WO2006126929A1

WO2006126929A1 - An apparatus and a method for cleaning an opening in a wall

Info

Publication number: WO2006126929A1
Application number: PCT/SE2006/000550
Authority: WO
Inventors: Mats Bertilsson
Original assignee: Teknik Support M. Bertilsson Ab
Priority date: 2005-05-24
Filing date: 2006-05-10
Publication date: 2006-11-30
Also published as: SE528651C2; SE0501170L

Abstract

A device for cleaning an opening (2) in the wall (1) of a soda recovery boiler has a carrier (5) with an elongate cleaning device (4) which is insertable in the opening. The carrier has or is connected to drive means for executing a cleaning movement. Gradually as the cleaning device (4) is consumed, a sensor registers the consumption and starts, in an advancement device (11) an advancement of the cleaning device for compensation of its consumption. A method for cleaning an opening (2) in the wall (1) of a soda recovery boiler comprises the steps that a consumption or shortening of the cleaning device (4) taking place during cleaning is sensed in order to trigger a compensatory advancement of the cleaning device (4).

Description

An apparatus and a method for cleaning an opening in a wall

TECHNICAL FIELD

The present invention relates to an apparatus for cleaning an opening in a wall, preferably in the wall of a soda recovery unit or boiler and comprising: a carrier for an elongate cleaning device which, in a cleaning movement, is insertable in the opening, and a drive means for generating the cleaning movement.

The present invention also relates to a method for cleaning of an opening in a wall, preferably in the wall of a soda recovery unit or boiler, and comprising the steps that an elongate cleaning device is held supported by a carrier, that the cleaning device is directed in towards the opening and that the cleaning device, in a cleaning movement, is moved towards and through the opening and back to a position of rest.

BACKGROUND ART

Soda recovery units or boilers of the type which are employed within the pulp industry have two purposes, namely to produce heat and to recover chemicals. The soda recovery boiler has, for this purpose, a lower combustion furnace where lye is sprayed in and residual products from the timber are combusted and the cooking chemicals are recovered. When this combustion takes place, a melt is formed of recovery chemicals in the lower region of the furnace. The melt is led via one or more outlet channels or flumes down to a melt dissolver which is placed beside the furnace. The temperature of the melt lies in the range of between 900 and 1100⁰C.

When the melt runs out through an opening in the boiler wall and down along the outlet channel, the melt often hardens and adheres in the outlet channel and in the opening of the boiler wall.

Previously, the opening of the boiler wall has been cleaned manually, as well as the outlet channel from slag and hardened chemicals. Because of the high temperature, this is an extremely risky and unpleasant job. If, for example, a plug were to occur in the opening of the boiler wall, the level of the recovery chemicals would rise in the boiler in order subsequently to pulsate out, when the plug has been removed. The risk of burn injuries is imminent.

As was mentioned above, the environment in the soda recovery boiler and also in its immediate surroundings is severe, partly because of the high temperature and partly because of the extremely corrosive effects which the recovery chemicals possess. This implies that already in manual cleaning, the spit or rod which is used for the cleaning will be burnt or corroded in that end which is used against the boiler. This implies that the spit or rod would gradually be worn out so that the person handling it must be positioned increasingly closer to the opening of the boiler. Naturally, the risks involved increase to a corresponding degree.

The use of machinery is also previously known in the art for carrying out the cleaning operation under consideration here.

Thus, Swedish Patent Application number 0300977-6 discloses a cleaning apparatus where a ram is supported by a drive mechanism for carrying out the cleaning. At the end of the ram facing towards the boiler there is a cleaning tool with a pivotal section which is intended to move along the outlet channel when the ram and the tool are retracted. The tool has a series of mechanical components and adjustment possibilities, for which reason it must be extremely sensitive to the high temperature, but above all to the corrosive environment in which it is to operate. Replacement of tools must therefore be feared at very short time intervals.

PROBLEM STRUCTURE

The present invention has for its objects to design the device intimated by way of introduction so that it wholly automatically and without risk to any operating personnel, can cater for the cleaning and, gradually as the cleaning device is worn out, advance this to a new position. The present invention also has for its object to design the device in such a manner that this will be simple and economical and extremely operationally reliable.

The present invention has for its object in respect of the method to design the method so that it is fully analogous with the device according to the invention.

SOLUTION

The objects forming the basis of the present invention will be attained in respect of the device if this is characterised by a sensor device which is disposed to directly or indirectly sense such consumption or shortening of the cleaning device as takes place during the cleaning operation and an advancement means which in response to signals from the sensor device, is disposed to advance the cleaning device in order to compensate for its consumption or shortening.

Regarding the method, the objects of the present invention will be attained if the method is characterised in that such consumption or shortening of the cleaning device as takes place during cleaning is sensed directly or indirectly and that the cleaning device, independently of the cleaning movement, in a compensation movement is advanced forwards in order to compensate for the consumption or shortening of the cleaning device.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The present invention will now be described in greater detail hereinbelow, with reference to the accompanying Drawings. In the accompanying Drawings:

Fig. 1 is a perspective view of a first embodiment of the device according to the present invention in front of a schematically represented portion of the wall of a soda recovery boiler with an opening, and an outlet channel extending therefrom obliquely downwardly and outwardly; Fig. 2 is a schematic side elevation of the device according to Fig. 1 in the same position as in Fig. 1 ;

Fig. 3 is a view corresponding to Fig. 2 of the device in a starting position before use;

Fig. 4 shows the device according to the present invention freely exposed in a view corresponding to Fig. 1 ; and

Fig. 5 is a perspective view of a modified embodiment of the device according to the present invention.

DESCRIPTION OF PREFERRED EMBODIMENT

In Fig. 1, reference numeral 1 relates to a wall to a soda recovery unit or boiler, where an outlet opening 2 is disposed in the wall, from which outlet extends an outlet or running channel or flume 3 outwards and obliquely downwards from the opening. While not being apparent from the Drawing, the lower end of the outlet channel or flume 3 discharges in a melt dissolver for recovery of cooking chemicals.

During operation of the soda recovery boiler, it often happens that the outlet opening is blocked by hardened cooking chemicals which are to be recovered, or by slag. The same relationship applies to the outlet flume 3. The environment in the area of the outlet opening 2, inside the boiler but also down along the outlet flume is extremely corrosive and moreover the cooking chemicals which are to be discharged from the boiler and recovered are at a temperature of the order of magnitude of between 900 and HOO⁰C.

In its most generic form, the present invention implies that a cleaning device 4 in the form of a spit, an elongate profile, solid or tubular, is moved along the outlet flume 3 reciprocally up in the outlet opening 2 and in therethrough to the interior of the boiler. Because of the elevated temperature of the cooking chemicals, but also because of their extremely corrosive effects, the cleaning device 4 will, in its area facing towards the wall 1, be powerfully heated and exposed to corrosion which, in a short time, consumes or shortens the cleaning device. For compensation of the consumption or shortening of the cleaning device, according to the present invention the cleaning device is advanced at the same rate as the consumption takes place.

According to the invention in its most generic form, the cleaning device 4 is connected to drive means 6 which is disposed to set the cleaning device in cleaning motion for cleaning of the outlet opening where the cleaning device is moved from the region outside the opening, through the opening proper and into the interior of the boiler, hi the cleaning movement, a movement component may also be included where the end of the cleaning device 4 facing towards the wall 1 is displaced up along the outlet channel or flume 3 and back down therealong. These movements, which may be included in a cleaning movement, correspond largely with the movements which manual cleaning of the outlet channel or flume and opening 2 would involve.

In the first embodiment, the cleaning device 4 is disposed on a carrier 5 which in turn is actuated by the drive means 6. The carrier 5 is designed so that it is, in its entirety, reciprocally movable in relation to the wall 1 according to the double-headed arrow 22, for example by being provided with wheels 7 which run in rails 8 disposed on an underlay. In this instance, the direction is such that, when the carrier is displaced along the rails, the end of the cleaning device facing towards the wall 1 will move along the outlet channel or flume 3 and up to the opening 2, through the opening and into the interior of the boiler. During this movement, the cleaning device is rigidly secured in the carrier 5.

Fig. 2 schematically shows the subject matter of the present invention in the same position as in Fig. 1, i.e. with the end of the cleaning device 4 facing towards the wall 1 in the region of the opening 2 in the wall 1. Fig. 3 shows the subject matter of the present invention in a hold position between the cleaning movements which the device according to the present invention has for its purpose to carry out. It will be apparent that the front end of the cleaning device, i.e. the end facing towards the wall 1 is located, in the vertical direction, in the area of the lower end of the outlet channel or flume 3 and at least so high that, on displacement of the cleaning device towards the wall 1, the front end of the cleaning device will impinge on the flume to be able to slide up along it.

It will apparent from Figs. 1 to 3 that the cleaning device 4 has a front effective section 9 (facing towards the wall 1) and a rear magazine section 10 (facing away from the wall). During operation of the device according to the present invention, the effective section 9 will, as was mentioned above, be consumed or shortened so that the effective section becomes steadily shorter gradually as operation continues. In order to compensate for this consumption of the effective section 9, the cleaning device 4 is moved in a direction towards the wall 1 (in Figs. 2 and 3 in a direction to the right) in relation to the carrier 5. For realising this displacement, the device according to the present invention includes an advancement means 11 which, when a cleaning movement is carried out, rigidly holds the cleaning device 4 fast, but which, between the cleaning movements, advances the cleaning device forwards in a compensatory movement according to the arrow 20 (Fig. 4), so that the length of the effective section 9 is continuously maintained approximately constant, at least until the magazine section 10 has been used.

During a cleaning movement, the cleaning device is thus fixed in the advancement device while the drive means 6 accounts for the movement. During the compensation movement, the drive means 6 is, on the other hand, passive while the advancement device 11 accounts for the movement of the cleaning device 4.

In a modified embodiment of the present invention, it is possible to combine to an integrated unit the advancement device 11 and the drive means 6. In this embodiment, the carrier 5 is preferably fixedly disposed in relation to the wall 1 and thus not drivable towards and away from the wall. In the embodiment illustrated in Figs. 1 to 4, the drive means 6 has not been described in detail. However, this may consist of a piston and cylinder assembly, both pneumatic and hydraulic. Other types of linear prime movers are, however, also conceivable, such as the combination of a screw and gear rack, crank mechanism, wire rope or chain mechanism etc.

In order to determine the consumption of the effective section 9 of the cleaning device 4, the subject matter of the present invention is provided with a sensor apparatus which activates the movements of the advancement device. In the embodiment illustrated in Figs. 1 to 3 (see Figs. 2 and 3), it is apparent that the inclination of the cleaning device 4 in relation to a horizontal plane is different in the position according to Fig. 2 and the rest position according to Fig. 3. On completion of a cleaning movement, the angle between the cleaning device 4 and the horizontal plane will increase from a small angle to a larger angle according to Fig. 2 in order subsequently once again to return to the starting angle. The angle will thus be changed with the stroke length of the drive means 6. If the effective section 9 were considerably shorter than that which is shown in Figs. 2 and 3, this angular change would be considerably greater, on condition that the effective section 9 actually does reach right up to and into the opening 2. This implies that a sensing of the above mentioned angle may be taken as a signal in order to activate an advancement movement of the advancement device 11 when a certain shortening or consumption of the cleaning device 4 has taken place.

Often, the cleaning movement of the cleaning device 4 takes place up to a stop. When the cleaning device is of sufficient length, the above described angle will first increase to a maximum level gradually as the length of the cleaning device is reduced. When the cleaning device has been consumed so much that in the stop position it is no longer sufficient to reach up into the opening 2, the angle will once again begin to reduce gradually as the cleaning device 4 is consumed (on cleaning of the channel or flume 3). These changes in angle may be taken as input signals to the regulation system which controls the advancement or compensation movements of the cleaning device. Fig. 4 shows, on a slightly larger scale, the device according to the present invention according to Figs. 1-3. It will be apparent that the carrier 5 includes a substructure 12 and a superstructure 13. In this instance, the substructure 12 is in the form of a rectangular frame which, in each corner, mounts a wheel. The wheels 7 are freely running in the illustrated embodiment but may also be driven so that the drive means of the wheels in such an embodiment would replace the above-described drive means 6.

The frame 12 or substructure supports a horizontal pivot shaft 14 which is transversely directed, preferably at right angles to the longitudinal direction of the cleaning device 4. The pivot shaft 14 supports the superstructure 13 so that this is pivotal about the pivot shaft 14. Further, the superstructure 13 is formed as a frame open in one short end and supporting, in its end facing towards the wall 1, the advancement device 11. The above mentioned pivotability of the superstructure 13 is illustrated in Fig. 2 by the double-headed arrow 15.

As is apparent from Fig. 4, the superstructure 13 has two mutually parallel arms between which the advancement device 11 is disposed. Between the arms, there are further disposed at least two transverse beams, and these are suitably provided with apertures through which the cleaning device 4 may extend. The advancement device further includes two grippers 17 and 18 which are provided for releasable retention of the cleaning device so that this may be positionally fixed in relation to the superstructure during the execution of a cleaning movement.

The one gripper 18 is disposed displaceably in the longitudinal direction of the superstructure in accordance with the double-headed arrow 20, while, on the other hand, the second gripper 17 is fixedly disposed, mounted in the superstructure 13. Between the one transverse beam 16 and the movable gripper 18 there is disposed at least one, but preferably two, prime movers for setting the first gripper 18 in advancement movements in the longitudinal direction of the superstructure 13. An advancement movement or a compensation movement is thus executed. In the starting position, both of the grippers 17 and 18 grasp about the cleaning device 4 in a positionally fixing manner. The second and fixed gripper 17 is first released, whereafter the prime mover or prime movers are activated so that the second gripper is displaced in the longitudinal direction 20 of the superstructure 13 in a direction in towards the wall 1. hi such instance, the cleaning device 4 naturally accompanies this movement. When the movement has been completed, the second gripper is activated once again while the first gripper is released and retracted to the starting position in a direction towards the transverse beam 16. Thereafter, the first gripper is also activated so that the cleaning device is reliably held positionally fixed in relation to the carrier 5.

The stroke length of the prime mover or prime movers 19 need not be particularly large, it being sufficient with a stroke length of the order of magnitude of one or a few millimetres.

As a principle alternative, the superstructure 13 is freely pivotal in relation to the substructure 12. This implies that the cleaning device 4, under the action of the forces of gravity, rests in the outlet channel or flume 3 during a cleaning cycle. According to the present invention, it is however possible to balance the superstructure 13 with the aid of suitable spring means if the action of forces of gravity were to be excessively large. It is also possible to use vertical adjustment means and positively control the angle between the superstructure and the horizontal plane during a cleaning movement.

Fig. 5 shows a modified embodiment of the present invention where the modifications substantially are restricted to modifications of the carrier 5. Those parts which are identical or closely analogous to one another in both embodiments have been given the same reference numerals.

It will be apparent from Fig. 5 that also this embodiment has a substructure 12 and a superstructure 13. The substructure 12 mounts, like the above described embodiment, a wheel 7 in each comer. Also like the above described embodiment, the superstructure 13 supports the advancement device 11 which has two grippers 17 and 18 as well as at least one prime mover 19. Correspondingly to the manner described above, the cleaning device 4 is positioned in the advancement device 11 in such a manner that it is positionally fixed during a cleaning movement. On the other hand, the advancement device 11 functions in the above described manner.

The embodiment according to Fig. 5 differs from the above described embodiments substantially in the manner in which the vertical adjustment of the front end of the cleaning device 4 is achieved. In the embodiment according to Fig. 5, there is disposed between the substructure 12 and the superstructure 13 a gantry linkage system which interconnects the superstructure 13 with the substructure 12 in such a manner that the superstructure 13 is displaced with retained horizontal position up and down in relation to the substructure 12. Also in this embodiment, the effects of force of gravity may be employed in order to cause the cleaning device to follow the outlet channel 3 during the cleaning movement. If the forces of gravity were to be excessively powerful, it is possible to balance out the superstructure 13 by spring means or by other means in relation to the substructure 12. It is also possible, via prime movers, to control the superstructure 13 in relation to the substructure 12. Such a movement in the vertical direction is synchronised during a cleaning movement with the movement 22 by the drive means 6 of the carrier 5 in a direction towards and away from the wall 1.

In the embodiments described hitherto, the cleaning device 4 has been described as an elongate rod with a solid or tubular profile. This profile may have any optional cross sectional shape and may be adapted to the configuration of the channel 3 or to the shape of the opening 2. In the design of the cleaning device 4, it is important that its transverse dimension is not allowed to be so large that it runs the risk of coming into contact and possibly damaging the boiler pipes which surround the opening 2. Suitably, the cleaning device is dimensioned in accordance with the uppermost region of the channel, which has a smaller transverse dimension than the opening 2. According to the present invention, it is also possible to adapt the form of the cleaning device 4 in response to the profile of the channel 3 or the opening 2 so that as complete a cleaning as possible is achieved.

In the production of the cleaning device 4, the only important factor is that the cleaning device 4 be produced so simply and economically that its consumption or shortening can be accepted. Further, there are also naturally demands placed on cooperation between the cleaning device and both of the grippers 17 and 18 in the advancement device 11. In the foregoing, it was disclosed that the cleaning device 4 has an effective section 9 and a magazine section 10. According to the invention, it may be possible to form the effective section 9 with a completely different cross section than the magazine section 10 proper. In one such embodiment, a more accentuated adaptation of the cross sectional configuration of the effective section to suit the channel 3 or opening 2 could be possible. Also in this embodiment, the notion is that the effective section 9 be so economical and simple in manufacture that its consumption after gradual use is wholly acceptable.

Claims

WHAT IS CLAIMED IS:

1. A device for cleaning an opening (2) in a wall, preferably the wall (1) of a soda recovery boiler, comprising: a carrier (5) for an elongate cleaning device (4) which, in a cleaning movement, is insertable in the opening (2), and drive means (6) for realising cleaning movements, characterised by a sensor device which is disposed to directly or indirectly sense such consumption or shortening of the cleaning device (4) as takes place during cleaning, and an advancement device (11) which, in response to signals from the sensor device, is disposed to advance the cleaning device (4) for compensation of its consumption or shortening.

2. The device as claimed in Claim 1, characterised in that the advancement device (11) and the drive means (6) are an integrated unit.

3. The device as claimed in Claim 2, characterised in that the sensor device is connected to a control system for the drive means (6).

4. The device as claimed in any of Claims 1 to 3, characterised in that the carrier (5) is fixedly disposed in relation to the wall (1).

5. The device as claimed in Claim 1, characterised in that the advancement device (11) is disposed on the carrier (5) and formed for positionally fixing the cleaning device (4) during a cleaning movement.

6. The device as claimed in Claim 1 or 5, characterised in that the carrier (5) is movable (22) towards and away from the wall (1) and the opening (2) for execution of a cleaning movement.

7. The device as claimed in any of Claims 1, 5 or 6, characterised in that the carrier (5) includes a substructure (12) which, under the action of the drive means (6) is movable towards and away from the wall (1), and a superstructure (13) which is pivotal in relation to the substructure about a horizontal pivot shaft (14) which is transversely directed in relation to the direction of movement of the substructure; and that the advancement device and the cleaning device (4) are disposed on the superstructure.

8. The device as claimed in Claim 7, characterised in that the sensor device is disposed to sense the inclination of the superstructure (13) in relation to a horizontal plane.

9. The device as claimed in any of Claims 1, 5 or 6, characterised in that the carrier (5) includes a substructure (12) which is movable towards and away from the wall (1), and a superstructure (13) which is raisable and lowerable in relation to the substructure and which supports the advancement device (11) and the cleaning device (4), the drive means (6) including a first drive unit for displacing the carrier (5) towards and away from the wall (1) and a second drive unit for vertical displacement of the superstructure in relation to the substructure.

10. The device as claimed in Claim 9, characterised in that the two drive units are drivable simultaneously in order to impart to the cleaning device (4) a pattern of movement which is formed of two mutually superposed part movements.

11. The device as claimed in any of Claims 1, 5 to 10, characterised in that the advancement device (11) includes a first and second gripper (17, 18) which both have, on the one hand, a gripping position in positionally fixing engagement with the cleaning device (4) and, on the other hand, a free position, the first gripper (18) being displaceable (20) in the longitudinal direction of the cleaning device (4) or parallel therewith under the action of drive means (19), while the second gripper (17) is fixed in relation to the superstructure.

12. A method of cleaning an opening (2) in a wall, preferably in the wall (1) of a soda recovery boiler, comprising the steps that an elongate cleaning device (4) is held supported by a carrier (5), that the cleaning device (4) is directed in towards the opening (2), and that the cleaning device, in a cleaning movement, is moved towards and through the opening and back to a position of rest, characterised in that such a consumption or shortening of the cleaning device (4) as takes place during cleaning is sensed directly or indirectly, and that the cleaning device (4), in a compensatory movement, is advanced for compensation of the consumption or shortening.

13. The method as claimed in Claim 12, characterised in that the compensation movement takes place between the cleaning movements.

14. The method as claimed in any of Claims 12 and 13, characterised in that the cleaning device, during a cleaning movement, is caused, on the one hand, to be displaced in its longitudinal direction and, on the other hand, to be pivoted about a horizontal shaft (14) which is transversely directed in relation to the direction of displacement.

15. The method as claimed in any of Claims 12 and 13, characterised in that the cleaning device, during a cleaning movement, is caused to move along a path of movement which is formed by the superpositioning of a vertical part movement on a horizontal part movement.

16. The method as claimed in Claim 14, characterised in that the end of the cleaning device (4) facing towards the wall (1) is caused to move up and down along an outlet channel or flume (3) associated with the opening (2) during the cleaning movement, that an angle between the longitudinal direction of the cleaning device and a horizontal plane is sensed, and that a compensation movement is triggered when the angle has reached or exceeded a predetermined level.

17. The method as claimed in Claim 15, characterised in that the two part movements are adapted in relation to one another so that the end of the cleaning device (2) facing towards the wall (1) is, during a cleaning movement, caused to move along an outlet channel or flume (3) in association with the opening (2).