The BCS Automatic Feeding System
Available for the 800,000 BTU/hr Hot Air Furnace
This system is designed to receive 1.5” minus fuel at a height of 65”. If the customer supplies the storage bin, the BCS supplied control panel will automatically regulate the customer supplied screw auger bringing fuel to the BCS supplied rotary air lock. This fuel is introduced into the firebox at grate level and pushed across the grate by fuel coming in behind it. Since the fuel moves, not the grates, the grate does not jam or wear. With the BCS feed method, the fuel cannot move too fast or too slow, as with step or traveling grates, but are always in proportion to oxidation rates.
The style of combustion and fuel feed across the grates is a unique and highly efficient design of Biomass Combustion Systems. Simple external adjustments are all that is required to burn wood fuel from sander dust to whole tree chips, and from 0 to 40% moisture content.
Forced-Draft Grate System --- Maintains Flexibility for Different Fuels
The underfire air is controlled using a variable speed fan. This fan is set during start up to gasifiy the fuel without blowing fuel off the grate where it can leave the firebox without complete combustion.
Adjustable Combustion Air --- For Varying Fuel Conditions
The combustion air manifold for the overfire air is controlled externally with a hand valve. This enables the operator to adjust the burner for changes in fuel and heat requirements.
Intelligent Thermostat --- Conserves Electricity and Provides Desired Heat
A thermostat senses temperature exiting the hot air plenum and controls the on/off cycling of the heat distribution fan. The thermostat enables the burner to conserve electricity when not at adequate temperature to distribute the hot air in the building. When the firebox is in the summer incineration mode, the fan cools the burner continuously. As a safety feature, the thermostat will shut off the induced draft fan in the case of over temperature.
High & Low Fire Mode --- Allows for up to 10:1 Turndown and Pilot Fire
A variable speed fan automatically modulates combustion air for high fire, low fire and interrupt modes of operation according to energy demand. High fire is required when the heat or process application demands full heat. Low fire is up to a 10 to 1 turndown on dry wood which idles the furnace when heat is not required, but maintains a fire in the event of high fire demand. The system has up to 5 to 1 turndown for green wood, while other systems using spreader stokers are capable of only a 3 to 1 turndown on any fuels. PLC timers in the BCS control panel regulate the duration of fuel feed and match the quantity of combustion air for both high fire and low fire modes of operation.
Interrupt Mode --- Uses Control Panel Intelligence to Alter Burner Activity
The interrupt mode, used in such cases as excessive firebox temperature, temporarily shuts off fuel feed and modifies combustion air until the system is running in normal parameters again. During interrupt mode, only fuel feed and combustion air are modified. Overfire air and induced draft fans are not shut down during interrupt mode, as this can cause adverse conditions in the chamber and create carbon monoxide.
One example of the interrupt mode is as follows: During start-up, the air is adjusted for high fire and the stoker is locked out of automatic until the minimum firebox temperature is achieved.
Another example of interrupt mode: If the customer hand fires some chunk wood through the loading door during automatic stoking, the control panel will sense an increase of temperature in the firebox. The control panel will temporarily interrupt the stoker's feed until that fuel is burned off and the temperature is back within normal range.
Automated System Operation --- Reduces the Need for a Furnace Operator
Continuous monitoring of all functions enables the system to run without the cost and labor of a furnace room operator (unless local law requires an operator.)
Uses Allen Bradley PLC --- Easy to Adjust and Maintain
The control panel is also simple in construction and maintenance. BCS uses an Allen Bradley PLC to control each function. Each PLC timer is independently adjustable so that the operator can easily modify the operation, if desired. In the rare event of failure, the bad component can be quickly identified and replaced.
Automatic Shutdown --- Provides for Fail-Safe Operation
The control panel will alter or shut down operation if:
- a forced draft or induced draft fan fails
- primary or secondary screw auger fails
- rotary air lock fails
- the fire extinguisher tank is not full and operable
- critical thermal overloads or magnetic starters fail
- firebox temperature is under or over pre-set range
Passive Fire Extinguisher --- Works in the Absence of Electricity or Water Pressure
A 40 gallon water tank extinguishes a burn back condition in the screw auger, should one occur, via hose and temperature sensitive plug connected to the trough. This passive design works in the absence of electricity or municipal water pressure, a critical time for safety. For this reason, it is not advisable to tie the fire extinguisher tank to a thermal sensing device, town or well water.
Auger Purge Cycle --- Reduces the Chance of Burn back
The firebox screw auger is timed to purge itself of fuel after every stoke to prevent a path for burn back. This purge is a one-time adjustment in the control panel based on the length of the secondary screw auger.
Rotary Air Lock --- Separates fuel storage from firebox
A rotary air lock is located between the primary and secondary screw augers for additional safety precaution. The air lock separates the fuel supply from the burner which reduces the risk of fire outside the combustion area.
Firebox Temperature Monitors Operation --- For Quick Reaction Time
The control panel can modulate fuel feed and combustion air due to the monitoring of firebox temperature. Because the system is monitored where combustion takes place, the control panel can react quickly to changes in the burner’s operation. In systems with stack temperature monitors, the panel reacts slowly which can cause problems.
Pre-Wired Control Panel --- Reduces Time for On-Site Electrician
Magnetic starters with adjustable, ambient compensating thermal overloads, main circuit breaker disconnect, and individual circuit breaker for all motors are included and pre-wired. Also included is a step down transformer for low voltage controls and fuses. All components in the panel are pre-wired and need only to have power brought to the box. (Wiring from the control panel to individual motors is not included. )
The Control Panel also Monitors:
- firebox temperature
- stack temperature
- building temperature
Installation/Startup
BCS is available for installation oversight although the installation may be easily accomplished by the customer or a local crew using our easy to follow Installation Manual. Please note: It is the customer's responsibility to ensure that this installation meets any and all codes or requirements. Start up services are included and involve the training of employees on the proper operation and maintenance of the system in one trip to the job site. Air fare and other related expenses for this trip are the customer's responsibility.
The package does not include any wiring, plumbing or heat distribution for the furnace, or a furnace room if necessary. Nor does it include any silos, fuel storage or material handling equipment, except as noted.
Make your wood waste work for you!
