K-Patents DD-01 - Manual (Page 3)

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2. GENERAL INFORMATION
The K-Patents Digital Black Liquor Divert Control System DD-01 provides a divert signal preventing black
liquor with dangerously low solids to reach the black liquor burners. The system is built strictly according to
the principles of Recommended Good Practice "Safe Firing of Black Liquor in Black Liquor Recovery Boil-
ers" (BLRBAC August, 1982 and revisions April, 1991, and March, 2001).
2.1. DIGITAL DIVERT CONTROL SYSTEM DD-01
Figure 2.10 Complete Digital Divert Control System DD-01
The system consists of the following parts (Figure 2.10): Two K-Patents Process Refractometers PR-01-S (A
& B) are installed in series in the main black liquor line. Each refractometer is complete with a Sensor, an
Indicating transmitter and Interconnecting cables. Each refractometer provides also a 4-20 mA % solids output
signal not used by the divert control system.
The Divert Control Unit DD-01 is contained in one enclosure with the same dimensions as the refractometer
Indicating transmitter enclosure. The control unit includes:
- an operator panel
- control logics
- contact outputs for prism wash, warnings, alarms and black liquor diversion
- Two isolation valves HIMP-2 (optional) for the refractometers above to allow removal of
the refractometers from a pipe with full flow and pressure. The isolation valve includes a
prism wash nozzle and two check valves (one for prism wash, one for stuffing box flush).
- A roofed mounting plate to mount the two Indicating transmitters and the Divert Control
Unit together.
- Two steam valves with steam traps for prism wash (pneumatic + solenoid valves).
- Two hand valves (one for prism wash, one for stuffing box flush).
- One alarm horn (supplied by the customer).
Note. BLRBAC (The Black Liquor Recovery Boiler Advisory Committee) recommends a spare sensor to be
maintained in stock on-site.
INSTRUCTION MANUAL FOR DD-01 DOCUMENT/REVISION: IMD 1/5
Effective: June 20, 2005