US2092680A

US2092680A - Sawdust burner

Info

Publication number: US2092680A
Authority: US
Publication date: 1937-09-07
Anticipated expiration: 1954-09-07

Description

J. PUDNEY sAwnusT BURNER Sept. 7, 1937.

Filed May 4, 195e tij;

Patented Sept. 7, 1937 UNITED STATES SAWDUST BURNER y i .I ames Stuart Pudney, Victoria, British Columbia, Canada Application May 4, 1936, Serial No. 77,841

In Canada December 2, 1935 Claims.

This invention relates to an improved sawdust burner.

' An object of the present invention is the provision of a sawdust burner in the form of a complete unit which may be applied to heating devices of all types, particularly ranges, domestic and industrial furnaces and Dutch ovens.

` Another object is the provision of a sawdust burner of greatly increased efiiciency in which substantially complete combustion is ensured by supplying preheated air to the products of combustion in a secondary combustion chamber.

A further object is the provision of a sawdust burner which will keep the smoke pipe and flue clear of soot by complete combustion of the fuel, thus eliminating` the re hazard created by clogged pipes becoming overheated.

In the known types of burners the fuel is burned and the products of combustion drawn off through the smoke pipe. In this way gases and soot containing relatively great heat value pass out through the flue and are lost. Not only does this reduce the efciency of the fuel but the soot settles on the walls of the smoke pipe and flue making frequent cleaning necessary in order to prevent the pipes from becoming overheated. This invention overcomes these objectionable features by providing a sawdust burner having a primary combustion chamber in which the fuel in burned. The products of combustion then pass into a secondary combustion chamber in which they are mixed with preheated air and completely burned. The preheated air breaks up the productsof combustion and mixes them with oxygen to form a highly combustible gas which is ignited by the heat from the primary combustion chamber.

'I'he present invention consists essentially of primary combustion chamber containing a grate and a hopper adapted to supply fuel to the grate, said chamber communicating with a secondary combustion chamber within the heating device to which the sawdust burner is applied, and means for supplying preheated air to the secondary combustion chamber as more fully described in the following specification and illustrated in the accompanying drawing, in which:-

Fig. 1 is a vertical section through a sawdust burner and the range to which it is applied, only a part of the latter being shown, and

Fig. 2V is a plan view of the sawdust burner with the hopper removed and having certain parts broken away for the sake of clarity.

Referring more particularly to the drawing, A is the sawdust burner applied to an ordinary range (Cl. 126-222) i B.` The-burner A comprises a hollow base I0 adapted to form a water reservoir I I. A housing I2, removably secured to the base I0 in a any suitable mannen forms therewith a primary combustion chamber i3. The base I0 has a raised section 5 I4 forming a slope I5 in the chamber I3.

A shoulder l5 surrounds an opening Il in the top of the housing I2 and plates I3 having slots I 3 are secured to the sides of shoulder. A hopper 23 `having a hinged cover 2| is formed at its lower l0 end with a reduced opening 22 and at each side thereof with flanges 23 adapted to ride in the slots I9. A plate 24'removably mounted on one end cf'the shoulder I5 has its upper surface in line with 'the bottoms of the slots I9 so that the hop- 15 per may be slid along the slots onto the plate when it is desired to gain access to the primary cornbustion chamber from above. The plate 24 -may be vremoved from the shoulder when it is not needed.

A sloping chute or plate 25 mounted on the inner side of the top of housing I2 extends beneath the opening II and has itslower end suspended above a grate 25 situated in the chamber I3. The inner end of the grate 26 isvlower than the 25 outer end lying beneath the plate 25 and abuts against the slope I 5; The outer end of the chamber I3 is provided with a door 28 having a damper 29 through which' air may pass into said chamber. The side walls of the chamber are'lined with 30 fire brick 30. 7

Theraised sectionV I4 of the hollow base Il) is provided with a tube 3| which extends through the base upwardly and terminates in an opening 32 in the top of the housing I2. A member 33, 35 'which may be cylindrical or any other desired shape, is mounted at its lower end in the opening 32, said member extends upwardly into the range B through a heating compartment 34 .in said range and passes through a partition 35. rIhis 40 partition 35 takes the place of the usual grate of the range B and the member 33 is sealed therein so that no air may pass from the compartment 34 between said member and the partition into the upper part of the range. 'I'he member 33 45 forms a secondary combustion chamber 36 and has a plurality of rows of holes 3l. A pipe 38 mounted in the upper end of the tube 3| extends upwardly into and centrally of the chamber 36 and terminates just below the level of the parti- 50 tion 35. A cap 39 is fitted onto the upper end of the pipe 38 and has a plurality of holes 40. The tube 3|, pipe 38 and holes 4|] form a passageway lII communicating at the lower end with the at mosphere outside the sawdust burner and at the 55 upper end with the interior of the secondary com.- bustion chamber 36.

Air enters the compartment 34 through the usual damper 42 of the range B. Water enters the reservoir Il through an inlet pipe 43 and passes therefrom through an outlet pipe 44 which extends through the chamber 36 and out through one of the walls of the range.

In operation, sawdust flows from the hopper through the opening 22, over the plate onto the grate 25 in the primary combustion chamber I3 where it is burned. Air entering the chamber through the damper 29 passes through the grate and sawdust to aid combustion. The products of combustion from this fire pass along the chamber I3 and up into the secondary combustion chamber 36. Air entering the passageway 4| is heated as it flows through the pipe 38 and passes out in jets through the holes 40 into the secondary combustion chamber where it mixes with the products of combustion. At the same time air flowing through the damper 42 is preheated in compartment 34 and is injected in jets through the holes 3l also to mix with the products of combustion in the secondary combustion chamber. These two streams of preheated air break up the products of combustion` and add oxygen thereto to form a highly combustible gas which ignites from the heat generated in the primary combustion chamber.

This burning of the products of combustion from the primary chamber not only completes the combustion of the fuel to give substantially 100% efficiency but it eliminates soot so that nothing but a useless gas passes on through the range and flue.

Water circulating in the reservoir Il is heated by the re in the primary chamber and is further heated by the fire in the secondary chamber as it flows through the outlet pipe 44.

While this device has been described as a sawdust burner, it is to be understood that coal or any suitable other fuel could be used without altering the construction of the device.

From the above it will readily be seen that a sawdust burner has been provided in which substantially complete combustion is ensured thus greatly increasing its efliciency and in which the soot is completely burned thus eliminating clogged pipes and fiues.

What I claim as my invention is:

1. A sawdust burner adapted to be applied to a heating device comprising a primary combustion chamber, means for supplying fuel to a grate in said chamber, a secondary combustion chamber associated with the primary chamber and extending into the heating device and means for supplying preheated air from the heating device and the atmosphere outside the heating device to the secondary chamber where it is mixed with the products of combustion from the primary chamber to ensure complete combustion thereof.

2. A sawdust burner adapted to be applied to a heating device comprising a primary combustion chamber, means for supplying fuel to a grate in said chamber, a secondary combustion chamber connected to the primary chamber and extending into the heating device, means extending centrally of the secondary chamber for supplying preheated air thereto and means for supplying preheated air to said secondary chamber through the walls thereof, said preheated air being mixed with the products of combustion from the primary chamber to ensure complete combustion thereof.

3. A sawdust burner adapted to be applied to a heating device comprising a primary combustion chamber, a hopper for supplying fuel to a grate in said chamber, a secondary combustion chamber connected to the primary chamber and extending into the heating device, a heating compartment surrounding the secondary chamber, means for supplying preheated air from said compartment to the secondary chamber and means communicating with the atmosphere outside the burner and the interior of the secondary chamber for supplying additional preheated air thereto, said preheated air being mixed in the secondary chamber with the products of combustion from the primary chamber to ensure complete combustion thereof.

4. A device according to claim 3 in which the wall of the secondary combustion chamber is provided with a plurality of rows of holes through which preheated air is injected in jets from the compartment into the secondary chamber and in which the means for supplying additional preheated air to the secondary chamber comprises a passageway communicating with the atmosphere outside the burner and extending upwardly centrally of the secondary chamber and terminating adjacent the top thereof.

5. A sawdust burner adapted to be applied to a heating device comprising a primary combustion chamber having a hollow base with a housing secured thereto, means for circulating water through said hollow base, said housing having an opening in its top, a shoulder surrounding the opening, plates secured to each side of the shoulder each having a slot therein, a hopper slidably mounted in said slots and a plate removably mounted on one end of the shoulder having its upper surface in line with the bottoms of the slots whereby said hopper may be slid onto the plate in order to gain access to the primary chamber from above.

JAMES STUART PUDNEY.