Preparations
1
Connect the pressure regulator and pressure gauges to the gas cylinders, secure
the gas cylinders.
2
Close the shut-off valve.
3
Fit the hose between the pressure regulator and one of the two GPP connections.
4
Set the pressure on the gas cylinder to the calculated primary pressure.
NOTE
Air is suctioned into the partial vacuum channels as soon as the gas connection
is opened. The measured values approach zero depending on the partial vacuum
present.
5
Connect a pressure gauge to the second gas connection.
6
Read off the current measured values on the control unit display.
Measurement
1
Start the EPA-SPAN test per menu,
see "SPAN test according to EPA Guidelines",
, or digital input.
2
Set T90 to 10 seconds.
3
Open the shut-off valve fully.
4
Observe the measured values on the display until the value is stable.
5
Read off the pressure on the second pressure gauge to correct measurement
when necessary.
6
Close the valve on the pressure reducer and the gas cylinder.
7
Now terminate data recording and start the evaluation.
8
Reset the T90 value.
9
Return to measuring mode.
10 When required, repeat the procedure (preparation and measurement) with further
test gases.
7.11.2.2
Carrying out a thermal adjustment
The cold test gas flow withdraws energy from the measuring probe body as it flows
through the device. Long purge times can therefore effect a difference between the
test gas temperature and the process temperature. The following factors influence the
difference:
•
Throughflow volumes of the test gas
•
Measurement duration
•
Gas velocity in the process
This is the reason why it is recommended to determine the SPAN points first and then
the zero point because a temperature drop does not influence the zero point measure‐
ment. A break between the measurements and the reduction in gas flow reduce this
effect.
7.11.2.3
One-off preliminary measurement/determining the basic setting
Each GPP measuring probe has certain production tolerances. The ideal pressure
parameters for the test must be determined once before the first measurement. The
GPP must be installed in the duct for this test because the length of the measuring
chamber and velocity of the exhaust gases in the duct also influence the initial pres‐
sure settings.
Carrying out a one-off determination of the basic settings
1
Prepare the gas (e.g. N
2
or air),
see "Carrying out a manual EPA SPAN test",
.
2
Start the EPA test,
see "Carrying out a manual EPA SPAN test", page 43
.
7
COMMISSIONING
44
O P E R A T I N G I N S T R U C T I O N S | GM901-02
8008932/16YT/V4-0/2022-02 | SICK
Subject to change without notice
