
Appendices
Manual CWD 2005
___________________________________________________________________
104
Manual CWD2005.doc
11.6.
Double Range
If an extended range is necessary (for example 20-100 %) it can´t be done with one
jet combination of Wobbe jet and air jet. For this purpose the CWD 2005 will be
equipped with a double orifice for 2 wobbe-jets and 2 air-jets. .The jet-change will be
made with 4 solenoid valves automatically. The instrument changes in a
predetermined point to the next range. The electronic calculates a continuous switch
from one range to the other range.
With similar ranges the air consumption may be very different from one gas to an
other gas. In this case it is switched, the wobbe-jet can be kept and the air-jet can be
changed.
In connection with carrier gas it is possible to measure
–if needed- with and without
carrier gas. The change considers the calibration with or without carrier gas. The
system checks, if carrier gas will be considered or not.
The decision, if carrier gas is necessary or not, can be made manually or
automatically. With manual change there is in the system-menu an additional point
“change range”. Next range change, for example carrier gas, switch on or off carrier
gas.
Figure 27: Double Range
1.
Carrier gas (Range change)
2.
Calibrating gas
3.
Process gas
4.
Solenoid valve Wobbe-jet 1
5.
Solenoid valve Air-jet 1
6.
Wobbe-jet 2
7.
Air-jet 2
8.
Wobbe-jet 1
9.
Solenoid valve Air-jet 2
10.
Air-jet 1
11.
Solenoid valve Wobbe-jet 2