FI122779B - Steam boiler tube wall and equipment for cleaning - Google Patents

Abstract

The wall (1) has horizontally running impact bars (8) for blending impact energy on the wall and spaced at a distance from the wall. The bars are connected with vertically arranged fins with the wall, where the fins are flexibly designed over its extension between the wall and the bars in a lateral direction to accommodate different horizontal linear expansions of the wall and the bars. A lateral deflection is included for the fins corresponding to its flexible design in the lateral direction.

Description

Steam boiler tube wall and means for cleaning it

The invention relates to a pipe wall of a steam boiler which defines a gas passage through which hot, dust or ash-laden gases flow and which are formed of a plurality of substantially vertically extending ribbed pipes or a combination of pipes and connecting connectors , and a knocking or impacting device is disposed outside the steam boiler tube wall which provides the knocking or impact energy to the steam boiler tube wall to clean the dust or ash accumulated inside the steam boiler tube wall.

The aforementioned types of steam boiler tube walls having one or more outwardly facing knocking or impacting devices used to clean dust or ash accumulated inside the steam boiler tube wall or toward the steam conduit 15 are generally known as a steam boiler. Such devices are required to maintain an effective heat transfer from the hot gas through the gas channel to the working fluid flowing through the steam boiler tube, which, however, is reduced when the boiler tube walls are covered with ash and dust.

US 3,835,817 discloses a device for cleaning the outside of steam boiler pipes or 20 boiler pipe walls that are not connected to one another. This is accomplished by a driven percussion hammer which, when spring-suspended using a pair of spring plates, delivers an impact pulse to the end of the unit block of the boiler tube wall. This shock pulse produces high accelerations that shake the sediment or slag out of the steam boiler tubes or the steam wall of the steam boiler tube. However, this device has proven to be quite un-

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for practical use in steam boiler tube walls using so-called reinforced walls or tube-mesh-tube combinations, i.e. steam boiler tubes, all of which are interconnected and thus form a gas-tight 'tube wall. The problem lies in the fact that such steam boiler pipe | The walls are substantially stiffer than those of the first mentioned tubes and thus the impact pulse at the end of the boiler tube wall unit block exhibits an unsatisfactory cleaning effect.

DE 202 11 156 U1 discloses a device for removing steam from the walls of a steam boiler, wherein at least one impact profile engages an opening in the wall of the steam boiler outside the steam boiler wall and wherein the impact profile is connected to at least one anvil profile. especially with a drop hammer. Thus, in this device, the impact profile does not directly impact the steam boiler wall but directly against the dried dust inside the steam boiler wall, since the impact profile extends through an opening in the steam boiler wall and when the impact is initiated, the impact profile comes into contact with the dried dust. The disadvantage of this device is that due to the impact profiles of penetration openings in the steam boiler wall, the steam boiler itself is no longer gas-tight to the outside air due to the openings and has to be sealed towards the outside by very complicated sealing devices for each individual device. Another drawback is that the impact profile 10 is directly exposed to gases and sedimentation in the steam boiler and is thus subject to corrosion and rust.

It is now an object of the present invention to provide a steam boiler tube wall and device for cleaning it which avoids the above disadvantages. In particular, the invention should provide a device for providing a boiler tube pipe wall defining a gas passage through which hot, dust or ash-laden gases flow, formed by a plurality of substantially vertical fluid-carrying fins or tubular mesh composite tubing. , can be largely cleaned of dust or ash accumulated on the inner wall of the steam boiler tube wall.

The above object is achieved by the features of claim 1. The solution provides, in order to render the knocking or impact energy more uniform on the boiler tube wall, said steam boiler tube wall being provided with a horizontally extending stroke spaced apart from the boiler tube wall by and laterally, elastically to absorb various horizontal linear expansions of the steam boiler tube wall and the impact beam.

Preferred embodiments of the invention may be inferred from the dependent claims.

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The solution according to the invention provides a steam boiler for the pipe wall

A device for cleaning said wall having the following advantages: § - a single impact pulse can be transferred to the boiler wall pipe n.

§ over a wide area, ^ 35 - the boiler tube wall may expand independently and independently of the various linear expansion of the impact beam; - since larger and wider impact beams can be used, only a small number of impact beams per boiler tube wall are required.

In a preferred embodiment, the vertical reinforcements are connected to a reinforcement located between the steam boiler tubes or to the mesh of the boiler tube wall located between the steam boiler tubes. As a result of this procedure, the impact pulse is transmitted to the reinforcement or mesh and not to the tube. No attenuation of the pulse occurs as a result of the fixed connection.

It is convenient if each of the reinforcements is arranged at two pipe intervals (2 x t) along the length of the impact bar. The impact pulse is thus uniformly introduced into the pipe wall of the steam boiler.

In a particularly advantageous manner, the reinforcements are welded to the tube wall and impact bar of the steam boiler. As a result of this operation, the reinforcements are connected in a simple and efficient manner to the boiler tube wall and impact bar.

In a preferred embodiment of the invention, each reinforcement consists of two parts when viewed perpendicular to their vertical extension. This procedure ensures that the individual reinforcements are substantially more accessible for welding.

Suitably, the impact bar is formed with a rectangular or other closed hollow profile or a closed profile. It may also be provided with an I or U profile or other open profile. This ensures, firstly, that the impact bar 5 has sufficient rigidity and, secondly, that it is easy to achieve as a finished semi-finished product.

A preferred embodiment of the invention provides that the impact bar is provided with one or two horizontally arranged | with reinforcement for connection to the boiler pipe wall. Axial forces, that is. which are present in the impact bar can be absorbed by placing them on the pipe wall of the steam boiler.

In a preferred embodiment of the invention, the length L of the impact bar may be 3535 0.5 to 5.0 m. This ensures that the boiler tube walls are covered with different widths.

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The distance X between the tube wall of the steam boiler and the impact beam is preferably 10 to 1000 mm. As a result of this operation, the impact bar can then also remain unobstructed for the impactor if, for example, the outer surface of the boiler tube wall is insulated.

5 For optimum cleaning of the steam boiler tube wall, it is preferable that, when multiple impact beams are used, the vertical distance of the impact beams is 2 to 5 m.

In order to transfer the impact or impact stroke directly from the impact bar to the boiler tube wall, the reinforcements at the front, i.e., in front of the impact bar or on the side facing 10, may be welded to said beam.

In order to efficiently transfer the impact energy from the impact bar to the boiler tube wall, it is expedient to arrange reinforcements perpendicular to the steam boiler tube wall and thus also perpendicular to the impact bar.

Exemplary embodiments of the invention will now be described in detail with reference to the drawings and description.

In the figures:

Figure 1 is a schematic longitudinal cross-section through a steam boiler tube subjected to a shock pulse (according to prior art 20); according to the prior art, Fig. 4 is a perspective view of a steam boiler tube wall with a hollow support in the prior art as a shock bar, Fig. 5 is a schematic cross-section through the tube wall of a steam boiler according to the invention; ", That is, the steam boiler steam boiler tube wall is off, Figure 6 as Figure 5, but with different linear expansions of the steam boiler | Fig. 7 is a perspective view of an alternative embodiment of a steam boiler tube wall according to the invention and a means for cleaning it, cv 5 is a perspective view of a second alternative embodiment of a steam boiler tube wall according to the invention, Fig. 9 is a schematic view of a pipe wall of a steam boiler 5 according to the invention using ribbed pipes; Fig. 10 is a schematic view of a pipe wall of a steam boiler using a pipe-mesh-pipe combination.

An inner part 6 of a steam boiler tube wall 1 defining a gas passage 7 through which hot, dust or ash-laden gases flow and which is formed of a plurality of substantially vertical ribs 2 (Fig. 9) or pipe-mesh-tube combination 3, 4 (Fig. 10), which carries the working fluid, can be cleaned of dust or ash using knocking! a percussion device disposed outside the boiler tube wall 1 5, wherein the knocking or impact energy is applied to a point in the steam boiler tube wall 15 1. In this case, a pair of spring plates 13 that give a shock or pulse to the target, i.e., the boiler tube wall 1 corresponds to a sinusoidal wave of approximately 1000 Hz. If the pulse receiver is a steam boiler tube 2, 3, the impulse is divided into two sine waves which extend further on both sides of the pulse point 14. In the case of the frequently used 38 x4.4 steam boiler 20 pipes (outer diameter 38 mm, wall thickness 4.5 mm), the blue hemispherical length is about 300 mm. If the pipe 2, 3 of the steam boiler is freely supported, the pulse proceeds very far, almost without loss. Fig. 1 schematically shows a longitudinal cross-section of a steam boiler tube 2, 3 with a pulse point 14, in which the impact pulse 15 is supplied to the steam boiler tube 2, 3 25 and thus produces a pressure wave 16 on both sides of the pulse point 14. In the immediate vicinity of the pulse point 14, the steam boiler tube 2, 3 is already at rest, and a thin flat wall, such as the steam boiler tube wall 1, has

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^ distribution of score stroke 15 more difficult. The pressure wave 16 propagates in a circular fashion and the length of the pressure wave 16 becomes progressively larger, thereby losing its power and magnitude. Such a phenomenon is observed, for example, in water when a falling object initiates a pulse, see Figure 2.

In order to send a sufficient impulse force, for example, a thin wall section to a sufficient area, the impact pulse 15 directed to the puncture point 14 must be o extremely large. However, this causes too much strain or tension on the impact or stroke point 14. To prevent such high strain, the stroke stroke 15 can be applied, for example, by means of a welded beam, for example a profile support. The stroke has a half wavelength in the beam of about 400 to 500 mm. If the wall consists of a flat sheet of 8 mm steel, the stroke 15 has a half wavelength of only 137 mm. In this case, the pressure wave 16 adopts an elliptical shape which corresponds to the front of a more linear pulse and thus to a significantly higher pulse force than the point pulse point 14.

Applying the impact pulse 15 to a flat steel plate, the application of the impact pulse 15 to the pipe wall 1 of a boiler made of ribs 2 or a tube-to-tube combination is even more difficult. This is because the ribs 11 or nets 4 between the steam boiler pipes 2, 3 are only 10 6-8 mm thick, but the steam boiler pipes 2, 3 alone are considerably stiffer than the ribs 11 or nets 4. The steam boiler pipe wall 1 consisting of The ribs 2, for example, are approximately 25 times stiffer about their horizontal axis than their vertical axis. It is therefore difficult to obtain a pressure wave 16 with a uniform elliptical shape with a shock pulse on such a steam boiler-15 pipe wall 1.

Fig. 3 shows a prior art technique which uses 140 mm l-support as a stroke bar 8. Ribbed tubes 2 of a steam boiler tube wall 1 filled with water as a working medium produce a pressure wave 16 having a half-wavelength of 15 mm as a result of impact stroke 15 loaded with the weight of the tube wall 20 and after the impact pulse 15, the I-beam represents a pressure wave 16 having a half wavelength of 424 mm. The front profile of pressure wave 16 is only slightly elliptical. Figure 4 illustrates the prior art in which a 250 x 150 x 10 mm casing profile is used as an impact bar 8. When the impact pulse 15 is applied to this impact bar 8, a pressure wave 16 is produced at half wavelength 743 mm. The front profile of this pressure wave 16 is clearly better than the front profile of the pressure wave 16 shown in Fig. 3, i.e. the impact pulse 15 is transmitted to the pipe wall 1 of the steam boiler by means of a box profile 5 with greater power or efficiency.

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^ The main problem with using the impact bar 8 is seen in moving the impact pulse 15 ° from the impact bar 8 to the boiler tube wall 1. Attempts have been made to press the shock bar 30 into the steam boiler tube wall 1. During printing, the pulse moves to the wall | only in muted form. Instead of just pressing isis. cup bar 8, attaching the impact bar 8 to the steam boiler tube wall 1 by means of a welding rod can be seen as a single useful method for cleaning the steam boiler tube wall 1 o.

However, welding the impact beam 8 to the tube wall 1 of the steam boiler poses new problems because the two parts experience different temperatures during operation and are therefore subjected to a very different expansion. The temperature of the pipe wall 1 of the steam boiler may vary very rapidly during use, particularly in the ribs 11 or in the nets 4 between the pipes 2, 3 of the steam boiler. Large temperature differences cause high stresses and eventually fatigue cracks between the impact beam 5 8 and the boiler tube wall 1. These cracks rarely cause leaks in the steam boiler tube wall 1, but the impact strokes 15 for cleaning cannot be further displaced as a result of the cracks.

The present invention solves the aforementioned problems, wherein, in order to make knocking or impact energy more uniform on the boiler tube wall, said horizontal boiler tube wall is provided with a horizontal striking bar 8 as shown in Fig. 5, separated by 1 with a plurality of vertically arranged reinforcements 9, which reinforcements 9 are arranged to extend between the boiler tube wall 1 and the impact bar 8 in the lateral direction, elastically to accommodate the where the lateral deviation E is 0.001 to 0.1 times the distance 20 X between the steam boiler tube wall 1 and the impact bar 8. Various horizontal linear horizontal expansions mean, on the one hand, the horizontal linear expansion of the steam boiler tube wall 1 over its width and, on the other hand, the horizontal linear expansion of the impact bar 8 over its length L. The impact stroke 15 is applied by means of a knocker or impact device to the central part of the rigid and heavy impact bar 8. This beam 8 preferably has a length of 0.5 to about 5 m and is capable of keeping the pipe walls of the steam boiler equally wide. Each horizontal impact bar 8 on the steam boiler tube wall 1 preferably comprises an operating height of about 2 to about 5 m from the steam boiler tube wall 1. The impact bar 8

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^ moves the impact pulse 15 to each end of the impact bar 8. The impact bar 8 may be connected or connected to each other rib 11 or every 30 of the steam boiler tube wall 1 to another net 4. This connection or connection is made vertically | The sealed reinforcements 9, described in detail above, wherein the selected bolts 9 are welded at each end to the impact beam 8, as well as steam to the boiler tube wall 1, by means of a welding seam 12.

o A plurality of vertically arranged reinforcements 9 means that the impact bar ^ 35 8 is configured over its length L by at least three, but usually more than three, reinforcements 9. In theory, one reinforcement 9 may be arranged between the steam boiler tube wall 1 and the impact bar 8 . Figures 5 to 10 show a preferred configuration in which one reinforcement 9 is provided after every other tube spacing, i.e. 2 x t. A triple or more tube spacing is also possible for the arrangement of reinforcement 9. The height or vertical extension of each reinforcement 9 is limited to the region of the impact bar 8. It will protrude or extend above and below the impact beam 8 so that each reinforcement 9 can be welded to the boiler tube wall 1 as well as the impact beam 8 and can reliably transfer the knock or impact energy from the beam 8 to the boiler tube wall 1. In this case preferably perpendicular to the pipe wall 1 of the steam boiler. Hammers or the like, not shown, are used as knocking or impacting devices, for example, which can be operated mechanically, hydraulically, pneumatically or also electrically.

Fig. 6 shows a device for cleaning the steam boiler tube pipe wall 1 during operation, i.e. in the hot state of the steam boiler pipe wall 1, in accordance with the present invention. In this case, as a result of high wall temperatures (up to 400 ° C), the steam boiler tube wall 1 expands significantly more than the stroke bar 8. The difference in horizontal expansion and viewed parallel to the steam boiler tube wall 1 between the two portions 20 1 and 8 6. In this case, the elastic reinforcements 9 absorb various lateral deviations E between the support beam 8 and the steam boiler tube wall 1 over the extension or length L of the impact beam 8. While the centrally arranged reinforcements 25 9 on the impact bar 8 have virtually no need to absorb any deflection E, the elastic reinforcements provided at each outer end of the impact bar 8 absorb the greatest deviation E.

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By means of this device it is possible to keep very large panels or areas of the pipe wall 1 of the steam boiler clean by using a knock or impact device. As a result of the size and weight of the impact bar 8, larger hammers £ for knocking or impacting can be used and the number of hammers or knocking devices required can thus be substantially reduced.

Fig. 7 shows a tube boiler wall 1 of the steam boiler according to the invention equipped with a device for cleaning it using a hollow profile ^ 35 as a striking bar 8. Each of the reinforcements 9 arranged vertically between the boiler tube wall 1 and the striking bar 8 is configured to the pipe wall 1 and the impact bar 8 by means of a weld 12. Due to the very thin wall thicknesses of the reinforcements 9a, 9b, the narrow and thus very flexible configuration can result in the impact bar 8 being located in the immediate vicinity of the steam boiler tube wall 1, i.e. the distance X between steam boiler 5 tube wall 1 and impact bar 8 can be kept short. The stroke stroke 15 is transmitted to a stroke point or stroke bar 8 on a centrally located anvil 14. The stroke stroke 15 formed by a hammer stroke at a value of about 1000 Hz is displaced by a plate or plate spring 13.

Impact pulse 15 may also possibly be caused by the social vibrations of the impact bar 8 ak-10. To prevent this, it is possible to position one or two horizontally! a reinforcement 10 in the center portion of the impact bar 8 between this and the steam boiler tube wall 1 and thereby replace the reinforcement 9 or reinforcements 9a, 9b otherwise located at this point as shown in Figure 8.

For optimum actuation of the impact stroke 15 from the stroke bar 8 to the steam wall 15 of the jet boiler tube wall 1, the reinforcements 9a, 9b of Figs. 7, 8 are welded to the strut bar 8, to the front thereof. That is, the reinforcements 9a, 9b are mainly located at the leading edge of the impact bar 8 and not at the rear edge which is closer to the boiler tube wall 1.

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Claims (13)

10 A steam boiler tube wall defining a gas passage (7) through which hot, dust or ash-laden gases flow, formed by a plurality of substantially vertically extending ribbed tubes (2) or a combination of tubes and connecting members (3, 4) the pipes carrying the working medium, and the knocking or impacting device is arranged outside the steam boiler tube wall (1) which provides the knocking or impact energy to the steam boiler tube wall (1) for cleaning dust or ash accumulated by the steam of the dust or ash on the inside of the pipe wall (6), characterized in that, in order to harmonize the knocking or impact energy on the pipe wall (1) of the steam boiler, said horizontal pipe equipped with the steam boiler wall is mentioned! with a movable impact bar (8) separated from the steam boiler tube wall (1) at a distance (X) and connected to the steam boiler tube wall (1) 15 by a plurality of vertically arranged reinforcements (9) which are arranged to reach the steam boiler tube (1) ) and the impact beam (8) in the lateral direction to elastically absorb various horizontal linear expansions of the steam boiler tube wall (1) and the impact beam (8), and which reinforcements (9) can absorb 20 lateral deflection E according to its lateral elastic configuration ) is 0.001 to 0.1 times the distance (X) between the boiler tube wall (1) and the impact beam (8). Steam boiler pipe wall according to Claim 1, characterized in that the reinforcements (9) are connected to a rib 25 (11) or a net (4) of the steam boiler pipe wall (1). C \ 1 Steam boiler pipe wall according to claim 1, characterized in that the reinforcements (9) are arranged at intervals (2 x t) of the pipe boom wall (1) of the two boiler pipe walls (1) over the length (L) of the impact beam (8). Steam boiler tube wall according to claim 1 or 2, characterized in that each of the reinforcements (9) is connected to the steam boiler tube wall (1) and the impact beam (8) by welding seams (12), g Steam boiler pipe wall according to claim 1, characterized in that each of the reinforcements (9) consists of two parts (9a, 9b) when viewed perpendicular to their vertical extension. 11 Steam boiler tube wall according to claim 1, characterized in that the impact bar (8) is formed with a rectangular or other closed hollow profile or a closed profile. Steam boiler tube wall according to claim 1, characterized in that the impact bar (8) is provided with an I or U profile or other open profile. Steam boiler tube wall according to claim 1, characterized in that the impact bar (8) is provided with one or two reinforcements (10) arranged horizontally from the central part of the impact bar (8) to the steam boiler tube tube wall (1). Steam boiler tube wall according to claim 1, 6 or 7, characterized in that the impact bar (8) has a length (L) of 0.5 to 5.0 m. Steam boiler tube wall according to Claim 1, characterized in that the distance (X) between the steam boiler tube wall (1) and the impact bar 15 (8) is between 10 and 1000 mm. Steam boiler tube wall according to claim 1, characterized in that, when a plurality of impact beams (8) are used, the vertical distance of the impact beams from each other is 2 to 5 m. Steam boiler tube wall according to claim 1, characterized in that the reinforcing bars (9) are welded to said beam at the front of the impact bar (8). Steam boiler tube wall according to claim 1, characterized in that the reinforcements (9) are arranged perpendicular to the steam boiler tube wall (1). 25 (M δ (M sj- o CO X en CL h- · Sj- Sfr o h- · o o (M 12