Solid Fuel Boiler Assembly

Abstract

A boiler assembly including primary and secondary combustion chambers includes primary and secondary air controls for controlling combustion air to the chambers respectively. The air controls are operable between open positions to allow combustion in the chambers and a closed position in which the combustion air passages are fully sealed to fully interrupt combustion responsive to heating demands. The air controls are supported externally on the main housing of the boiler assembly so as to be modular and readily releasable from the main housing and the respective combustion air passages. The primary combustion chamber communicates with the secondary combustion chamber at a location partway in between introduction of the secondary combustion air and the exhaust passage.

1 . A boiler assembly comprising:
 a primary combustion chamber enclosed by surrounding walls and being arranged to receive a solid fuel for combustion therein;   a primary blower;   a primary combustion air passage arranged to deliver primary combustion air to the primary combustion chamber from the primary blower;   a primary air control arranged to control air flow through the primary combustion air passage from the primary blower to the primary combustion chamber;   a secondary combustion chamber enclosed by surrounding walls below the primary combustion chamber;   a combustion passage communicating between a bottom end of the primary combustion chamber and a top end of the secondary combustion chamber therebelow;   a secondary blower;   a secondary combustion air passage arranged to deliver secondary combustion air to the secondary combustion chamber from the secondary blower;   a secondary air control arranged to control air flow through the secondary combustion air passage from the secondary blower to the secondary combustion chamber;   a boiler chamber arranged to receive fluid to be heated therein;   a heat exchanger passage communicating through the boiler chamber so as to be arranged to exchange heat with fluid in the boiler chamber; and   an exhaust passage communicating from the secondary combustion chamber to the heat exchanger passage;   the primary and secondary air controls each being operable between an open position arranged to communicate combustion air through the respective combustion air passage and a closed position in which the respective combustion air passage is fully sealed and air flow to the combustions chambers is prevented.   
     
     
         2 . The boiler assembly according to  claim 1  wherein there is provided a combustion air actuator arranged to proportionally control each of the air controls through a range of positions between the open position and the closed position thereof. 
     
     
         3 . The boiler assembly according to  claim 1  wherein each air control comprises a peripheral seating surface surrounding the respective combustion air passage and a gate supported for pivotal movement between the open position in which the gate is positioned externally between the seating surface and the respective blower and the closed position in which gate is sealed against the seating surface. 
     
     
         4 . The boiler assembly according to  claim 3  wherein there is provided an actuator mechanism arranged for displacing each gate between the open and closed positions in which the gate being supported on the actuator mechanism so as to be readily releasable therefrom. 
     
     
         5 . The boiler assembly according to  claim 4  wherein each gate is supported on the respective actuator mechanism by a slidably releasable mounting pin. 
     
     
         6 . The boiler assembly according to  claim 3  wherein an inner surface of each gate comprises a rigid plate arranged to span partway across the respective air passage and a resilient sealing member spanning outwardly beyond a periphery of the rigid plate so as to be arranged to engage the respective seating surface about a full periphery thereof in the closed position of the gate. 
     
     
         7 . The boiler assembly according to  claim 1  wherein there is provided an adjustable damper supported between each blower and the respective air control arranged to adjustably control maximum available air flow from the blower to the respective air control. 
     
     
         8 . The boiler assembly according to  claim 7  wherein there is provided a damper actuator arranged to proportionally control each of the dampers through a range of positions between a fully open position and a closed position thereof. 
     
     
         9 . The boiler assembly according to  claim 1  wherein the primary combustion chamber, the secondary combustion chamber and the boiler chamber are supported in a common main housing and the primary and secondary air controls each comprise a respective control housing supported externally on the main housing and coupled to the respective combustion air passages such that the control housings are readily releasable from the main housing and the respective combustion air passages. 
     
     
         10 . The boiler assembly according to  claim 1  wherein the surrounding walls of the primary combustion chamber comprise four upright side walls, each of the four side walls being inclined downwardly and outwardly away from an opposing one of the side walls. 
     
     
         11 . The boiler assembly according to  claim 1  wherein the combustion passage is in communication with the secondary combustion chamber at a location partway in between communication of the secondary combustion chamber with the secondary combustion air passage and with the exhaust passage. 
     
     
         12 . The boiler assembly according to  claim 11  wherein one of the surrounding walls of the secondary combustion chamber comprises an upright diffuser wall comprising a plurality of openings communicating therethrough and wherein the secondary combustion air passage communicates with the secondary combustion chamber through the openings in the diffuser wall. 
     
     
         13 . The boiler assembly according to  claim 12  wherein the diffuser wall comprises a perforated metallic plate member. 
     
     
         14 . The boiler assembly according to  claim 12  wherein the secondary combustion chamber is elongate in a longitudinal direction between two opposed ends of the chamber and the diffuser wall is supported at one of the two opposed ends. 
     
     
         15 . The boiler assembly according to  claim 14  wherein the exhaust passage communicates with the secondary combustion chamber at the end of the secondary combustion chamber opposite the diffuser wall. 
     
     
         16 . The boiler assembly according to  claim 1  wherein the secondary combustion chamber is elongate in a longitudinal direction and wherein the exhaust passage extends in the longitudinal direction along opposite sides of the secondary combustion chamber between communication of the exhaust passage with the secondary combustion chamber at one end of the secondary combustion chamber and communication of the exhaust passage with the heat exchanger passage adjacent an opposing end of the secondary combustion chamber. 
     
     
         17 . The boiler assembly according to  claim 1  wherein there is provided a combustion actuator associated with each air control and wherein there is provided a boiler control arranged to determine a heating condition and a standby condition, the combustion actuators being arranged to displace each air control into the open position so as to initiate combustion responsive to determination of the heating condition by the boiler control and being arranged to displace each air control into the closed position so as to interrupt combustion responsive to determination of the standby condition by the boiler control. 
     
     
         18 . A boiler assembly comprising:
 a primary combustion chamber enclosed by surrounding walls and being arranged to receive a solid fuel for combustion therein;   a primary blower;   a primary combustion air passage arranged to deliver primary combustion air to the primary combustion chamber from the primary blower;   a primary air control arranged to control air flow through the primary combustion air passage from the primary blower to the primary combustion chamber;   a secondary combustion chamber enclosed by surrounding walls below the primary combustion chamber;   a combustion passage communicating between a bottom end of the primary combustion chamber and a top end of the secondary combustion chamber therebelow;   a secondary blower;   a secondary combustion air passage arranged to deliver secondary combustion air to the secondary combustion chamber from the secondary blower;   a secondary air control arranged to control air flow through the secondary combustion air passage from the secondary blower to the secondary combustion chamber;   a boiler chamber arranged to receive fluid to be heated therein;   a heat exchanger passage communicating through the boiler chamber so as to be arranged to exchange heat with fluid in the boiler chamber; and   an exhaust passage communicating from the secondary combustion chamber to the heat exchanger passage;   the primary combustion chamber, the secondary combustion chamber and the boiler chamber being supported in a common main housing; and   the primary and secondary air controls each comprising a respective control housing supported externally on the main housing and being coupled to the respective combustion air passages such that the control housings are readily releasable from the main housing and the respective combustion air passages.   
     
     
         19 . The assembly according to  claim 18  wherein each air control is coupled to the respective air passage by a tubular member formed of resilient material. 
     
     
         20 . A boiler assembly comprising:
 a primary combustion chamber enclosed by surrounding walls and being arranged to receive a solid fuel for combustion therein;   a primary blower;   a primary combustion air passage arranged to deliver primary combustion air to the primary combustion chamber from the primary blower;   a primary air control arranged to control air flow through the primary combustion air passage from the primary blower to the primary combustion chamber;   a secondary combustion chamber enclosed by surrounding walls below the primary combustion chamber;   a combustion passage communicating between a bottom end of the primary combustion chamber and a top end of the secondary combustion chamber therebelow;   a secondary blower;   a secondary combustion air passage arranged to deliver secondary combustion air to the secondary combustion chamber from the secondary blower;   a secondary air control arranged to control air flow through the secondary combustion air passage from the secondary blower to the secondary combustion chamber;   a boiler chamber arranged to receive fluid to be heated therein;   a heat exchanger passage communicating through the boiler chamber so as to be arranged to exchange heat with fluid in the boiler chamber; and   an exhaust passage communicating from the secondary combustion chamber to the heat exchanger passage;   the combustion passage being in communication with the secondary combustion chamber at a location partway in between communication of the secondary combustion chamber with the secondary combustion air passage and with the exhaust passage.