Enclosed granular fuel burning boiler

1. An enclosed granular fuel burning boiler including:

an enclosed combustion chamber;

a fuel-fired brazier mounted in the combustion chamber and comprising an apertured brazier base and upstanding side walls, namely, a proximal wall, a distal wall at least portion of which distal wall adjacent the base is either vertical or inclined downwardly and away from the proximal wall, and a pair of connecting side walls;

an actuator for moving the brazier base from an operative position retaining fuel in the brazier to a discharge position to allow ash contents to fall out of the brazier;

fragmentation means comprising a vitrified ash engaging crushing tooth mounted on and projecting upwardly from the brazier base whereby, on moving the brazier base to the discharge position, the vitrified ash engaging crushing tooth moves the vitrified ash across the brazier from the proximal wall and against the opposed distal wall;

a plenum chamber mounted outside the combustion chamber;

a fan for delivery of air from the plenum chamber to the brazier; and

a burner hood projecting over the brazier and forming part of a substantially sealed brazier enclosure mounted on a side wall of the boiler, the brazier enclosure including an enclosure base and two upstanding spaced-apart side walls carrying the burner hood and the brazier's upstanding side walls, the enclosure base having an enclosure ash contents discharge hole, a movable support plate having an upright end wall forming portion of the brazier enclosure and having a support plate discharge hole offset from the ash contents discharge hole when in a boiler firing condition, the support plate carrying the brazier base.

2. The enclosed granular fuel burning boiler as recited in claim 1 , in which the brazier base is formed from an elongate plate having a discharge hole which is over and communicates with the support plate discharge hole.

3. The enclosed granular fuel burning boiler as recited in claim 1 in which the burner hood forms at its distal end portion of a combustion gas outlet in the brazier enclosure, at least portion of which burner hood is hollow and comprises an upper enclosed air chamber connecting with the fan and a plurality of air discharge outlets in the air chamber for delivery of air above the brazier.

4. An enclosed granular fuel burning boiler, including:

an enclosed combustion chamber;

a fuel-fired brazier mounted in the combustion chamber on a side wall of the combustion chamber, said brazier comprising an apertured brazier base and upstanding side walls, namely, a proximal wall adjacent said side wall of the combustion chamber, a distal wall remote from said side wall of the combustion chamber, at least portion of which distal wall adjacent the brazier base is either vertical or inclined downwardly and away from the proximal wall, and a pair of connecting side walls;

an actuator for moving the brazier base from an operative position retaining fuel in the brazier to a discharge position to allow ash contents to fall out of the brazier;

fragmentation means comprising a vitrified ash engaging crushing tooth mounted on and projecting upwardly from the brazier base whereby, on moving the brazier base to the discharge position, the vitrified ash engaging crushing tooth moves the vitrified ash across the brazier from the proximal wall and against the opposed distal wall;

a plenum chamber mounted outside the combustion chamber;

a fan for delivering air to the brazier from the plenum chamber; and

a burner hood projecting over the brazier and forming part of a substantially sealed brazier enclosure mounted on a side wall of the boiler, the brazier enclosure including an enclosure base and two upstanding spaced-apart side walls carrying the burner hood and the brazier's upstanding side walls, the enclosure base having an enclosure ash contents discharge hole, a movable support plate having an upright end wall forming portion of the brazier enclosure and having a support plate discharge hole offset from the ash contents discharge hole when in a boiler firing condition, the support plate carrying the brazier base.

5. The enclosed granular fuel burning boiler as recited in claim 4 in which the vitrified ash engaging crushing tooth is inclined and configured such that when it projects into a receiving through-slot in the proximal wall when in the operative position, its surface facing the distal wall is parallel to the opposed surface of the distal wall.

6. The enclosed granular fuel burning boiler as recited in claim 4 in which a load absorbing connector is mounted between the actuator and the brazier base.

7. The enclosed granular fuel burning boiler as recited in claim 4 , in which a plurality of air inlet holes are provided in the upstanding side walls of the brazier.

8. The enclosed granular fuel burning boiler as recited in claim 4 in which a plurality of air inlet holes are provided in the upstanding side walls of the brazier the number of which is varied depending on the heat output requirements of the boiler.

9. The enclosed granular fuel burning boiler as recited in claim 4 , in which a diverter plate is mounted on or adjacent the distal wall of the brazier to direct granular fuel into the brazier.

10. The enclosed granular fuel burning boiler as recited claim 4 , in which an air flow diverter is mounted above each connecting side wall of the brazier.

11. The enclosed granular fuel burning boiler as recited in claim 4 , in which an air flow diverter is positioned above each of the side walls of the brazier, said air flow diverter provided by a plate projecting from each of the side walls on the brazier enclosure base.

12. The enclosed granular fuel burning boiler as recited in claim 4 , comprising a granular fuel supply tube mounted above the brazier for delivery of fuel under gravity to the brazier and in which flow control means are provided.

13. An enclosed granular fuel burning boiler, including:

an enclosed combustion chamber;

a fuel-fired brazier mounted in the combustion chamber on a side wall of the combustion chamber, said brazier comprising an apertured brazier base and upstanding side walls, namely, a proximal wall adjacent said side wall of the combustion chamber, a distal wall remote from said side wall of the combustion chamber, at least portion of which distal wall adjacent the brazier base is either vertical or inclined downwardly and away from the proximal wall, and a pair of connecting side walls;

an actuator for moving the brazier base from an operative position retaining fuel in the brazier to a discharge position to allow ash contents to fall out of the brazier;

fragmentation means comprising a vitrified ash engaging crushing tooth mounted on and projecting upwardly from the brazier base whereby, on moving the brazier base to the discharge position, the vitrified ash engaging crushing tooth moves the vitrified ash across the brazier from the proximal wall and against the opposed distal wall;

said vitrified ash engaging crushing tooth having a surface facing the distal wall which is parallel to the opposed surface of the distal wall portion adjacent the brazier base,

a plenum chamber mounted outside the combustion chamber;

a fan for delivering air to the brazier from the plenum chamber; and

a burner hood projecting over the brazier and forming part of a substantially sealed brazier enclosure mounted on a side wall of the boiler, the brazier enclosure including an enclosure base and two upstanding spaced-apart side walls carrying the burner hood and the brazier's upstanding side walls, the enclosure base having an enclosure ash contents discharge hole, a movable support plate having an upright end wall forming portion of the brazier enclosure and having a support plate discharge hole offset from the ash contents discharge hole when in a boiler firing condition, the support plate carrying the brazier base.

14. The enclosed granular fuel burning boiler as recited in claim 4 comprising a granular fuel supply tube mounted above the brazier for delivery of fuel under gravity to the brazier, and in which flow control means are provided comprising a bore reducing constriction in the granular fuel supply tube.