Wood Gun™ Multi-Fuel
Gasification Wood Boiler

The Wood Gun™ wood gasification boiler by Alternate Heating Systems, Inc. utilizes the most advanced technology available in wood burning today.  We believe, and *independent testing laboratory results indicate, that this is the most efficient wood-burning device built today.  This uncompromising multi-fuel system is ideal for residential, commercial, and industrial applications where wood and wood by-products are available as a primary fuel source.  The Wood Gun™ wood boiler comes in sizes ranging from 100,000 to 1,000,000 BTU's.  

The Wood Gun™ wood boiler employs a down-draft wood gasification design which burns wood of all types and moisture content.  These wood boilers work by drawing the wood gases off using an induction fan and then burning them underneath the wood so that much more complete combustion occurs. The wood is continually heated by the burning gases beneath it so that the gases continue to rise from the wood - the wood itself doesn't burn, only the gases.  Since only the gases are combusted, the AHS wood boiler can burn wood with a wider range of moisture content than can a non-gasification wood boiler.  An additional feature is automatic switchover to oil heat, gas heat or electric heat backup.  An optional lockout feature maintains the secondary fuel mode in the event the wood charge is expended.

Particle Fuel Delivery

When burning chunk wood in an AHS wood boiler, if the system is properly sized, the fire box typically only needs to be loaded two or three times a day (unless extreme cold conditions prevail).  Our automatic particle fuel delivery option is ideal for customers with access to uniformly sized wood pieces, chips, pellets, etc.  If you want to burn both chunk wood and wood particles in your AHS wood boiler, it only takes about fifteen minutes (after shutting the system down and allowing it to cool) to change the system from one wood type to the other, but chunk wood can still be loaded even when using the particle fuel delivery mechanism.

A close inspection will quickly reveal why the Wood Gun™ wood gasification boiler is the standard by which all other wood burning appliances are judged. Many of these unique features are found only on the Wood Gun™.

How Superior is the Efficiency of the Wood Gun™ wood boiler?

The Wood Gun™ wood boiler is a combustion system capable of burning wood and wood-based waste at a very high combustion efficiency, resulting in very low stack emissions.  Stack sampling on operating units has yielded particulate levels 50% less than the best results obtained by conventional up-draft boilers.  This level of performance is due to a number of unique design features not found on other wood waste combustion equipment.  In fact, the Wood Gun™ is so different that conventional wood boilers cannot be modified to incorporate these features without a complete redesign.

Stack Temperature

The stack temperature is an indicator of how completely the fuel is being combusted.  The Alternate Heating Systems Inc. Wood Gun™ Boiler operates with one of the coolest stack temperatures of any wood boiler on the market (if not the coolest).  The stack temperature of a Wood Gun™ runs at less than 300 degrees fahrenheit (typically 260 - 280 degrees).  The low stack temperatures of our boilers are almost unheard of on the market.

Carbon vs. Stainless Steel in our Wood Boilers

The internal surfaces of a Wood Gun™ Wood Boiler include any surface touched by the flame, smoke, wood or exhaust.  The internal surfaces may be manufactured with carbon steel or stainless steel - it's your choice.  We recommend stainless steel because carbon steel will show deterioration within 10 years though the unit may continue to function for as much as 20 years.  We have had stainless steel boilers in service for 19 years, and they show no sign of deterioration.  We use 1/4" thick 304 stainless steel (as opposed to 409) for unsurpassed quality.

Features

• Automatic cycling on and off in response to heating or hot water demand.

• Domestic hot water coil provides abundant quantities of hot water.

• Exceptionally safe and clean burning. The use of dense refractory material cast into specific shapes causes complete combustion to occur at temperatures of up to 2000° F.

• When operated properly in the gasification mode, visible smoke is eliminated and creosote formation inside the chimney is prevented.

• The large cyclone separator removes most of the fly ash resulting in very low emission.

• Spontaneous re-ignition of the wood will occur after an off period of 2-8 hours. Factors such as the quality and quantity of the fuel charge as well as the size of the unit also determine how long a system can go without burning and then have spontaneous re-ignition occur.

• Automatic fuel delivery systems are available for wood waste products such as sawdust, shavings, woodchips and densified biomass.

• Wood Gun™ readily adapts to new or existing hot air systems through the use of a heat convection coil.

• The design maintains all heated walls at the same temperature using a "water wall".  This constant temperature eliminates stress fractures caused by differences in temperature between components of the stove thus increasing the life of the stove.  In addition, this design produces greater efficiency because heat that is normally lost through a drywall is captured in the water wall.

Diagram of Wood Gasification Boiler

The Swirl Chamber

HOW DOES THE UNIQUE DESIGN OF THE WOOD GUN SWIRL CHAMBER DIFFER FROM OTHER WOOD GASIFICATION BOILERS?

The SWIRL CHAMBER is where 90% of the heat exchange takes place in the Wood Gun. The Wood Gun refractory emits 2000 degree fahrenheit exhaust air temperature which is directed into the SWIRL CHAMBER and has an exiting exhaust air temp of only 275 degrees at high fire. This unheard of heat transfer efficiency is due to our unique design. The exhaust air spins through a large diameter drum assisted by a 3400 rpm draft inducer making a swirling action. Both the exhaust air and the ash from the wood, scrub the walls of the heat exchanger at a high rate of speed, in turn keeping it clean and efficient. This self-cleaning action prevents the troublesome routine cleaning of the heat exchanger that has plagued the Wood Boiler industry for years.

*The temperature varies from Boiler size, wood quality, moisture content and flue height. 

The CYCLONE ASH SEPERATOR is where the majority of the ash is collected. Since the design of the Swirl chamber is to use the ash as a cleaning agent, we can allow the ash to exit the boiler with the exhaust air.  The speed of the ash is increased using a high velocity orifice, discharging it into a cyclonic action device (the CYLCONE), spinning the heavy particles out of the exhaust stream and finally funneling them into the stainless steel ash pan allowing the exhaust to exit the cyclone top into the chimney pipe. 

Illustrated Features

Routine cleaning of combustion chamber is necessary to maintain optimum performance. Easy-open Inspection Doors Front and rear make cleaning a snap.

Improved Air Valve design permits easy replacement of gasket disc.

	The Air Valve closed.
			Removable Clean-out Plug provides direct access to combustion chamber

Draft inducing fan produces high velocity and intense flame in combustion chamber. Unlike conventional heating equipment, the flame production in the Wood Gun ™ follows a downward path with temperatures of up to 2000° Fahrenheit.
	Inside the wood chamber looking through the wood loading door.

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Specifications

Alternate Heating Systems, Inc. standard sized Wood Gun™ Boilers are smaller than the intermediate sized boilers but pack in the same features and performance.