The present invention relates to a fastening device for a cleaning device based on the introduction of high-amplitude pressure waves through a hollow cylindrical nozzle into a boiler to be cleaned through an opening in the boiler wall, wherein the housing body of the cleaning device can be fastened to the boiler wall with the aid of a fastening flange on the boiler side, wherein advantageously the longitudinal direction of the hollow cylindrical nozzle is concentric to the opening in the boiler wall and is orthogonal to the boiler axis.
A cleaning device and a cleaning method for generating high-amplitude pressure waves, in particular for boiler cleaning, is known from WO 2019/185736. The corresponding device has a discharge opening for the directed discharge of the gas pressure generated in a combustion chamber. This outlet opening is usually a hollow cylinder which is guided through the boiler wall to be cleaned. For the purpose of cleaning, when the boiler is not in operation, the said high-amplitude pressure wave is generated in the device and introduced into the boiler volume.
When the boiler cleaning device is in operation, the explosion thrust triggers a force along the longitudinal axis of the device, which can damage this mounting of the cleaning device used to fix the device to the boiler wall.
To overcome this problem, the hollow cylinder intended for releasing the explosive gases can have a flange to which the said device is attached. The corresponding tensile and shear forces then act on this connection. In addition to the load on the hollow cylinder, which is then itself attached to the boiler wall, a further disadvantage is that this device cannot be easily adjusted to different exhaust gas volumes. The system is usually scaled by using hollow cylinders of different diameters, so that the system then has to be adapted to the correspondingly larger or smaller diameter of the hollow cylinder with corresponding additional flanges.
Most of the time, however, the boiler is in its operational function and the boiler cleaning device is in its idle function. The disadvantage of this is that aggressive gases can flow from the boiler through the hollow cylinder to the drain opening and thus to the piston valve seat. These gases can impair the tightness to such an extent that the rapid pressure build-up, which is advantageous for boiler cleaning, is impaired by a reduction in the quality of the valve seat.
Based on this prior art, it is an task of the invention to provide a device in which lower forces and torques act on the attachment of the boiler cleaning system to the boiler. It is another aim of the present invention to improve the attachment in such a way that the boiler cleaning system can be easily adapted to different requirements.
This task is solved for a fastening device for a cleaning device according to the invention in that a series of damping units are provided which are arranged at regular angular intervals around the hollow cylindrical nozzle in its longitudinal axis and are each fastened with one free end to the fastening flange on the boiler side and with the other free end to the housing body, so that when the said high-amplitude pressure wave is triggered in the cleaning device, its housing body is resiliently retained in the longitudinal direction away from the boiler and can be returned to the starting position.
At the same time, it may be advantageous that maintenance can be carried out without having to completely dismantle the system. Finally, another aim of the present application is to prevent aggressive gases from flowing from the boiler through the hollow cylinder to the drain opening and thus to the piston valve seat.
Advantageously, each damping unit can have a pneumatically or hydraulically controllable damping cylinder and a piston that can be extended from it, resulting in a retraction unit with which the cleaning device can be retracted, especially if it is suspended above on a trolley so that it can be retracted.
The damping units preferably comprise hydraulic dampers that are rotationally symmetrical around the tube of the cleaning device. The hydraulic dampers of the damping unit can also have two tension/compression springs arranged in a row in the longitudinal direction, which are inserted between the boiler-side fastening flange and a damping plate or between the centre plate and the damping plate, wherein the housing body is rigidly fastened to the centre plate with first longitudinal rods, that the damping plate is rigidly fastened to the boiler-side fastening flange with second longitudinal rods, and wherein additional hydraulic dampers are provided between the damping plate and the centre plate in the longitudinal direction around the hollow cylindrical nozzle.
Advantageously, the two tension/compression springs of each damping unit arranged in a row in the longitudinal direction can then be arranged around one of the second longitudinal rods and supported on the centre plate directly or on bushes facing the tension/compression springs on this centre plate, while the associated second longitudinal rod is guided through an opening in the centre plate. In particular, the springs are preloaded compression springs in the rest position.
In a further advantageous embodiment of the damping units, instead of tension/compression springs, these consist of toroidal or tyre-shaped elastomers arranged in a row, each of which is arranged around one of the second longitudinal rods and is supported on the centre plate directly or on bushes facing the directly adjacent elastomers on this centre plate, while the associated second longitudinal rod is passed through an opening in the centre plate. In particular, the elastomers can be copolyester elastomers. Spacers, in particular metal plates, can be provided as washers between every two elastomers and the second longitudinal rod can be surrounded by a hollow radial guide tube, against which the inner edges (=inner continuous opening of the torus directed inwards towards the longitudinal axis of symmetry) of the elastomers abut, so that these are provided with only a small amount of play around their longitudinal axis.
The mounting flange on the boiler side can be part of a one-piece or composite closure housing that has a boiler wall flange that can be fixed to the boiler at the longitudinal end opposite the mounting flange.
The closure housing can have a guide tube in which the hollow cylindrical nozzle is freely guided so that it can be retracted separately.
Cooling to protect the guide tube and the nozzle can be realised in the fastening device in that the guide tube is double-walled with an internal cavity which is provided in a helical shape from a feed point into the guide tube pointing away from the boiler to the front edge of the guide tube, in that the inner cavity can be supplied with a cooling fluid from a fluid source arranged outside the closure housing and in that the wall or front edge of the guide tube directed towards the boiler wall has openings for an outlet of the cooling fluid. The guide tube thus protects the breakthrough opening of the boiler wall in the event of a pulse event, i.e. a continuous cleaning pulse.
Advantageously, the mounting flange on the boiler side can be moved back and forth relative to the boiler wall flange in the longitudinal direction of the hollow cylindrical nozzle, whereby the guide tube can be at least partially withdrawn from the opening in the boiler wall in a rearward rest position. As a result, boiler gases can only partially attack the guide tube.
To protect the nozzle and to simplify maintenance by separating the cleaning device from the fastening device, a closure flap can be provided in the interior of the closure housing, which consists of two to four closure wings, each of which can be swivelled about a bearing axis arranged tangentially transverse to the longitudinal axis in order to be opened by swivelling against the inner walls of the closure housing when the hollow cylindrical nozzle is pushed forward through the front edge of the nozzle. These flaps are arranged in the longitudinal direction in such a way that an actively cooled guide tube is arranged in front of the flaps and in the longitudinal direction between these and the boiler wall.
The closure wings can be double-walled with an inner cavity, whereby the inner cavity can be supplied with a cooling fluid from a fluid source located outside the closure housing and the wall of the closure wing facing the boiler wall has openings for an outlet for the cooling fluid, so that the closure wing itself can also be protected from the temperature and aggressive media in a boiler.
If a swivelling axis is arranged above the housing body for the fastening device, which is aligned transversely to the longitudinal axis of the hollow cylindrical nozzle of the cleaning device, and on which the housing body is suspended via a pendulum arm, the recoil of the cleaning device can be absorbed in a simple manner, whereby the pendulum movement combines a larger return movement with only a small height deflection.
If the swivel axis is attached to a trolley that can be moved in the longitudinal direction of this hollow cylindrical nozzle on a trolley profile provided above the hollow cylindrical nozzle, the cleaning device can also be easily retracted, which is particularly feasible when using active pneumatic or hydraulic lifting cylinders in the damping units.
Further embodiments are given in the dependent claims.
The terms FIG., FIGS., Figure, and Figures are used interchangeably in the specification to refer to the corresponding figures in the drawings.
Preferred embodiments of the invention are described below with reference to the drawings, which are for explanatory purposes only and are not to be construed restrictively. The drawings show:
The three damping spring assemblies 150, 156 are arranged in the circumferential direction around the longitudinal axis of the hollow cylinder 19 at an angular distance of 120 degrees. Four or more, for example six or eight such packs can also be arranged, preferably at the same angular spacing. In addition to the damping spring packs 150, 156, hydraulic dampers 250 are provided between the centre plate 151 and the damping plate. The number of hydraulic dampers 250 can be one or two between each of the three damping spring packs 150, 156, i.e. a total of three or six. If there are four, six or eight damping spring assemblies 150, the same number of hydraulic dampers 250 can also be arranged at the same angular distance from one another, if possible. The hydraulic dampers 250 usually absorb between 50% and 90%, usually more than 75% to 90%, for example between 80% and 90% of the recoil energy. The advantage of the hydraulic dampers 250 also lies in the even distribution of the recoil forces over the stroke compared to the spiral springs of the spring assemblies 150, 156.
When the pressure wave shock of the shock wave generator 10 is directed in the longitudinal direction through the tube of the hollow cylinder 19 through the boiler wall 20 into the boiler, the hydraulic dampers 250 are lengthened or shortened by the recoil of the shock wave generator 10 due to the flow dynamics in the dampers and the damping springs 150, 156 are stretched or compressed in parallel and the shock wave generator 10 moves away from the boiler wall 20 in the longitudinal direction.
Advantageously, the weight of the shock wave generator 10 is supported by a holding lever 12 via a holding chain 11, which holding lever 12 is fastened via a horizontal swivelling axis 13 to a supporting frame 14, which is also fastened in a longitudinally displaceable manner in the longitudinal direction of the hollow cylinder 19 via a trolley 16 to a trolley profile 15. The holding chain 11 is provided with a length such that the axis of symmetry or longitudinal axis of the shock wave generator 10 corresponds to the axis of symmetry or longitudinal axis of the boiler nozzle 31 and the boiler wall flange 30, i.e. they coincide. In this way, the pressure wave is emitted around the same axis as the axis of the boiler outlet and the recoil is absorbed in an ideal manner.
The axis of the trolley profile 15 is advantageously arranged in the vertically aligned plane, which is also encompassed by the aforementioned longitudinal axis of the shock wave generator 10. This allows the shock wave generator unit with the hollow cylinder 19 to be pulled directly backwards out of the boiler nozzle 31.
Identical features are labelled with the same reference signs in all figures. The difference between the two devices shown in
The inside of the shutter housing 60 has the 120° closures 81 of the shutter 80 described below.
The essentially triangular convex mounting flange 40 on the cleaning device side accommodates the abutments of the three damping cylinders 50 at its corners. The pistons 51 protruding from the damping cylinders 50 on the opposite side are attached to the shockwave generator 10, which is shown here only schematically as a simple cylinder. In other words, the weight of the shock wave generator 10 would act on the mounting flange 40 with a corresponding moment. It is also possible that the damping cylinders 50 are supported via a support plate, not shown in
The hollow cylinder 19 is inserted in the connecting tube 43. Although it could also transmit the weight of the shock wave generator 10 with play and thereby tilting, it is preferably inserted freely in the tube 43. When an explosion is triggered by the shock wave generator 10 to clean the boiler, a shock wave travels through the hollow cylinder 19 in the longitudinal direction of the cleaning device, moving the shock wave generator 10 in a direction opposite to the boiler wall 20 via the recoil. The damping cylinders 50 have a damping effect on this movement and pull the shock wave generator back again after the first large amplitude. This can be achieved in particular by using active damping cylinders 50 as hydraulic cylinders, in which the pistons 51 can be extended and retracted in a correspondingly controlled manner.
A further advantage of the use of damping cylinders 50 over damping springs 150 will become apparent in connection with the description of
The hydraulic dampers 250 are arranged between the damping plate 152 and the centre plate 151, as they have to absorb the first recoil and the weaker springs should only return the then compressed hydraulic dampers.
From attachment points 153 on the shock wave generator 10, a series of here six first tension rods 155 are fixedly connected to the centre plate 151 at an angular distance of 60 degrees to each other, for example passed through the centre plate 151 with a reduced cross-section through a corresponding bore and fastened with a screw on an external thread located on each end of a first tension rod 155.
When the shock wave generator 10 is triggered, it moves away from the boiler wall 20 and exerts a tensile force on the centre plate 151 via the tension rods 155, which causes the right-hand damping springs 150 close to the mounting flange to stretch. At the same time, the left damping springs 156 on the damping plate side and the hydraulic dampers 250 are shortened so that a damping movement in the opposite direction results once the shock wave generator 10 has reached a maximum distance from the boiler wall 20. The damping springs 150, 156 and the hydraulic dampers 250 are designed in such a way that the oscillating movement is minimised.
The hydraulic dampers 250 are mounted on one side in the damping plate 152 and abut against the centre plate 151 by means of a piston and a spring (package 251) surrounding it.
Hydraulic dampers 250 are provided between damping plate 152 and centre plate 151 parallel to the springs 156, which reduce the peak force with the same energy absorption.
It can also be seen in
The detailed view in
In
The inner shape of the closure housing 60 extends from the shoulder on which the position axes 84 are provided for disciples and to the boiler wall flange 30 of the housing 60 so that the outward-facing sides and surfaces of the closure 81 can position themselves in this widened rear space when the shock wave races through the hollow cylinder 19, which is guided in the guide tube 31.
In this context,
The individual closing elements 81 are pressed on by the front edge of the hollow cylinder 19 until the tip of the closing elements rests on the outside of the hollow cylinder 19 and this is pushed further into the boiler wall area if necessary.
The guide tube 38 itself is double-walled and has a helical inner cavity 36. It can also be said that a helical intermediate wall is inserted between the two walls of the guide tube 38, which allows air to be blown in in the area of the mounting flange 32, via an air connection 70 not shown here, which then moves between the double walls of the guide tube 31 in the direction of the boiler, heating up, and finally flows into the boiler at the mouth of the opening in the boiler wall 20.
There is a cylindrical gap 37 between the boiler wall and the guide tube 38, which gap 37 is closed off from the shock wave generator 10 by the orifice 35. In the advanced position, the hollow cylinder 19 is always surrounded by the guide tube 38 and cooled by the air volume flow.
The guide tube 38 itself is designed with a flange 33 for this purpose, which is firmly connected to the mounting flange 32 of the housing 60′ in the receptacle provided by the mounting flange 29. One or more passages may be provided in the receiving flange 29 for the cooling fluid, which can be fed into and via the flange 33 into the guide tube 38 at this point.
In an embodiment not shown in the drawings, a telescopic extension is provided for the retraction option of the guide tube 38, whereby the retraction mechanism can be pneumatic or hydraulic. By briefly advancing the guide tube 38 to the position shown in
In a further advantageous embodiment of the damping units, these consist of toroidal or tyre-shaped elastomers 350 arranged in a row, each of which is arranged around one of the second longitudinal rods or tensioning rods 354 and is supported on the centre plate 151 directly or on bushes 352 (such as bushes 157) facing the directly adjacent elastomers 350 on this centre plate 151, while the associated second longitudinal rod 354 is passed through an opening in the centre plate 151. In particular, four such elastomers 350 are provided at an angular spacing of 90 degrees, each with two times seven elastomers 350 on the corresponding four longitudinal rods 354. Two first tension rods 155 are arranged between each of these four longitudinal rods 354 as in the other embodiments, i.e. between the centre plate 151 and the housing of the cleaning device with the damping plate 152. In particular, the elastomers 350 are copolyester elastomers. Spacers 351, in particular metal plates, can be provided between every two elastomers 350 and the second longitudinal rod 354 can be surrounded by a hollow radial guide tube 353, against which the inner edges of the elastomers 350 abut, so that the elastomers 350 have essentially no play with respect to the centre axis 355 of guide tube 353 and elastomers 350.
One advantage of using groups of elastomers 350 over hydraulic solutions is that the damping works satisfactorily in both directions. The drawing of the embodiment example shows a symmetrical arrangement of the same number of elastomers on both sides of the centre plate 151. It is also possible to use differently damping elastomers 350 based on a different material or different dimensions or to arrange a different number on both sides of the centre plate 151 in order to achieve asymmetrical damping.
Number | Date | Country | Kind |
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21215632.7 | Dec 2021 | EP | regional |
This application is the United States national phase of International Patent Application No. PCT/EP2022/086186, filed Dec. 15, 2022, and claims priority to European Patent Application No. 21215632.7 filed Dec. 17, 2021, the disclosures of which are hereby incorporated by reference in their entireties.
Filing Document | Filing Date | Country | Kind |
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PCT/EP2022/086186 | 12/15/2022 | WO |