EP1552233A1

EP1552233A1 - A robot for cleaning a melt stout included in a soda pan

Info

Publication number: EP1552233A1
Application number: EP03723583A
Authority: EP
Inventors: Pär SÖDERSTRÖM; Tommy Carlsson
Original assignee: SODAHUS TEKNIK IGGESUND AB; Sodahus-Teknik Iggesund AB
Current assignee: Valmet Power AB
Priority date: 2002-05-03
Filing date: 2003-05-02
Publication date: 2005-07-13
Also published as: AU2003235371A1; SE0201370D0; SE0201370L; SE522148C2; WO2003093747A1

Abstract

The invention relates to a robot for cleaning a melt spout (8), included in a soda recovery boiler, of the type that extends obliquely outwards/downwards from an opening (7) in the incinerator of the soda recovery boiler to a dissolving tank placed beside the same. The robot comprises a fixed carrier (18) to which a main arm (19) is connected via a first hinge (26), which main arm is turnable around said hinge by means of a main cylinder (20), and which in the area of a free end being connected to a rocker arm (23) via a second hinge (24), which rocker arm in turn is turnable in relation to the main arm by means of tilt cylinder (25) arranged on the main arm and, at a free end, carries a cleaning device (29), which by turning of the respective arms (19, 23) is movable between, on one hand, a parking position located outside the spout, and, on the other hand, an active state in which the same may be moved reciprocally along the bottom of the spout (8) from the lower part of the spout to the opening (7) in the incinerator.

Description

A ROBOT FOR CLEANING A MELT SΕOUT INCLUDED IN A SODA PAN

Technical Field of the Invention

This invention relates to a robot for cleaning a melt spout, included in a soda recovery boiler, of the type that extends obliquely outwards/downwards from an outlet opening in the incinerator of the soda recovery boiler to a dissolving tank placed beside the same.

Prior Art

Soda recovery boilers of the type that are used in pulp industries using sulphate processes have two main functions, viz. to produce heat and recycle cook chemicals. For this purpose, the soda recovery boiler includes a lower incin- erator into which black liquor from an evaporator is injected and incinerated. During said incineration, a melt is formed on the bottom of the incinerator, which is led down into a dissolving tank beside the incinerator via one or more melt spouts. The environment in and around the incinerator is in many respects highly demanding, above all as a consequence of the melt during the exit thereof from the incinerator having a very high temperature (900-1100°). When the melt flows out through the outlet opening of the incinerator and down along the melt spout, cinder is formed that adheres to the inside and bottom of the spout. Not infrequently, also the proper outlet opening in the wall of the incinerator is choked up by the fact that the cinder hardens to an approximately compact plug or crust. In order to keep the outlet opening free from plugs and the melt spout clean so that the melt may be led down in an appurtenant dissolving tank in a correct way, it is necessary to clean the spout, as well as the outlet opening, every now

^' and then. Hitherto, this has been effected in a manual way by means of iron bars and/or rakes. On top of the melt spout, a particular annealing hood is usually arranged, which has the purpose of protecting the surroundings from^' the heat emission from the running melt and which includes a turnable door, which is normally kept closed, but which may be opened when cleaning of the spout and the outlet opening is to be effected. The work of cleaning the spout and the outlet opening is not only physi- cally demanding but also involves health hazards and risks of accidents. The work may become particularly unsafe when the outlet opening is to be freed from an obstructing plug, inasmuch as that the melt inside of the incinerator can be built up to a higher level than the outlet opening and rush out with great force and speed when the plug has been prized loose with an iron bar. By virtue of the high temperature thereof, the out-rushing melt may seriously damage people as well as mechanical equipment.

Objects and Features of the Invention

The present invention aims at overcoming the above- mentioned problems and facilitating the work of cleaning the melt spout and keeping the outlet opening free from obstructing plugs. Therefore, a primary object of the invention is to provide a robot, which is able to carry out the requisite cleaning operations in a mechanical way and without the presence of people in the immediate vicinity of the melt spout. A particular object of the invention is to provide a cleaning robot that is able to clean both the melt spout and the appurtenant outlet opening in the incinerator wall by means of one and the same cleaning device.

According to the invention, at least the primary object is attained by means of the features that are defined in the characterizing clause of claim 1. Preferred embodiments of^' the robot according to the invention are furthermore defined in the dependent claims .

Brief Description of the Appended Drawings In the drawings :

Fig 1 is a schematic side view showing a lower part of a soda recovery boiler, a robot according to the invention being shown mounted on a melt spout that extends obliquely downwards from the incinerator of the^' soda recovery boiler to a dissolving tank placed beside the same,

Fig 2 is an enlarged side view of the robot viewed from one side of the melt spout, a door to a hood on the melt spout being shown in a closed state, Fig 3 is an analogous side view viewed from the opposite side of the melt spout, the door being shown in an opened state, Fig 4 is a partial perspective view showing a cleaning device included in the robot along with an appurtenant rocker arm, Fig 5 is a front view of the robot viewed from the right in fig 2, and Fig 6-8 are side views showing the robot in three different functional states.

Detailed Description of a Preferred Embodiment of the Invention In fig 1, numeral 1 generally designates a soda recovery boiler, built-in in a house 2, the lower part 3 of which consists of an incinerator for incineration of black liquor.

Air for the incineration is introduced into the interior of the incinerator via a plurality of holes 5 in the walls of the incinerator, the black liquor being injected by means of black liquor spray nozzle assemblies (not shown) placed on approxi- mately the level .that is outlined by 4. Adjacent to a bottom 6 in the incinerator, a wall opening 7 is formed, to which a melt spout 8 is connected, via which a melt obtained after incineration of the air may be led down into a dissolving tank 9 placed beside the^' incinerator. The melt spout 8 leans at approximately 45° to the horizontal plane and is fastened on the outside of a metal lining 10, which in a suitable way is fixed in connection with the opening 7 in the wall of the incinerator. The actual outlet opening for the melt is formed in the metal lining 10 and des- ignated 7' in fig 5. On the melt spout, an annealing hood is mounted, in its entirety designated 11, which includes two spaced-apart, parallel and vertical side walls between which a gap-like space is defined enabling access to the inside of the spout (in the form of a cross-section-wise V-shaped bottom) . On one of the side walls of the hood, a turnable door 12 is mounted. By means of an adjusting mechanism 13, e.g. a pneumatic piston-cylinder mechanism, shown in fig 3, the door 12 may be turned between an open position, shown in fig 3, and a closed position according to fig 2. The uppermost part of the annealing hood includes a roof-like, horizontal plate 14, which is fixedly united to both side walls of the hood. The proper spout 8 is manufactured from double walls that define envelope spaces through which cooling water may pass, more precisely from an inlet pipe 15 to an outlet pipe 16.

As far as the shown equipment has been described hitherto, the same is in all essentials previously known.

A robot according to the invention, in its entirety designated 17, is mounted adjacent to the described melt spout. In this robot, a carrier 18 is included, that in the example is in the form of a stand made of box profiles, which is fastened on the roof panel 14 of the annealing hood 11. Two of the box profiles included in the stand, viz . the box profiles that are designated 18', 18" (see fig 5), are spaced-apart from each other and extend horizontally and parallel to each other. Between these two box profiles 18', 18", a main arm 19 is arranged that is articulatedly connected to the box profiles via a first hinge or main hinge 26. Turning of the main arm 19 is carried out by means of a suitably pneumatically operating piston-cylinder mechanism 20, the cylinder part 20" of which is connected to the support stand via a second hinge 21, while the piston rod 20' of the mechanism is connected to the main arm 19 via a third hinge 22. In the area of the free end thereof, the main arm 19 is connected to a rocker arm 23 via a fourth hinge 24. Said arm 23 is tiltable or turnable around the hinge 24 by means of a piston-cylinder mechanism, in its entirety designated 25, which is henceforth denominated tilt cylinder. The cylinder part 25" for this tilt cylinder 25 is fixed on the outside of the main arm 19 and extends parallel to the main arm. From the cylinder part 25", a piston rod 25' protrudes. Also the tilt cylinder 25 is advantageously pneumatically driven.

As may be seen in fig 4, the main arm 19 is composed of two spaced-apart, mutually parallel components 19', 19" in the form of flat bars, box girders or the like. The rocker arm 23 is located between said two components 19', 19" and is carried by a pin that forms the hinge 24 and that extends between the components.19 ' , 19". In the shown example, the rocker arm is not articulatedly connected to the piston rod 25' of the tilt cylinder. Instead, the rocker arm, in the rear end thereof, is formed with a curve-shaped guiding member 28, against which the free end of the piston rod 25' may be pressed. In the front end thereof, the rocker arm 23 has a cleaning device 29, in the example consisting of a box profile, the lower part 30 of which is in the form of a profile piece, the cross-section shape of which corresponds to the cross-section shape of the bottom of the melt spout. More precisely, the lower profile piece 30 is cross-section-wise V-shaped in order to suit a V-shaped spout bottom. The cleaning device is connected to the rocker arm via a bolt joint 31 that fixes the cleaning device in a fixed position in relation to the rocker arm. In the shown, preferred example, the cleaning device has a comparatively large axial extension. Thus, the axial length of the cleaning device is approximately equally large as the width thereof. However, in this connection, it should be pointed out that the cleaning device may have another axial extension than in the example. It should also be mentioned that it is feasible to spare the upper part of the box profile, while leaving only the lower profile piece 30. In such cases, the cleaning device will be upwardly open.

By the fact that the cleaning device is hollow and consists of fairly thin walls, melt can pass axially through the same without hindrance when the device is applied against the spout bottom in order to scrape the same clean.

Function and Advantages of the Invention

Under normal circumstances, the door of the annealing hood 12 is closed, as is shown in fig 2, more precisely with the purpose of protecting the surroundings against the heat emission from the hot melt. In this state, the cleaning device is 29 parked in an inactive position or parking position outside of the annealing hood. The parking position is assumed as a consequence of the piston rod 25' of the tilt cylinder 25 being pushed out relatively far out from the cylinder part 25", at the same time as the piston rod 20' of the main cylinder 20 is retracted comparatively far into the cylinder part 20". In this connection, it should be pointed out that the cleaning device may be even more distanced from the annealing hood by additional retraction of the piston rod 20' and additional pushing out of the piston rod 25'.

When need arises to clean the melt spout 8 and the outlet opening 7, the door 12 is opened, more precisely by means of the cylinder 13, as is shown in fig 3. As may be seen in figs 6-8, the cleaning device 29 may after this be inserted into the annealing hood and applied against the bottom of the melt spout. By manoeuvring the main and the tilt cylinders 20, 25 in a suitable way, the cleaning device may first be pressed against the bottom of the spout in the area of the lower end thereof, as is shown in fig 7. After this, the cleaning device is brought to move upwards along the spout by simultaneous pushing out of the rod pistons 20', 25' from the appurtenant cylinder parts. When the cleaning device reaches a point along the upper part of the melt spout, the abutment of the piston rod 25' against the guiding member 28 on the rocker arm will cease. During continued pushing out of the piston rod 20' from the appurtenant cylinder part 20", the hinge 24 between the main arm 20 and the rocker arm 23 will, however, guarantee continued transfer of the cleaning device in direction upwards along the spout bottom, while adherent cinder is removed from the inside and bottom of the spout. Finally, the cleaning device reaches up to the outlet opening for the melt, oriented at an obtuse angle to the melt spout, where possible adherent cinder crusts are removed. This position constitutes an upper end position for the track of motion of the cleaning device. After this, the cleaning device may be brought to move downwards along the melt spout, more precisely by retraction ^'of the piston rod 20'. If need arises, the described motions upwards and downwards may be repeated one or more times.

After a cleaning operation having been performed in the described way, the cleaning device is brought back to the parking position according to fig 2, and then the door 12 is closed.

A primary advantage of the robot according to the invention is that the same may clean the melt spout in a mechanical way without the presence of people. Thus, the motions of the cleaning device may be pre-programmed in ■ an electronic control unit, the control unit following activation automatically controlling the different motion phases of the cleaning device by pushing out and retracting, respectively, the rod pistons of the main cylinder and tilt cylinder in a suitable way. The work of an operator may in this way be limited to a remote supervision of the robot not failing.

Feasible Modifications of the Invention

The invention is not limited solely to the embodiment described above and illustrated in the drawings. Thus, for instance, it is feasible to permanently connect the piston rod of the tilt cylinder to the rocker arm via a suitable hinge arrangement. Said hinge arrangement may be constructed with a particular spring that via the rocker arm applies a pressure force to the cleaning device that presses the cleaning device against the spout bottom during the downward motion along the spout. Furthermore, the design of the proper cleaning device may vary in multiple ways without deviating from the primary general idea of the invention.

Claims

1. Robot for cleaning a melt spout (8), included in a soda recovery boiler, of the type that extends obliquely out- wards/downwards from an outlet opening (7') in the incinerator (3) of the soda recovery boiler to a dissolving tank (9) placed beside the same, c h a r a c t e r i z e d in that the same comprises a fixedly mounted carrier (18) to which a main arm (19) is connected via a first hinge (26) , which main arm is turnable around said hinge by means of a main cylinder (20) , and which in the area of a free end is connected to a rocker arm (23) via a second hinge (24) , which rocker arm in turn is turnable in relation to the main arm by means of a tilt cylinder (25) arranged on the main arm and, at a free end, carries a cleaning device (29) , which by turning of the respective arms is movable between, on one hand, a parking position located outside the melt spout (8), and, on the other hand, an active state in which the same may be moved reciprocally along the bottom of the spout from the lower part of the spout to said outlet opening (7) in the incinerator (3).

2. Robot according to claim 1, c h a r a c t e r i z e d in that the cleaning device comprises a profile piece (30) having a cross-section shape that corresponds to the cross-section shape of the melt spout (8) and through which running melt can pass when the cleaning device moves along the melt spout.

3. Robot according to claim 2, c h a r a c t e r i z e d in that the profile piece (30) constitutes a part of a continuous hole profile (29) .

4. Robot according to any one of the preceding claims, c h a r- a c t e r i z e d in that a free end of a piston rod (25') included in the tilt cylinder (25) is arranged to interact with a curve-shaped guiding member (28) on the rocker arm without connection.