Australian Kent Charcoal Gasifier

During a visit to Melbourne Australia on August 2006, I had the opportunity to inspect an original gasifier made in Melbourne in the 1940's.  It's condition was very poor, but had obviously been well used judging by the repair plate patches around the sides.

Built during a time when foundry castings were used instead of fabrication, they survive in new condition, while the steel components rusted away with time. As a design, it is as basic as gasification can be achieved, but at a price needing regular servicing every 10 bags of charcoal. Failure to do this, or lacking appreciation of understanding the problems of why clean-outs were so important, saw ash fuse into clinker around the air inlet, and the oxidation lobe diverted towards the  sheet metal walls, burning out the sides. A clean out hinged lid in the bottom, under the air nozzle enabled the central char and ash to drop out, leaving the char around the sides and corners to remain in place up to the nozzle position.

The air nozzle appeared to be set into the air inlet pipe with a fire clay type cement, which considering the time is a bit unlikely. In Australia, the soil, or clay from termite mounds was used to line forges and other fire box applications, by first wetting it to a mud and and molding it around the surface to be protected. When fired it turned into a very hard and durable surface, and as a material, easy to obtain in remote places.

With the gas rising vertically up through the charcoal, not much char ejected from the bed, so a grill at the top, on the opposite side to the inlet air at the bottom, only stopped char from entering the gas outlet during filling operations. The cyclone is a very crude design, and I would doubt if it collected any dust which was emptied out the bottom via a missing removable lid.

As these gasifiers were used on tractors and cars, the mountings allowed their fitting to front or back of the vehicle, so the gas exit pipe has a little length for cooling, and a downwards vertical outlet. This usually went to a filter canister containing packed cotton or other fibrous filling, and was not found with this gasifier.

The success of these simple box type updraft gasifiers was due to the availability of high quality hard charcoal made from Australian hardwoods (Eucalyptus), and I doubt if the design would work well with softwood charcoal (Conifers).  No steam was introduces with the air in this design, which possibly was a cheaper system than the inclined cross draft gasifiers that had self clearing air nozzles.

Doug Williams.
November 2006.


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Instruction plate for operation.

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Front view, size about 48”x18”x18” in size. Cyclone on the left, air inlet bottom right, gas outlet across back top to vertical outlet on right.

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Cyclone rusted out.

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Ditto
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Rusted out cyclone gas exit pipe.
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Vertical air inlet pipe has spaced cover pipe. Internal pipe possibly extends almost full length to reduce burning gas coming out during gear changes.

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A Tee fitting forms the mounting of the air inlet pipe, and has a swivel plate (missing) over the end to cover the ignition port.

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Cast iron lid and view of gas exit pipe across the back side.
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Internal gas exit grill. Top hopper flange also cast in cast iron.

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Asbestos lid gasket fits into cast grove in lid, lubricated with graphite.

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Pivoting lid clamp, with spring steel lid bar.

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Simple hinge point positioned to lift lid seal vertically off seal flange.

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Air nozzle 3/4” pipe located just off centre on thick steel (1/2”)angled plate. This is to slide ash off nozzle and enable fire clay to be packed in around replacable pipe nozzle. Clean out port can be seen under the nozzle assembly.

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Ditto

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Ditto

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Ditto