresh air flows from outside into the device casing via a sintered metal frit (air filter). Upon
detection of > 1.0% of methane(= 20% LEL),all actuators will be shut down and the valve V1 cuts off the
supply of measuring gas. Optionally, a potential-free contact is opened. Additionally, an error message
is shown at the display. A potentially explosive atmosphere could thus be prevented behind valve V1
despite leakages. The gas path up to V1 is made with pressure-resistant pipes and clamp ring screw
connections in a technically permanently leak-tight manner as described above.
For devices without methane sensor or with continuous methane measurement, safety is ensured by
other means (e.g. reduced number of potential leakage points, see risk assessment).
4.5.6
Release of Potentially Toxic and Harmful Gases
The device itself releases no gases, only the gases contained in the measuring gas can be released. In
accordance with its intended use, the device is used for the analysis of biogas and upgraded biogas
and the gases contained therein may be released correspondingly.
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