K-Patents DD-01 - Manual (Page 5)

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A light test button (10) switches all 11 lights on. An alarm reset button (11) resets the alarm lights. For normal
operation the operator panel has four green lights on (A OPERATING/B OPERATING/ VALVE TO
BURNER/SAFE% SOLIDS).
2.3. ALARMS
The divert control system has four alarms, audible and indicating:
1. Black liquor SOLIDS WARNING, yellow light (60% or below)
2. Black liquor SOLIDS ALARM, red light (58% or below)
3. Refractometers reading more than 2% absolute DIFFERENCE, yellow light
4. Refractometer MALFUNCTION, yellow light
The alarms 1, 2 and 4 are initiated by either refractometer. System contains also optional alarms, see wiring
drawing 3.11.
The operator panel contains four indicator lights and an ALARM RESET button. The reset button will silence
the audible alarm, but the visual indication will remain until the condition has returned to normal.
To avoid unnecessary alarms the following interlocks are implemented:
- A refractometer can initiate an alarm only when it is operating.
- Alarm 4 can be initiated only if both refractometers are operating.
The parameters (2%, 58% and 60%) are default settings, which can be changed from the Indicating transmitter
keyboard (Sections 5.3 and 5.4). The parameter for 2% can be decreased and the parameter for 58% and 60%
can be increased.
2.4. PRISM WASH
For K-Patents Process Refractometer, the need of prism wash is reduced and even in some cases eliminated.
The prism keeps clean due to the probe design features:
- The prism is flush mounted in a surface deflecting the black liquor main flow, which causes
a strong mechanical cleaning action.
- The prism has the same temperature as the black liquor.
In any case, however, an automatic regular prism wash provides an efficient check that the refractometer re-
acts. A steam wash of 3 seconds every half hour should be sufficient. Automatic single (one-of-two) diversion
will occur if either of the refractometers is in wash cycle.
The Divert Control Unit contains two relays for prism wash, WASH A and WASH B. To follow the BLRBAC
recommendation not to wash both prisms at the same time, there is an interlock. If both refractometers try to
wash simultaneously, one will display "WAIT" and perform the wash when the other has finished.
K-Patents recommends to use a steam trap instead of preconditioning valve to remove condensate from the
steam line. The wash times can be seen pressing soft keys "Display"/"System configuration"/"Wash times". To
change the wash times, see Section 5.6.
INSTRUCTION MANUAL FOR DD-01 DOCUMENT/REVISION: IMD 1/5
Effective: June 20, 2005