WO2007093676A1

WO2007093676A1 - Burner and atomizer for the burner

Info

Publication number: WO2007093676A1
Application number: PCT/FI2007/050081
Authority: WO
Inventors: Anssi Hovinen; Teemu Sundelin; Kai Asikkala
Original assignee: Beneq Oy
Priority date: 2006-02-16
Filing date: 2007-02-15
Publication date: 2007-08-23
Also published as: FI20065118A0; FI20065118A; FI118355B

Abstract

The invention relates to a burner for forming a line-shaped flame. The burner comprises a frame having an elongated burner head (2) including ports for substance to be introduced into the flame of the burner and a feed pipe (4) mounted inside the elongated frame and provided with one or more feed openings (28) for gas to be supplied to the burner. The burner also comprises a curved first separating plate (8) that opens into a burner head (2), is mounted around a feed pipe (4) inside the burner frame, and whose edges in parallel with the burner head (2) extend to the burner head (2), and one or more raising parts (16) mounted inside the first separating plate (8) for forming one or more flow channels inside the first separating plate (8) and extending to the burner head (2) so as to pass the gas to be supplied to the burner head (2) from the feed pipe (4) to the burner head (2).

Description

BURNER AND ATOMIZER FOR THE BURNER

BACKGROUND OF THE INVENTION

[0001] The invention relates to a burner for providing a line-shaped flame and, in particular, to a burner according to the preamble of claim 1 for providing a line-shaped flame, the burner comprising a frame having an elongated burner head including ports for substance to be introduced into the flame of the burner and a feed pipe mounted inside the elongated frame and provided with one or more feed openings for gas to be supplied to the burner. The invention also relates to an atomizer for atomizing liquid to be fed into the flame and, in particular, to an atomizer according to the preamble of claim 23 for atomizing liquid to be fed into a line-shaped flame of an elongated burner, the atomizer comprising a liquid pipe for supplying liquid into an atomizing head, the liquid pipe comprising a liquid spraying head having one or more liquid ports for generating a liquid spray, a gas passage for feeding gas to the atomizing head, the gas passage comprising one or more gas ports for generating a gas spray.

[0002] According to prior art, burners producing a line-shaped flame have been achieved with an in-line array of circle-symmetric burners, whereby the successive, aligned burners produce a flame that is generally line-shaped. However, a problem with the structure of these successive circle-symmetric burners is that properties of the produced line-shaped flame in the area between the burners differ considerably from those in the area exactly at the burner. Consequently, the produced flame is not even unless the covering areas of adjacent burners overlap, which in turn results in excessive consumption of chemicals to be introduced in the flame.

[0003] Ribbon-like burners, in which corrugated metal plates of various corrugation sizes have been mounted on the burner head, have also been used for producing a line-shaped flame. The shape and size of corrugations affect the velocity of gases discharging from the burner head. One solution of this type is disclosed in US patent 2,499,482. However, this structure does not allow accurate adjustment of the size of ports in a burner head, and gas consumption cannot be minimized. Another structure is disclosed in US patent 2,807,320. In that solution the flame is controlled with slit bushings mounted around the supply tube and turnable to a desired position with respect to the supply tube and the orifices thereof. On the burner head there is also mounted a corrugated metal plate whose function is not, however, stream regulation in the burner. The above-described arrangements have a drawback that they do not enable even gas supply to the burner head, which further prevents minimization of the use of gas leading to large gas consumption.

[0004] Burners producing a line-shaped flame are used, for instance, for various colouring processes of glass, ceramic material or the like, whereby, in addition to gases, a liquid substance that has to be atomized to mist can be introduced into the flame. Consequently, from the viewpoint of the colouring or another operation to be performed it is substantial that the flame is as uniform as possible for the whole length of the burner head, and thus it is necessary to be able to control the atomization of the liquid and mist to be introduced into the flame as precisely as possible so as to provide even atomization in the flame.

[0005] In accordance with prior art, the liquid to be sprayed into the flame is to be atomized, for instance, with gas- and pressure-dispersed atomizers, by means of ultrasound or some other mechanical resonator or by vaporization. The prior art atomizing means have a drawback that it is difficult to control the homogeneity of the droplet mist and the size distribution of droplets produced thereby. In addition, in the prior art gas-dispersed atomizers combustion gases or at least one or more components of burner gases serve as the dispersion gas. In an elongated burner this results in an extensive need of gas, because atomization of a liquid typically requires large amounts of gas. These atomization-related needs of combustion gases, such as hydrogen or hydrogen/oxygen mixed gas, do not often coincide with the requirements of the flame. This leads to compromises in the amount of gas supply, and consequently the quality and homogeneity of either the flame or the liquid atomization will not attain the optimal quality.

BRIEF DESCRIPTION OF THE INVENTION

[0006] The object of the invention is thus to provide a burner and an atomizer for liquid to be atomized into a flame of the burner such that the above problems can be solved. This is achieved by a burner in accordance with the characterizing part of claim 1 , which is characterized in that the burner comprises a first curved separating plate which opens into a burner head, is mounted around a feed pipe inside the burner frame, and whose edges in parallel with the burner head extend to the burner head, and one or more raising parts mounted inside the first separating plate for forming one or more flow channels inside the first separating plate and extending to the burner head so as to pass the gas to be supplied to the burner head from the feed pipe to the burner head. The object of the invention is also achieved by an atomizer in accordance with the characterizing part of claim 23, which is characterized in that the gas passage is arranged to supply a gas spray circumferentailly around a liquid spray discharging from liquid ports such that the gas spray and the liquid spray collide with one another at an angle and atomize the liquid into mist.

[0007] The preferred embodiments of the invention are disclosed in the dependent claims.

[0008] The basic idea of the present invention is to provide means for producing nanoparticles. The means in accordance with the invention comprise a burner having an elongated burner head producing a line-shaped flame. The burner also comprises atomizers that are mountable throughout the length of the burner head for spraying liquid into the flame for the whole extent of the burner head so as to produce mist that is as homogeneous as possible.

[0009] The invention is based on the fact that a gas feed pipe comprising one or more feed openings is mounted inside the burner frame. The burner frame is provided with an elongated opening that constitutes the burner head. Inside the burner frame there is mounted a separating plate that is arcu- ately bent around the feed pipe such that the edges of the separating plate that run parallel with the burner head extend to the burner head. Thus, the separating plate forms a trough inside which the feed pipe is installed and whose lateral edges extend to the burner head. The function of one or more raising parts mounted inside the separating plate, preferably on the inner surface thereof, is to provide one or more flow channels between the feed pipe and the burner head for supplying gas into the flame. The raising parts and the first separating plate are mounted against the feed pipe such that the gas is able to flow to the burner head only through the provided flow channels. This structure may further comprise a second separating plate that is mounted in the corresponding manner within the burner frame inside the first separating plate, whereby the raising part or the raising parts are mounted between these two separating plates. Alternatively, the outer surface of the feed pipe may be designed to extend to the burner head, whereby the outer surface may serve as the second separating plate and the raising part or the raising parts are mounted between the outer surface of the feed pipe and the first separating plate.

[0010] It is also possible to mount two or more feed pipes on the burner frame, whereby for each one of them there will be provided a structure described above comprising a trough-like separating plate mounted around each feed pipe with the lateral edges thereof extending from inside the burner frame to the burner head. In that case the feed pipes may be placed in the burner frame one below the other such that the first separating plates mounted around them extend in a superimposed manner to the burner head, whereby the first separating plate relating to an upper feed pipe may form a second separating plate relating to a lower feed pipe. Between these separating plates there is then installed a raising part or raising parts for forming separate, adjacent flow channels from the feed pipe to the burner head.

[0011] In a preferred embodiment the raising parts are formed, like the separating plates, of a folded, trough-like plate, which is installed inside the first separating plate. This raising plate comprises at least one pectinate structure with spaces between the dents constituting the flow channels. These flow channels are provided to extend from the feed pipe to the burner head.

[0012] In the above-described manner the burner has a modular structure with one or more modules consisting of a feed pipe, separating plate(s) and raising part(s). All parts of each module are independently replaceable, whereby the burner may always be assembled to meet any specific needs.

[0013] The burner of the invention has an advantage that the invention allows very accurate implementation of the burner head ports simultaneously enabling easy modifications of the burner head and the ports thereof to meet various needs. At the same time pressure distribution of ports may be optimized such that the burner head receives an even stream, whereby a flame line of uniform quality is obtained. In addition, the modular structure enables easy cleaning of parts and disassembly and modification of the burner according to need.

[0014] The invention is also based on the fact that at the burner head of the burner, which forms a line-shaped or elongated flame, there is provided one or more atomizers for atomizing and introducing liquid into the flame. In accordance with the present invention the atomizer comprises one or more liquid pipes for supplying liquid into the atomizing head, the liquid pipes being provided with one or more liquid ports for spraying the liquid. The atomizer also comprises one or more gas passages for supplying a dispersing gas into the atomizing head, the gas passages comprising one or more gas ports for spraying the gas. In accordance with the present invention, the gas passages and the gas ports and the liquid passages and the liquid ports are arranged such that the dispersing gas is fed circumferentially around the liquid spray discharging from liquid ports such that the dispersing gas spray and the liquid spray collide with one another at an angle, whereby the dispersing gas splits the liquid spray into droplets and directs the resulting mist controllably in a desired direction. In the solution of the invention the intersecting angle of the liquid and the gas is preferably within the range of 0 to 90 degrees, and consequently the liquid in the atomizer will not discharge in reversed current in relation to the gas discharge. The object of the invention is thus to provide an atomizer for use in a line-shaped burner so as to provide homogeneous droplet mist uniformly for the entire length of the elongated burner head. In that case a plurality of atomizers in accordance with the invention are placed in succession throughout the whole length of the elongated burner head.

[0015] This atomizer solution makes it possible to provide sufficiently small droplets irrespective of the flame. At the same time there is provided efficient mixing of liquid and gas, which enables homogeneous mist formation and better control than before of the aperture and direction of the generated mist beam. Thus, the use of an atomizer of this kind in a burner forming a line-shaped flame improves, e.g. in glass colouring, the homogeneity and quality of the flame and the liquid droplets introduced therein for the entire length of the burner head.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In the following, the invention will be described in greater detail in connection with preferred embodiments with reference to the attached drawings, in which

Figure 1 is an exploded view of a burner in accordance with the present invention,

Figure 2 is a schematic view of a part of the burner head in the burner of Figure 1 ,

Figure 3 shows an embodiment of an atomizer in accordance with the present invention for atomizing liquid, and Figure 4 shows a second embodiment of an atomizer in accordance with the present invention for atomizing liquid.

DETAILED DESCRIPTION OF THE INVENTION

[0017] With reference to Figure 1 there is presented an embodiment of a burner in accordance with the present invention. The burner comprises a frame 1 (shown in Figure 2) including an elongated, narrow opening that constitutes a burner head 2 (shown in Figure 2). Gases and other optional substances, such as liquids or solids, to be introduced to the burner flame, discharge from this burner head 2. Figure 1 shows an exploded view of burner parts. Actually the presented parts are interfitted in the burner frame in the order shown in Figure 1. The embodiment of Figure 1 comprises two gas feed pipes and one liquid feed pipe. However, it is to be noted that the burner may also comprise just one gas feed pipe and no liquid feed pipe at all, or alternatively, three or more gas feed pipes. The invention is thus not restricted to any number of gas feed pipes.

[0018] As in Figure 1 , the burner comprises a liquid feed pipe 40 that comprises liquid feed ports 42. The liquid feed pipe 40 is installed right in the burner head 2 such that the liquid to be fed therethrough discharges from the liquid feed ports 42 directly in the burner flame. In other words, the liquid feed ports constitute ports for liquid to be introduced into the flame through the burner head 2. The liquid to be supplied to the liquid feed pipe 40 is introduced to the liquid feed pipe through both ends thereof via pipes 44. Around the liquid feed pipe 40 there is provided a casing 46 that is designed to be substantially triangular tapering towards the burner head 2. The casing 46 is provided with holes (not shown) at the liquid feed ports 42 for feeding the liquid from the burner head 2. It should be noted that this liquid feed pipe 40 may also be replaced by a gas feed pipe and that there may be one or more feed ports. The liquid feed port 42 or the corresponding gas feed port may also be a narrow slit in parallel with the burner head 2.

[0019] Beneath the liquid feed pipe 40 there is installed a first gas feed pipe 4 having feed ports (not shown), wherefrom the gas supplied to the first feed pipe 4 through both ends discharges. The first gas feed pipe 4 is placed inside a first raising plate 16 having a trough-like shape provided with a pectinate structure and below the liquid feed pipe 40 seen from the burner head 2. The first raising plate 15 is dimensioned such that the lateral edges of the trough-like structure provided with the pectinate structure extend on the sides of the first feed pipe 4 and the liquid feed pipe 40 (and its casing 46) up to the burner head 2. The pectinate structure of the first raising plate 16 is provided on the trough's lateral edges which comprise dents 24 and spaces 22 therebetween. Both the first feed pipe 4, the first raising plate 16 and the first separating plate 8 extend substantially throughout the length of the burner head 2.

[0020] On top of the first raising plate 16 there is placed a first separating plate 8, which is trough-like in shape like the first raising plate 16. In accordance with Figure 1 , the first separating plate 8 encloses, in the following order, a first raising plate 16, a first feed pipe 4 and a liquid feed pipe 40 with the casing 46. In other words, the lateral edges of the trough-shaped first separating plate 8 extend substantially in parallel with the burner head 2 up to the burner head 2. The first separating plate 8 and the first raising plate 16 to be fitted therein are designed to match and dimensioned such that the outer surface of the first raising plate 16 will rest tightly against the inner surface of the first separating plate 8. When the liquid feed pipe 40, the first feed pipe 4, the first raising plate 16 and the first separating plate 8 are fitted in the burner frame, the first raising plate 16 and the first separating plate 8 will rest tightly on the casing 46 of the liquid feed pipe 40, while the first feed pipe 4 will be located beneath the liquid feed pipe 40 and inside the trough-shaped first separating plate 8 and first raising plate 16. This assembly makes it possible that the spaces 22 between the dents 24 of the pectinate structure of the first raising plate 16 extend from the first feed pipe 4 to the burner head 2 between the first separating plate 8 and the casing 46 of the liquid feed pipe 40. Thus, these spaces 22 form channels which extend from the first feed pipe 4 to the burner head 2 and along which the gas discharging from the feed ports of the first feed pipe 4 is able to flow to the burner head 2. The spaces of the pectinate structure of the first raising plate 16 thus form flow channels for directing the gas supplied from the first feed pipe 4 to the burner head 2. Spaces 22 are provided substantially for the entire length of the burner head 2, whereby the gas may be evenly distributed throughout the length of the burner head 2.

[0021] In accordance with Figure 1 , on top of the first separating plate 16 there is mounted a second raising plate 26 comprising a pectinate structure like the first raising plate 16. This second raising plate 26 is also designed to have a trough-like shape and dimensioned such that the sides thereof rest on the first separating plate 8 and extend up to the burner head 2. Thus, the pectinate structure of the second raising plate 26 comprises dents 32 and spaces 34 therebetween. Seen from the burner head 2, beneath the second raising plate 26 there is installed a second feed pipe 28 comprising one or more feed ports (not shown), in one of which feed pipes 28 the gas supplied from the pipes 48 discharges.

[0022] Around the second feed pipe 28 there is mounted a second separating plate 10 which is shaped into a trough such that the lateral edges thereof extend up to the burner head 2. The second separating plate 10 is mounted such that the lateral edges thereof rest on the second raising plate 26, whereby all above-mentioned burner parts the liquid feed pipe 40, the first feed pipe 4, the first raising plate 16, the first separating plate 8, the second raising plate 26 and the second feed pipe 28 will be located inside the trough- shaped second separating plate 10. Thus, the second raising plate 26 rests tightly between the first separating plate 8 and the second separating plate 10, whereby the spaces 34 in the pectinate structure thereof extend from the second feed pipe 28 to the burner head 2, between the first and the second separating plates 8, 10. Thus, the spaces 34 in the pectinate structure of the second raising plate 26 form flow passages for supplying gas from the second feed pipe 28 to the burner head 2.

[0023] The separating plates 8, 10, the raising plates 16, 26, the feed pipes 40, 4 and 28 extend all in this embodiment substantially throughout the entire length of the burner head 2, but alternatively they, or one or more thereof, may be provided to extend only for a portion of the length of the burner head 2. Thus, the burner flame may be rendered different in various points of the longitudinal extent of the burner head 2. The separating plates 8, 10, the raising plates 16, 26, the feed pipes 40, 4 and 28 are all mounted inside the burner frame such that two gases and a liquid may be introduced independently in the elongated burner head 2.

[0024] The inlet pipes 44, 46 and 48 are connected to corresponding feed pipes 40, 4 and 28 by fitting perforated plates 50 at the ends of the second, trough-shaped separating plate 10, which perforated plates comprise holes 52, 54, 56 substantially corresponding to the diameters of the feed pipes 40, 4 and 28. Connecting rings 62, 64, 66 are inserted in these holes 52, 54, 56 and they will be located at the junctions of the inlet pipes 44, 46, 48 and the feed pipes 40, 4, 28. This is how a desired gas, gas mixture or liquid may be introduced independently into each feed pipe 40, 4, 28. The perforated plates 50, the separating plates 8, 10 and the raising plates 16,26 are set in the burner frame sealably with respect to one another such that the gases to be supplied will not mix inside the burner, but they may be directed to the burner head 2 separately.

[0025] Figure 2 shows a portion of the frontal surface of the burner head 2 in the burner structure of Figure 1. The burner frame 1 is thus provided with an elongated slit that constitutes a burner head 2, which appears as a slit between the outermost horizontal lines in the figure. In accordance with Figures 1 and 2, in the middle of the burner head 2 there is placed a liquid feed pipe 40 that comprises liquid feed ports 42. The size, shape and number of the liquid feed ports may vary in accordance with the specific liquid and the desired flame properties. Discharge openings 42 of the liquid feed pipe 40 may be on the same level with the burner's frontal surface, in a recess, i.e. below the frontal surface, or they may protrude like a crest or a pin from the burner's frontal surface. On the sides of the liquid feed pipe 40 there are tightly fitted the lateral edges of the first raising plate 6 such that dents 24 of the pectinate structure of the first raising plate 16 extend to the burner head 2 in the manner shown in Figure 2. The spaces 22 between the dents 24 of the pectinate structure in the first raising plate extend, between the liquid feed pipe 40 and the first separating plate 8, from the first feed pipe 4 to the burner head and form ports in the burner head for the gas to be supplied from the first feed pipe 4. In a corresponding manner, the dents 32 of the pectinate structure in the second raising plate 26 extend to the burner head 2, whereby the spaces between the dents 32 form flow channels that extend, between the first and the second separating plates 8, 10, from the second feed pipe 28 to the burner head 2 and form ports for the gas to be supplied from the second feed pipe 28. Thus, in the burner head 2 there is formed a layer structure of Figure 2, in which gas and/or liquid may be fed symmetrically on both sides of the centre line of the elongated burner head. This symmetrical configuration may be varied, for instance, such that a pectinate structure is only provided on one side of the trough-shaped raising plate, whereby flow channels only extend on one side of the centre line of the burner head.

[0026] The above-described structure is just one embodiment of the burner in accordance with the present invention. It should be noted that the burner consists of modules, each of which comprises a feed pipe, two separat- ing plates or corresponding separating surfaces extending to the burner head, between which there are mounted raising parts whereby flow channels are provided between these separating surfaces. The feed pipe is mounted between the separating plates such that the gas discharging from its ports may flow along the flow channels between the separating plates to the burner head. It is possible to install one, two or more modules in the burner. The modules may be arranged in the burner frame in the manner indicated by Figure 1 one beneath the other seen from the burner head, whereby the separating plates will be superimposed and the flow channels extend in layers to the burner head. Alternatively, the above-defined modules may be installed in the burner also in juxtaposition or in some other configuration. In that case the flow channels may be arranged in a layered configuration either symmetrically or asymmetrically with respect to the centre line of the burner head. The configuration may also be such that the flow channels of some modules extend symmetrically to the burner head with respect to its centre line, while the flow channels of other modules extend only to one side of the centre line of the burner head. So, the burner may be modified according to particular needs. The same may be achieved by changing the raising plates as described above. In that case the burner may be used correspondingly as a vertical nozzle by means of symmetrical flow channels or as an oblique nozzle by means of asymmetrical flow channels. The thickness of the raising plates directly affects the cross-sectional area of the created flow channels, so the size of the flow channels may be adjusted, in addition to slit adjustment, by varying the thickness of the raising plate. The same also applies to the use of separate raising parts, which solution will be described in greater detail below.

[0027] The liquid feed pipe may be omitted from the burner, or it may be replaced by a gas feed pipe having ports, which is placed directly in the burner head. In addition, in the solution of Figure 1 the liquid feed pipe 40 and the first feed pipe 4 may be combined into the same structure, within which there extend two channels: a liquid feed channel and a gas feed channel. The ports of the liquid feed channel may be provided directly in the burner head 2 as in Figure 2, whereas the ports of the gas feed channel may be provided on the sides of the structure, whereby the outer surface of the structure serves as a separating plate, on top of which the raising parts will be mounted. When there is no liquid feed pipe, the feed pipe 4 may be designed such that the outer surface thereof extends from within the burner frame to the burner head 2, whereby the raising part or raising parts 16 are installed between the outer surface of the feed pipe 4 and the first separating plate 8 so as to form one or more flow channels extending to the burner head 2.

[0028] The raising parts are those of Figure 1 comprising a pectinate structure that consists of dents and spaces therebetween. The dent structure of this kind enables implementation of precise flow channels of even less than 0.1 mm high and simultaneously pressure distribution in the flow channels is optimized, whereby an even flow is obtained in the burner head, which further enables a flame line of uniform quality. The pectinate structure may be made such that the widths of spaces and dents thereof are equal throughout the pectinate structure. Alternatively, the widths of spaces and dents of the pectinate structure are different in at least a portion of the pectinate structure, whereby the widths or width ratios of the spaces and dents in the pectinate structure may vary symmetrically or asymmetrically over the length of the pectinate structure. This enables feed control to the burner head by adjusting the cross-sectional area of the ports and/or the flow channels. The pectinate structure is further provided such that the dents and the spaces, or some of them, extend to the burner head perpendicularly to the longitudinal direction of the burner head, whereby at least some of the flow channels extend to the burner head substantially perpendicularly to the longitudinal direction and/or frontal surface thereof. Alternatively, the pectinate structure is provided such that the dents and the spaces, or some of them, extend to the burner head at an angle to the longitudinal direction of the burner head, whereby at least some of the flow channels extend to the burner head at an angle to the longitudinal direction and/or frontal surface thereof. Setting the flow channels at an angle to the frontal surface of the burner head improves mutual coverage of the ports.

[0029] Instead of raising plates with pectinate structure, the raising parts may also be separate raising parts that are mounted between two separating plates, or between a separating plate and the outer surface of a feed pipe. These separate raising parts thus form flow channels extending to the burner head like the pectinate structure. These separate raising parts may be secured to or provided in the separating plate, or correspondingly, to the outer surface of the feed pipe, whereby the burner ports may be modified by altering the separating plate or the feed pipe.

[0030] The burner head of the burner in accordance with the present invention and/or the frontal surface of the burner may be arranged in a straight line, whereby the flame generated by the burner head is a straight flame line. Alternatively, the burner head and/or the frontal surface thereof may be given a curved, wavy or some other shape to follow the contours of a specific piece or surface to be processed with the burner. In connection with the latter case it is also possible to design the feed pipes, the separating plates, the raising plate or other raising parts to follow the shape of the burner head or the frontal surface of the burner.

[0031] These burners of the invention may be further combined by means of connecting pieces and/or bypass manifolds such that even over the connection area of the burners the burner line is continuous. Hence, a plurality of burners, mutually similar or different, may form considerably long burner lines without having to produce a separate burner for the purpose.

[0032] In a burner forming a line-shaped flame and including an elongated burner head it is preferable, instead of mere liquid feed ports 42, to employ nozzles, atomizing heads, droplet-forming heads or the like for atomizing the liquid and directing it into the flame. When only a hole is employed for feeding the liquid into the flame, due to the surface tension the liquid tends to adhere to the frontal surface of the burner, and consequently it will not be well sprinkled into the flame. This is one of the reasons, in addition to those mentioned above, why the operation of the burner will be improved by using the atomizers in accordance with the invention, embodiments of which are shown, for instance, in Figures 3, 4 and 5. For the sake of clarity, like reference numerals refer to like or corresponding atomizer parts in Figures 3, 4 and 5.

[0033] Figure 3 shows an embodiment of an atomizer, in which the atomizer 100 comprises a gas passage 110, by means of which dispersing gas for atomizing the liquid is fed to an atomizing head 104 of the atomizer 100, wherefrom the gas and the liquid discharge as mist 200. In this connection the atomizing head 104 refers to a point in the atomizer 100, where the gas and the liquid discharge from the atomizer 100. The gas passage 110 may be a pipe installed to pass in the burner head in the direction of the elongated burner head thereof, like for instance the feed pipe 40 in the above-described burner. In the side wall or casing of the gas passage 110 there is further provided a gas port 114 for supplying gas to the atomizing head 104 of the atomizer 100. Thus, the gas to be supplied to the gas passage 110 discharges from the gas passage 110 radially to its longitudinal axis in the manner shown in Figure 3, whereby the atomizing head 104 corresponds to the liquid feed ports 42 and the gas passage 110 corresponds to the feed pipe 40. Further, in accordance with Figure 3, the atomizer 100 is provided with a liquid pipe 102 for supplying liquid to the atomizing head 104. The liquid pipe 102 comprises a liquid spraying head 108 that extends to a gas port 114 in the gas passage 110 and to the atomizing head 104 or in the vicinity thereof, whereby in a preferred embodiment it may also extend beyond the gas port. In other words, the liquid discharge opening may also be placed outside the gas port or in the vicinity thereof. In a preferred embodiment the liquid pipe 102 and/or the liquid spraying head 108 are centralized in the middle of the gas port 114 such that a gap is formed between the outer wall of the liquid pipe 102 and the side walls 116 of the gas port 114, through which gap the gas is able to flow to the atomizing head 104. In the sidewall or casing 118 of the liquid pipe 102 in the vicinity of the liquid spraying head 108 there is provided one or more liquid ports 106 for spraying the liquid into the atomizing head 104. In accordance with Figure 3, the liquid ports 106 are provided in the liquid pipe 102 at the side- walls 116 of the gas port 114, whereby the liquid discharges from the liquid ports 106 towards the sidewalls 116 of the gas port radially to the longitudinal axis of the liquid pipe 102. The liquid ports 106 may also be placed to positions other than at the side walls of the gas port 114, but nevertheless close to the gas port such that the gas discharging from the gas port 114 and the liquid spraying out from the liquid ports 106 collide and discharge through the atomizing head 104.

[0034] In Figure 3 the liquid pipe 102 is led through the gas passage 110 such that it traverses the whole gas passage 110. Thus the liquid discharges from the liquid ports towards the side walls 116 of the gas port 114 and radially to the liquid pipe 102, whereby the gas, in turn, flows from the gas port 114 substantially in parallel with the liquid pipe 102 and radially to the gas passage 110. Accordingly, the gas discharging from the gas passage 110 collides with liquid sprays discharging from the liquid ports 106 while dispersing the liquid spray into droplets and directing it out from the atomizer 100 in the atomizing head 108. In accordance with the embodiment of Figure 3 the gas flow direction in the gas port 114 is substantially perpendicular to the flow direction of the liquid discharging from the liquid ports 106. By modifying the cross section of the gas port 114 it is possible to arrange the gas flow direction in the gas port 114 at another angle to the liquid flow direction. It is also possible to shape the liquid ports 106 or the liquid pipe 102 in order to alter the an- gle between said flow directions. It is substantial, however, that the gas flow direction in the gas port 114 is transversal and/or at an angle to the flow direction of liquids discharging from the liquid ports 106, whereby the gas splits the liquid spray into droplets and forms mist 200 that will further discharge from the atomizing head 104.

[0035] Because in the preferred embodiment the liquid pipe 102 and/or the liquid spraying head 108 are placed in the middle of the gas port 114, the liquid spray discharges in the midst of the gas flowing in the gas port 114, whereby the gas flow surrounds the liquid spray discharging from the liquid ports 106 circumferentially. However, the gas spray need not encircle the liquid spray or liquid sprays circle-symmetrically. Hence, in some cases the liquid pipe 102 may be placed eccentrically in the gas port 114.

[0036] The structure as described above provides a venturi-like structure in the gas port 114 for the gas flow, which can be achieved by using a gas passage 110 having a sufficiently small wall thickness. Appropriate dimensioning of the gas passage 110, gas port 114, liquid pipe 102 and liquid ports makes it possible to affect the droplet size distribution in mist 200 produced in the atomizer 100 and the spray beam in a desired manner. Thus the liquid to be introduced into the flame can be atomized efficiently and homogeneously and directed controllably from the atomizing head 104.

[0037] Figure 4 shows a second embodiment of the atomizer in accordance with the present invention for atomizing liquid into the burner flame. In this embodiment the atomizer 100 comprises a gas passage 110, inside which there is a concentrically placed liquid pipe 102 such that gas is able to flow between the inner wall of the gas passage 110 and the outer wall of the liquid pipe 102. The gas passage 110 comprises a gas port 114, through which the gas discharges from the atomizer 110. The gas port 114 also constitutes an atomizing head 104 of the atomizer 110. In accordance with Figure 4, the liquid spraying head 108 of the liquid pipe 102 extends to the atomizing head 104. The liquid spraying head 108 is provided with a conical portion 122 that tapers towards the liquid spraying head 108. The liquid port 106 of the liquid pipe 102 is provided in the tip of the conical portion 122, whereby the liquid spray discharges from the liquid pipe 102 substantially in the direction of its longitudinal axis.

[0038] In accordance with Figure 4, the gas discharges from the gas port 114 circumferentially around the liquid spray discharging from the liquid port 106. In addition, the conical portion 122 of the liquid pipe 102 controls the gas flow that follows the contour of the conical portion 122 such that the gas flow direction is at least partly at an angle to the flow direction of the liquid discharging from the liquid port 106, whereby the gas flow collides with the liquid flow at an angle. So the gas discharges in the atomizing head 104 around the liquid spray coming from the liquid port 106 and additionally, thanks to the conical portion, at least part of the gas collides with the liquid spray at an angle, because the gas flows along the surface of the conical portion 122. Thus the gas colliding with the liquid spray disperses the liquid spray into droplets in an efficient and controllable manner.

[0039] In Figure 4 the atomizing head 104 of the atomizer 100 is additionally provided with a tubular extension 124, in which the gas and the liquid discharge from the atomizing head 104. The extension 122 is configured to be a throttling part such that the inner diameter of the extension 122 is smaller than the inner diameter of the gas passage 110. Hence, as the liquid and the gas collide the flow rate of produced mist will rise in the extension 122. The extension 122 is preferably made of liquid-repellent material, such as Teflon, which is able to prevent liquid adhesion or liquid film formation on the walls of the extension 122. In this manner the mist flow rate may be increased using a relatively small amount of dispersing gas. At the same time, as the flow rate increases the liquid droplet size in the mist will be further reduced. On the distal end of the extension 124 in relation to the atomizing head 104 there is mounted a perforated plate 126 having one or more holes 128, or another corresponding perforated part for directing mist out of the atomizing head 100. The purpose of the perforated plate 126 is to further reduce the liquid droplet size in the mist. The perforated plate 126 preferably comprises one hole 128 that is centralized according to the diameter of the Teflon pipe. The perforated plate works particularly effectively when the thickness of the perforated plate 126 is less than the diameter of the hole 128. The diameter of the hole 128 may be, for instance, 0.2 to 0.8 mm, whereby the thickness of the perforated plate 126 is 0.2 mm or less. In this manner, in connection with the atomizer 100 of the invention it is possible to further use an extension 124, wherewith the droplet size may be further reduced.

[0040] It is to be noted that in the solution of Figure 4 the liquid ports 106 may also be provided in the side walls of the liquid pipe 102 in the liquid spraying head 108, whereby there will be achieved a structure that is similar to the solution of Figure 3. Thus the liquid ports 106 may be provided in the walls of the conical portion 122, or the conical portion may be omitted, whereby the liquid ports will be provided in the straight walls of the liquid pipe 102. So, in the case of Figure 4 the liquid spray would also be directed towards the side walls of the gas port 114 the gas discharging circumferentially around the liquid and colliding therewith at an angle. Consequently, it would be possible to affect the angle of collision between the gas and the liquid by means of the shape of the conical portion, i.e. the slope of the cone.

[0041] It is also to be noted that it is possible to use an extension 124 and a conical portion also in the embodiment of Figure 3.

[0042] It is apparent to a person skilled in the art that as technology advances the basic idea of the invention may be implemented in a variety of ways. Thus, the invention and the embodiments thereof are not restricted to the above-described examples but they may vary within the scope of the claims.

Claims

1. A burner for providing a line-shaped flame, the burner comprising a frame having an elongated burner head (2) including ports for substance to be introduced into the flame of the burner and a feed pipe (4) mounted inside the elongated frame and provided with one or more feed openings (28) for gas to be supplied to the burner, characterized in that the burner comprises a first trough-like separating plate (8) that is mounted around the feed pipe (4) inside the burner frame and whose lateral edges in parallel with the burner head (2) extend to the burner head (2), and one or more raising parts (16) mounted inside the first separating plate (8) for forming one or more flow channels extending to the burner head (2) inside the first separating plate (8) so as to lead the gas to be supplied to the burner head (2) from the feed pipe (4) to the burner head (2).

2. The burner of claim 1, characterized in that it additionally comprises a corresponding, second separating plate (10) that is mounted inside the first separating plate (8) and whose lateral edges in parallel with the burner head (2) extend to the burner head (2), whereby the raising part or raising parts (16) are mounted between the first and the second separating plates (8, 10) for forming one or more flow channels extending to the burner head (2).

3. The burner of claim 1, characterized in that the feed pipe (4) is designed such that its outer surface extends from inside the burner frame to the burner head (2), and the raising part or raising parts (16) are mounted between the outer surface of the feed pipe (4) and the first separating plate (8) for forming one or more flow channels extending to the burner head (2).

4. The burner of any one of the preceding claims 1 to 3, character i z e d in that the raising part (16) consists of one or more plates having a pectinate structure, the pectinate structure consisting of dents (24) and spaces (22) therebetween and extending from the feeding means (4), or in the vicinity thereof, to the burner head (2) the spaces (22) in the pectinate structure forming the flow channels.

5. The burner of claim 4, characterized in that the width of the spaces (22) and the dents (24) in the pectinate structure is equal throughout the length of the pectinate structure.

6. The burner of claim 4, characterized in that the widths of the spaces (22) and the dents (24) in the pectinate structure are different at least in a portion of the pectinate structure.

7. The burner of claim 6, characterized in that the widths or the width ratios of the spaces (22) and dents (24) in the pectinate structure vary over the pectinate structure.

8. The burner of any one of the preceding claims 4 to 7, character i z e d in that the plate having a pectinate structure is provided substantially trough-like, the lateral edges thereof in parallel with the burner head (2) extending to the burner head (2).

9. The burner of claims 4 to 8, characterized in that the pectinate structure or pectinate structures of the plate having one or more pectinate structures is provided such that spaces (22) in the pectinate structure extend from the feeding means (4), or in the vicinity thereof, to the burner head (2) on both sides of its longitudinal centre line or on one side alone.

10. The burner of any one of the preceding claims 1 to 3, characterized in that the raising parts (16) are separate raising pieces which form one or more flow channels extending from the feeding means (4), or in the vicinity thereof, to the burner head (2).

11. The burner of claim 10, characterized in that the flow channels formed by the separate raising pieces (16) are equal in width.

12. The burner of claim 10, characterized in that the flow channels formed by the separate raising pieces (16) are at least in part different in size.

13. The burner of claim 11, characterized in that the widths of the flow channels formed by the separate raising pieces (16) vary in the longitudinal direction of the burner head (2).

14. The burner of any one of the preceding claims 1 to 13, c h a r - acterized in that at least some of the flow channels (14) extend to the burner head (2) substantially perpendicularly to the longitudinal direction and/or the frontal surface thereof.

15. The burner of any one of the preceding claims 1 to 13, characterized in that at least some of the flow channels extend to the burner head (2) at an angle to the longitudinal direction and/or the frontal surface thereof.

16. The burner of any one of the preceding claims, characterized in that the burner comprises at least two modules of a separating plate (8) or separating plates (8, 10), a raising part or raising parts (16) and a feed pipe (4), respectively, for gas to be supplied to two or more burner heads (2) so as to form a line-shaped flame.

17. The burner of claim 16, characterized in that the modules are mounted on the burner one below the other such that the separating plates of the assemblies extend superimposedly to the burner head (2).

18. The burner of claim 16 or 17, ch a racte r ized in that the first separating plate (8) of one module is the second separating plate (10) of another module.

19. The burner of any one of the preceding claims, characterized in that the burner additionally comprises a direct feed pipe (40) that is mounted on the elongated burner head (2) and that comprises one or more direct feed openings (42), through which the substance supplied via the direct feed pipe discharges directly into the burner flame.

20. The burner of claim 19, characterized in that the direct feed pipe (40) is provided in the middle of the burner head (2), in parallel with the burner head (2), such that the flow channels formed by the separating plate (8) and the feeding means (4) or the separating plate (10) and the raising part or raising parts (16) extend to the burner head (2) on the sides of the direct feed pipe (40).

21. The burner of claim 19 or 20, characterized in that the direct feed pipe (4) is provided to serve as liquid feeding means.

22. The burner of any one of the preceding claims, characterized in that the burner head (2) is designed to have a straight line shape or it is designed to have a curved, wavy or some other continuous line shape to follow the contours of a piece to be treated with the burner.

23. An atomizer (100) for atomizing liquid into a line-shaped flame of an elongated burner, the atomizer (100) comprising a liquid pipe (102) for supplying liquid to an atomizing head (104) of the atomizer (100), the liquid pipe (102) comprising a liquid spraying head (108) having one or more liquid ports (106) for generating a liquid spray, a gas passage (110) for feeding gas to the atomizing head (104) of the atomizer (100), the gas passage (110) comprising one or more gas ports (114) for generating a gas spray, characterized in that the gas passage (110) is arranged to feed the gas spray circumferen- tially around the liquid spray discharging from the liquid ports (106) such that the liquid spray and the gas spray collide with one another at an angle so as to atomize the liquid into mist (200).

24. The atomizer (100) of claim 23, characterized in that the flow direction of the gas spray is transverse to the flow direction of the liquid spray such that the angle between the flow directions thereof is within the range of 0 to 90 degrees.

25. The atomizer (100) of claim 23 or 24, c h a r a c t e r i z e d in that the liquid pipe (102) is placed in the middle of the gas port (114) in the gas passage (110) such that the liquid spray discharges from the liquid port or liquid ports (106) in the middle of the gas port (114).

26. The atomizer (100) of any one of the preceding claims, characterized in that the liquid pipe (102) is configured such that the liquid spray discharges from the liquid port or liquid ports (106) towards the walls (116) of the gas port (114) at a distance from the walls (116) of the gas port (114).

27. The atomizer (100) of any one of the preceding claims 23 to 26, characterized in that the liquid openings (106) are placed in the side wall (118) of the liquid pipe (102) in the liquid spraying head (108) or in the vicinity thereof.

28. The atomizer (100) of any one of the preceding claims 23 to 27, characterized in that the gas port (114) is provided in the side wall (120) of the gas passage (110).

29. The atomizer (100) of claim 28, characterized in that the liquid pipe (102) is arranged to go through the gas passage (110) such that the liquid spraying head (102) of the liquid pipe (102) will be placed inside the gas port (114).

30. The atomizer (100) of any one of the preceding claims 23 to 26, characterized in that the liquid pipe (102) is arranged to pass inside the gas passage (110) substantially in parallel with the gas passage (110) and at a distance from the side walls of the gas passage (110).

31. The atomizer (100) of claim 30, characterized in that the liquid spraying head (108) of the liquid pipe (102) is placed in the middle of the gas port (114) of the gas passage (110).

32. The atomizer (100) of claim 30 or 31, characterized in that the atomizer (100) comprises means for controlling the flow direction of the gas spray such that the gas spray encounters the liquid spray at least partly at an angle.

33. The atomizer (100) of claim 32, characterized in that the liquid pipe (102) is designed to be in the form of a tapering cone at the liquid spray head (108).

34. The atomizer (100) of claim 33, characterized in that the liquid port or liquid ports (106) are provided in the side walls of the conical portion (122) of the liquid pipe (102).

35. The atomizer (100) of claim 33, characterized in that the liquid port or liquid ports (106) are provided at the tip of the conical portion (122) of the liquid pipe (102).

36. The atomizer (100) of any one of the preceding claims 30 to 35, characterized in that in the gas port (114) of the liquid port there is further mounted a tubular extension (124) whose inner diameter is smaller than the inner diameter of the gas passage (110) so as to reduce the droplet size in mist (200).

37. The atomizer (100) of claim 36, characterized in that at the distal end of the tubular extension with respect to the gas port (114) there is installed a perforated plate (126) having one or more holes (128) so as to further reduce the droplet size of the mist (200) and to direct the mist out of the atomizer (100).

38. The atomizer (100) of claim 37, characterized in that the thickness of the perforated plate (126) is less than the diameter of the hole (128) therein.

39. The atomizer (100) of claim 37, characterized in that the tubular extension (124) is made of Teflon or of similar liquid-repellent material.