Training material for ash handling system (fly)

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© CBM Clyde Bergemann Materials Handling Ltd.
Clyde Bergemann Materials Handling Ltd.  Tel +44 (0)1302 552200  eMail: powersales@cbmh.co.uk  www.cbmh.co.uk

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Customer Training ~
General Overview of the Ash Conveying System
Document No. C063160060
Clyde Bergemann Materials Handling Ltd.  Tel +44 (0)1302 552200  eMail: powersales@cbmh.co.uk  www.cbmh.co.uk
“to guide and partner our customers
to success through world-class solutions”

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General overview of fly ash handling plant –
including
Pneumatic conveying
“MD-Pump” technology
“Ash Vessel” technology

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Detail operation of ash handling plant
Dome Valve
Operation
Dome Valve maintenance

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Associated equipment
Level probes
Pipeline components
Silo dust filter
Pressure relief valve

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Overview
 The complete control system consists networked Allen Bradley PLC Control
Panels. Each system is dedicated to the control of one of the aspects of the
plant operation.
 The fly ash system comprises of two unitised PLC panels.
 Each PLC control panel will be used for the control and sequencing of the ash
conveying machines complete with their associated pneumatic panels and
instrumentation.
 The Operator Interface is remotely via 2 off SCADA operator terminals (per
unit) located in the Ash Control Room, or remotely via the DCS located in the
DCS control room.
Control system

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Control Panel Configuration
 The system configuration is based on Allen Bradley 1756 processors complete
with I/O cards.
 Communications between each processor panel and the SCADA system is via
Ethernet.
Control system

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Operator Interface
 Remote operation will also be available via the DCS system. The local / remote
operating mode is selected via the Local/Remote selector at the SCADA/DCS.
 When the command is set to “LOCAL” the SCADA will have sole control of the
plant. When the command is set to “REMOTE” the DCS will have sole control of
the plant. The deselected location will only provide indication and alarms.
 The SCADA / DCS screens will show status of remote / local selection.
Control system

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System Operation
 The Ash Conveying Systems consist of multiple vessels but operate as a single
conveying system.
 Each system can be started and stopped from either the SCADA or remote DCS
system depending on the operating mode selected. Switching between local
and remote modes will be bump less and any plant which is operational prior to
changeover, will continue with its current operational status after changeover
and until selected otherwise.
 The SCADA provides the required operator control facility including system
start / stop functions, conveying target selection, system supervision and
status monitoring, and alarm indication.
 Once a system has been started, its conveying sequence will be automatically
controlled, regulated and monitored by the PLC without any further
intervention by the operator. The system will continue to carry out conveying
sequences until selected to stop by the operator.
Control system

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Schematic of the CBD system

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CBD system
CONVEYING RATES – UNIT 1/2
SYSTEM NORMAL
RATE
MAXIMUM
RATE
CONVEYING
DISTANCE U1/U2
ESP Field 1
MD-Pumps
34.68 TPH 46.4 TPH 147 / 263 m
ESP Field 2
MD-Pumps
6.94 TPH 34.68 TPH 152 / 268 m
ESP Field 3
MD-Pumps
1.39 TPH 6.94 TPH 157 / 273 m
ESP Field 4
MD-Pumps
0.28 TPH 1.39 TPH 162 / 278 m

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CBD system
CONVEYING RATES – UNIT 1/2
SYSTEM NORMAL
RATE
MAXIMUM
RATE
CONVEYING
DISTANCE U1/U2
ESP Field 5
MD-Pumps
0.055 TPH 0.28 TPH 167 / 283m
ESP Field 6
MD-Pumps
0.011 TPH 0.055 TPH 172 / 288 m
Economiser
Ash Vessels
6.1 TPH 8.1 TPH 180 / 240 m
Air Heater ash
vessels
3.7 TPH 5.0 TPH 180 / 240 m

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Pneumatic conveying for fly ash
There are Three basic modes of pneumatic conveying :
 Lean-Phase (the oldest method)
• high volumes of low-pressure air entrain material in a high velocity air stream
(16 – 30 m/s)
 Medium-Phase
• uses higher pressure air to convey material over longer distances at lower
velocities (8 – 22 m/s)
 Dense-Phase (a more modern technology)
• uses high-pressure air to convey material in ‘plug’ form through smaller
pipelines at low velocity and high efficiency (1.5 – 10 m/s)

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Lean-Phase
16 – 30 m/s
Medium-Phase
8 – 22 m/s
Dense-Phase
1.5 – 10 m/s

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0
1
2
3
4
5
6
7
8
9
10
SpecificWearRate
5 10 15 20 25 30
Conveying Velocity (m/sec)
Lean Phase Conveying
Medium Phase Conveying
Dense Phase Conveying
Wear Rate of pipe & bends due to velocity

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What is a DensPhase system ?
Conveying
Time
Pressure
Peak Air Duration
Peak Air
Flow
the DensPhase cycle
Conveying
System
Silo
Air
Compressor
Air
Receiver
process
blow
valve
open
Reset blow valve
closed
Filling
Average Air Flow

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The DensPhase cycle
at ‘normal’ conveying rate
Waiting Time for
level probe to cover
Transfer Cycle 2
Peak Air
Flow
Time
Fill Conveying
Pressure
Peak Air Duration
Transfer Cycle 1
Average Air
Flow

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The DensPhase cycle
at ‘maximum’ conveying rate
Transfer Cycle 3
Time
Fill Conveying
Pressure
Transfer Cycle 1 Transfer Cycle 2

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Conveying technology: MD-Pump
 Multi-vessel systems available for
continuous conveying
 Low conveying pressures and power
consumption
 Longer distance capability - more
than 1000 metres
 Can handle high temperature
materials - more than 250ºC
 Effectively handles a mixture of
particle sizes

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Overview
 During normal operation of the boiler fly ash will accumulate in the outlets
from the Electrostatic Precipitator. The fly ash will be discharged into the MD-
Pumps mounted beneath the outlet and will then be pneumatically conveyed to
the silos. The MD-Pump system transfers ash in batches at a frequency set to
achieve the system design transfer rate.
 Each Field / Row of MD-Pumps located beneath the ESP outlets will convey ash
along a common pipeline.
 A conveying sequence will be initiated when all of the start interlock conditions
become true and will proceed as follows: All the Inlet Dome valves will be
opened, the outlet Dome Valve will be closed and ash will fall under gravity into
the vessels. During filling the Vent Dome valves will be opened to allow the
displaced air to be released from the vessels. A level probe located in each MD-
Pump (conical vessels) will signal the presence of ash. When a level probe
becomes covered (conical vessels) or a fill timer expires (tube vessels), and
after a short timed delay to allow the vessel to completely fill, the Inlet and
Vent Dome valves for that particular MD-Pump will be closed. This will be
repeated until both MD-Pumps have been filled or the system filling
requirement becomes true, following this the outlet Dome Valve will be opened.

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Overview Cont.
 The Outlet Slave vessel fluidising air valve and Air Blend valve will then both be
opened. Following a short time delay the Master vessel fluidising air valve will
be opened. The conveying air entering the MD-Pump system will discharge ash
from all of the vessels into the conveying pipeline from where it will be
conveyed to the ash silos. When the ash has been discharged into the
conveying pipe signalled by a drop in pressure in the conveying pipe, the
conveying air valves will be closed. after a short timed delay the cycle will be
complete.
 The ash will be routed to one of two ash silos by means of a switch valve. A
high level switch in each silo will signal when it is full and the control system
will change the route to another silo if available, or will inhibit further
operation of the MD-Pumps.
 The conveying air from the ash silo will be vented to atmosphere via a filter. It
is important that the filter cleaning is operated continuously while the ash
system is in operation. The exhaust from the filter must be unobstructed and
open to atmosphere at all times, even when the ash system is not in operation.
This is to permit any compressed air leakage into the system, or expansion of
the air due to an increase in temperature, to be safely vented.

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Cycle 3 - Conveying
Convey
Air
Cycle 4 -Rest
Cycle 2 - FullCycle 1 - Filling
Vent

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Conveying technology: Ash vessel
 One piece cast vessel construction
 Single Dome Valve
 Low maintenance
 Over 400 installations
 Can maintain precipitators in empty
condition, preventing “caking”
 High material-to-air ratio and low
conveying velocity reduces pipe wear
 Low profile vessel requires minimum
headroom ~ ideal for retrofit
applications
 Simple construction ~ only One
moving part
 Multiple vessels connected to one
pipeline
 Standard construction can handle
< 200ºC ash
 Water-cooling available for higher
temperatures

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Overview
 During normal operation of the boiler, ash will accumulate in the outlets from
the Economiser / Air Heater. The ash will be discharged into the ash vessels
mounted beneath the outlets and will then be pneumatically conveyed to the
silos. The Ash Vessels will transfer the ash in batches at a frequency set to
achieve the system design transfer rate.
 The ash vessels located beneath the hopper outlets and will be connected to a
common pipe.
 A conveying cycle for the ash vessels will be initiated when all start interlocks
become true and will proceed as follows: The master vessel inlet Dome Valve
will be opened and ash will fall into the vessel. The inlet Dome Valves on the
other vessels will be opened sequentially, with a short time delay between each
one. During filling the outlet Dome Valve will be closed to seal the pipeline and
prevent air from being drawn through the conveying pipeline by the vacuum in
the Economiser / Air Heater or ash from flushing down the conveying pipe.
After a timed delay, the inlet Dome Valves will be closed and the outlet Dome
Valve will be opened. When all of the inlet Dome Valves have closed and sealed
and the outlet Dome Valve has opened, air is introduced into the master ash
vessel. The ash will then be discharged into the conveying pipeline and will be
conveyed to the silos.

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Overview Cont.
 When the material has been discharged into the silos, signalled by a drop in
conveying pressure, the conveying air valves will be closed and the cycle will be
complete.
 The ash will be routed to the selected silo. A high level switch in each silo will
signal when it is full and the control system will inhibit further operation of the
Ash Vessels or switch to the alternative silo if available.
 The conveying air will be vented to atmosphere via reverse jet filters located on
the silo. It is important that the filter cleaning is operated continuously while
the system is in operation. The exhaust from the filter must be unobstructed
and open to atmosphere at all times, even when the system is not in operation.
This is to permit any compressed air leakage into the system, or expansion of
the air due to an increase in temperature, to be safely vented.

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Operating cycle – simultaneous filling:

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Detailed operation of the Dome Valve
Dome Valve
Operation
Dome Valve maintenance

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The CBM Dome valve®
The most important piece of equipment is the ‘Dome Valve’. This is a critical
component that enables the silo to be completely sealed to avoid transfer of
pressure.

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used in the most crucial area
for pneumatic conveying systems
The Air to Material interface
 full bore unobstructed material flow
 simple, proven design: > 15,000 in operation
 forms pressure tight seal when closed
 cuts through moving or static material columns
 wide range of valve sizes: 50mm to 500mm
 pressures up to 30 bar
 temperatures from -20ºC to +450ºC
 high availability and long operating life
 low maintenance
 up to 1,000,000 cycles between major overhauls

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seal (inflated)
seal inflation
air inlet
OpenClosed
seal (deflated)

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Basic configurations
Bulkhead
for pressure vessel inlet use
In-Line
for pipeline use

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Full bore flow
valve closed valve open

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Typical key components
 1: Top adapter (optional).
 2: Top plate.
 3: Insert ring.
 4: Inflatable seal.
 5: Seal retaining ring.
 6: Gasket.
 7: Valve body.
 8: Pneumatic cylinder / actuator.
 9: Cylinder guard.
 10: Dome.
 11: Limit switch.
 12: Torque arm.
 13: Bottom adapter (optional)
1
2
3
4
5
6
7
8
9
10
11 12
13

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Changing the seal

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Routine maintenance
Changing the seal
1) Unscrew the top plate set screws. 2) Remove top plate to gain access to the
insert seal and insert seal ring.

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Routine maintenance
Changing the seal (continued)
3) Lift out insert seal and separate from the insert
seal ring. Inspect the seal and ring for damage. Fit
new seal to the ring.
4) Replace seal and insert ring into spigot ring.
Note: The seal / dome clearance is set by using shim gaskets
that are fitted underneath the spigot ring and top plate. The
gaskets have a thickness of 0.4 mm, 0.8 mm and 1.5 mm.
Nominal clearance is generally set to 0.3 mm. (Please consult
the Operator and Maintenance manual for correct setting.)

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Routine maintenance
Changing the seal (continued)
5) Refit the top plate and check the seal to dome
clearance with feeler gauges.

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Routine maintenance
 Weekly – General visual inspection of the equipment including
operating function check.
 Monthly
1. Recommended grease the Dome Valve shafts and bearings (hydraulic
grease nipples located on the Dome Valve body) using Shell Malleus
JB1 grease, or equivalent.
2. Check control air lubricators mounted on the outside of the
pneumatic panels and top up as required (If applicable). Monitor the
condition of the filters and clean as required as described in the
proprietary parts section of the operator and maintenance manual.
Caution! If the filter is to be removed for cleaning or renewal then
the air supply to the control panel must be isolated.
3. Visually inspect flexible adapter / bellows, where fitted, for signs of
wear.

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Routine maintenance
 Yearly
Check Dome Valve air limit and position feed back switch settings (where
applicable). Refer to Dome Valve information in the operator and
maintenance manual.
1. Pneumatic control panel: Inspect the condition of exhaust silencers
(located on the underside of the panel) renew as required. Clean control
air filter where applicable.
2. Isolation valves: (Manually operated types) Clean off dirt build up from
the threaded spindle, grease spindle and check function.
3. General functional checks of all valves.
4. Visually inspect condition of connections to level probes for signs of
deterioration.
5. Clean control airline filter traps.
6. Clean out air strainers and check non-return valves.

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 Two yearly.
 Note! Close the isolation valves above the valves, run the system
until empty and remove lower adapter located below the isolation
valve. The Dome Valve can now be removed using suitable lifting
equipment.
1. Remove the Dome Valves as described, and check head of dome and
seal for signs of wear, and replace bearings and seals as described.
When abrasive product materials are used it is recommended to
check the head and seal annually.
2. Control panels: As yearly, plus visual inspection of electrical and
pneumatic connections and condition of equipment.
3. Dome Valves fitted with pneumatic cylinders: Inspect cylinder barrel
for score marks, scratches, pitting and rust etc, as this can lead to
premature failure of the cylinder seals.
Routine maintenance

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Fault finding – common problems
 Dome valve not closed and sealed.
If this alarm is indicated on the control room screen, there could
be three possible causes.
1) The seal pressure switch has failed.
2) The seal air limit switch has not been operated (Dome not fully
closed.)
3) The insert seal has been damaged.
Remedies: Check the seal pressure switch and gauge in the
pneumatic control panel. If the gauge is reading zero, check the air
limit switch. If the pressure gauge is reading 2.0 to 4.0 Barg there
is a good possibility that the seal has been damaged and needs
renewing. If the pressure gauge is reading control air pressure, i.e.
6.0 to 7.0 Barg then the pressure switch operation should be
checked.

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Seal pressure switch and gauge Position of air limit switch on the inlet dome valve.

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 Dome valve not open.
 Inlet dome valves interrogate the seal air pressure switch to determine if open.
 If the control room screen indicates the ‘Inlet dome valve not open’ alarm then
the fault could either be with the seal air pressure switch or the inlet dome valve
solenoid valve located in the pneumatic control panel.
Inlet dome valve solenoid valve
Inlet dome valve seal pressure
switch

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 Route dome valves and inline dome valves.
 Route dome valves use both the seal air pressure switch and a limit
switch. The seal air pressure switch is used for the closed and sealed
position, the limit switch is used to indicate the fully open position.
 Route valve not closed and sealed – repeat the same checks as for the
‘Inlet dome valve’.
 Route valve not open – repeat the same checks as for ‘Inlet dome valve,
in addition, check the open limit switch’.

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Inline dome valve showing limit switch enclosure.
(Open and closed limits)
Route valve showing limit switch enclosure.
(Open limit only)

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Level probes
FTI77
Capacitance Level Switch
FMP54
Guided radar level probe

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Level probes
 The most likely problem encountered with level probes is usually the
sensitivity setting drifts, which basically means the probe will either
continually ‘see’ a material level even though there is no material present
in the silo, or, the probe will not sense the material at all and never
indicate a level in the silo.
 If either problem occurs it may be necessary to recalibrate the level
probe.
 Initial checks should be:
1. Check all electrical connections.
2. Make sure there is no material build up on the sensing rod (i.e. wet
material)
3. Check to make sure that the fail safe has not been changed (Probes are
normally set Fail Safe High.)
4. If re-calibration is necessary then make sure there is no material on the
probe.

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Pipeline components
Dome Switch Valve
 Used to provide material routing where a
system is delivering to multiple reception
points in different locations
 Can also be used to connect incoming
pipelines together
 The CBM Dome Switch Valve offers the
same high performance and durability
benefits of the Dome Valve

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Pipeline components
Dome Switch Valve

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Pipeline components
Dome Switch Valve Overview
 The material from the ash system will be routed to one of three silos (east,
centre or west)
 To permit the route to be changed the conveying cycles on the relevant fields
must be “at rest”.

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Pipeline components
Dome Switch Valve Alarms
 Dome Valves Not Open Alarm
Definition: Dome Valve open solenoid is energised and Dome Valve close
solenoid de-energised and open position indication not made for more than
5 seconds.
Control Action: Visual alarm only and conveying cycle start inhibited.
 Dome Valves Not Closed And Sealed Alarm
Definition: Dome Valve close solenoid is energised and Dome Valve open
solenoid is de-energised and seal pressure < 5 Barg for more than 5
seconds.
Control Action: Visual alarm and conveying cycle start inhibited.

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Silo dust filter
Reverse pulse-jet cleaned Bag Filter
 Fly Ash Silo
• 300 m² filtration area
• Dura-life bags

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Silo dust filter
DEC Donaldson Dalamatic filter unit

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Relief valve
CBD Relief Valve Vacuum Relief Valve

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Silo discharge
Silo discharge system – Tanker Loading Spout

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Tanker Loading Spout
 The loading system is suitable for all applications.
 Into, road tankers, open-top vehicles, wagons, ships, sheds and containers.

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Tanker Loading Spout
Tanker Loading Spout Overview
 The dustless loading spout system will be controlled by a dedicated PLC located
in the silo area.
 There is a local pendant controller for use by the tanker driver for discharge via
the loading spout.

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Control system
Tanker Loading Panel

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Troubleshooting
Tanker Loading - Troubleshooting
 Loading Chute hoists irregularly or not at all
 a) System is full of material
 b) Spring is broken or too slack, check and replace / tighten as required
 Lowering of Loading Chute is irregular or will not fully lower
 a) Spring is too tight on slack rope switch, loosen spring and recheck

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Silo discharge
Silo discharge system – Ash Conditioner

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Ash Conditioner
Ash Conditioner Overview
 The ash conditioner system will be controlled by a dedicated PLC located in the
silo area.
 There is also a separate control pendent for use by the operator, this interfaces
with the PLC to perform the requested operation.
 The system will automatically run through the cycle when the start button is
pressed and stop when the stop is pressed.
 In case of a longer shutdown the washout button should also be pressed after
the stop to perform a washout of the system of any residual ash.

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Control system
Ash Conditioner Panel

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Ash conditioner
 The intersecting mixer paddle design insures a thorough blending of dust and
moisture, producing a uniform distribution prior to discharge. The low speed
mixer operates at a constant 30 rpm to minimize paddle wear and control
mixer residence time. Precise timing between the two shafts is maintained by
twin spur gears enclosed in an oil tight case. During operation, a stationary
layer of material forms along the interior of the tub, protecting it from wear.
As the ash is mixed by the inter-leaving paddles, it is conveyed forward at a
controlled rate, thus establishing a constant residence time and mixer
efficiency. Precise changes to mixer paddle angle and shaft speed are possible
to suit individual process requirements. Alternate paddle materials are
available to address wear, corrosion, or material build-up. Mixer drive
components, bearings, and shaft seal systems are external-mounted for ease
of maintenance and inspection
Ash Conditioner Mixing Chamber

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Ash conditioner

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Troubleshooting
Ash Conditioner- Troubleshooting
 Water not entering system
a) Check water supply pipe and pump to ensure valves are open and pump is
running
 Dome Valve Fault
a) Check dome valve troubleshooting
 Motor not running alarm
a) Check isolator to motor and check motor for signs of damage

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Operating & maintenance manual
Operating & Maintenance Manual
Volume 1 CBD proprietary Conveying
Systems, products and
equipment
Volume 2 OEM Proprietary Equipment

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End
Thank you for your attention

Training material for ash handling system (fly)

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