M&C TechGroup SP2020-H_C_I_BB_F Operator's manual - Manual (Page 10)

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Gas sampling and gas conditioning technology 2-1.1.6.1-ME
9.1 PROBE STRUCTURE
The filter housing with its all-round heating element forms a unit with the standard mounting flange
DN65 PN6 and the laterally mounted electrical connection box.
The heat-insulated shield is mounted on the stainless steel angle sheet which is mounted on the
mounting flange. It is secured with 2 pressure clamps. The cover ensures a uniform distribution of
heat over the probe heater and at the same time serves as protection against weather and accidental
contact.
The connecting clamp for attaching heated M&C sample lines with external dimensions of between
40mm and 50mm is located at the aperture on the underside of the angle sheet, which is closed with a
silicon lid. The clamp is mounted on an adjustable mounting bracket which allows adjustment for vari-
ous sample line diameters.
The standard probe's sample gas outlet connection has a ¼" NPT internal thread to which the cus-
tomer must connect a suitable size of temperature resistant and threaded connector to connect the
sample line in a gas tight manner. These connectors can be supplied by M&C.
After the threaded pipe connector and sample line have been mounted, the sample gas outlet connec-
tion is enclosed in special heat-conducting jaws in order to avoid temperature failures in the critical
connection areas. The size of the heat-conducting jaws allows connection joints up to an external pipe
dimension of 10mm.
In the standard version, temperature control is ensured by way of the capillary tube thermostat which
is built into the connection box and which has a regulation range between 0°C to 180°C. Rated values
can be set to a maximum 180°C. The temperature has an excess temperature limiter which perma-
nently switches off the heating if the set temperature is exceeded by 30°C. The heating can be
switched back on again by pressing the RESET button which is located below the aperture in the
thermostats mounting and which is marked RESET.
The thermostat has a temperature failure alarm which activates a contact if the temperature falls 30°C
below the set temperature. This status alarm is located on the terminal strip as a potential-free switch
over contact.
If temperature control is to be achieved using external electronic equipment, a PT100 (a max. of two
can be built in) or an Fe-CuNi thermoelement is provided as a temperature sensor.
For test gas feeding and back purging, check valves are integrated in the gas sample probe. To pre-
vent a flow of test gas back to the process while test gas feeding, a pneumatic isolation valve is
mounted in the sample gas outlet.
To prevent the analyser from a pressure surge while back flushing the pneumatic isolation valve has
to be used as well.
The gas sample probe SP2020-H/C/I/BB is designed for back flushing via the filter chamber. The de-
sign of the SP2020-H/C/I/BB/F allows back flushing via the filter element (see Fig.2).