SINTERING FURNACE

Field of the invention

The invention relates to a strand sintering furnace comprising a number of sequential process zones having different temperature conditions as defined in the preamble of independent claim 1.

The invention also relates to a windbox for a strand sintering furnace comprising a number of sequential process zones having different temperature conditions as defined in the preamble of independent claim 10.

In strand sintering of mineral material, a layer of material is formed on a conveyor belt in a sintering furnace, the layer being called herein a material bed. The material bed is conveyed by the conveyor belt through the process zones of the sintering furnace, which have different temperatures. During the conveyance, gas is conducted through the conveyor base and the material bed when the material bed travels through the process zones. Each process zone is normally provided with a windbox configured to promote conduction of gas through the conveyor base and the material bed. The windboxes can for example be connected to suction means in order to promote conduction of gas through the conveyor base and the material bed. Objective of the invention

The object of the invention is to provide an improved strand sintering furnace and an improved windbox for a strand sintering furnace.

Short description of the invention

The strand sintering furnace of the invention is characterized by the definitions of independent claim 1.

Preferred embodiments of the strand sintering furnace are defined in the dependent claims 2 to 9.

The windbox for a strand sintering furnace of the invention is correspondingly characterized by the definitions of independent claim 10.

Preferred embodiments of the windbox are defined in the dependent claims 11 to 18. Because the damper configured to adjust the exhaust gas flow in said at least one windbox section is provided in the windbox channel between the exhaust gas collection channel and said at least one windbox section of the windbox, several advantages are achieved. One advantage is that the windbox is easy to service. Another advantage is that the windbox has a simple construction, which means that it is also inexpensive to manufacture. The invention can also be utilized when upgrading or modernizing existing windboxes. List of figures

In the following the invention will described in more detail by referring to the figures, of which

Figure 1 is a schematical illustration of a strand sintering furnace,

Figure 2 shows a first embodiment of a windbox for a strand sintering furnace,

Figure 3 shows a second embodiment of a windbox for a strand sintering furnace, and Figure 4 shows a third embodiment of a windbox for a strand sintering furnace.

Detailed description of the invention

First the strand sintering furnace comprising a number of sequential process zones 1 having different temperature conditions and some embodiments and variants of the strand sintering furnace will be described in greater detail.

The strand sintering furnace comprising a conveyor belt 2 that is arranged as an endless loop around a deflector roll 3 and a driven roll 4 and which conveyor belt 2 is configured to convey a pellet bed (not illustrated in the figures) through said sequential process zones 1 of the strand sintering furnace, said conveyor belt 2 being gas permeable.

Each sequential process zone 1 is provided with an upper gas feeding arrangement 5 configured to conduct gas to be sucked through the pellet bed and the conveyor belt 2 to the process zone 1.

Each process zone 1 is provided with a lower exhaust gas arrangement 6 configured to conduct gas that was sucked through the pellet bed and the conveyor belt 2 away from the process zone 1.

Each lower exhaust gas arrangement 6 comprising a windbox 7 that is sealed towards the conveyor belt 2 by means of sealing means 8.

The windbox 7 is divided into windbox sections 9 by dividing wall members 10.

At least one windbox section 9 of the windbox 7 is provided with a damper 11 configured to individually the exhaust gas flow in each windbox section 9. Preferably, the windbox 7 is provided with a damper 11 configured to individually the exhaust gas flow in each windbox section 9.

The strand sintering furnace comprising an exhaust gas collection channel 14 that is configured to conduct gas from each windbox section 9 of the windbox 7,

The strand sintering furnace comprising a windbox channel 15 between the exhaust gas collection channel 14 and each windbox section 9 of the windbox 7.

The damper 11 configured to adjust the exhaust gas flow in said at least one windbox section 9 is arranged in the windbox channel 15 between the exhaust gas collection channel 14 and said at least one windbox section 9 of the windbox 7. Preferably, each windbox channel 15 between the exhaust gas collection channel 14 and said at least one windbox section 9 of the windbox 7 is provided with a damper 11 configured to adjust the exhaust gas flow in a windbox section 9 of the windbox 7.

Each windbox section 9 has preferably, but not necessarily, a bottom 16 that is at least partly inclined and/or curved towards a first end 17 of the windbox section 9 forming a downstream end of the windbox section 9, and one windbox channel 15 of the windbox channels 15 is preferably, but not necessarily, connected to each windbox section 9 at said downstream end of the windbox section 9, as shown in figures 2 to 4. In such case, the windbox sections 9 are preferably, but not necessarily, arranged in alternating order so that the bottom 16 of every second every third, every fourth or every fifth windbox section 9 being least partly inclined and/or curved towards a first side 12 of the windbox 7 and so that the bottom 16 of every second every third, every fourth or every fifth windbox section 9 being least partly inclined and/or curved towards a second side 13 of the windbox 7, which second side 12 is on the opposite side of the windbox in relation to the first side 12.

The windbox section 9 may, as shown in the figures, be longitudinal windbox sections 9 extending in a direction of movement A of the conveyor belt 2.

Each exhaust duct has preferably, but not necessarily, a circular cross section as shown in figures 2 to 4.

The windbox sections 9 may be formed of separate windbox section modules releasable attached at the windbox 7. This makes maintenance work easier, because single separate windbox section modules 19 can be replaced.

The windbox channel 15 may be releasable attached at the windbox 7. This makes maintenance work easier, because single separate windbox channel 15 can be replaced.

At least one windbox section 9, preferably each windbox section 9, can be provided with an emergency cooling valve 18, as shown in figures 3 and 4. A purpose of the emergency cooling valve is to provide cooling gas from the outside of the windbox sections 9 of the windbox 7 in case the temperature pf the conveyor belt 2 in the process zone 1 in which the windbox 7 is arranged rises too high.

At least one windbox channel 15, preferably each windbox channel 15, can be provided with an emergency cooling valve 18, as shown in figure 2.

Next the windbox 7 for a strand sintering furnace comprising a number of sequential process zones 1 having different temperature conditions and some embodiments and variants of the windbox 7 will be described in greater detail.

The windbox 7 comprises sealing means 8 for sealing the windbox 7 towards a conveyor belt 2 of the strand sintering furnace, which conveyor belt 2 is arranged as an endless loop around a deflector roll 3 and a driven roll 4 and which conveyor belt 2 is configured to convey a pellet bed through said sequential process zones 1 of the strand sintering furnace, said conveyor belt 2 being gas permeable.

The windbox 7 is divided into windbox sections 9 by dividing wall members 10.

At least one windbox section 9 of the windbox 7 is provided with a damper 11 configured to adjust the gas flow in said at least one windbox section 9. Preferably, the windbox 7 is provided with a damper 11 configured to individually the exhaust gas flow in each windbox section 9.

The windbox 7 comprises an exhaust gas collection channel 14 that is configured to conduct gas from each windbox section 9 of the windbox 7.

The windbox 7 comprises a windbox channel 15 between the exhaust gas collection channel 14 and each windbox section 9 of the windbox 7.

The damper 11 configured to adjust the exhaust gas flow in said at least on windbox section 9 is arranged in the windbox channel 15 between the exhaust gas collection channel 14 and said at least one windbox section 9 of the windbox 7. Preferably, each windbox channel 15 between the exhaust gas collection channel 14 and said at least one windbox section 9 of the windbox 7 is provided with a damper 11 configured to adjust the exhaust gas flow in a windbox section 9 of the windbox 7.

Each windbox section 9 has preferably, but not necessarily, a bottom 16 that is at least partly inclined and/or curved towards a first end 17 of the windbox section 9 forming a downstream end of the windbox section 9, and one windbox channel 15 of the windbox channels 15 is preferably, but not necessarily, connected to each windbox section 9 at said downstream end of the windbox section 9, as shown in figures 2 to 4. In such case, the windbox sections 9 are preferably, but not necessarily, arranged in alternating order so that the bottom 16 of every second, every third, every fourth or every fifth windbox section 9 being least partly inclined and/or curved towards a first side 12 of the windbox 7 and so that the bottom 16 of every second every third, every fourth or every fifth windbox section 9 being least partly inclined and/or curved towards a second side 13 of the windbox 7, which second side is on the opposite side of the windbox 7 in relation to the first side 12.

The windbox section 9 may, as shown in the figures, be longitudinal windbox sections 9 extending in a direction of movement A of the conveyor belt 2.

Each exhaust duct has preferably, but not necessarily, a circular cross section as shown in figures 2 to 4.

The windbox sections 9 may be formed of separate windbox section modules 19 releasable attached at the windbox 7. This makes maintenance work easier, because single separate windbox section modules 19 can be replaced also in existing windboxed for upgrading or modernization purposes

The windbox channel 15 may be releasable attached at the windbox 7. This makes maintenance work easier, because single separate windbox channels 15 can be replaced.

At least one, preferably each windbox section 9 can be provided with an emergency cooling valve 18, as shown in figures 3 and 4.

At least one, preferably each windbox channel 15 can be provided with an emergency cooling valve 18, as shown in figure 2. It is apparent to a person skilled in the art that as technology advanced, the basic idea of the invention can be implemented in various ways. The invention and its embodiments are therefore not restricted to the above examples and which is described in the description or in the figures, but they may vary within the scope of the claims.