EP0844438B1 - Grate for a furnace - Google Patents

Abstract

The fixed and movable bedding layer units in rows are confined by side walls. Each unit (11,12,13) consists of supply and discharge pipes (15,16) and cooling ducts. Adjacent units swivel and are restricted by a support. The cooling ducts are positioned across the grid and are arranged sinusoidally in the form of pipes (9) between which are openings for the entry of primary air.

Description

The invention relates to the field of combustion technology. It affects a grate for a furnace at least one grate track with several alternating in the longitudinal direction, Fixed and bounded on both sides by side walls Moving grate lining unit rows, each consisting of at least one with supply and discharge lines and cooling channels Rust covering unit exist, the rust covering units each with a swivel in the area of their rear end fixed or movable grate lining carrier are connected and with its front end on or above the following Grate covering unit are arranged movably, and the grate covering units one row of rust coverings each below the same arranged connecting means connected in this way are that neighboring grate covering units with respect to them assigned grate lining carrier are pivotable to a limited extent.

The invention relates to a prior art, as it results for example from CH-PS 684 118 or DE-U-94 16 320.

State of the art

Grates of the type mentioned above are used for burning and at the same time further transport of fired goods mainly used in waste incineration plants.

In addition to air-cooled grate lining units, also grate bars or Grate plates have been called water-cooled grate units for years used. Changes in composition of waste lead to considerable increases in calorific value and thus to higher rust wear and higher Operating costs. The use of primary air as a cooling medium is therefore no longer sufficient for these purposes.

From the German patent application RA 515691, designed on Dec. 10, 1953, is a poker grate known from alternating fixed and moving There are rows of grate bars, the fixed rows of grate bars from the boiler water circuit lying at right angles to the grate direction switched on cooling pipes exist on which some of the pipes are fully enclosed by rust bars are attached, the cooling tubes at a constant distance are arranged from each other.

This solution only allows a very modest cooling effect achieve. On the one hand, only the fixed ones Rows of grate bars can be cooled because the cooling tubes cover all of the grate span across. On the other hand, the cooling effect decreases in the transverse direction of the grate bar row, so that the side the grate bar row from which the cooling water is discharged, is subjected to greater thermal stress than the side on which the Cooling water is supplied.

Furthermore, from DE-PS 498 538 is a water-cooled stair grate known with movable grate members. It will be like stairs described grate steps offset downwards, where cooling water is arranged across the individual stages Water troughs with a loosely placed lid are closed and only the middle area of the grate cool directly, transverse to the longitudinal direction of the grate, d. H. across to the direction of transport of the combustion material flows. The inflow and drain pipes for the coolant are located each at the opposite ends of the trough. Disadvantageous at this prior art is that the molded comb-like Grate bars that are particularly thermally stressed this technical solution cannot be cooled directly.

The thrust combustion grate known from CH-PS 684 118 has a grate plate, which consists of a substantially rectangular Hollow body made of sheet metal, which on one side a connector on its underside and on the other Side of its bottom a discharge pipe for the inlet and Has removal of a cooling fluid flowing through the hollow body. A large number of primary air are supplied tubular elements passing through the cavity, wherein the primary air supply for each tubular element individually is dosed.

A disadvantage of this prior art is in addition to the complex Production of the grate plate that no differentiation cooling of the cooling element is possible, although it is known that the thermal load on the grate is very strong changes in the longitudinal direction of the grate. The undifferentiated cooling has the disadvantage that different temperatures in the element generated which lead to internal voltages and possible corrosion contribute. In addition, this solution the cooling room is much larger than the supply and discharge lines. However, with cross-sectional changes there is a risk that particles, e.g. B. corrosion products and Dirt, and thus the flow pattern and the Change heat transfer over time. An abrupt change in cross-section also promotes eddy formation, so that Air bubbles can remain in the cooling duct, causing heat transfer influenced and can also lead to erosion.

Furthermore, from EP 0 663 565 A2 is a grate bar with a cooling device and an inlet and outlet opening arranged in the grate bar known, in which at least one channel for guidance of cooling water essentially in the longitudinal direction of the grate bar runs. The channel arranged in the grate bar preferably has two substantially parallel sections with each other opposite flow direction, this with a deflection arranged in the head region of the grate bar are connected. A disadvantage of this prior art is that here also no differentiation of the cooling in the longitudinal direction and thus no adaptation to the course of the thermal Load can take place.

As a rule, funnelshaped beneath the rows of grates nowadays Underwind zones attached. This funnel shape limits often the accessibility to the fringes of the grate especially for the supply and discharge hoses that have a movement in a level require not to be subjected to any torsional stress to be.

Presentation of the invention

The invention tries to avoid all of these disadvantages. It is based on the task, one with cooling channels for Water or another cooling medium provided with rust to create a firing system, which is inexpensive to manufacture and which is a differentiated cooling in the longitudinal direction of the grate allowed. In addition, the supply and discharge hoses be easily accessible for the cooling medium and a uniform flow cross-section available for the cooling medium his.

According to the invention this is achieved in that one Rust according to the preamble of claim 1 which essentially Cooling channels running transversely to the longitudinal direction of the grate meandering, cast into the grate lining units Pipes are, the pipe division of which is to be expected adjusted thermal load of the grate lining units is. The pipe division is from the rear end to the front end the grate covering unit.

The advantages of the invention include that this grate can be manufactured relatively cheaply. The Cooling pipes are prefabricated as semi-finished products and then in cast the grate lining unit. The cooling pipe casting forms a perfect construction where the known problems a cast steel weld seam cannot occur. Furthermore the cooling capacity is due to the different pipe division adapted to the thermal stress, which is special is efficient.

It is particularly expedient if, in the case of a row of rust covering units, which from two inventive grating units and at least one intermediate according to the invention arranged between them There is a rust lining unit, the side rust lining units with respect to the course of the cooling channel mirror image are designed to each other and the connection points for the supply and discharge lines in the side Grate covering units each on one and the same side of the Grate covering unit are arranged. This makes it possible that none in the hard-to-reach edge zones of the rust track Supply and discharge lines for the coolant arranged more must be, but that this outside the peripheral zones of the funnel-shaped underwind box can be arranged.

It is also advantageous if the cooling tubes are adjacent Rust covering units of a rust covering unit row over one Coupling, preferably a pipe or a hose connection, which have a U or S shape, in connection with each other stand and the supply and discharge lines, the couplings and the cast pipe have the same inner diameter. This creates a uniform flow cross-section reached for the cooling medium. There are no abrupt changes in cross-section on so that vortex formation and deposition are prevented or made more difficult by foreign particles.

Brief description of the drawing

In the drawing is an embodiment of the invention shown schematically.

Fig. 1

eine perspektivische Darstellung eines aus Bewegtund Festrostbelageinheitenreihen bestehenden Vorschubrostes;

Fig. 2

einen prinzipiellen Längsschnitt durch drei benachbarte erfindungsgemässe Rostbelageinheiten;

Fig. 3

eine schematische Draufsicht auf eine Rostbelageinheit gemäss Fig. 2;

Fig. 4

einen Rostquerschnitt in Förderrichtung gesehen;

Fig. 5

eine Draufsicht auf eine seitliche Rostbelageinheit;

Fig. 6

einen Schnitt entlang der Linie VI-VI gemäss Fig. 5;

Fig. 7

einen Schnitt entlang der Linie VII-VII gemäss Fig. 6;

Fig. 8

eine Draufsicht auf eine Rostbelageinheitenreihe mit zwei seitlichen Rostbelageinheiten und einer mittleren Rostbelageinheit.

Show it:

Fig. 1

a perspective view of a moving grate consisting of moving and fixed grate unit rows;

Fig. 2

a basic longitudinal section through three adjacent grate covering units according to the invention;

Fig. 3

a schematic plan view of a grate covering unit according to FIG. 2;

Fig. 4

seen a grate cross section in the conveying direction;

Fig. 5

a plan view of a side grating unit;

Fig. 6

a section along the line VI-VI of FIG. 5;

Fig. 7

a section along the line VII-VII of FIG. 6;

Fig. 8

a plan view of a row of grate units with two side grate units and a central grate unit.

It is only essential for understanding the invention Elements shown.

Way of carrying out the invention

The invention is described below using exemplary embodiments and FIGS. 1 to 8 explained in more detail.

1 shows a combustion grate for a furnace, for example a waste incineration plant with a Grate track 1, which is delimited on both sides by side walls 2. The grate can also have two or more juxtaposed have grate tracks 1 separated by central beams.

The grate track 1 is constructed from a grate covering, which from grate covering units 11, 12, 13, so-called grate bars or grate plates. In the longitudinal direction of the grate are alternating rows of fixed grate pads 3 and moving grate pads 4 arranged. At the back end is each grate covering unit 11, 12, 13 as a semi-open tube 5 formed with which the grate covering unit 11, 12, 13 a rust covering unit carrier 6, which here as a rod circular cross section is formed, rests (see. Fig. 2). The grate covering unit supports assigned to the fixed grate covering unit rows 3 6 are firmly connected to the side walls 2, while those assigned to the moving grate lining unit rows 4 Grate covering unit carrier 6 interconnected are and are slidably arranged in the longitudinal direction of the grate. The latter can be arranged on both sides, not shown here double-acting hydraulic or pneumatic cylinders relative to the fixed grating unit rows 3 back and forth be moved.

The grate covering units 11, 12, 13 themselves largely exist from a flat plate that follows at its front end is bent down and there in a roughly parallel to the plate running slider 7 ends. The grate covering unit is located there 11, 12, 13 on the in the direction of movement of the combustion material next grate covering unit 11, 12, 13. In the example case are three rows of narrow openings 8 (slots) provided that down both in longitudinal, as also extend in the transverse direction and parallel to the grate longitudinal direction run. Through these openings 8 of the The bottom of the grate is supplied with primary air.

Each row of grate coverings 3, 4 consists according to the arrangement shown in FIG. 1 shown example from two lateral 11, 12 and two middle grate covering units 13, which are mounted in laterally Openings arranged screws with the neighboring ones Grate covering units are connected. The number of middle ones Rust covering units 13 in a row 3, 4 can of course also be different from two. In another Embodiment can also only one designed according to the invention Grate covering unit, which extends from a side wall 2 extends to the other side wall 2 of the grate track 1, per row of grate covering units 3, 4 can be arranged.

As already mentioned at the beginning, the grate is during the operation of the combustion system considerable thermal stress exposed. Because the cooling with the bottom primary air flowing through the grate alone is not sufficient, to get a rust covering with a long service life, it is provided according to the invention that essentially transversely to the longitudinal direction of the grate, the longitudinal direction of the grate corresponds to the direction of movement of the combustion material, meandering arranged in the grate covering units 11, 12, 13 cast pipes 9 are arranged, the pipe division is not constant, but the respective thermal load the grate covering unit 11, 12, 13 is adapted. So is e.g. B. one from the rear end to the front end of the grate covering unit decreasing pipe pitch provided. Through these tubes 9 is a cooling medium during the operation of the combustion grate, preferably water.

Fig. 2 shows an example of a simplified longitudinal section by three arranged one behind the other in the longitudinal direction of the grate Rust covering units according to the invention, above the left shown part schematically the respective thermal load Q of the grate covering unit is applied. One can see that in this example the thermal load from the rear end increases towards the front end of the grate covering unit and in the head area is greatest. That is why the division of the cooling pipes 9 selected so that the smallest division exists in the head area is, d. H. the distance of the parallel, transverse to the grate longitudinal direction arranged pipe sections 9 is in the head area, the lowest at the front end of the grate covering unit. In general, for the present solution according to the invention, that the pipe division of the expected thermal Load is adjusted, d. H. that in another embodiment the smallest pipe pitch on another Place than can be provided in the head area.

Fig. 3 shows schematically a top view of an inventive Rust covering unit. This example will be close of the rear end designed as a half-open pipe section 5 the grate covering unit via a connection 10 coolant introduced into the tube 9. This essentially flows through that transversely (meandering) arranged pipe 9, the pipe division in the longitudinal direction of the grate to the front end of the grate covering unit decreases until the second, at the front end of the grate covering unit located connector 10 and from there into a drain line not shown here. Of course can also supply the cooling medium at the front end of the grate lining unit and the discharge at the rear end of the grate covering unit respectively. The direction of flow of the coolant 3 with arrows is of minor importance Significance because of the temperature difference of the coolant between entering and leaving the Rust coating unit is relatively low.

The solution according to the invention ensures that the cooling effect in the thermally most stressed area is largest, so as a result of the differentiation cooling in the longitudinal direction of the grate due to temperature and voltage conditional wear of the rust coating reduced becomes.

The manufacture of the grate covering units according to the invention is comparatively simple and economical. The cooling pipes 9 are prefabricated as semi-finished products, then a finished product Pipe 9 inserted into the mold for the grate covering unit and poured the grate.

Fig. 4 shows a grate cross section (seen in the conveying direction). In this example there is a row of grate pads 3 from four grating units arranged side by side, and a left 11 and a right side 12 grate covering unit and two middle grate covering units 13. The grate is in the peripheral zones, d. H. in the funnel-shaped underwind zones 14, which is shown in Fig. 4 as a tightened area are difficult to access. With the inventive Solution, it is possible to supply and discharge lines 15, 16, which are preferably hoses, for the cooling medium to order that they are outside this area.

The tubes 9 of the two central grating units 13 are with each other as well as with the tubes 9 of the adjacent lateral grate covering unit 11, 12 with one another via couplings 20 connected. The coupling 20 is preferably a tube or a hose connection which has a U or S shape. Fig. 4 shows how to make two middle grate units 13 between the edge units in principle with two S-shaped and can use a U-shaped coupling 20.

5 to 7 in detail is a lateral (the right) Rust covering unit 12 of a row of rust covering units is shown. 5 shows a plan view from which it is clear that that the connection points 10 of the supply and discharge lines 15, 16 arranged in this lateral grate covering unit 12 are that one at the rear end and one at the Front end of the grating unit 12 is present and both are off Accessibility on one and the same narrow Side (in Fig. 5 top) of the grate covering unit 12 is arranged are. The differentiation of the pipe division in the longitudinal direction is also easy to see.

Fig. 6 shows a section along the line VI-VI in Fig. 5, So again a side view of the grate covering unit 12, in which also the supply line 15 and the discharge line 16, and the side part 17 are shown, via which the lateral grate covering unit 12 into the openings 18 introduced screws 19 (see also Fig. 8) with a middle grate covering unit 13 is connected. One recognises, that the supply and discharge lines 15, 16 have the same inner diameter d have like the tubes 9 and thus cross-sectional jumps with the known negative effects, e.g. B. Favoring the deposition of foreign particles avoided become.

7 shows a section in the head region, that is to say at the front end the grate covering unit 12, along the line VII-VII in Fig. 6,. In this example are in the head area of the grate covering unit Openings 8 arranged for the primary air supply and in 7 can be clearly seen.

It is essential to the invention that on the other Second lateral side of the grate lining unit row, d. H. here left, rust covering unit 11 mirror image is formed to the grate covering unit 12, d. H. the connections 10 for the supply and discharge lines 15, 16 are on the other narrow side of the grate lining unit and would thus in a representation analogous to FIG. 5 not at the top but at the bottom be arranged.

Fig. 8 shows an overall plan view of a row of grate pads with two side grating units 11, 12 and a middle grate covering unit 13. The inventive mirror-image design of the side grating units 11, 12 is clearly visible.

The central grate covering unit 13 is characterized by that the two connection points 10 on the opposite one another Narrow sides of the grate covering unit 13 are arranged are and not as on the side parts 11, 12 on one Side, with a connection point 10 in the front end and each a connection point 10 in the rear end of the grate covering unit 11, 12, 13 are provided. The pipe 9 of the central grate covering unit 13 is with the tubes 9 of the two side grate covering units 11, 12 via an S-shaped and a U-shaped Coupling 20 connected, the couplings 20, the tubes 9 and the supply and discharge lines 15, 16 have the same inner diameter d have. This will make it more even Flow cross-section for the cooling medium reached and vortex formation in the flow and the deposition of foreign particles prevented.

The left side grating unit 11 is with the middle Rust covering unit 13 and this with the right side Grate covering unit 12 via a screw connection of the side parts 17 connected with screws 19. The feed line 15 and the Discharge line 16 of the pipes 9 is in the side grate covering units 11, 12 each on the narrow side of the Grate covering unit 11, 12 arranged that the middle grate covering unit 13 is immediately adjacent. Therefore, the Zu and Discharge lines 15, 16 not as in a known one State of the art in the hard-to-reach border area of the Rosondern more shifted towards the middle of the grate, so that they are easily accessible.

Reference list

1

Rostbahn

2nd

Side wall

3rd

fixed grating unit row

4th

movable grate lining unit series

5

formed as a semi-open tube piece of the rear Rust covering unit

6

Grate covering unit carrier (rod)

7

Slider

8th

Openings in pos. 3 and pos. 4

9

Cooling ducts / pipes

10th

connection

11

left grating unit

12th

right grating unit

13

middle grate covering unit

14

funnel-shaped underwind zone

15

Supply line

16

Discharge line

17th

Side panel

18th

Openings for item 19

19th

screw

20th

clutch

d

Inner diameter of pos. 9, 15, 16, 20

Claims (6)

1. Grate for a firing plant, having at least one grate track (1) with a plurality of fixed and moving rows (3, 4) of grate-lining units, which rows (3, 4) alternate in the longitudinal direction, are bounded on both sides by side walls (2) and in each case comprise at least one grate-lining unit (11, 12, 13) provided with feed and discharge lines (15, 16) and with cooling passages, each grate-lining unit (11, 12, 13) being pivotably connected in each case in the region of its rear end to a fixed or movable grate-lining bearer (6) and being movably arranged with its front end on or above the following grate-lining unit (11, 12, 13), and, in the case of more than one grate-lining unit (11, 12, 13) per row (3, 4) of grate-lining units, the grate-lining units (11, 12, 13) of a row (3, 4) of grate-lining units in each case being connected by connecting means, arranged below the same, in such a way that adjacent grate-lining units (11, 12, 13) are pivotable to a limited extent relative to the grate-lining bearer (6) allocated to them, characterized in that the cooling passages are arranged essentially transversely to the longitudinal direction of the grate, in that the cooling passages are tubes (9) which are arranged in a meander shape and are integrally cast in the grate-lining units (11, 12, 13), the spacing of the tubes (9) decreasing from the rear end to the front end of the grate-lining unit (11, 12, 13) such that their spacing is adapted to the thermal loading on the grate-lining units (11, 12, 13).
2. Grate for a firing plant according to Claim 1, a row (3, 4) of grate-lining units comprising two lateral grate-lining units (11, 12) and at least one centre grate-lining unit (13) arranged in between, characterized in that the lateral grate-lining units (11, 12) are designed to be a mirror image of one another with regard to the path of the cooling passage (9), and the connection points (10) for the feed and discharge lines (15, 16) are in each case arranged in the lateral grate-lining units (11, 12) on one and the same narrow side of the grate-lining unit (11, 12).
3. Grate for a firing plant according to Claim 2, characterized in that the connection points (10) for the feed and discharge lines (15, 16) are arranged in the grate-lining units (11, 12, 13) in such a way that there is in each case one at the rear end and one at the front end of the grate-lining unit (11, 12, 13).
4. Grate for a firing plant according to one of Claims 1 to 3, characterized in that the tubes (9) of adjacent grate-lining units (11, 12, 13) of a row (3, 4) of grate-lining units are connected to one another via a coupling (20), preferably a tube or a hose connection, which has a U-shape or an S-shape.
5. Grate for a firing plant according to Claim 4, characterized in that the feed and discharge lines (15, 16), the couplings (20) and the integrally cast tube (9) have the same inside diameter (d).
6. Grate for a firing plant according to one of Claims 1 to 5, characterized in that openings (8) for the primary-air feed are arranged between the tubes (9).

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