ES2684436T3 - Oven rack roller equipped with a cooling circuit - Google Patents

Abstract

Roller (1) for oven rack, intended to be mounted in rotation in the home of said oven around a longitudinal axis A of said roller (1), comprising: - a structure (2) forming a cylindrical cage; - a fuel support surface (4) mounted around said structure and provided with means (5) for the passage of the combustion gas through the roller, said support surface being formed by at least one surface of a conduit (3) which allows the passage of a cooling fluid; said roller (1) being characterized in that said cooling fluid passage passage (3) comprises: - a series of hollow rings (6), coaxial with the axis A, distributed over the length of said roller (1), comprising each an inlet (7) and a fluid outlet (8); and - bridges (9) connecting the fluid outlet (8) of a ring (6) to the fluid inlet (7) of the next ring, in order to form a cooling fluid passage circuit wound around said structure (2).

Description

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DESCRIPTION

Oven rack roller equipped with a cooling circuit Technical field of the invention

The invention relates to a roller for combustion and / or incineration furnace grid, and mainly for waste incineration.

The invention also relates to an incineration oven and the use of such an oven.

State of the art

The combustion and / or incineration oven rollers are well known in the prior art. Currently, the rollers are composed of a cylindrical metal structure on which bars are arranged in order to form a support surface for the waste. Annular slits are formed so as to allow the passage of combustion air through the roller. Rollers of this type are mainly described in EP 0 124 826. This document shows an oven rack roller according to the preamble of claim 1.

However, the bars on which the waste rests are subject to very strong thermal stresses due to the high level of temperatures that reign in the combustion zone and the large temperature deviations between the heating due to radiation and the contact of the combustion matter and cooling from combustion air blowing. These large thermal stresses cause dilations and contractions of the constituent material of the bars, involving dimensional variations and deviations between the bars and thus making possible the occurrence of slag or metal smelting between the bars. In addition, the air that passes through the rollers is not always conveniently distributed.

In this way the useful life of the bars that must be changed regularly is reduced in order to avoid the aforementioned drawbacks.

On the other hand, the grilles equipped with said rollers do not allow to take more than partially the calorific value of the waste. Indeed, in order to limit the thermal stresses exerted on the bars, the temperature prevailing in the furnace home is limited so that the combustion of certain wastes remains incomplete.

In order to solve these problems, it is known to provide the rollers with a cooling device that allows the bars to be kept at a limited temperature.

US 5,042,401 describes a roller that has hollow longitudinal bars that form the outer support surface of the debris and that allow the passage of a cooling fluid. The bars are fed in parallel by means of a flow distribution device disposed at one end of said roller. However, in this case, the bars undergo significant deformations linked to the "all or nothing" exposure in the home of the incineration oven. In addition, due to this arrangement of the bars and the risks of deformation, the risks of blocking the rollers by the transit zones between two adjacent rollers and / or slag falls at the height of the transit zones are great.

Document GB 251 849 describes a roller composed of a cylindrical central tube inside which a cooling fluid circulates and around which curved bars are arranged that form rings around said central tube. However, the refrigeration circuit allows only the surface of the bars really in contact with the products to be cooled to be cooled in a mediocre manner and the thermal stress applied to the bars is only diminished weakly.

On the other hand, the unpublished patent application FR 2908180, filed by the present applicant describes rollers comprising a structure, a support surface mounted around the structure and formed by a passage passage of a cooling fluid that forms a helical winding around the longitudinal axis of the roller. In this way, the particular shape of the passage of the cooling fluid makes it possible to ensure uniform cooling of the support surface. In addition, the shape of the winding allows the air present in the duct to be purged during the rotation of the roller.

However, the manufacture and installation on a roller of a helically shaped duct are relatively complex.

In addition, due to its helical arrangement, the passage of the cooling circuit suffers, however, deformations that degrade its useful life.

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Object of the invention

The invention aims to remedy these problems by proposing an oven rack roller that resists the temperature conditions that reign in the oven, in order to limit maintenance operations and allow the incineration of waste at elevated temperatures so as to obtain complete combustion of waste, and whose manufacture, maintenance and assembly are simple.

To this end, and according to a first aspect, the invention proposes a roller for oven rack, intended to be mounted in rotation in the home of said oven around a longitudinal axis A of said roller, comprising:

- a structure that forms a cylindrical cage;

- a support surface of the fuel, mounted around said structure and provided with means of passage of the combustion gas through the roller, said support surface being formed by at least one surface of a conduit that allows the passage of a cooling fluid.

The roller is notable because the cooling fluid passageway comprises:

- a series of hollow rings, coaxial with the A axis, distributed over the length of said roller, each comprising an inlet and a fluid outlet; Y

- bridges connecting the fluid outlet of a ring to the fluid inlet of the next ring, in order to form a cooling fluid passage circuit wrapped around said structure.

Thus, the manufacture and assembly of the rollers according to the invention are relatively easy because the conduit that allows the passage of cooling is made up of rings that are simpler to make and assemble than turns.

In addition, the particular shape of the passage of the cooling fluid also ensures uniform cooling of the fuel support surface.

In addition, the angular orientation of the duct makes it possible to limit the dilations and contractions. Consequently, the fuel support surface is subject only to slight dilations and / or contractions during the rotation of the roller and its successive exposures to the combustion home and to the combustion blow zone. In this way, the dimensional variations of the means of passage of the oxidizing gas are limited.

Advantageously, the inter-ring bridges are fixed to the structure.

Advantageously, the structure carries at least one longitudinal mounting plate of the inlets and fluid outlets of the rings to the bridges.

Advantageously, the bridges are U-tubes.

Advantageously, the cooling fluid inlets and outlets of the rings are arranged such that the cooling fluid circulates in the same direction in each of the rings.

Advantageously, the bridges extend in an inclined plane with an angle between 0 and 90 ° in relation to the plane of the rings.

In a preferred embodiment, the rings comprise a plurality of peripheral sector elements that communicate through internal fittings. Consequently, the assembly of the rings, as well as access to the interior of the roller for maintenance operations and the change of the elements are simple operations.

Advantageously, the connections are fixed to the structure.

The structure has longitudinal mounting plates from the ends of the peripheral sector elements to the internal fittings.

Advantageously, the fittings are U-pipes.

Advantageously, the rings consist of six sectoral elements.

According to a second aspect, the invention relates to a combustion and / or incineration furnace comprising a plurality of rollers according to the first aspect of the invention.

Finally, according to a third aspect, the invention relates to the use of a combustion furnace according to the second aspect of the invention, in which at least one roller is driven around its axis

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longitudinal A in a z direction and the cooling fluid passage passage is fed so that the cooling fluid travels in a direction w around the structure, inverted in relation to z.

Brief description of the figures

Other objects and advantages of the invention will emerge in the course of the following description, made with reference to the accompanying drawings, in which:

- Figure 1 is a schematic view of a roller according to the invention, in longitudinal section, implanted in an oven;

- Figure 2 is a schematic view of the coaxial supply and evacuation tubes of the cooling fluid passage circuit;

- Figure 3 is a partial schematic view in longitudinal section of a roller according to the invention;

- Figure 4 is a schematic view of a longitudinal plate for mounting the inlets and fluid outlets of the rings to the bridges;

- Figure 5 is a schematic view of a longitudinal plate for mounting the ends of the peripheral sector elements to the internal fittings;

- Figure 6 is a cross-sectional view of an internal fitting;

- figure 7 is a sectional view according to the plane VN-VN of figure 6;

- Figure 8 is a top view of the connecting ends of two outer peripheral elements;

- Figure 9a is a sectional view according to the plane IX a-IX a of Figure 3;

- Figure 9b is a sectional view according to the plane IX b-IX b of Figure 3;

- Figure 10 is a sectional view according to the X-X plane of Figure 12, illustrating an internal fitting;

- Figure 11 is a sectional view according to the plane XI-XI of Figure 13, illustrating a bridge;

- Figure 12 is a top view of a longitudinal plate for mounting the ends of the outer peripheral elements to the internal fittings;

- Figure 13 is a top view of a longitudinal plate for mounting the inlets and fluid outlets of the rings to the bridges;

- Figure 14 is a detailed schematic view of the fixing of the peripheral sector elements to a longitudinal plate;

- Figure 15 is a top view of the end of a peripheral sector element;

- figure 16 is a sectional view according to the plane XVI-XVI of figure 15; Y

- Figure 17 represents a double rotating sealing device for feeding and evacuating the

cooling fluid; Y

- Figure 18 is a partial view in longitudinal section of a roller according to the invention.

Execution Example

The waste burning and / or combustion furnace, illustrated in Figure 1, is equipped with several rollers 1 according to the invention. The rollers 1 are cascaded and operated in rotation at relatively reduced speeds, from approximately 0.5 to 3 revolutions / hour, around the horizontal axes A, parallel in order to allow the advance of the debris in the oven. In practice, the grilles include approximately 6 rollers of approximately 1.50 meters in diameter. The rollers follow one another in the direction of fuel travel, according to a downward slope of approximately 15 °.

The roller comprises a hollow metal structure 2, which forms a cylindrical cage and a support surface 4 of the fuel mounted around said structure 2.

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At each end of the structure 2, a shaft 14a, 14b of the structure 2 protrudes outwardly and is mounted on axes 15a, 15b arranged on one side and another of the furnace hearth. A drive system 16 cooperates with one of the shafts 2b in order to drive the roller 1 in rotation. In order to ensure the rigidity of roller 1, the structure 2 is further provided with a central core 16 that extends longitudinally between the two ends of said structure 2. In this way, the maximum arrow of the structure 2 is reduced . The structure 2 is hollow and allows the passage of a combustion gas through the roller 1.

Advantageously, the structure 2 may be equipped with fixed blades, not shown, welded on the central core 16, which allow to assure a homogeneous distribution of the combustion gas through the roller 1 and the disposal of the waste in the transit zone between the rollers 1.

The support surface of the fuel 4 includes means that allow the combustion gas to pass through the roller. Thus, in operation, for combustion maintenance, a combustion gas, such as air, is blown substantially vertically through the rollers 1 (arrow and).

According to the invention, the support surface 4 is formed by a conduit 3 that allows the passage of a cooling fluid, for example water. The conduit 3 comprises a plurality of hollow rings 6, coaxial to the A axis, distributed along the length of said roller 1, each comprising an inlet 7 and an outlet 8 of fluid, and bridges 9, inter-rings, which connect sealing the fluid outlet 8 of a ring 6 to the fluid inlet 7 of the next ring 6.

The rings 6 are separated from each other in order to form the annular holes or slits 5 of the combustion gas. The distance between the rings 6 can be constant or vary in the length of the roller 1. The distance between the rings 6 is chosen according to the type of waste treated by the installation and the desired flow of oxidizing gas.

In each of the rings 6, the cooling fluid circulates in the z direction, illustrated in Figures 9a and 9b. In addition, the bridges extend in an inclined plane with an angle between 0 and 90 ° in relation to the plane of the rings. In this way, the cooling fluid passage circuit is wrapped around structure 2.

In use, the rollers 1 are rotated in a direction z opposite the direction of circulation w of the cooling fluid in the circuit. Consequently, in case of degassing of the cooling liquid or the appearance of a bubble, it moves from ring 6 to ring 6 to the last, during rotation of the roller 1, and then joins the evacuation of the cooling fluid.

In the embodiment shown, detailed in Figures 9a and 9b, the rings are composed of six removable peripheral sector elements 10a, 10b, 10c, 10d, 10e, 10f that communicate, in a sealed manner, through the internal fittings 11 , or inter-element bridges, fixed to structure 2. The sector elements 10a, 10b, 10c, 10d, 10e, 10f are hollow bars, made of cast iron, and longitudinally curved at an angle of about 60 °. The elements 10a, 10b, 10c, 10d, 10e, 10f have, at each end of their inner face, a passage 17 for the cooling fluid. The internal fittings 11 are formed in this case with U-tubes.

The structure 2 carries at least one longitudinal plate 12 for mounting the inlets 7 and the fluid outlets 8 of the rings 6 to the bridges 9, shown in Figures 4, 11 and 13. In the embodiment shown, the Longitudinal plate 12 extends over the entire length of the roller 1 and supports the assembly of the bridges 13 of the roller. The longitudinal plate 12 also makes it possible to support the ends of the rings 6 that include the fluid inlets and outlets and fix them tightly by the fixing means detailed in the following.

Similarly, the structure 2 carries five longitudinal plates 13 for mounting the ends of the peripheral sector elements 10a, 10b, 10c, 10d, 10e, 10f to the internal fittings 11, shown in Figures 5, 10 and 12. These plates 13 they extend, in the embodiment shown, over the entire length of the rollers 1 and support the internal fittings 11. The plates also allow receiving and fixing the ends of the sector elements 10a, 10b, 10c, 10d, 10e, 10f a the structure 2.

In the embodiment shown, the longitudinal plates 12 and 13 are identical and the fixing of the sector elements to these plates 12, 13 is carried out identically. Similarly, bridges 9 and internal fittings 11 are made up of similar elements. However, the internal fittings 11 extend in the plane of the ring while the bridges 9 are inclined relative to this in order to connect two successive rings 6.

The longitudinal mounting plates 12 and 13 are fixed to the central core of the structure by means of radial rods 18. In addition, the longitudinal mounting plates 12 and 13 comprise circular openings 24 into which the ends of the bridges 9 or of the internal fittings 11. The bridges 9 or the internal fittings 11 are joined to the plates 12 and 13, by welding 19 for example.

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The hole 17, formed on the inner face of the sector elements 10a, 10b, 10c, 10d, 10e, 10f, is surrounded by a collar 20. As shown in Figure 14, the inner face of the sector elements 10a, 10b , 10c, 10d, 10e, 10f is positioned against the rigid plate 12, 13 and the end of the internal fittings 11 (or of the bridges 9) is inserted inside said collar 20 in order to ensure the connection between the internal fitting 11 and sector element 10a.

The longitudinal plates 12, 13 comprise sealing means for fixing the sector elements 10a, 10b, 10c, 10d, 10e, 10f. In the example shown, the plates 12, 13 include two drilled holes 23a, 23b, arranged on one side and another of the circular openings 24. Screws 22a, 22b inserted in the housings 21a, 21b of the sector elements 10a, 10b, 10c, 10d, 10e, 10f are intended to be engaged in the drilled holes 23a, 23b, in order to fix the sector elements 10a, 10b, 10c, 10d, 10e, 10f to the rigid plate 12, 13. The housings 21a, 21b of the screws 22a, 22b are arranged at solid ends of the sector elements 10a, 10b, 10c, 10d, 10e, 10f in order not to bring the screws 22a, 22b directly into contact with the cooling fluid, and limit So corrosion. The screws 22a, 22b may mainly be hex head screws.

When it is desired to disassemble a part of the cooling fluid passage circuit, mainly due to maintenance needs, the screws 22a, 22b can then be removed in order to release one or more removable sector elements 10a, 10b, 10c, 10d, 10e , 10f. In this way, a chosen part of the circuit can be easily disassembled to access the inside of the roller or replace the most used parts.

In order to ensure the tightness of the fixation, a gasket 25 is housed in a groove formed in the plate 12, 13, which places in front of the collar 20 of the sectorial element 10a, 10b, 10c, 10d, 10e, 10f. The joint 25 may be made mainly of modified polytetrafluoroethylene.

The two ends of the removable sector elements 10a, 10b, 10c, 10d, 10e, 10f are separated by a slight gap that allows longitudinal expansion of said sector elements 10a, 10b, 10c, 10d, 10e, 10f.

The cooling fluid is introduced and evacuated inside the structure 2 through a feed tube 26 and a coaxial evacuation tube 27, of axis A, shown in Figure 2. Preferably, the feed tubes 26 and evacuation are introduced into the structure by the end of the roller 1, opposite the drive system 16. At the upstream end of the roller 1, shown in Figure 9a, the fluid inlet 7 of the first ring 6 is connected to the tube of fluid supply 26 through a connecting tube 28. Similarly, at the downstream end of the roller 1, shown in Figure 9b, the fluid outlet of the last ring 6 is connected to the fluid evacuation tube 27 of a connection tube 29.

Outside the roller 1, the feeding and evacuation tubes 26, are connected to a rotating joint system 30, illustrated in Figure 14, by means of a flange / counter flange assembly 31 provided with an O-ring. The rotating joint is connected, on the one hand, to a fluid supply network 35 through a conduit 36 provided with a valve 37 and, on the other hand, to an evacuation network 32 through conduit 33 provided with a valve 3. 4.

The invention has been described above by way of example. It is understood that the person skilled in the art is in a position to carry out different embodiments of the invention without thereby departing from the scope of the invention.

Claims (13)

5 10 fifteen twenty 25 30 35 40 Four. Five fifty 55 1. Roller (1) for oven rack, intended to be mounted in rotation in the home of said oven around a longitudinal axis A of said roller (1), comprising: - a structure (2) that forms a cylindrical cage; - a fuel support surface (4) mounted around said structure and provided with means (5) for the passage of the combustion gas through the roller, said support surface being formed by at least one surface of a conduit (3) which allows the passage of a cooling fluid; said roller (1) being characterized in that said cooling fluid passage passage (3) comprises: - a series of hollow rings (6), coaxial with the A axis, distributed over the length of said roller (1), each comprising an inlet (7) and a fluid outlet (8); Y - bridges (9) that connect the fluid outlet (8) of a ring (6) to the fluid inlet (7) of the next ring, in order to form a cooling fluid passage circuit wrapped around said ring structure (2). 2. Roller (1) for oven rack according to claim 1, wherein the inter-ring bridges (9) are fixed to the structure (2). 3. Roller (1) for oven rack according to claim 1 or 2, wherein the structure (2) has at least one longitudinal plate (12) for mounting the inlets (7) and outlets (8) of fluid from the rings (6) to the bridges (9). 4. Roller (1) for oven rack according to one of claims 1 to 3, wherein the bridges (9) are U-tubes. 5. Roller (1) for oven rack according to one of claims 1 to 4, wherein the inlets (7) and the outlets (8) of the ring cooling fluid are arranged such that the cooling fluid circulates in the same direction in each of the rings. 6. Roller (1) for oven rack according to claim 5, wherein the bridges (9) extend in an inclined plane with an angle between 0 and 90 ° in relation to the plane of the rings (6). 7. Roller (1) for oven rack according to one of claims 1 to 6, wherein the rings (6) comprise a plurality of peripheral sector elements (10a, 10b, 10c, 10d, 10e, 10f) which communicate a through internal fittings (11). 8. Roller (1) for oven rack according to claim 7, wherein the connections (11) are fixed to the structure (2). 9. Roller (1) for oven rack according to claim 7 or 8, wherein the structure (2) has longitudinal plates (13) for mounting the ends of the sector elements (10a, 10b, 10c, 10d, 10e, 10f) peripheral to the internal fittings (11). 10. Roller (1) for oven rack according to one of claims 7 to 9, wherein the fittings (11) are U-pipes. 11. Roller (1) for oven rack according to one of claims 6 and 7, wherein the rings (6) consist of six sectoral elements (10a, 10b, 10c, 10d, 10e, 10f). 12. Combustion and / or incineration furnace comprising a plurality of rollers (1) according to one of claims 1 to 11. 13. Use of a combustion furnace according to claim 12, wherein at least one roller (1) is driven in rotation about its longitudinal axis A in a z-direction and is fed to the passage (3) of the cooling fluid passage so that the cooling fluid travels in a direction w around the inverted structure (2) in relation to z.