Abstract: The arrangement is for cleaning and controlling airflow and where appropriate pushing away melt in an air channel of recovery boilers within the paper and pulp industry. By inclining the regulating device 10 at an angle to the horizontal plane and at the same time making the piston of the regulating device run in contact with the side and upper walls 24a, 24b and, respectively, 22 of the air channel, optimum airflow control and a more compact installation can be achieved. The airflow can be adjusted more rapidly with a small regulating movement at the same time as very good penetration of the air into the furnace 4 is achieved.

Abstract: The invention relates to an arrangement for cleaning, airflow control and where appropriate pushing away melt in air ports of recovery boilers within the paper and pulp industry. By inclining the regulating device (10) at an angle to the horizontal plane and at the same time making the piston of the regulating device run in contact with the side and upper walls (24a, 24b) and, respectively, (22) of the air port, optimum airflow control and a more compact installation can be achieved. The airflow can be adjusted more rapidly with a small regulating movement at the same time as very good penetration of the air into the furnace (4) is achieved. The regulating device is allowed to penetrate into and down into the furnace so that the regulating device can push away any melt/slag in the event of a high level of melt (3) in front of the opening (30) of the air port into the furnace (4).

Abstract: The invention relates to a throttle device for delivery of a current of gas through a channel (1), the device comprising a flap (4) which is arranged so that it can pivot on an axle (5) and which is designed in such a way that, at a certain pressure force exerted by the current of gas, it is opened from a position in which the channel (1) is essentially closed. The invention is characterized in that it comprises at least one weight (7) which is arranged to rotate together with the flap (4) and is designed to deliver a torque to the axle (5) in conjunction with the pivoting of the flap (4). The invention is intended in particular for recovery boilers, or heating boilers or steam boilers for solid fuels. The invention achieves an improved air penetration in respect of air flowing into the boiler.

Abstract: The invention relates to a boiler for the production of steam, the boiler having a maximum capacity of 100 ton/hr or more and comprising a furnace having a substantially constant rectangular cross-section and a back pass with a substantially constant rectangular cross-section. The furnace and the back pass are mounted close to each other and means are provided for superheating the steam. The steam superheating means are positioned within the back pass, so that no superheater is positioned within the furnace.

Abstract: The invention relates to a boiler for the production of steam, the boiler having a maximum capacity of 100 ton/hr or more and comprising a furnace having a substantially constant rectangular cross-section and a back pass with a substantially constant rectangular cross-section. The furnace and the back pass are mounted close to each other and means are provided for superheating the steam. The steam superheating means are positioned within the back pass, so that no superheater is positioned within the furnace.