Method and device for controlling the supply of combustion air to a combustion chamber

Abstract

A device is supplying combustion air to a combustion chamber, in which solid fuel is being burned, and the air supply is controlled in accordance with at predetermined program as a function of combustion time. The predetermined program is preferably based on empirical data. The combustion air may be supplied by means of a valve member, which is displaceable between first and second positions, and the valve member may expose varying areas of air supply opening(s) when moved between said positions. Biasing means, such as spring means, may bias the valve member towards said second position and slowing-down means may delay the movement of the valve member.

1 . A method for controlling the supply of combustion air to a combustion chamber ( 11 ), in which solid fuel is being burned while combustion air is supplied thereto, the combustion air being supplied by means of a displaceable valve member ( 13 ,  17 ) which is displaceable between first and second positions, the valve member exposing varying areas of air supply opening(s) ( 12 ,  14 ) when moved between said positions
 characterised in that,   the valve member ( 13 ,  17 ) is biased towards said second position, where the movement of the valve member is delayed by slowing-down means,   that the air supply is controlled in accordance with a predetermined program as a function of combustion time, and   in that the air supply hereby is gradually decreased during the combustion time.   
   
   
       2 . A method according to  claim 1 , wherein the air supply is decreased three or more times. 
   
   
       3 . A method according to  claim 1  or  2 , wherein the air supply is controlled in accordance with said predetermined program only as a function of the combustion time. 
   
   
       4 . A method according to any of  claims 1 - 3 , wherein said predetermined program is based on empirical data. 
   
   
       5 . A method according to any of  claims 1 - 4 , wherein the amount of combustion air supplied per unit of time is substantially higher at the beginning of the combustion process than at the end of the process. 
   
   
       6 . A method according to any of the  claims 1 - 5 , wherein said valve member is a slide valve member ( 13 ), the air supply openings ( 12 ,  14 ) being formed in said valve member and/or in an adjacent wall ( 10 ) of an air duct or of the combustion chamber ( 11 ). 
   
   
       7 . A method according to any of the  claims 1 - 6 , wherein the valve member ( 13 ,  17 ) is moved between said positions at a substantially constant rate. 
   
   
       8 . A method according to  claim 6  or  7 , wherein the valve member ( 13 ,  17 ) is moved between said first and second positions by means of clockwork. 
   
   
       9 . A device for controlling the supply of combustion air to a combustion chamber ( 11 ), the device comprising means ( 13 ,  15 ,  16 ,  17 ) for controlling the air supply having
 a displaceable valve member ( 13 ,  17 ), which is displaceable between first and second positions, the valve member being adapted to expose varying areas of air supply opening(s) ( 12 ,  14 ) when moved between said positions,   characterised in that   the device comprises biasing means ( 15 ), such as spring means, for biasing the valve member ( 13 ,  17 ) towards said second position and slowing-down means for delaying the movement of the valve member,   that the air supply will be controlled in accordance with a predetermined program as a function of combustion time, and   that the air supply hereby will be gradually decreased during the combustion time.   
   
   
       10 . A device according to  claim 9 , wherein the air supply will be decreased three or more times. 
   
   
       11 . A device according to  claim 9  or  10 , wherein the air supply will be controlled in accordance with said predetermined program only as a function of the combustion time during the combustion. 
   
   
       12 . A device according to any of the  claims 9 - 11 , wherein said valve member is a slide valve member ( 13 ), said air supply openings ( 12 ,  14 ) being formed in said valve member ( 13 ) and/or in an adjacent wall ( 10 ) of an air duct or of the combustion chamber ( 11 ). 
   
   
       13 . A device according to any of the  claims 9 - 12 , comprising means ( 15 ,  16 ) for moving the valve member ( 13 ,  17 ) between said positions at a substantially constant rate. 
   
   
       14 . A device according to any of the  claims 9 - 13 , comprising clockwork for moving the valve member ( 13 ,  17 ) between said first and second positions. 
   
   
       15 . A device according to any of  claims 9 - 14 , wherein the displaceable valve member is redirectable to or at least towards the first position upon opening a combustion chamber door for loading or reloading solid fuel to the combustion chamber.