GB2026980A

GB2026980A - Installation for facilitating inspection and repair of the interior of chimneys

Info

Publication number: GB2026980A
Application number: GB7926644A
Authority: GB
Original assignee: Politechnika Wroclawska
Current assignee: Politechnika Wroclawska
Priority date: 1978-07-31
Filing date: 1979-07-31
Publication date: 1980-02-13
Also published as: SE7906471L; BE877913A; PL118497B1; PL208779A1; DE2930906A1

Abstract

The installation of this invention is particularly for use in an upwardly tapering chimney (1) and comprises a working platform (4) whose area can be varied. Hoisting ropes (5) are suspended on outriggers (6), which are mounted in a detachable manner to the top of the chimney (1). The platform (4) includes a part of fixed area fastened to the ropes (5) and a part built up from separate elements which are detachably fastened together, so that elements can be added to, or detached from, the platform to increase or decrease its area as required. <IMAGE>

Description

SPECIFICATION Installation for facilitating inspection and repair of the interior of chimneys This invention relates to an installation forfacilitat- ing the inspection and repair of the interior of chimneys, particularly chimneys which taper towards the top, such as those which are often used for discharging corrosive gases.

In industries such as the chemical, metalurgical and food industries gases which are produced during the production of materials or goods can be very corrosive. They are often discharged into the atmosphere by means of chimneys made of steel, brickwork or reinforced concrete. Such chimneys are very tall and are being built higher than ever before because of the requirements relating to the protection of the environment. These chimneys cannot be provided with steel manholes because of the corrosive power of the gases which pass therethrough.

For this reason, the interior of the chimneys are inaccessible and nobody knows what takes place inside the chimneys. Damage possibly caused by corrosion is only revealed when the damage becomes visible on the external faces of the chimneys, that is only when the interior of the chimney is already seriously damaged and when time-consuming, expensive and difficult major repairs are necessary. As has previously been said, the chimneys currently being built are very tall, for example, approximately 200 m high.

For structural reasons, brickwork and reinforced concrete chimneys taper towards their tops, and the degree of taper may be from 2 to 3 per cent. The difference between the diameters at the chimney base and outlet at the top can be considerable, particularly in very high chimneys. Anti-corrosion protection of the internal surfaces of the chimneys is not always sufficient and, for this reason, periodical technical inspections and repairs must be carried out, in orderto keep the chimneys properly maintained. As far as tapered chimneys for discharging corrosive gases are concerned, the above mentioned technical inspections of the interior of the chimneys are very difficult to carry out. The interiors of the chimneys are only accessible and can only be visually inspected over a small length at the bases or the outlets at the tops.

A known installation for facilitating access to the interiors of chimneys comprises a car moving over the chimney coping, and a basket for workmen suspended from the car. The installation is provided with a hoisting winch for raising and lowering the basket to the required depth. However, such installations can only be effectively used for the inspection and repair of cylindrical chimneys, since in case of the tapered ones, they permit only effective inspection and repair of small portions of the chimneys near the outlets at the top because of the considerable distance of the bottom portions of the chimney walls from the vertically suspended basket.

Another known installation for checking and cleaning the interior of the chimney provides a basket which is suspended on two ropes depending from a beam which is supported on the chimney coping.

The basket is raised and lowered by a hoisting winch which is situated outside the chimney. This installation may be used with chimneys having a diameter within the range from 1.5 up to 3m, whereas considerable portions of the sloping walls of the tapered chimneys are hardly accessible as in case of an installation with a movable car.

When making chimney linings in new brickwork or reinforced concrete chimneys, access to the interior of tapered chimneys is ensured by the construction of a working platform mounted on a scaffolding erected inside the chimney. As the lining is made from the base to the top of the chimney, the scaffolding is extended upwardly whilst the area of the working platform is decreased in accordance with the decreasing diameter of the chimney.

The present invention consists in an installation for facilitating inspection and repair of chimneys comprising one or more outriggers, hoisting tackle suspended from the or each outrigger, and a working platform supported by the hoisting tackle so that it can be raised and lowered, said platform including a portion of fixed area and a portion built up from separate elements which are detachably fastened together whereby the area of said platform can be varied to suit the cross-section of the chimney at the region where the platform is to be used.

When fitted to a tapered chimney, an installation according to this invention can render possible access to any point of the internal surface of the chimney. Moreover, the installation is transportable, can easily be mounted in the chimney and, due to this, can be used in the chimneys even if they are out of use for a short time only. Owing to the easy access to any point inside the chimney, macroscopic examination of the interior of the chimney, the obtaining of samples for tests, the drilling of holes in the chimney lining in order to check the thermal insulation and the carrying out of minor repairs are possible. The installation also enables emergency repairs and major overhauls to be carried out and it can be easily adapted to the existing circumstances depending on the required working platform area and the loading which will be carried by the platform during its use.

In order that the invention may be more readily understood, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 shows the cross-section of a tapered chimney with one embodiment of installation according to the invention mounted inside the chimney, Figure 2 is a diagrammatic plan view of the working platform of the installation, half of which shows the beams supporting the floor exposed, and Figure 3 is a side view of one of the beam sections and the associated angle irons.

Referring to the drawings an installation according to this invention is mounted inside a tapered chimney 1. At the bottom of the chimney there is a ballast plate 2, to which safety ropes 3 are fastened. Platform 4 of the installation is suspended on hoisting ropes 5 mounted on four articulated outriggers 6 which are fastened in a detachable mannertothe chimney at its outlet by means of suitable expand able connectors 7. Safety ropes 3 are also fastened to the outriggers 6. On the hoisting ropes 5 there are provided hoists 8 for moving the platform 4 up and down. A hydraulic pump 9 is mounted on the plat form for driving the unit. Four grips 10 are fastened to the platform 4 and are provided with jaws embrac ing the safety ropes 3. The grips 10 serve to limit the driving speed and stop the platform 4 in case of an emergency.The safety ropes 3 are also provided with the top limit switches 11 and bottom limit switches 12, the latter being located at the ballast plate 2. Platform 4 comprises a part of fixed area attached to ropes 5 and a part whose area can be varied detachablyfixed to the partoffixed area. The latter part includes as supports an internal ring 13 and an external ring 14 concentric with the internal ring, on which beams 15 of fixed length are mounted. The beams 15 are arranged around the axis of the platform 4 so as to extend radially and are supported by cantilevers 16. A floor 17 supported on the beams 15 has a generally annular shape.The part of the platform whose area can be varied comprises built up beam sections 18 which are fastened in a detachable manner to beams 15 and sets of trapezium-shaped panel segments which form panels 19 supported on the beams 18. The beam sections 18 are each made of steel I section provided with angle irons 20 welded at the ends thereof to the top of the said I section and having holes 21 for receiving fastening means e.g. bolts (not shown) so that the beam sections can be connected together.

The ends of the beams 15 are provided with similar angle irons (not shown).

The installation is mounted for use in the following way:- The part of fixed area of the platform 4 is mounted inside the chimney 1 at the bottom. Simultaneously, the articulated outriggers 6 are mounted on the crown or coping of the chimney 1. Safety ropes 3 and hoisting ropes 5 are then suspended from the outriggers 6, the ropes next being connected to the platform 4 and ballast plate 2. After assembly of the various elements and the driving units 8, 9, 10, 11 and 12 the installation is ready for use. The part of the platform 4 of variable area, that is the beam sections 18 and the segments of trapezoidal panels 19 are added as required to the part of the platform 4 of fixed area when it is being lowered, or detached when it is being lifted, depending upon the sequence of the inspection or repair of the interior of the chimney 1 being serviced.

Claims

1. An installationforfacilitating inspection and repair of chimneys comprising one or more outriggers, hoisting tackle suspended from the or each outrigger, and a working platform supported by the hoisting tackle so that it can be raised and lowered, said platform including a portion of fixed area and a portion built up from separate element" which are detachably fastened together whereby the area of said platform can be varied to suit the cross-section of the chimney at the region where the platform is to be used.

2. A hoisting arrangement as claimed in claim 1, in which the platform portion of fixed area comprises radially extending beams which are adapted at their outer ends so that said elements can be detachably fastened thereto.

3. An installation as claimed in claim 2, in which the radially extending beams are supported on two ring-like supports which are arranged concentrically.

4. An installation as claimed in any one of claims 1,2 and 3, in which the elements each comprise a beam section adapted to facilitate securing the beam sections of end-to-end.

5. An installation as claimed in claim 4, in which the beam sections supporttrapezium-shaped panel segments which together form panels constituting a part of the floor of the working platform.

6. An installation for facilitating inspection and repair of chimneys substantially as hereinbefore described with reference to the accompanying drawings.