K-Patents DD-23 - Manual (Page 29)

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7 Divert control logics
A logical description of the system is provided to complement the operational descrip-
tion given in the previous chapters.
7.1 Safety decision logic
The core of the Divert control system is the safety decision logic, which makes the
ultimate decision whether the black liquor can be safely fed to the burner or not.
The logic is described in the 󰅮low diagram in Figure 7.1. The factors affecting the de-
cision are the number of instruments in operation (none, one or two) and their mea-
surement results. Also the selected divert rule is taken into account when two instru-
ments are in operation. For a description of different rules, see Section 5.2.
As a result of this logic, the system is either in SAFE SOLIDS or UNSAFE SOLIDS state.
When the system is in the SAFE SOLIDS state, the
SAFE SOLIDS light is illuminated.
no
no no
no
yes
UNSAFE SOLIDS SAFE SOLIDS
NO INSTRU-
MENTS!
Rule 2-of-2
2 instruments
available?
1 instrument
available?
Both ≥ 58%?
Either ≥ 58%? CONC ≥58%?
yes
yes yes
yes
no
Rule 1-of-2?
yes
no
DIVERT
Figure 7.1 Safe solids decision logic
"One instrument available" may mean that only one instrument is in operation or that
both instruments are in operation, but one of them is washing when queried.