ASTEC PHOENIX Talon, Operation And Service Manual, Page: 8 / 31

PHOENIX Talon - Operation and Service Manual
8
Combustion Flighting
1. The flight design in the combustion zone of the drum is especially important for minimizing flue gas
pollutant emissions.
2. The flights provide heat shielding to keep the drum skin temperature low. (Protecting the metal drum
skin from the flame radiating directly onto the drum.)
3. For the lowest possible emissions of CO and Total Hydrocarbons, the combustion zone must be clear
of veiling material. (Showering material through the flame is a common cause of incomplete
combustion.)
4. The combustion zone must be large enough to accommodate complete combustion. (The length and
diameter of the combustion zone must be large enough for the burner flame to fit inside. See the
Burner Performance Data Sheets for the flame dimensions.)
5. The combustion flights are designed to be self-cooling, to prevent their failure through overheating.
(A good combustion flight design plows most of the material over the fights, while allowing some to
flow under them next to the shell, insulating the drum from radiant heat, and using the aggregate to
cool the flights.)
6.
The ASTEC Parts Department can supply combustion flights designed for your application.
Operation
1.
The PHOENIX Talon utilizes a variable frequency drive (VFD) to control the combustion air blower.
2. The fuel valve(s) have independent control motors, or actuators. (There is no mechanical linkage
between the fuel and air controls.)
3. A programmable logic controller (PLC), or other ratio control system approved by ASTEC Burner
Systems Group, controls the air and fuel flows independently.
4. The combustion air blower pressure switch (normally open) must be made to prove the blower is
operating. (This pressure switch is usually set at 1/2” W.C. It will close as the air pressure exceeds
the set point.)
Note:
When the blower first comes on it will be turning slowly (about 240 RPM). This is a normal operating
condition.
5. The combustion air blower will adjust to high speed automatically.
6.
These conditions must be met to initiate the purge cycle prior to lighting the burner.
a.
The safety limit parameters must be satisfied.
b.
The purge pressure switch (normally open) must be energized for the purge cycle to begin. (This
pressure switch is usually set at 10
” W.C. It will close when the air pressure exceeds the set
close point.)
c.
The plant flue gas exhaust fan must be confirmed to be running.
d.
The purge timer must be set so that a minimum calculated volume of air flows through the drum
during the purge cycle. (The minimum purge time is the time required for this calculated volume
of air to flow through the heating chamber. This is usually 4 times the chamber volume.)
7. Before light-off, the combustion air blower must be set at the low-fire speed.
8.
The low-fire combustion air pressure switch (normally closed) must make to prove that the blower is
at the low fire speed. (This switch is usually set at about 1-
1/2” W.C. It will make as the air pressure
falls below the set point.)
9.
For the light-off sequence to begin, the fuel valve(s) low fire switch must be made, to prove that the
fuel valve(s) are at the low fire position.