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7835
Hydrazine Monitor
5 Commissioning
Warning. This equipment uses chemical solutions in its
operation. Suitable precautions must be taken to ensure
safe handling.
Caution. This equipment will be damaged if subjected to
freezing conditions.
5.1 Start-Up
Perform the following procedure:
1. Power-up the transmitter at the external source.
2. Assemble the sensor as described in Section 9.4.5,
page 25.
3. Check that the solution flows through the sensor – see
Section 5.3, page 13.
4. Fill standard solution and reagent solution containers with
appropriate solutions – see Section 9.1, page 21.
5. Ensure the outlet valve on the reagent solution container is
closed and remove the reagent tube from the membrane
clamp, situated on the top of the reagent dosing chamber.
6. Hold the reagent tube over the tundish and open the
reagent container valve. Allow the reagent to flow through
the tube to displace any air bubbles.
7. Close the reagent container valve and reconnect the tube
to the membrane clamp.
8. Open the reagent container valve and establish flow
through the new disc by clamping the sample inlet tube
and applying suction from a plastic syringe to the reagent
dosing chamber outlet – see Fig. 4.6, page 11.
9. Replace the outlet tube and remove the clamp.
10. Allow approximately one hour for caustic dosage to be
established (the pH of the effluent at the sensor outlet
must be at least 10.5).
11. Program the transmitter as described in Section 6, page
16.
12. Enter the concentration of the standard solution in the
Calibrate menu.
13. Alarms and analog outputs are configured in the
Input/Output menu.
14. Calibrate as detailed in Section 7, page 19.
15. The transmitter is now in operation.
Note. If, during normal operation, the transmitter
does not display the expected hydrazine level, refer to
Section 8, page 20 for fault-finding information.
IM/7835–EN Rev. P
5.2 Sensor Unit
The sensor unit is shown in Fig. 4.6, page 11. It consists of a
metal case of similar construction to the transmitter case, with
the pipework carrying the sample mounted on a panel bolted to
the back with 4 x M6 captive bolts.
Sample enters through a grommet in the bottom of the case and
travels to a constant head unit via the sample inlet coupling.
From there it flows to a solenoid operated changeover valve
that, when energized during the calibration sequence (see
Section 4, page 8) replaces the sample with a standard solution.
From the valve, the sample flows through the reagent dosing
chamber containing a porous disc (through which reagent is
added to raise the pH of the sample to 10.5) and then on to the
mixing coil before passing to the hydrazine sensor.
The hydrazine sensor and its overflow funnel are mounted on a
sub-panel whose height relative to the standard solution can be
adjusted to provide the correct rate of flow through the sensor.
In addition, when the sensor is supplied with sample from the
constant head unit, the flow can be adjusted by raising or
lowering the overflow tube in the head unit. These flows are
preset in the factory but can be adjusted if necessary – see
Section 5.3, page 13.
Overflows from the constant head unit and the sensor drain to a
tundish in the bottom of the case. Normal operation flow paths
are shown in Fig. 5.1, page 15 and, for the calibration sequence,
in Fig. 5.2, page 15.
5.3 Setting Flowrates
The flowrates of standard solution and sample through the
sensor are preset at the factory. To check and, if necessary,
reset these flow rates, proceed to the following sections.
5 Commissioning
13
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