DE10117793A1 - Ceramic firing kiln temperature control has a tubular perforated collector at the gas flow opening with a moving perforated closure to set the gas flow distribution across the kiln width - Google Patents

Abstract

The temperature control in a kiln for firing ceramics, through the distribution of the gas flow through an opening, has two units moving against each other. A horizontal and tubular collector (60) is fixed at the outflow opening across the kiln width, with at least one longitudinal row of lateral openings (160). A moving closure (61) has a dividing wall (70) and openings (260) to cover and expose the openings (160) wholly or partially.

Description

The invention relates to so-called single-layer kilns, as typically used in the manufacture of Ceramic tiles are used.

Similar furnaces are designed as a tunnel in which a motorized roller conveyor that moves one layer Tiles transported and designed so that the Tiles in the transverse direction at the same distance from each other are arranged.

This tunnel is opposite by two rows Burners that are usually heated with methane be driven and on the side walls of the tun  arranged or to the opposite Facing the wall.

Usually are located on each individual wall of the tunnel two rows of burners, one of which is upper half and one arranged below the roller conveyor is.

In addition, the fuel gas or combustion gas ver takes place supply of burner groups of the aforementioned series via valves that are based on general control and regulation technology system of the furnace.

The purpose of this is to ensure that the temperature in the Tunnel to the burning diagram of the currently processed Material is adjusted so that it is generally egg gradually heating the tiles after they have been turned on come in the oven and that the tiles one for a predetermined time at a fixed temperature temperature in the oven and that it is before leaving cooled from the oven in a controlled manner.

Since the quality of the end product largely depends on the Compliance with the respective burning diagram depends on it is very important to check the temperature in the ver to be able to control different zones of the furnace, so that the aforementioned burning diagram is adhered to can.

The zones of the furnace in which compliance with the above known burning diagram is not so easy  is near the side walls of the Tunnels where the temperature normally varies significantly the temperature deviates in the middle of the tunnel.

In these side areas of the tunnel, the tempe rature is higher than the temperature in the center len area when the convection effect of the smoke duct se, which flow continuously in the furnace, prev is harmful, and then lower when the effect of Radiation of the hot flue gas flows through the bren ner or the surrounding areas is predominant.

This uneven temperature distribution in the ver different furnace cross-sections come all the more to the tra the faster the firing cycle is, especially but if the furnace cross section is relatively large, like that is the case with modern single-layer kilns, which is characterized by high productivity and utility mark width of 3 meters.

Added to this is another factor related to the above unevenness: the breadth of the layer of tiles transported through the oven, the largely on the format of the tiles to be burned hangs.

The problem described above often leads to an irregular burning of the tiles that are in near the side walls of the tunnel, which results in both size and shape errors,  so that in turn the proportion of rejects increases or it complaints from customers.

With a view to reducing these problems have been used several times, including by Applicant, special types of burners designed, some of which with a very characteristic arrangement of the Burners and others with the use of partitions in close to the burner outlet opening, which the task be part of the leak from this opening redirect the hot gases.

In the practical implementation, these solutions have However, they are unsuitable for industrial use net, especially because it is difficult to design equipment that adapt to the changing operating conditions in the side areas of the oven, adapt can sen, d. H. typically the first of the first conditions mentioned, namely the predominance a convection effect of the combustion gases (lateral areas of the tunnel), or the predominance the beam effect of the burners (central furnace area).

In addition, the known solutions are not suitable for regulation of temperature in the cooling area of such Ovens.

It is therefore an object of the present invention to perfected device for heating the single layer ovens to ensure improved control  the temperature in each oven cross section regardless of the oven width and therefore also independent of the porridge te of the layer of kiln transported through the furnace enables. This result is said to be as possible simple, robust, reliable and economical structural solution can be achieved.

According to the invention, this task is characterized by the drawing part of claim 1 mentioned features ge solves.

The invention therefore particularly includes a front direction, at the outflows for the gases installed with which the temperature of an on Layer ceramic furnace should be regulated, and that in is able to flow out of these openings To control gas flow or according to the requirements regulate, like the one with the flame mouth Burner or the nozzle of a blow pipe happens.

This device comprises two mutually movable Elements, one of which acts as a collector manifold acts, is firmly connected to the outflow opening and the other, which is called the shutter, is slidably coupled to the first.

The collector distributor consists of a horizontal one Tubular body, the length of which corresponds to the furnace width, and has at least one longitudinal row of transverse openings; the closure, however, includes a partition that is practical table in contact with the collector distributor area,  in which the aforementioned openings are located, is arranged, and is made with transverse bushings which is at least as big in size be interpreted as the aforementioned openings, wherein the closure is able to face the Kol editor to move to an inactive position to reach all openings of the min least one longitudinal row are uncovered, and in one active position in which at least one of these openings gene is closed.

The aforementioned openings and the aforementioned through tours must be trained or distributed that when the closure is in the above at least one opening of the row, which is closed, as follows is built: either at least from the middle in line or at least from the two opposite openings at the beginning or at End of this row.

In the first case, more hot gas gets to the sides areas of the corresponding tunnel cross-section, where whereas in the second case the opposite is the case, provided, of course, that the same thermal Power of the burner is present.

Thanks to the solution shown above, the Invention underlying task can be realized since the proposed device is able to comply with the aforementioned changing operating conditions  towards the oven in its lateral longitudinal areas to fit.

The characteristics and advantages of the invention - both structural as well as functional - go out of the following detailed description, in which on the Fi guren reference to the accompanying drawings will, clearly emerge; explain these figures - each but purely as an example - some details or preferred te embodiments.

Fig. 1 is a schematic side view in elevation, illustrating a single-layer furnace, which is equipped with a device according to the invention.

Fig. 2 is a part of section II-II of FIG. 1 on an enlarged scale, in which the device according to a first embodiment, provided with a manual regulating device, is provided.

Fig. 3 is a part of Fig. 2 on an enlarged scale.

FIG. 4 is the section IV-IV according to FIG. 3.

Fig. 5 is a view similar to that of Fig. 3; it shows the device according to the invention in another embodiment with automatic regulating device.

FIG. 6 is the section VI-VI according to FIG. 5.

Fig. 7 is a view on a reduced scale, which results from the direction VII shown in Fig. 2, in which, for the sake of clarity, the cylindrical walls of the collector gate distributor and the closure in the plane unwound in a first operating position are shown.

Fig. 8 is similar to Fig. 7, but has a larger scale and shows the collector or the circuit in a different operating position.

Fig. 9 is similar to Fig. 8 and shows the collector or the shutter in a further operating position Be.

Fig. 10 is a view on a reduced scale, which results from the direction X shown in Fig. 5, in which, for the sake of clarity, the cylindrical walls of the collector manifold and the closure in the plane are shown in a first operating position are.

Fig. 11 is similar to Fig. 10, but to a greater extent, and shows the collector or the circuit in a different operating position.

Fig. 12 is similar to Fig. 11 and shows the collector or the closure in a further operating position Be.

Figure 13 is a cross-section through the furnace showing the manner in which the hot gases exit a burner through the aforesaid device when in the inactive position of Figures 7 and 10.

Fig. 14. Fig. 13 is similar and shows the way the outlet of the gases from the Vorrich tung in the operating position shown in FIGS. 9 and 12.

Fig. 15 Fig. 14 is similar and shows the way the outlet of the gases from the Vorrich tung in the operating position shown in FIGS. 8 and 11.

The aforementioned figures show a conventional one-layer furnace with a horizontal tunnel 1 , in which a motor-driven roller conveyor 2 is installed, on which a layer of tiles 3 is transported.

This tunnel 1 is equipped with conventional thermal probes, which are shown in FIG. 2 and marked there as position 4 , or with equivalent temperature measuring devices (with direct or indirect effect); these usual thermal probes (or equivalent measuring devices) are connected to an equally usual system for regulating and checking the furnace.

In addition, there are two longitudinal rows with burners 5 placed at the same distance on each side wall of the tun nels 1, one row of which is placed above the roller conveyor 2 and the other row below the roller conveyor 2 (see FIGS. 1 and 13 to 15 ).

These burners 5 are designed as normal burners, that is to say as a type which is normally referred to as an axial flame burner (see FIG. 2).

In addition, the burners 5 of each upper row are arranged ver to the burners 5 of the opposite upper row; likewise, the burners 5 of the upper row are offset from the burners 5 of the corresponding lower row.

The aforementioned burners 5 , which are supplied with a mixture of air and methane gas in the illustrated case, are divided into groups, each group being connected in the usual way to a likewise conventional operating circuit, part of which is shown in FIG. 13 to 15 is shown.

On the representation of other special features of Tun 1 and the burner 5 is dispensed with, since these are not relevant for the purpose of the invention.

According to the invention, these burners 5 , advantageously each of them, are connected to a device 6 before, which can be regulated according to the requirements, which depend on the operating data, which is continuously detected by the probe 4 and with the in general control and control system of the furnace stored combustion diagram to be compared.

It is also noted that - and this will immediately shine a specialist lights of the area in question - the devices that are the subject of the invention, at every cross-section of the furnace 1 , that is, in the preheating area, in the burning area and in the cooling area, used can be.

In all of the solutions shown, the aforementioned device 6 comprises two coaxial, tubular elements which are inserted into one another in such a way that - as will be shown - they can slide freely in the direction of translation and rotation.

The device comprises in particular an internal collector distributor 60 and an outer lying closure 61 , the collector distributor 60 being stationary and the closure 61 being able to move with respect to it.

The collector 60 consists of a cylindrical body, the length of which corresponds to the width of the tunnel 1 ( FIG. 2) and which is made of a high-temperature-resistant material such as silicon carbide or metal.

In the case shown, the collector has a total length (non-useful part + useful part) of 2.15 m, an Au Outside diameter of 60 mm and a thickness of 5 mm.

The collector 60 has an open end in which the flame opening of the burner 5 sits; the other end is hen with a stopper 7 made of insulating material, such as rock wool or a similar material.

Said collector 60 is equipped with a longitudinal row of small transverse openings 160 which are directed towards the firing material 3 .

In the case shown, the aforementioned openings 160 consist of forty circular bores which are arranged symmetrically to the center line 200 on the useful side of the collector 60 ; these holes have the same diameter (7 mm) and are in the same distance from each other (50 mm).

The closure 61 also consists of a cylindrical body made of metal or silicon carbide, the length of which corresponds to the length of the collector 60 .

For example, the closure has a total length of 2.15 m, an inner diameter of 60.5 mm and one 3 mm thick.  

The closure 61 is on the side opposite the side with the burner 5 on the collector 60 ge, and is held at the ends of two flange sockets 8 , the corresponding coaxial holes in the side walls of the tunnel 1 are assigned.

On the side on which the aforementioned plug 7 of the collector 60 is located, the closure 61 is closed by a partition 70 which is connected to a regulating device, which will be discussed later.

The closure 61 has a longitudinal row with transverse bushings, of which there are as many as the holes 160 , namely forty.

According to a first embodiment - see FIGS. 2, 3, 4, 7, 8 and 9 - these bushings consist of identical slots 260 , which are arranged along the lower surface line of the closure 61 , that is, below half of the bores 160 .

In addition, these elongated holes 260 have a width B which is greater than the diameter of the bores 160 (B = 15 mm), and are arranged along the abovementioned surface line, so that - as will be shown further above - either all bores 160 are uncovered or min at least one pair of these bores (at least partially se) is covered, the two bores 160 of this pair - it must be at least one pair - are arranged symmetrically to the center line 200 of the collector 60 and the two bores of the (middle) pair can consist of a single, larger bore.

In the illustrated case - see Figures 7 to 9 -., The aforementioned forty identical oblong holes tert approaches 260 un in ten groups A, each with four long holes 260, with respect to a transverse plane 100 which is coincident with the center line 200 of the collector, if all Bores 160 are uncovered (see FIG. 7):

• the elongated holes 260 of each group A have the same distance P,
• - the five groups A start on the right at level 100 ,
• - the five groups A start at one point on the left, which has a distance D from the aforementioned plane D,
• - the five groups A to the left of each other a distance each have D1,
• - The five groups A on the right each a distance among themselves from D2,
• - D1 <D <D2 and
• D2 <L, where L is the length of the elongated hole 260 .

For example, each group A has a total length of 180 mm and the aforementioned dimensions D1, D, D2, P and L are 15, 20, 25, 20 and 30 mm, respectively.

According to a first embodiment - a better specification can be found in FIG. 3 - a threaded shaft 51 is responsible for the axial regulation of the closure 61 , which is rotatably but fixedly mounted in the axial direction on a plate 52 which is on the outside of the side wall of the tunnel 1 is attached.

This shaft 51 is connected to a bushing 53 , which has a thread on the inside and is fastened in the middle of the partition wall 70 , and extends beyond this plate 52 , where an actuating wheel 50 is then located.

In addition, an off-axis rod 54 is provided, which comes from the partition wall 70 and engages with a precise fit in a through hole in the plate 52 in order to prevent premature rotations of the closure 61 .

This rod 54 - see also FIG. 3 - is provided with a series of notches, which represent a straight reading zone, which the operator uses as a reference.

As a variant, it is provided that the shaft 51 is driven by a small worm-worm-geared gear motor, which in turn is controlled by the general control and regulating system of the furnace.

According to a second embodiment - see FIGS. 5, 6, 10, 11 and 12 - the bushings provided on the closure 61 consist of forty identical elongated holes 360 with a peripheral development, which in the illustrated case has a width of 15 mm and a length of 65 mm and have a center distance of the holes 160 of 50 mm.

In particular, the two elongated holes 360 are slightly offset in two steps, so that they are arranged overall according to a symmetrically divided line that forms a wide open "V" with an angle of approximately 260 °.

According to a first embodiment - for a more detailed representation see Fig. 5 - the angle adjustment of the closure 61 is taken over by a small geared motor 55 in worm-worm wheel configuration, which is fastened to the plate 52 and whose emerging shaft 510 the plate 52 through and then connected to the partition 70 of the closure 61 Ver.

Of course, the geared motor becomes general control and control system of the furnace ert.

Alternatively, the aforementioned rotary movement can also be carried out with a hand-adjustable rotary wheel, which is provided with a radially arranged pointer, which is coupled to an angular radius on the outside of the plate 52 .

The invention works according to the following scheme:
If in a special cross-section of the tunnel 1 the temperature distribution is on the whole regular, that is to say both in the center and on the sides the same, then the closure 61 is in the inactive position, which is shown in FIG. 7 and in FIG . 10 is set to represent and in which the own long holes 260 and 360 allow all the bores 160 uncovered and is discharged to the hot gas stream as shown in FIG. 13.

If, on the other hand, the temperature on the side walls of the tunnel 1 is significantly higher than the temperature in the center, as is the case, for example, if the flue gas convection effect prevails or if the firing material 3 passing through the furnace is significantly less wide than the tunnel 1 , then the shutter is - as explained - regulated manually or automatically accordingly, possibly in combination with a special automatic regulation of the thermal power supplied by the burner 5 .

In this case, the closure 61 must be moved or rotated in such a way that some bores 160 are closed at the beginning or at the end of the collector 60 - as is given as an example in FIGS. 8 and 11, so that the hot gas flow is distributed, as clearly shown in Fig. 15.

Conversely, the closure 61 is placed as shown in FIGS. 9 and 12, optionally together with a specific regulation of the burner 5 , if the temperature in the center of the corresponding tunnel cross-section is substantially higher than the temperature in the peripheral areas, as in the example the case is when the burner 5 or the surrounding walls radiate heat.

The situation explained above is shown in FIG. 14.

Of course, not all business positions could are shown because the devices explained enable fine adjustment, which of course like already mentioned at the beginning for all operating areas surface of the furnace or tunnel, i.e. for heating area, the firing area and the cooling area, it is a possibility.

The advantages and disadvantages of the invention go from above description and from the attached Illustrations clearly.

It goes without saying that the invention not on the explained or described execution is limited, but that they are all equivalent technical variants of the invention and their Combination options, as far as these under the the following claims.

For example, the closure 61 can also be fitted inside the collector 60 instead of outside.

The collector 60 can also be made simpler or lighter; it may, for example, comprise part of a cylindrical surface which is provided with the aforementioned elongated holes 260 or 360 and has two or more narrow curved tabs for connection to the collector 60 .

Finally, the collector 60 can comprise a plurality of longitudinal rows of bores 160 , and accordingly the closure 61 can also contain as many rows of elongated holes 260 and 360, respectively.

Claims (19)

1. Device for the controlled distribution of the gas flow, which is output from an opening with which the temperature of a ceramic furnace is to be re-regulated, characterized in that this device comprises two mutually movable elements, of which the first (collector 60 ), is firmly connected to the outflow opening and has a horizontal tubular body, the length of which corresponds to the width of the furnace and has at least one longitudinal row of transverse openings ( 160 ), whereas the second element (closure 61 ) has a partition ( 70 ) which is practically in the Contact is made with the collector area in which the openings ( 160 ) are located, and is equipped with transverse feedthroughs ( 260 , 360 ) which are at least as large as the openings ( 160 ), the closure ( 61 ) is able to move towards the collector ( 60 ) to either move to an inactive position in which all che openings ( 160 ) of at least one longitudinal row are uncovered, or in an active position in which at least one of these openings ( 160 ) is closed. 2. Device according to claim 1, characterized in that the collector ( 60 ) consists of a cylindrical element which is closed at one end. 3. Apparatus according to claim 1, characterized in that the openings ( 160 ) are designed as circular bores with the same diameter. 4. The device according to claim 3, characterized in that the holes at the same distance from each other are arranged. 5. The device according to claim 1, characterized in that the partition ( 70 ) is designed as a thin wall which is formed in the form of part of a cylindrical surface. 6. The device according to claim 1, characterized in that the partition ( 70 ) on the collector ( 60 ) is introduced. 7. The device according to claim 1, characterized in that the partition ( 70 ) is arranged around the collector ( 60 ). 8. The device according to claim 1, characterized in that the openings ( 160 ) and bushings ( 260 , 360 ) are shaped or distributed so that when the closure ( 61 ) is in the active position, the at least one opening ( 160 ) of the row, which is closed in each case, is constructed as follows: either at least from the opening located in the middle of the row or at least from the two opposite openings at the beginning or at the end of this row. 9. The device according to claim 1, characterized in that the closure ( 61 ) is slidably connected to the collector ( 60 ) and is controlled by an external regulation unit. 10. The device according to claim 9, characterized in that the bushings ( 260 , 360 ) comprise at least one longitudinal row of elongated holes which are formed in the longitudinal direction and of which there are as many as openings ( 160 ), but which are distributed differently. 11. The device according to claim 9, characterized in that the regulating unit is provided with a handwheel ( 50 ) which is rotatably mounted on the side wall of the tunnel and is kinematically connected to the United circuit ( 61 ) via a worm-worm wheel mechanism. 12. The apparatus according to claim 9, characterized in that the regulating unit is equipped with a micromotor with a reduction gear, which is kinematically connected to the head of the closure ( 61 ) via a worm-worm wheel mechanism and whose operational control by the general guide - and control system of the furnace. 13. The apparatus according to claim 1, characterized in that the closure ( 61 ) is rotatably connected to the collector ( 60 ) and that it is controlled by an external regulation unit. 14. The apparatus according to claim 13, characterized in that the bushings ( 260 , 360 ) comprise at least one row of elongated holes which develop in the circumferential direction and the number or their distribution step equal to the number or the distribution step of the openings ( 160 ) is, the elongated holes are slightly offset from each other and arranged in a symmetrical divided line, so that there is a wide open "V" he gives. 15. The apparatus according to claim 13, characterized in that the regulating unit is equipped with a handwheel ( 50 ) which is rotatably mounted on the side wall of the tunnel and so connected to the head of the closure ( 61 ) that a torsion movement is possible . 16. The apparatus according to claim 13, characterized in that the regulating unit is equipped with a micromotor with reduction gear, the outgoing shaft ( 51 ) is so connected to the head of the closure ( 61 ) that a Torsionsbe movement is possible, and its operational Controlled by the general control and regulation system of the furnace. 17. burners for industrial furnaces, characterized in that  he with a device according to claims 1 to 16 is equipped. 18. ceramic oven, characterized in that he with at least one burner according to claim 17 Is provided. 19. Plant for the production of ceramic tiles, characterized in that them with at least one oven according to claim 18 Is provided.