EP0341394B2 - Device for enlarging a chimney which is to be lined at the interior by milling and applications - Google Patents

Abstract

PCT No. PCT/EP89/00265 Sec. 371 Date Jan. 12, 1990 Sec. 102(e) Date Jan. 12, 1990 PCT Filed Mar. 13, 1989 PCT Pub. No. WO89/08802 PCT Pub. Date Sep. 21, 1989.An apparatus for cross-sectionally enlarging a chimney flue includes a fluid motor; a milling cutter mounted on the fluid motor and being driven thereby for removing constructional wall material from walls defining the flue; a suspension device for supporting the fluid motor and the milling cutter as a unit and for raising and lowering the fluid motor and the milling cutter in the chimney flue; a fluid pressure source; a hose connecting the fluid pressure source with the fluid motor for supplying the fluid motor with pressurized fluid from the fluid pressure source; a guiding device arranged about and travelling with the fluid motor for engaging the flue walls to guide the fluid motor in the flue; and a device for varying a radial position of the guiding device relative to the motor axis.

Description

The invention relates to a device according to the features of the preamble of claim 1. The invention further relates to applications of the device according to claims 19 to 22.

Chimney sweepers, boiler cleaners and other pipe cleaners are constantly tasked with cleaning exhaust pipes from deposits of flue gas and thereby restoring the original clear cross-section of such pipes. This is done partly manually, partly by means of motorized servo assistance. Even more stubborn deposits can be removed with relatively little effort, so that brush-like cleaning tools and relatively weak servomotors are generally sufficient. FR-A 2 074 527 shows an example of cleaning flue gas pipes of a boiler system. In this known device, a cleaning brush is inserted into the boiler pipe to be cleaned together with a pneumatic motor driven by compressed air. The use of fluid motors in the cleaning of chimney flues is also known from DE-A-2 756 561. In terms of type, the device does not act as a milling device, but rather as a radial grinding machine (cf. also DE-A1 29 53 685 working with a washing brush). A chimney cleaning device with a servo motor shows the unpublished DD-A1 262 073. Solid residues are first removed using a milling head. Then the milling head is replaced by a brush head and the inner wall surface of the chimney is further cleaned. In all these known cleaning methods, the inner wall surface of the pipe to be cleaned should be exposed as unharmed as possible.

The renovation of old building chimneys in need of renovation is much more difficult, with which the invention is concerned exclusively.

The need for renovation can have very different reasons. For example, only the original pipe carrying the flue gas can become inoperable due to sooting, cracks, becoming worn, becoming flue gas permeable, loss of thermal insulation or, according to modern assessments, thermal insulation too small, or for other reasons. The application of an inner lining layer in a first attempt at refurbishment may or may not have been suitable. Finally, chimney structures that are intact per se can be a change in the desired clear cross-section. In all these cases, a new flue gas-carrying inner pipe string must be drawn into the chimney in need of refurbishment (so-called lining), in certain cases with an additional radial distance outside this inner pipe string to be pulled in, be it because of the need to pull in a thermal insulation layer together with this, be it for Arrangement of another space, for example for ventilation purposes. Now the new flue gas-carrying inner pipe string must each have a predefined inner and thus also an order of magnitude predefined outer diameter, so that, as a rule, pulling the new inner pipe string used for refurbishment into the existing clear width of the chimney in need of renovation is out of the question. It is therefore necessary in all of these cases to remove at least the inner shell of the chimney in need of renovation prior to the installation of renovation pipe elements. In many cases of multi-layer chimney constructions, you will have to remove the entire original inner pipe carrying flue gas. In other cases, such as in the example of a refurbishment of a previous unsuccessful refurbishment attempt, it may be sufficient to remove an ejection layer or the like again, possibly with marginal zones of the original chimney construction.

Furthermore, the materials of the inner pipes of existing chimneys and also of the rehabilitation layers to be included are very different and almost always very resistant. Older chimneys made of natural or artificial stones, e.g. certain bricks, bricked up or in single-shell moldings made of concrete, in particular made of heat-insulating concrete. In newer chimney constructions, the flue gas-carrying inner pipes often consist of chamottes of different qualities up to glass, ceramic and stainless steel pipes. In the case of older chimneys, the inner pipe lining was also made from elements in the manner of ceramic tiles.

In addition, chimneys are often placed in sections on floor openings, so that, for example, actual building material in the floor area, such as concrete from floors or ceilings of rooms and reinforcing elements embedded therein, including reinforcing irons, reach into the clear cross section of the flue gas pipe and often even there Form cross-sectional constrictions. Corresponding cross-sectional constrictions are often found even when mortaring work was carried out improperly when moving the original chimney.

Finally, it has been shown that chimneys in need of renovation do not run along a straight vertical axis, but in individual cases often have very surprising drawn curvatures and curved dislocations.

It has already been considered to generate the required cross-sectional enlargement of a chimney in need of renovation by means of a drilling device (reference number 6 in DE-U1 87 01 745.8; see also reference number 12 of DE-U1 86 26 492.3). However, drilling out chimneys is only possible with certain materials in the inner layer and is also undesirable because uncontrollable pressure effects are exerted on the chimney construction. A relatively low working speed alone speaks for drilling out.

Less stress is placed on the chimney structure when grinding. However, this is time consuming. If, in addition, grinding tools with flying chains of the type of SE-C 177 343 or SE-C 177 783 are used as grinding tools, washboard-like grooves are also formed on the inner surface of the chimney. This also applies if these flying chains are arranged according to the teaching of WO 86 00 391 of WIPO in immediately axially successive planes of the turning tool; the washboard effect only becomes more compact.

Using a milling tool, on the other hand, both good protection of the existing chimney construction and a high working speed can be achieved. This is combined with a greater variety of usable tool geometries and thus better adaptability to the existing conditions on the one hand and to the work objective on the other.

In addition to the above-mentioned expansion methods of the clear width of a chimney in need of renovation by drilling, grinding or milling, it is also known to provide an impact effect of the tool. For example, US-A 4,603,747 a rotating rocking hammer. However, this is only suitable for special purposes, here for knocking off tiles serving as the inner lining of the flue gas pipe string.

Finally, it is known to additionally set a turning tool, which expands the clear cross section of a chimney in need of renovation, into axial impact vibrations via a striking mechanism. However, this also leads to undesirable vibrations of the chimney structure (AT-A 325 290).

According to the preamble of claim 1, the invention is based on AT-A 203 707, in which, in addition to the use of grinding or beating tools, milling tools have also already been considered. The grinding or milling tool in question can be moved up and down in this known device together with its drive motor in the clear cross section of the chimney. CS-B1 232 019 also shows a drive motor that can be moved in the clear cross-section of a chimney with a connected milling cutter.

The invention prefers the use of actual milling tools. To the extent that milling tools are mentioned, they can also be replaced, in particular for special applications or additional work steps, by drilling or grinding tools, which are included in the term cutting tools. In any case, the interior wall material of the chimney should be removed and not just an interior wall surface cleaned.

This previously known device differs from further-standing devices in which the drive motor is arranged outside the chimney and its torque is transmitted into the interior of the chimney via a possibly flexible shaft (cf. DE-A 1 229 230, WO 86/00391 of WIPO ).

In such devices, because of the limited length with which the torque-transmitting shaft is formed the drive can be mounted on the roof, whereby a greater range than about 10 m can only be achieved by further coupling flexible extension shafts in the event of loss of power. In this case, starting the drive motor has only proven possible if the shaft end piece is removed from the chimney with tools. The flexible shaft and the tool therefore move outdoors and pose a great danger to the operator (s). In addition, the shafts, together with their connecting couplings, wear out quickly and also tend to break suddenly. Their handling is generally problematic. Use in chimneys that do not run in a straight line is only of limited use.

However, the AT-A 203 707 and the CS-B1 232 019 (in the exemplary embodiment) each have an electric motor drive. In a preferred embodiment of the known device according to AT-A 203 707, the stator of the electric motor also serves as a guide for the motor on the inside wall of the chimney. In all of the embodiments shown, the expenditure on equipment and the associated minimum diameter of the device are so great that they do not appear to be suitable for drilling out chimneys with nominal diameters of less than 150 mm. It certainly does not seem possible to pass such a device through the clear cross-section of a chimney of this nominal diameter, which is additionally provided with internal deposits, in order to then mill from bottom to top.

In addition, electromotive drives do not appear to be suitable at all for insertion into a chimney. For example, consider the risk of explosion in soot that is separated if there is a spark, the risk of electrical short circuits on conductive areas of the inside wall of the chimney (e.g. protruding metal reinforcements or as a result Sooting due to areas that have become conductive), fire risk due to overheating due to insufficient ventilation while avoiding the additional space required by liquid cooling, risk of accidents for the operators, large working weight, infrequent availability of high-voltage electricity at the place of work and the like. In addition, milling tools driven by electric motors tend to seize in the masonry, even if, as in the case of the aforementioned AT-A 203 707, decoupling devices acting against it are provided. Sensitive, stepless control is also difficult. Finally, the entire device completely covers the cross-section of the chimney, so that it is not possible to directly observe the milling process from the upper chimney mouth. An insight from below is not an option because of the falling milling lift.

As far as can be seen - certainly for the reasons mentioned - electric motors lowered into the chimney together with the milling tool have not found their way into practice. It is not without reason that, in the case of WO 86/00391 of WIPO, the electric motor also used there is arranged outside the chimney and the effort is taken to connect this electric motor to the rotary tool, there chain grinding tool, located inside the chimney via flexible rods.

Both AT-A 203 707 and CS-B1 232 019 already have a guide device for interacting with the inner surface of the chimney for the up and / or down movement of the work unit, which has guide and support elements whose radial distances from the motor axis of the Drive motor are variable. The guide and support elements guide the work unit and with it the milling tool along the working axis in the chimney and also support the working torque of the milling tool in the chimney. In the known guide devices, the guide and support elements are arranged axially offset with respect to the drive motor, so that the overall arrangement is not very compact and the drive axis between the drive motor and milling tool of the work unit is exposed to high lateral moments, which lead to inaccurate axial working direction and damage to the drive axis can.

Starting from AT-A 203 707, the invention has for its object to provide a device for milling a chimney to be lined, which is safe, convenient and universally applicable while retaining the advantages of the known device, and a compact, optical inspection of the work site construction of the milling tool permitted from above.

This object is achieved in a device with the features of the preamble of claim 1 by its characterizing features.

The fluid motor used in the device according to the invention can be operated, for example, with oil or with compressed air. If compressed air or another pneumatic gas is used, for example an inert gas such as nitrogen, there is no danger to the chimney from the outset. Pressure oils are expediently chosen in a non-inflammable manner. If such pressure oil escapes in a sooty chimney, it could even lead to the liquid binding of the soot and thus to a reduction in the original soot fire risk. In addition, fluid lines are less likely to get caught on projections and joints on the inner surface of a chimney to be milled out than electric lines.

To ensure an optical view from above along the fluid motor to the milling tool, the guide and support elements for the fluid motor, which are designed as runners, are expediently arranged only locally around the fluid motor in the chimney. In contrast to this, the guide elements under consideration in AT-A 203 707 are each designed to be closed in a ring.

It is essential that the runners can be adjusted by changing the inside diameter of the chimney. The runners, which are slightly curved like sled runners in their central area and can be bent at their ends - also for maneuverability both upwards and downwards - ensure smooth sliding even if the inside wall of the chimney is not uniform, without the risk of getting caught too often. For adjustment, one can optionally use the pressure fluid, which is also used as the operating means of the fluid motor, but is expediently supplied via a separate control line and is controlled outside the chimney, for example at the upper end of the chimney. Appropriately, but not necessarily, the control line and the pressure fluid line are connected to form a line part, for example by tying them together by means of fastening tapes distributed over the length, in particular adhesive strips.

Of particular importance is the possibility of being able to build the fluid motor together with the guide device so that it can be inserted into the chimney itself and the guide and support elements arranged radially variably on its circumference in the case of chimneys with a very small clear width. With a relatively small axial length, both the drive unit itself and the drive shaft between the drive motor and the milling tool can transmit a very high torque, which, with a suitable choice of interchangeable milling tools, is practically possible for all existing wall materials of the chimney to be milled.

Small diameter and small axial design can be combined conveniently into an overall compact design, especially with fluid motors. This has a whole series of advantages, such as light weight and thus easy accessibility even at very large working depths, even with chimneys with a round inner cross section, sufficient visual insight into the working location of the milling tool from above, and easy maneuverability along uneven working paths.

Fluid motors also do not require cooling to prevent the motor from overheating. The internal structure is technically simple and at the same time robust. There is therefore no risk if the fluid motor strikes the inner wall surface of the chimney even at greater working depths. Even a construction that is safe against damage when falling from a great height can be easily constructed. The operating elements can be protected against the dust generated during milling with simple means, e.g. a simple housing that can be shielded, especially since the elements of a fluid motor show from the outset a narrow, elongated design affecting the chimney. An oil pressure pump which provides the operating fluid from outside the chimney, or in the case of a pneumatic pump of a compressor, can be driven at any work location simply by means of an internal combustion engine, for example a modern low-noise diesel engine, without the need for a high-voltage connection.

For such reasons, there is now a general broad acceptance in all conceivable areas of application for the device according to the invention, while all comparable devices known hitherto came into question at most under special conditions. Of particular importance are the use cases of claims 19 to 22 for which, until now, no practical solution was available. However, the device according to the invention is not limited to the applicability in these problem cases because of its universal applicability, but the same fluid motor can be used for all applications with a respectively adapted milling tool, ie even a fluid motor of very small diameter with chimneys of maximum width.

The device according to the invention can be used both for milling flue gas-carrying inner tubes with a round, clear cross section and for those with a non-round, for example approximately rectangular or square, cross section. In all cases, the end cross-section is round due to the rotating mode of operation of the milling tool, with non-circular cross-sections initially only partially hollowing out the cross-section in the smallest diameter areas.

The use of pressurized oil as the operating fluid is known to offer the advantage of being able to work with rod-like and relatively delay-free working with relatively high working pressures. According to claim 2, however, the use of compressed air or other pneumatic gases is preferred for the present application of milling a chimney to be lined. Even if a leak should ever occur in a compressed air line, the leakage flow disappears without residue as long as the pneumatic fluid is not provided with moist components, which may even be preferred according to the description below. However, any moisture it contains evaporates from a chimney.

In addition, an operation with compressed air or the like. The operating gas can be regulated very simply and continuously from the outside of the chimney by changing the pressure of the compressed air via a control valve, for example directly on the compressor, but also at the location of the worker on the chimney, e.g. on the roof. Because of the compressibility of a pneumatic pressure fluid, the milling tool also runs gently against any resistances, so that the milling tool will hardly ever seize in the chimney, depending on the mode of operation.

Also of particular importance is the still smaller-diameter construction possibility of pneumatic motors compared to hydraulic motors as fluid motors.

Basically, the exhaust air (atmospheric air or other pneumatic pressure fluid) can be led out of the chimney via a separate outlet line. Preferably, however, in the structural arrangement of the exhaust outlet according to claim 3, the exhaust air is allowed to escape directly into the flue gas duct of the chimney. This creates an air cushion with a slight overpressure in this area. It has been shown that the dust formed during the milling process, which, in contrast to larger-sized milling lift - which has the tendency to fall down under the force of gravity from the outset - has the tendency to rise upwards, has a flow direction for flowing downward receives. This has a double advantage. On the one hand, the dust formed can flow downwards in a simple manner without or only with a low suction power; the suction power of a suction device arranged at the lower end of the chimney can also be kept small. On the other hand, the possibility of a geometric optical cross-section of the view from above past the fluid motor in the direction of the working place of the tool can be made fully usable for the operator, since the space above the milling tool or the air cushion mentioned remains free from dust clouding. A pleasant side effect is that the operators are not soiled by dust.

If, according to claim 4, the exhaust air outlet is even directed downward onto the milling tool arranged below the fluid motor, it can be continuously cooled and kept free of undesired deposits. You can even do without an air dryer in the open pneumatic circuit; because it has been found that moisture in the compressed air is even favorable for binding fine dust.

It is known per se to hold and guide an electric motor, which is inserted into the chimney to be renovated with a drill head, from the upper end of the chimney via a guide rod. In the context of the invention, however, the unit of fluid motor and milling tool is preferably suspended from a pure tension element, as is known per se from AT-A 203 707. In the simplest embodiment, according to claim 6, the fluid hose itself can serve as the pulling element, which must then be suitably equipped with a load. Alternatively, the use of a separate traction element, such as a traction cable actuated by a winch, for example made of steel, is possible. The suspension chain used in AT-A 203 707 can be easily replaced by such a pulling cable because of the lower weight of the fluid motor according to the invention. Despite the relatively low weight of a fluid motor and milling tool unit, it has been shown that
When milling from top to bottom, the weight load of the milling tool by the fluid motor and the other elements of the fluid motor / milling tool unit is sufficient, even if there are materials that are very difficult to mill, such as a chamotte tube or a steel tube that has to be milled away. The decisive factor here is the right choice of milling tool. If desired, however, it is also possible to press down from the top to the bottom by means of a pressure element within the scope of the invention. For example, one could provide a pressure cylinder fed by the same compressor at the upper end of the chimney, which pressurizes the pressure element downwards. Alternatively, you can also train in a manner known per se from below (reference number 15 in AT-A 203 707).

Preferably, the distance of the runners from the axis of the fluid motor is adjustable. A radial movement control for this provides claim 8.

Fluid motors, in particular pneumatic motors, can in principle achieve very high speeds, even in transition areas from milling to grinding (20,000 rpm and more). Without gear reduction, however, only relatively crumbly materials can be milled off.

For more difficult materials, however, it is advisable to intensify the action of the milling tool on the masonry to be milled out, be it through a reduction gear (claims 9 to 11) or be it through switchable impact action in the angular direction (claims 13 to 16). A high speed of the rotor of the fluid motor is converted into a high torque on the milling tool by means of the reduction gear. In both cases, the reduction gear or the striking mechanism can be provided as a short axial extension piece without additional external diameter expansion, if necessary as a removable insert. Reduction gears can in particular be formed in several stages in succession in the axial direction, with planetary gears individually and in series connection have proven to be particularly suitable.

The design of the fluid motor provided in the device according to the invention, in particular as a pneumatic motor, is suitable not only to be carried along with the milling tool in an already milled-out area of the chimney, as is usually the case with milling from top to bottom, but instead also to be guided downwards together with the milling tool through an area of the chimney that is still to be milled, in order to then carry out the milling upwards. It is known per se to connect milling tools of devices for milling a chimney to be lined with a drive motor arranged above the milling tool via a flexible shaft and to close the chimney cross-section with the milling tool moving up and down expand (preamble of claim 1 of DE-A 12 29 230). Such a milling process can be carried out in one step from bottom to top (see, for example, WO 86/00391 of WIPO) or in several steps with milling in layers, optionally with finishing finishing. The device according to the invention is suitable for all possible working methods upwards and downwards as well as in one stage and in multiple stages.

All milling tools in question can be designed so that the same milling tool can easily be converted from one orientation for milling from top to bottom into a milling from bottom to top, or vice versa, by repositioning.

However, a reversible milling tool requires retrofitting after every working stroke. Particularly for a machining expansion in several stages under chip removal both in the downward stroke and in the upward stroke of the milling tool, however, analogous to the double-acting design of the guide elements according to claim 12, a double-acting design of the milling tool is recommended, so that it is designed to cut both upwards and downwards.

With regard to the workflow, the cheapest is a double-acting geometry of the milling tool. This can e.g. be easily realized with known chains on the milling tool. If the working edge of the milling tool lies on a knitting cone, this is expediently arranged in tandem in such a way that the large areas of the knitting cone face each other.

For some applications, however, milling tools are preferred in which such an arrangement is not possible. Training is then recommended in which the effectiveness of the working direction of the milling tool in question can be changed in one direction at the end of the working stroke without having to disassemble and reassemble the milling tool. Such a changeover can again be carried out, for example, by means of the operating fluid, in particular pneumatically, by having a separate changeover line to the operator's workplace leads outside the chimney. This reversing line can also be combined with the fluid hose to form a unit.

For similar considerations, it is also generally recommended (cf. claim 12) forcing the fluid motor to be double-acting, i.e. leading upwards as well as downwards to train what has already been discussed as a possibility in connection with the skid guidance according to claims 7 and 8.

The milling tools with hammer mechanism according to claims 13 to 16 have already been mentioned above in connection with an increase in the milling effect. In addition, they offer the advantage of being able to keep the torque support (the support function of the guide and support elements) to a minimum, since the milling element bounces back like a hammer on an anvil at its place of work and a compensation of the counter-torque occurs.

Additionally or alternatively, the measure according to claim 17 can also be provided to compensate for a counter torque.

Claim 18 specifies a measure for quickly changing various milling tools in order not to impair the very high working speed possible within the scope of the invention due to set-up dead times.

It should also be added to the application claims 19 to 22 that single-family houses have chimney heights from the basement floor to the upper chimney mouth, as a rule, at most in the range of 8 to 12 m height. Three-story apartment buildings start at a height of 16 to 17 m from the basement level. Eight-story apartment buildings, for example, have a corresponding height of around 48 to 50 m. All such heights from three-storey dwellings upwards can be easily milled with the device according to the invention in one go with the torque remaining the same, with basically no height restriction due to the very low weight and great flexibility. Should you ever want to work from the side of a chimney, this is also easily possible because of the simple construction of the device according to the invention. In particular, there is practically no limitation with regard to the length of the pressure fluid hose, so that it is also possible to mill far from the location of a pressure oil pump or a compressor. As a rule, the latter can always be set up next to the building whose chimney is to be renovated.

• Fig. 1 eine perspektivische Gesamtdarstellung als Übersichtsdarstellung;
• Fig 2 einen Demonstrationslängsschnitt mit einem aufwärts fräsenden Lamellen-Fräswerkzeug;
• Fig. 3 einen entsprechenden Demonstrationsquerschnitt mit einem aufwärts fräsenden Frässtift-Fräswerkzeug;
• Fig. 4 denselben Demonstrationslängsschnitt mit abwärts arbeitendem Frässtift-Fräswerkzeug;
• Fig. 5 einen axialen Längsschnitt durch einen Pneumatikmotor als Fluidmotor mit einstufigem Planetengetriebe;
• Fig. 6 eine Expositionszeichnung eines alternativ hierzu einsetzbaren zweistufigen Planetengetriebe;
• Fig. 7 in teilweise axial geschnittener Darstellung eine alternative Ausführungsform eines Pneumatikmotors mit Schlagwerk;
• Fig. 8 eine Draufsicht auf die Längsseite eines mit Kufen zwangsgeführten Pneumatikmotors in der Bauart gemäß Fig. 5;
• Fig. 9 eine entsprechende Draufsicht auf die Längsseite des Pneumatikmotors gemäß Fig. 5 mit andersartiger Zwangsführung;
• Fig. 10a bis 10d kranzbildende Elemente für die Zwangsführung gemäß Fig. 9;
• Fig. 11 eine entsprechende Draufsicht auf die Längsseite des Pneumatikmotors mit Zwangsführung gemaß Fig. 9 in doppeltwirkender Anordnung;
• Fig. 12 im axialen Längsschnitt eine bevorzugte Weiterbildung des in Fig. 1 angewendeten Fräswerkzeugs;
• Fig. 13 eine perspektivische Darstellung des in Fig. 2 verwendeten Fräswerkzeugs;
• Fig. 14 eine perspektivische Darstellung des in den Fig. 3 und 4 verwendeten Fräswerkzeugs;
• Fig. 15 eine Expositionszeichnung eines Ausgleichschlagwerks, das vorzugsweise zwischen dem Fluidmotor und seiner Aufhängung, gegebenenfalls aber auch im Bereich von dessen Abtriebswelle angeordnet werden kann, und
• Fig. 16 einen axialen Längsschnitt dieses Schlagwerks.

The invention is explained in more detail below with the aid of schematic drawings using several exemplary embodiments. Insofar as guide and support elements other than runners are described and illustrated in the exemplary embodiments, these exemplary embodiments serve only to explain the other features, the described guide and support elements having only illustrative meaning. Show it:

• Figure 1 is an overall perspective view as an overview.
• 2 shows a demonstration longitudinal section with an upward milling lamella milling tool;
• 3 shows a corresponding demonstration cross section with an upward milling burr milling tool;
• 4 shows the same demonstration longitudinal section with the milling cutter milling tool working downwards;
• 5 shows an axial longitudinal section through a pneumatic motor as a fluid motor with a single-stage planetary gear;
• 6 shows an exposure drawing of a two-stage planetary gear which can be used as an alternative;
• FIG. 7 shows an alternative embodiment of a pneumatic motor with striking mechanism in a partially axial section; FIG.
• FIG. 8 shows a plan view of the longitudinal side of a pneumatic motor of the type shown in FIG. 5 which is positively guided with runners; FIG.
• 9 shows a corresponding top view of the longitudinal side of the pneumatic motor according to FIG. 5 with a different type of positive guidance;
• 10a to 10d ring-forming elements for the positive guidance according to FIG. 9;
• 11 shows a corresponding top view of the longitudinal side of the pneumatic motor with positive guidance according to FIG. 9 in a double-acting arrangement;
• FIG. 12 shows a preferred development of the milling tool used in FIG. 1 in axial longitudinal section;
• FIG. 13 is a perspective view of the milling tool used in FIG. 2;
• 14 shows a perspective illustration of the milling tool used in FIGS. 3 and 4;
• 15 shows an exposure drawing of a compensating impact mechanism, which can preferably be arranged between the fluid motor and its suspension, but possibly also in the region of its output shaft, and
• Fig. 16 is an axial longitudinal section of this striking mechanism.

Fig. 1 shows a schematic representation of a "cut" house with a chimney also shown in section.

A compressor 10 parked on the floor is connected to a fluid motor 12 which is drained off in the chimney and is designed as a pneumatic motor via a fluid hose 14 which supplies compressed air. The fluid motor carries a milling tool 16, which is here formed by chains, e.g. but can also be formed by a suitably designed milling crown.

When the fluid motor 12 is pressurized with the compressed air, the milling tool 16 is set in rotation and thereby mills the chimney to the desired diameter, also with removal of sooting in the inner shell of the chimney and with the removal of protruding wall parts. In this example, the chimney is continuously milled from bottom to top by slowly pulling up the fluid motor 12 together with the milling tool 16. Working from top to bottom is also possible, e.g. with the milling crown mentioned.

At the lower end of the chimney, a suction device is introduced, through which the dust that is formed is suctioned off.

By means of exhaust air from the fluid motor fed by the compressor, an excess pressure is generated in the chimney, which enables the dust formed to flow off easily, so that little or no suction power is required.

In hydraulic operation with oil, a pressure oil pump 10 can replace the compressor 10 and the pneumatic motor and a hydraulic motor as the fluid motor 12.

The device according to the invention is explained in more detail below.

A chimney 4, here as a house chimney, is erected on a chimney foundation 2 and has an outer chimney construction 6 running all around and an inner shell surrounded by it, which is provided as an inner pipe string 8 carrying flue gas.

Without restricting the generality, the load-bearing chimney structure 6 is shown here as masonry made of artificial or natural stones and the inner pipe string 8 as a continuous layer, for example made of centrifugal cement. Any other single or multi-layer chimney construction with or without additional intermediate shells, such as thermal insulation layers or vapor diffusion insulation layers, is alternatively possible. In particular, the inner pipe string can also consist of fireclay or steel pipes and can also consist in the usual way of axially adjoining and mostly sealed by grout or other sealing strands.

In the area of the lower end of the chimney 4 above the chimney foundation 2 there is an opening with a chimney slide 18 through which soot is usually removed. The chimney 4 ends at the top in a frontal plateau 20, on which a chimney head (not shown), in the case of more modern chimneys, possibly via an end plate (not shown), can be placed on the building. The chimney 4 is expediently milled out with the chimney head removed and, if appropriate, also with the end plate removed. On the plateau 20, a support frame or support frame 22 is mounted so that it is immovable laterally, for example by Clinging on the upper outer chimney edge. Aligned to the axis of the chimney 4, optionally laterally adjustable in the two horizontal degrees of freedom, the supporting frame 22 carries a roller 24, via which the fluid hose 14 in the arrangement according to FIG. 1 and a pull rope in the arrangement according to FIGS. 2 to 4 26 is performed. The fluid motor 12 is suspended here on this traction cable 26, for which purpose the fluid hose 14 itself is used according to FIG. 1. If this fluid hose 14 itself is to take over the traction function, it must be designed to be suitably tensile, for example by a tensile hose reinforcement or hose casing.

The pulling cable 26, for example a steel cable, is actuated by a cable winch 28, in the place of which, in the case of the suspension of the fluid motor on the fluid hose 14 according to FIG. 1, an embodiment of the roller 24 can take place as a hose winding roller which can also be actuated in the region of the supporting frame 22. The cable winch 28 or a hose unwinding roller are rigidly attached to the support structure with their shaft during operation, so that the winding forces are absorbed via the support structure at the upper end of the chimney 4. The cable winch 28 is expediently adjustable in height.

The fluid hose 14 is here guided separately from the pull cable 26 from the upper end of the chimney 4 and connected to a compressor (cf. compressor 10 in FIG. 1) outside the chimney, which is driven by an internal combustion engine, expediently a diesel engine. Both the compressor and the internal combustion engine are mounted on a chassis 30 with a parking brake 32 and surrounded by a sound-absorbing hood 34. The chassis 30 can on any flat base 36, next to the building in which the chimney 4 is built, set up and braked against this base.

A pre-separator 42 for coarse milling removal and a main separator 44 for milling dust communicating with it in the suction direction behind it, which is also driven by a motor, is also arranged on the same base area 36 on chassis 38 and 40. For this purpose, about two electric motors 46 or, alternatively, compressed air motors can be provided, which can then be appropriately fed by the compressor arranged under the hood 34. The two electric motors 46 enable the available drive power to be multiplied correspondingly when supplied by local mains voltage and can thus save a high-voltage connection. If necessary, more than two such motors 46 can also be provided.

The main separator is designed, for example, as an industrial vacuum cleaner and is connected via the suction lines shown through the opening of the chimney slide 18 to the floor space of the chimney 4 above the chimney foundation 2.

The milling tool 16 shown in FIG. 2 is described in more detail below with reference to FIG. 14. The milling tool 16 used in FIGS. 3 and 4 is described in more detail below with reference to FIG. 15.

2 to 4, the fluid motor 12 also carries a guide 48, as is described in more detail with reference to FIGS. 9 and 10a to 10d.

The fluid motor 12 itself has the type described below with reference to FIG. 5, possibly with FIG. 6, which requires guidance. When using a fluid motor that does not require external positive guidance, for example the fluid motor according to FIG. 7, the guide 48 is omitted with the basic construction according to FIGS. 2 to 4 remaining the same.

2 and 3, the flue gas-carrying inner pipe string 8 is milled in one go from bottom to top, in the arrangement according to FIG. 4 also in one go from top to bottom. Alternatively, the inner layer 8 interpreted here as inner pipe string 8 could also only be used include an inner zone detected during the milling process, with radially successive zones being able to be removed downwards, upwards, downwards, etc., one after the other, in alternating milling operations. Post-processing steps, such as finishing operations, can also be carried out by changing the milling tool 16 by means of the same fluid motor 12.

Since the fluid motor 12 in the embodiments of FIGS. 1 to 4 is each arranged above the milling tool 16, it is inevitable that the guide 48 according to FIGS. 2 and 3 with the inner pipe string not yet milled out or the flue gas leading inner pipe string with a single Work, in the case of milling from the top down, on the other hand, is guided according to FIG.

With a suitable connection of the fluid hose 14, the milling tool 16 can optionally also be arranged at the top and the fluid motor 12 at the bottom in a manner not shown; however, this presents the difficulty of having to direct the fluid motor through the body of the milling tool when it is supplied from above or, alternatively, of supplying the fluid hose 14 from the start through the opening of the chimney slide 18, or another opening.

The pneumatic motor 12 shown in FIG. 5 has a cylinder 50, along the axis of which the rotor 52 of the pneumatic motor 12 extends. The cylinder 50 is delimited on the outside and inside by a cylinder surface, but the inner cylinder surface is arranged eccentrically to the outer cylinder surface. As a result, the cylinder 50 has a correspondingly changing wall thickness. The rotor 52 has a cylindrical outer surface which, with the eccentric inner surface of the cylinder 50, delimits a compression space 54 (shown in cross-hatching). The rotor 52 is in turn attached to a rotor shaft 56.

Slits 58 extending tangentially to the rotor shaft 56 are distributed over the circumference of the rotor 52, which is formed from a solid cylinder shell, and extend over the entire axial length of the rotor 52 and end at a radial distance from the rotor shaft 56. In practical embodiments, between four and six such slots are provided, for example. Rotor blades are loosely inserted in the slots. While the fluid motor 12 can otherwise be made of steel, the rotor blades 60 can be made of a suitable plastic, for example of phenoplasts or melanin resins, such as are sold under the protected trade name "Pertinax", for example. The rotor lamellae 60 are rectilinear on their longitudinal edge interacting with the cylindrical inner surface of the cylinder 50 and complementary to a corresponding one on their longitudinal edge engaging in the slots Basic design of the slots is flattened to be axially guided in the slots in their radially lowest engagement position. When the rotor shaft rotates under the centrifugal force, the rotor lamellas are pressed outwards into contact with the inner wall surface of the cylinder 50. They divide the compression space 54 into traveling chambers distributed over the circumference of the rotor shaft, short-circuit air between the chambers being largely avoided by sufficiently close contact of the slots on the rotor lamellae.

In the thick wall area of the cylinder 50, two continuous axially parallel bores 62 run alongside one another in the circumferential direction, via which the compressed air supplied by the compressor 10 via a compressed air hose 14 is fed to the compression space 54 via four slots 64. The slots 64 extend in the circumferential direction of the cylinder 50 and are arranged in pairs in the vicinity of the two ends of the cylinder.

Radially through outlet holes 66 are distributed in the sickle of the tapering wall thickness of the cylinder, which decreases in the running direction of the rotor 52, and several, for example five, of these holes are expediently arranged in several, for example two, rows across the axial area between the slots 64 Distributed circumference of the cylinder 50. The cylinder 50 is sealed off at both ends by a cover 68. Each cover 68 carries on its side facing away from the compression space 54 a ball bearing 71 for the rotor shaft 56, which extends through axial openings in both covers 68 and is secured against axial displacement.

On the side facing the milling tool 16, the rotor shaft 56 is extended beyond the ball bearing 71 as an input shaft of a single-stage reduction gear, here a planetary gear. In this respect, the planetary gear corresponds to the lower half of the exposure drawing according to FIG. 6, in the upper half of which further elements for the two-stage design of the reduction gear are shown, here an axially connected two-stage planetary gear.

Accordingly, a pinion 70 is seated on the driven end of the rotor shaft outside the cylinder 50. This pinion engages in an internal toothing of a planet gear cage 72. The planet gears 74 supported in this mesh with a sun gear ring 76. This is rigid on the inside of a pot-shaped extension 78 of an output shaft 80 , on which the shaft of the milling tool 16 is coupled in a rotationally fixed manner.

In the variant shown in FIG. 6, a second planetary gear stage is arranged axially between the output shaft 80 and the described first stage of the planetary gear, the elements of which in FIG. 6 are identified with the addition a while the functional parts are otherwise the same.

The only difference is that the first stage of the planetary gear is not connected directly to the output shaft 80, but that with an otherwise identical design as the end of the output shaft facing the pneumatic motor, an axially aligned intermediate shaft 82 is used, on which a pinion 70a sits, which corresponds to the pinion 70 in the force introduction function at the input of the first gear stage.

The entire unit, which is described by the cylinder 50 together with covers 68, the rotor shaft 56 mounted therein and the planetary gear (85) (designated as a whole) (85), is surrounded by a two-part solid armored housing 84 on its side facing the suspension and all around , wherein a solid lower end plate 86, which carries a first ball bearing 88 for the output shaft 80 on the inside and is connected tightly to the armor housing 84, closes the housing on the side facing the milling tool 16.

The output shaft 80 is also supported by a second ball bearing 90, which is fastened to the inside of a first part 92 of the tank housing. This first part 92 is arranged in the form of a hood and, starting from the end plate 86, comprises all the above-mentioned parts of the output housing (s) and pneumatic motor, the hood base 94 being opposite the free end 96 of the rotor shaft 56 opposite the output shaft 80.

The cylinder 50 is provided with a slightly protruding ring flange at each of its two ends, and these ring flanges are tightly fitted into the housing of the first part 92 of the armored housing 84. This creates a certain annular gap between the outer surface of the cylinder 50, the two ring flanges and the inner surface of said first part 92, through which the exhaust air from the compression space 54 emerging from the outlet holes 66 can be freely distributed. This exhaust air can escape radially further outwards through a ring of outlet holes distributed over the wall of the first part 92 in the circumferential direction.

The compressed air is fed to the pneumatic motor through an inlet nozzle 100 projecting axially upwards, which is integrally formed in the hood bottom 94. From there, the compressed air reaches the bores 62 via the free space 102 formed below the hood base 94 within the first part 92 and from there finally into the compression space 54 in the manner described.

On the first part 92 of the armor housing 84, the second part 104 is screwed around the outside on the side of the suspension of the fluid motor. As will be described later with reference to FIG. 9, the entire unit of fluid motor 12 and milling tool 16 is suspended from this second part 104.

The second part 104 surrounds the first part 92 of the armor housing 84 to below the exit holes 98 and is screwed into a recess on the first part such that both parts 92 and 104 of the armor housing 84 have a common, small-diameter cylindrical outer surface.

In addition, an annular gap 106 is formed in the overlapping area between the two parts 92 and 104 of the armor housing 84, which lies opposite the exit holes 98 and is sealed in the area of the joint located underneath between the two parts of the armor housing.

The annular space 106 is extended radially inward in relation to the outer end face of the hood base 94 by an annular gap 108 between the outer end face of the hood base 94 and a massive continuation part 110 of the second part 104 which leads axially upward.

In the continuation part, a radial bore 112 is first formed, which extends outside the tank housing with an inlet connection piece extending axially next to it leads to the connection with the compressed air hose 14. This connection bore 112 is sealed off from the outer end of the inlet connector 100 on the hood base 94.

Bypassing the connection bore 112, the annular gap 108 communicates with axially and radially extending bores 105 and 107 in the continuation part 110 of the second part 104 of the armored housing 84, in order to finally exhaust the air from the pneumatic motor through an exhaust shaft 114 attached to the side of the armored housing, and during milling to escape into the interior of the chimney. The exit direction of this exhaust shaft is chosen axially parallel to the milling tool 16. The exhaust air escaping only over a portion of the circumference of the armor housing is distributed as a jacket flow in such a way that not only blowing on the milling tool is possible, but also a barrier against the rising of milling dust over the entire circumference of the armor housing.

With the exception of the reduction gear 85 (possibly including 85a), the pneumatic motor according to FIG. 7 can basically be constructed in the same way, without prejudice to the graphic deviations in FIG. 7. The torque transmission from the pneumatic motor to the milling tool takes place here in the absence of a reduction gear in the ratio 1: 1, i.e. directly.

Instead, the free end of the rotor shaft 56 protruding from the cylinder 50 on the milling tool 16 side is connected to an output shaft 115, which corresponds to the output shaft 80 according to FIG. 5, via a striking mechanism 117. This converts the continuous rotary movement of the rotor shaft 56 into a rotary impact movement with impact action in the angular direction due to one per revolution of the Rotor shaft effective interaction of a so-called hammer and a so-called anvil of the striking tool. An axial oscillation of the milling tool 116 can be dispensed with entirely if an axial component could also be included if necessary.

Various structural designs of such a striking mechanism are known, so that a description in detail is unnecessary. A possible and also preferred construction method is explained in more detail below in another application context with reference to FIG. 16. 16 can in particular be interposed between the fluid motor 12 on the one hand and its suspension on the other hand.

An essential feature of switching on such a striking mechanism is to compensate for a counter torque occurring when the milling tool 16 is working - an elastic hammer blow between the hammer and anvil of the striking mechanism per revolution - by the impact of the impact in the striking mechanism.

This not only eliminates the reduction gear 85 or 85a, which extends the axial length, but also considerably increases the action of the milling tool on the material to be removed, comparable to the way a hammer drill works.

Another special feature of the pneumatic motor according to FIG. 7 is that the output shaft 115 is hollow, with a polygonal inner cross section, in particular as a hexagon. This allows marketable Milling tools, which are generally provided with a hexagon connection, can be simply plugged in while transferring very high torques. A corresponding plug-in piece 118 of a milling tool 16 is shown in FIG. 7.

In addition, the bore of the hollow output shaft 115 can also be used as a supply channel for control fluid, in particular compressed air, for the milling tool. For this purpose, a control line connection 120 is led out at the milling-side end of the hollow shaft, for example in order to reverse a milling tool which can be reversed for working directions upwards and downwards when the working direction changes.

8 and 9 to 11 show two possible preferred construction types of positive guides which can be used in the construction of a pneumatic motor according to FIG. 6 which requires torque support. Both types are characterized by a relatively little covered viewing gap between the tank housing 84 and the inner surface of the chimney 4.

In general, these figures also show a connection coupling 124, here a so-called socket, for connecting the output shaft 80 according to FIG. 5 to the milling tool 16. Furthermore, an eyelet 122 is provided at the upper end on the second part 104 of the tank housing, on which the Pull rope 26 can be latched.

If the suspension is via the fluid hose 14 according to FIG. 1, one would have to axially arrange the connecting piece 126, which is arranged here laterally on the tank housing and communicates with the connecting bore 112, on the fluid motor analogously to the eyelet 122 in a manner not shown and train to transmit force, ie with connecting means to the reinforcement or tensile casing of the fluid hose 14.

In the case of both types of guidance in FIGS. 4 to 11, a retaining washer 128 is arranged with sufficient axial spacing for guidance in the area of both ends of the armor housing 84 (see in particular also FIGS. 10a and 10b, in which the retaining washer 128 in plan view and in Side view is shown). The retaining washer is clamped along the action line 130 shown in dashed lines in FIG. 10a by means of tensioning screws 132 on the outer circumference of the armored housing 84.

The dashed double line 134 in FIG. 10 a describes in the large square cross section of the holding disks 128 in the area of the center of the boundary lines of the square a pivot axis 134 for swivel arms 136. These are straight levers, one end of which in the area of the axis 134 on a pivot pin 138 on the armored housing 84 is articulated and the other end is articulated to a cheek 140 on the radially inner side of a runner 142. Accordingly, four runners 142 are distributed over the circumference of the pneumatic motor. These have an elongated, at least approximately rectilinear central section 144 and, at the top and bottom, ends 146 which are each curved inwards or at an angle.

In this embodiment, the outer surface of the armor housing 84, the runners and the two swivel arms articulating the respective runners above and below form a parallel guide linkage.

All four parallel guide rods are radial in their axially displaceable actuating plate 147 Width adjusted together. For this purpose, the circumference of the actuating plate in the region of a linkage 148 is connected to a linkage 152 in the central region of the respective upper swivel arm 136 via a pull lever 150 which extends along the outside of the tank housing.

The actuating plate 147 is axially displaceably guided on two diagonally opposite guide rods 154. The guide rods in turn are screwed with their lower ends into the upper holding disk 128 and connected at their upper ends by a transverse yoke 156 to which the eyelet 122 is welded.

Without an applied displacement force, the actuating plate 147 lies in its lowest position due to the weight of the rods with runners articulated on it. A pneumatically actuated servo cylinder 158 is used to lift the actuating plate 147, which is fastened to the end face of the armor housing 84 and can be loosely supported with its stamp 160 at the axial center of the actuating plate. However, for positive control of the actuating plate 147 in both axial directions, a fastening 162 at the point of attack on the actuating plate 147 is preferred.

In the embodiments according to FIGS. 9 and 11, the holding disk 128 is bevelled at the corners of its large square floor plan, and in each of the corners a radially extending incision 163 is provided, which in the area of the line of action 130 for tightening on the circumference of the Armor housing is formed as a continuous slot as in the above-described embodiment.

Within the cuts 163 is one end of a straight lever 164 along the three-dashed line Axle 166 articulated. The shape of the lever 164 can be seen from the top view according to FIG. 10c or the side view according to FIG. 10d. The axis of action 166 corresponds to the pivot pin 168 according to FIG. 10d.

The free end of the lever is formed with a one-sided projection as fork 169, a shaft 172 being arranged on the two arms 170 of fork 169, on each of which a cutting wheel 174, or alternatively a roller or roller, is rotatably mounted.

An elastic, flexible buffer element in the form of a circumferential cellular rubber ring 176 is secured against the axial displacement, under which the central area of the respective lever lies loosely to limit its downward pivoting position. If necessary, the axial position of this buffer element 176 can also be adjusted. With the appropriate setting, it is also possible to choose the same or desired different radial exposure (for example in adaptation to the conical shape of the chimney) with different lengths of the levers 164. In this sense, the upper levers 164 are drawn with a shorter length than the lower levers 164. The somewhat further radial projection of the lower levers 164, which can also be seen in FIG. 9, is not intended here to correspond to an adaptation to a conical course of the chimney with a narrow cross section at the top and wide at the bottom, but to compensate for different loads on the upper and lower levers, since the lower levers are heavier due to the closer milling tool. You can get by with the same material of the buffer elements 176. As can be seen, for the same reason, the lower buffer elements 176 in FIG. 9 have a further radial projection outsourced as the top.

In addition, a notch 178 can be seen in FIG. 9 on the outer circumference of the armored cylinder. This notch 178 is opposite a corresponding parallel notch on the covered other side. As a result, the two parts 92 and 104 of the armor housing 84 can be screwed on with a tool by applying a sufficient torque.

Because of the different construction of this guide, the guide rods 154 of the embodiment according to FIG. 8 are replaced here by a connecting pin 180 which is fixed at the top by the eyelet 122 and is rigidly connected to the end face of the armored housing 84 at the bottom.

Recognizable is the connecting pin 180, a solid cylinder, with a smaller diameter than the armored housing 84. This has the advantage of being able to arrange the upper levers 164 with a particularly small radial projection. Because of the greater load on the lower levers, the problem does not arise to such an extent. All in all, this has the possibility of adapting to particularly small clear chimney widths.

In the embodiment according to FIG. 9, however, the guidance is only one-sided, namely in the upward direction. Fig. 11 shows a simple modification with which the same structure of the guide can be designed double-acting, with a constant geometry without the need for conversion work. For this purpose, the levers, which are arranged in the form of a ring at the top and bottom, are connected to one another by tension elements 182 which extend along the armor housing 84 and which are expediently tension springs. At this Configuration even the lower buffer element 176 is entirely unnecessary. However, it can be provided if the pulling elements 182 are provided releasably.

While in the two guides described four guide elements are distributed equidistantly around the armor housing in the circumferential direction, a different number of these guide elements can optionally also be provided, advantageously at least three of them.

12, 13 and 14 also show three particularly preferred types of milling tools which can be used in the device according to the invention.

In all three cases, the milling tool has a central support body 192 around which milling-effective elements held by the support body extend. The upper end of the support body is shown here as a square, with hexagons instead being provided in the case of a design which complies with the standards. These are rigidly attached to the output shaft of the respective fluid motor 12 in axial alignment with its effective axis via fastening pins 194 which engage in corresponding fastening bores in the support body 192. In the borderline case but you can also provide fastening couplings with slight lateral bendability, but which should absorb the torque acting in the angular direction.

In the case of the embodiment according to FIG. 12, the support body 192 extends with a constant cross section over the entire axial height of the milling element. The lower end is formed as a support 196 which is fastened axially immovably to the support body 192 via a fastening pin 194.

Above the support, a series of spacer sleeves 198 and spacers 200 are loosely attached to the support body. The spacers 200 are preferably arranged equidistantly, in which case the spacer sleeves 198 arranged between them each have the same axial length or can each be of the same design. The bottom spacer sleeve 198 can be made shorter, as shown. Alternatively, you can do without them entirely and place the lowest spacer directly on the support 196.

The outer end of each spacer disk has a single chain link 202 distributed around the circumference of the milling tool, each chain link 202 carrying a milling disk 204 at its outer end.

In this case, an illustration is drawn in FIG. 12, in which the rotational state of the milling tool is assumed, so that the outer chain links 202, which are connected in a chain-like manner to both the spacer disks 200 and the milling disks 204, fly horizontally outward, as is also the case in FIG. 1 for longer chain-like Milling tools is shown. In the idle state, such chains hang down under their own weight so that they can then easily be passed through areas of the chimney that have not yet been milled out.

The milling disks 204 describe an active cone which initially widens conically from top to bottom and then tapers again conically, and which is axially symmetrical with respect to the middle spacer disk 200a in order to be able to mill equally effectively both upwards and downwards with the same geometry. Since the milling disks of the middle spacer 200a are subjected to the greatest stress due to their largest radial projection and should therefore be chosen to be particularly robust in each case, it is also advisable, as shown, to make the middle spacer 200a stronger than the other spacers (with the same Material with greater thickness). The spacers have different radial widths corresponding to the respective radial radius of the active cone at the point in question, while the individual chain links 202 can all be selected in the same way.

In the embodiment of a milling tool according to FIG. 13, the support body 192 is, as mentioned with regard to the milling tool described above, provided with a lower support, not shown, analogous to the support 196, on which a single elongated spacer sleeve 198a rests (instead of the majority of the spacer sleeves) 198 and spacers 200 of the previously described embodiment).

Between the support and the spacer sleeve 198a on the one hand and on the upper end face of the spacer sleeve 198a on the other hand, one with the support body 192 is rotationally fixed connected support plate 206 is arranged, which is square here.

A radially extending slot 208 is formed in each of the four corner regions of this square support plate 206, in each of which a set screw 210 engages from the sides facing away from the spacer sleeve 198a. On the set screws 210, four bow-shaped milling blades 212 can be pivoted out over the circumference of the milling tool, but can also be fixed in a specific angular position when the set screws 210 are tightened. In addition, if the adjusting screws are set sufficiently loosely, the milling blades 212 can be freely axially displaced along the elongated holes 208, this displaceability also being excluded when the adjusting screw is tightened.

The milling tools each have a cutting edge 214 on at least one outer narrow side. It is also conceivable to provide a cutting edge 214 on both edges of the milling lamella, although only one cutting edge is used in one working direction, be it for working under different operating conditions, be it for reverse assembly for subsequent wear of both cutting edges.

However, in order to produce particularly advantageous milling conditions, the cross section of the milling lamella 212 can also be selected such that a cutting edge 214 is only possible on one edge.

In the drawing, the cutting edges 214 are also radially axially from top to bottom issued on the outside to describe a conical knitting cone again. If the working direction is reversed, this workpiece can also be repositioned by exchanging the legs of the bow-shaped milling blades, on which the set screws 210 engage between the support plates 206. Alternatively, to create a double action, one can also choose to issue the milling lamella itself in the manner of a double cone, as has already been described with regard to the embodiment according to FIG. Here the double cone would then be formed by the same milling element. Alternatively, one can also connect two milling tool elements according to FIG. 13 axially one after the other in the manner of the embodiment according to FIG. 12 and thereby achieve the display for generating the double-conical cross-section with similar milling lamellae, which, however, are shown differently above and below. As an alternative to the particularly preferred embodiment described with elongated holes 208 and set screws 210, articulations of the bow-shaped milling lamellae can also be provided simply via individual chain links, as is the case in the embodiment according to FIG. 12 with regard to the connection of the spacer disks 200 there with the outer milling disks 204 on the basis of the individual ones Chain links 202 is described.

In the third embodiment of a preferred milling tool according to FIG. 14, a support disk 216 is fastened to the lower end of the support body 192 in a manner similar to the previously described support 196, for example by means of a fastening screw, not shown, with which the support disk 216 is attached to the form-fitting from below is partially screwed into the support body 216 engaging support body 216.

Three rectangular grooves 218 which are equidistant in the circumferential direction and which run axially are distributed over the circumference of the support disk 216. In each rectangular groove 218, an oscillating block 220, which forms a straight, short lever and essentially occupies the width of the rectangular groove with relative mobility, is articulated on a bearing pin 222 so as to be oscillatable. The bearing pin 222 is driven in with a form fit by means of through bores 224 opposite each other on the respective rectangular groove 218.

The oscillating blocks are essentially flush with the upper end face of the support disk 216. The upper ends of the oscillating blocks 220 are also beveled at least on their radially inner side of the milling head. In the figure, a roof 226 of the same type inside and outside is shown with a flat ridge design. The ridge is essentially flush with the surface of the support plate 216 after the pivoting position of the oscillating block 220, while the radially inner roof slope 228 strikes the base of the rectangular groove 218 at a predetermined pivoting position of the oscillating block 220 and thus limits the pivoting out. The double-sided roof design can be used to reverse the direction of installation if the vibrating block wears on one side.

At the lower end of the swing block 220 protruding somewhat axially downward from the support disk 216, a threaded bore 230 is recessed. In this, a high stress-absorbing stud 232 is screwed in, which, with a little radial play, serves as a bearing shaft for a cylindrical shell-shaped base body 234 of a milling head 236. The milling head is complemented by milling pins 238, which fit into the cylindrical circumferential surface of the base body 234 are rigidly embedded and protrude radially from this peripheral surface, so that the base body and burrs together form a kind of radial hedgehog. The burrs have the same length, so that the peripheral surface of the hedgehog describes a cylindrical, but possibly also a different envelope surface, for example an envelope surface slightly bulged in the middle axial length. The pins themselves are straight and made of hard metal, for example a steel alloy or other hard metals or hard metal alloys.

As can be seen from the course of the bore of adjacent axial rows 240 of receiving holes in the peripheral surface of the base body for the burrs 238, the receiving holes of these rows are offset from one another with a gap, the rows being arranged equidistantly.

The mounting of the base body 234 of the milling heads 236 on the stud bolts 232 with a little play forms a ball joint, which can optionally also be designed differently. It has been shown that the hard stresses of such a milling tool are better absorbed when laying out a chimney if the milling head is arranged on its bearing shaft to shake somewhat than if a precise bearing were provided here.

As shown, the head of the respective stud 232 is embedded in the base body on its outer end face.

As was made clear with reference to FIGS. 3 and 4, this tool can be used with the same geometry working both downwards and upwards, with a support body 192 then optionally being provided on both end faces the support disc 216 provides. This is not realized in the embodiment according to FIG. 14. According to the embodiment shown, the oscillating blocks 220, which act as straight oscillating arms, can still hang vertically downwards somewhat freely, if the milling tool is not set in rotation. Then the outer enveloping surfaces of the three milling heads 236 are supported against one another in such a way that all three milling heads are essentially axially aligned, so that insertion into a chimney cross-section which has not yet been milled is conveniently possible. Alternatively, the vibrating blocks can also be brought into contact with their internal longitudinal surface at the bottom of the rectangular groove 218 in this operating mode. You can also design the bottom of the "rectangle" groove bulged, in order to hold the vibrating block axially if necessary.

However, the embodiment shown does not permit a double-acting operation in terms of its geometry without repositioning a support body 192 provided on both sides when attaching it to the output shaft of the fluid motor 12.

In a manner not shown, the stop of the oscillating block 220 on the bottom of the rectangular groove 218 can be made detachable by means of a servo device such that the oscillating block is pivoted out of the hanging arrangement according to FIG. 5 into an essentially standing arrangement and there also by an outside, also servo-adjustable support is fixed. Such a servo control can in turn be carried out by means of the same equipment which is used for the operation of the fluid motor 12, but via a separate control line.

15 and 16, essential functional elements of a commercially available percussion mechanism are finally explained, which overlays the angular rotation of the drive shaft of the fluid motor, in particular a pneumatic motor, in the angular direction with a pulsating impact movement, with repetition of the same percussion mechanism sequence per revolution of the output shaft. In a manner not shown, the impact operation can only be switched on at a target number of revolutions, for example in order to provide smooth starting processes.

Although such a striking mechanism can also be arranged at a different location, in particular between the fluid motor and its suspension, it is described below in a direct connection after the rotor of the fluid motor. In this respect it replaces a separate reduction gear, in which the torque amplification of a reduction gear is exchanged for an increase in effectiveness by hammering. However, one can also combine torque amplification through reduction and hammer action by means of striking mechanism if necessary.

A hammer carrier 242 of the striking mechanism is driven with a ratio of 1: 1 by the rotor 52 of the pneumatic motor.

Two hammers 246 and two hammer pins 244 are loosely arranged in the hammer carrier 242 at diametrically opposite circumferential locations, the hammer pins 244 as end stops limiting a movement of the hammers 246 radially outwards under the centrifugal force.

When the hammer carrier 242 rotates, the hammers 246 are carried in the direction of rotation. The arrangement of the hammers 246 in the hammer carrier 242 is designed differently, which manifests itself in different circumferential lengths of the circumferential grooves to be accommodated and their different geometries. When the hammer carrier is rotated, the hammers 246 make a wobbling movement.

The hammers 246 interact in the direction of rotation with an anvil 248, which forms a non-rotatable, preferably rigid, unit with the output shaft 80 carrying the milling tool 16. The anvil 248 is supported in the impact tool housing 250 via the bearing bush 252. The output shaft 80 is thus also given a uniform mounting.

The different arrangement of the hammers 246 in the hammer carrier 242 is designed in spite of their differences so that both hammers 246 hit the anvil 248 at the same time.

Claims (22)

1. A device for milling out a chimney (4) to be lined, having

   a. a working unit (12, 16) which has a drive motor (12) and a milling tool (16) which is driven by the latter and which is designed in such a way that constructional wall material of the chimney (4) can be milled away;

   b. a power source (10), which can be disposed outside the chimney (4), for the drive motor (12);

   c. a suspension device (14, 26) for the working unit (12, 16), by means of which the working unit (12, 16) can be moved up and down in the chimney (4);

   d. a power transmission line (14) by means of which drive force can be transmitted from the power source (10) to the drive motor (12); and

   e. a guidance device, which cooperates with the inner surface of the chimney (4), for the upward and/or downward movement of the working unit (12, 16) and which has guidance and support elements, the radial distances of which from the motor axis of the drive motor (12) are variable,
   characterised in that

   f. the drive motor is a fluid motor (12);

   g. the power source is a fluid source (10);

   h. the power transmission line is a fluid hose (14), and

   i. the fluid motor (12) has runners (142) as the guidance and support elements, which runners extend over the circumference of the fluid motor (12) and along the axis of the fluid motor (12).
2. A device according claim 1, characterised in that the fluid motor (12) is a pneumatic motor, the fluid hose (14) is a compressed air line and the fluid source (10) is a compressor.
3. A device according to claim 2, characterised in that the exhaust air outlet (114) of the pneumatic motor (12) is disposed on the working unit (12, 16).
4. A device according to claim 3, characterised in that the exhaust air outlet (114) is directed downwards on to the milling tool (16).
5. A device according to any one of claims 1 to 4, characterised in that the working unit (12, 16) of the fluid motor (12) and milling tool (16) is suspended on a pure traction element (14; 26).
6. A device according to claim 5, characterised in that the working unit (12, 16) is suspended on the fluid hose (14).
7. A device according to any one of claims 1 to 6, characterised in that the distance of the runner (142) from the axis of the fluid motor (12) is adjustable.
8. A device according to claim 7, characterised by a fluid control system, which is preferably pneumatic, for the adjustment of the runners (142).
9. A device according to any one of claims 1 to 8, characterised in that the rotor of the fluid motor (12) is connected to the milling tool (16) via a reducing gear (85, 85a).
10. A device according to claim 9, characterised in that the reducing gear (85, 85a) is of multi-stage construction.
11. A device according to claim 9 or 10, characterised in that the respective reducing gear (85, 85a) is constructed as a planetary gear.
12. A device according to any one of claims 1 to 11, characterised in that the runners (142) of the fluid motor (12) are of double-acting construction, i.e. guiding both upwards and downwards.
13. A device according to any one of claims 1 to 12, characterised in that an impact tool (117) which acts in an angular direction is interposed between the fluid motor (12) and the milling tool (16).
14. A device according to claim 13, characterised in that the impact tool (116) is constructed as a removable axial extension piece and is optionally disposed between the fluid motor (12) and a reducing gear (85, 85a).
15. A device according to claim 13 or 14, characterised in that the fluid motor (12) is connected with a transmission ratio 1:1 to the impact tool (117) and the latter is connected to the milling tool (16) with a transmission ratio of 1:1.
16. A device according to any one of claims 13 to 15, characterised by a controller which only automatically switches on the impact tool (117) at a limiting speed of rotation of the milling tool, for example of 2500 rpm.
17. A device according to any one of claims 1 to 16, characterised in that a compensating impact tool is connected between the fluid motor (12) and its suspension (14; 26).
18. A device according to any one of claims 1 to 17, characterised in that the coupling between the fluid motor (12) and the milling tool (16) is constructed as a quick-acting lock.
19. Application of the device according to any one of claims 1 to 18 to the milling out in one pass of chimney lengths of more than 15 m, for example of at least 3-storey residential buildings or entire factory chimneys.
20. Application of the device according to any one of claims 1 to 18 to chimneys with a curved axial course.
21. Application of the device according to any one of claims 1 to 18 to chimneys to be milled out which have a nominal diameter of 140 mm or less (smallest diameter in the case of non-round chimneys) of their inner cross-section.
22. An application according to claim 21 with the proviso that the nominal diameter is 100 mm at most.

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