GB1586674A

GB1586674A - Device for inspecting the interior of an enclosure

Info

Publication number: GB1586674A
Application number: GB4581077A
Authority: GB
Original assignee: Centre de Recherches Metallurgiques CRM ASBL
Current assignee: Centre de Recherches Metallurgiques CRM ASBL
Priority date: 1976-11-04
Filing date: 1977-11-03
Publication date: 1981-03-25
Also published as: IT1116341B; DE2748651C3; DE2748651B2; BE847998A; CA1085662A; DE2748651A1

Description

(54) DEVICE FOR INSPECTING THE INTERIOR OF AN ENCLOSURE (71) We, CENTRE DE RECHERCHES METALLURGIQEES - CENTRUM VOOR RE SEARcH IN DE METALLURGIE, a Belgian body corporate, of 47, rue Montoyer, 1040 Brussels, Belgium, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to a device which makes it possible to inspect the interior of an enclosure through a window in a wall thereof, for example for making some specific measurements.

The following description illustrates an application of the device to the inspection of the burden in a blast furnace. This is done, however, by way of example and without implying any limitation. A device according to the invention can be used for observing the interior of any enclosure.

There is a well-recognized interest in observing, for example, the evolution of the shape of the upper surface of the burden in a blast furnace, the distribution of the surface temperatures from its centre to its periphery and the appearance of hot spots or cold zones, etc. These indications allow the operation of the blast furnace to be improved, this depending on appropriate addition of coke, ore, and fluxes as well as on accurate distribution of these materials across the whole of the upper surface of the burden.

The value of all data is of course subordinate to the fact of being able to correctly observe the burden by means of a device which is as reliable as possible.

Theoretically, these conditions cannot easily be met, because the space above the burden in the blast furnace may contain a compressed gas (for example, at a pressure of 2 kg/cm2) and is practically always very dusty.

In order to observe the charge inside a blast furnace, various devices have already been suggested which are generally of the scanning type and form a component of a practically fixed device, or of the telemetric type.

In most cases, these devices permit observation of the burden in a blast furnace through an inspection window of transparent material permanently cleaned from inside.

The applicants have already suggested a device of this type which comprises, on the one hand, an observation or measuring instrument whose sighting axis, or at least its terminal part, is orientated so as to pass through an opening and, on the other hand, means for deviating the sighting axis of the instrument. Such a device makes it possible to orientate the axis of the instrument in any directions compatible with the aperture of the instrument.

Some devices of this type have already been available on the market, in particular thermographic apparatus whose means for deviating the sighting axis of the camera are polygonal prisms. In general, use of these devices requires the formation of a relatively large opening in the side wall of the enclosure to be inspected in order to be able to make all the necessary measurements.

The present invention provides a device for inspecting from outside the interior of an enclosure through an opening, the device comprising: an observation or measuring instrument; an observation orifice; a plurality of light path deflectors arranged so that radiation from the interior of the enclosure passing through the observation orifice is transmitted to the instrument along a folded optical path which lies in a plane, the end part of the said path adjacent the instrument coinciding with the sighting axis of the instrument; means for rotating one of the deflectors about an axis perpendicular to the said plane containing the sighting axis and the said path so as to vary the angle of the end part of the said path adjacent the orifice; and means for rotating the assembly of deflectors relative to the instrument about an axis contained in the said plane and coinciding with the sighting axis.

The deflectors may advantageously be formed by mirrors. The mirrors may be plane and/or cylindrical with a circular, or elliptical, or parabolic cross section, and/or having an ellipsoid surface portion and/or a paraboloid surface portion and / or a spherical surface portion.

According to a particularly advantageous embodiment of the invention, the mirrors are plane and the axis of rotation of the movable mirror is located outside the path followed by the radiation from the orifice to the instrument. It is thus obtained that the common intersection of the received radiation and the radiation reflected by the movable mirror is subjected to combined rotary movement and displacement during the displacement of the movable mirror.

According to a modification, one of the mirrors is a fixed, curved mirror which is located on the optical path between the orifice and the movable mirror. A particularly advantageous embodiment is a concave shape. The surface of the curved mirror can be either continuous (which is preferred) or formed by facets.

The device preferably comprises a diaphragm which ensures a constant aperture for the optical system used. The device may comprise means for focusing onto the instrument the radiation passing through the diaphragm or the observation opening.

The movement of the movable deflector may be derived through a cam or a rack.

The movement of the movable deflector and the rotational movement of the deflector assembly are advantageously controlled by the same motor by way of a drive system which is arranged to drive them at predetermined relative speeds.

Moreover, the observation or measuring instrument, the deflector assembly, and the means for rotating this assembly may be mounted on a support movable towards and away from an opening formed in the side wall of the enclosure or of an isolation valve. The end of the approaching movement stroke 'of the assembly comprising the observation instrument and the deflectors, in front of the opening formed in the side wall of the enclosure to be inspected or of the isolating valve, advantageously coincides with the closing of a seal.

A shield protecting the optical system from the inner atmosphere of the enclosure to be inspected is advantageously rigid with the support of the observation instrument and with the axis of rotation of the deflectors, thereby making it easier to clean it. A second shield is advantageously made rigid with the movable asembly of the deflectors in order to tight seal the element formed by the observation instrument and the said deflectors. In the case in which a single shield is used, the shield can be made rigid with the movable assembly of the deflectors in order to tight seal the element formed by the observation instrument and the said deflectors. In the case in which a single shield is used, the shield can be made rigid with the movable assembly of the deflectors in order to tight seal the optical system.

The support to which the observation or measuring instrument and the axis of rotation of the deflectors are fixed, is advantageously contained in a tight sealed casing so as to prevent any danger which might come from the enclosure to be inspected.

The invention will be described further, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a device for inspecting the interior of an enclosure, comprising a movable plane mirror having an axis of rotation located outside the path followed by radiation from an observation opening to an observation instrument; Figure 2 shows a device comprising a fixed concave mirror and at least one movable 'mirror having an axis of rotation located on the path' followed by radiation from an observation opening to an observation instrument; and Figure 3 shows a device movable towards and away from the opening formed in the side wall of the enclosure whose interior is to be inspected.

The device illustrated in Figure 1 has a measuring instrument in the form of a pyrometer P having a sighting axis 1. The pyrometer P is mounted indirectly on a support 2. The optical path from the pyrometer is contained in a single plane, but is folded so as to follow a non-rectilinear path by the action of deflections formed by plane mirrors 3, 4, 5, 6, and passes through an observation orifice 8 befpre entering the enclosure (not shown) the temperature of whose interior is to be measured. The orifice 8 is located in front of a transparent shield 9. A diaphragm 7 delimits a constant aper- ture for the optical system. A focusing device (not shown) focuses onto the pyrometer P the radiation received along the optical path.

The plane mirrors 3, 4, 5 are fixed with respect to one another and only the plane mirror 6 is movable, in the sense that it cdn rotate about an axis 10 perpendicular to the plane containing the optical path and the sighting axis 1. The axis 10 is located outside the path followed by .the radiation from the orifice 8 to the pyrometer P. The movable mirror 6 is shown in two different positions. As can be clearly seen, the position of incidence of the optical path (respectively 11 and 12) is subjected to a translational movement, while the' angle of incidence changes during the displace ment of the movable mirror 6, so as to vary the angle of the end part of the optical path adjacent the observation orifice 8.

The movement of the mirror 6 is obtained as follows. A tube 13 rigidly fixed to the support 2 is connected to a rotatable tube 14 by means of needle bearings 15.

Within the rotatable tube 14, a second rotatable tube 16 is kept in position by two needle bearings 17. Rotary movement is transmitted to the tubes 14 and 16 by means of toothed rings 18 and 19 respectively driven by two toothed wheels 20, 21 which are in turn driven by a motor 22 mounted on the support 2. A position indicator 23 is also provided. A cam 24 is located at the end of the tube 16, the movement of the cam 24 displacing the axis of a roller 25 mounted on the arm 26 rigid with the mirror 6. A return spring 27 acting on the rotatable arm 26 urges the roller 25 to contact with the cam 24. The shape of the cam 24 may be such as to define a trajectory of a predetermined given shape across the surface to be inspected in the enclosure.

The assembly of the mirrors 3, 4, 5, 6 is rotatable with tube 14 about an axis coincident with the sighting axis 1, so that the plane in which the optical path lies can be rotated about the said axis.

The system formed by the components 18, 19, 20, and 21 drives the tubes 14 and 16 at different predetermined speeds so that, if the tube 14 effects for example 10 rotations, the tube 16 effects 11 rotations in the same direction. Consequently, during the ,10 rotations of the tube 14, the mirror 6 effects a complete forward and backward movement, since the tubes 14 and 16 perform a complete revolution relative to each other.

Scanning of the surface to be inspected inside the enclosure is ensured by the two movements: on the one hand, the movement provided by the rotation of the movable mirror 6 about an axis transverse to the axis 1 and, on the other hand, that provided by the rotation of the assembly of the mirrors 3, 4, 5, 6 about -an axis coinciding with the axis 1.

An air box 28 is provided in front of the shield 9 so as to act as a cushion between the shield and the inside of the enclosure.

The air box 28 is fed from a circular space 29 by way of conduits 30.

It is possible to readily disassemble the shield 9 from its support, which is mounted on the air box 28, which is, in turn, bolted to a cooling water jacket 31.

In FIGURE 2, the observation instrument is a pyrometer P having a sighting axis 41. This pyrometer is fixed on a support 42. The deflectors are formed by mirrors 43, 44, 45, 46. A diaphragm 47 ensures a constant aperture for the optical system used. The optical path is folded along a non-rectilinear path in a plane containing the axis 1 under the action of the mirrors 43 to 46 and passes through an observation orifice 48 before entering the enclosure the temperature in which is to be measured.

The orifice 48 is located in front of a transparent shield 49.

The mirrors 43 and 44 are plane and mutually fixed; the mirror 46 is cylindrical and fixed with respect to mirrors 43 and 44.

The mirror 45 is plane and can rotate about an axis 50 perpendicular to the plane containing the optical path and the sighting axis 41. The axis 50 is located on the said optical path. Rotary movement of the mirror 45 can be obtained by means of a cylindrical cam 51 and a roller 52 which displaces a cranked arm 53 actuating a rack system 54.

The surface of the mirror 46 is a portion of a right circular cylinder. The curvature of the mirror 46 is such that it is possible to use the pivoting mirror 45 to select the path followed by the radiation from the orifice 48 to the pyrometer P.

The assembly of the mirrors 43, 44, 45, 46 can rotate about an axis which coincides with the sighting axis 41.

Scanning of the surface to be inspected inside the enclosure is ensured by two movements: on the one hand, the movement given by the oscillation of the movable mirror 45 and, on the other hand, that given by the rotation of the assembly of mirrors 43, 44, 45, 46 about an axis coinciding with the sighting axis 41.

The angular position of these two movements is adjusted to selectively position the optical path so that it is directed to the part of the surface to be observed, e.g. for the measurement of the temperature of the burden in a blast furnace. An air box 55 is provided in front of the shield 49 to act as a cushion between the shield and the inside of the furnace. The air box 55 is fed by a circular space 56. It is possible to easily-disassemble the shield 49 from its support, which is mounted on the air box 55, which is, in turn, bolted to a cooling water jacket 57.

In FIGURE 3, the assembly 61 formed by the system of mirrors is associated with a pyrometer 62 for measurement of the temperature of the burden in a blast furnace. Rotational movement of the assembly 61 is controlled by a drive 63. Furthermore, FIGURE 3 shows a location 64 for control devices indispensable for maintaining transparent the shield designed to protect the optical system against the internal atmosphere of the enclosure to be inspected.

To enable the components 61, 62, 63, 64 to moved near to and away from an opening formed in the side of the enclosure whose internal temperatures are to be measured, the said components are mounted on a support 65 which is displaced along guides 66 and 67 by a jack 68.

The components 61 to 68 are located in an enclosure 69 under pressure, which encloses the outer end of a conduit 70 attached to a support plate 71 fixed to the plating of the blast furnace.

This movement makes it possible to obtain an extremely large observation field 73 independently of the ratio of thickness of useful diameter of the conduit 70. One end position of the movement within the enclosure 69 is determined by the value of the said observation field 73, whereas the other end position is chosen so as to completely withdraw the components 61 to 64 from the conduit.

The stroke limit 72 for the downward movement of the components 61 to 64 relative to the isolation enclosure 69 coincides with the closing of a seal 74 of a circular space 75 fed with air. Consequently the air contained in the circular space 75 is discharged from this space and enters the assembly 61 and the shaft 70 and thus assists in keeping these in good working condition.

WHAT WE CLAIM IS:- 1. A device for inspecting from outside the interior of an enclosure through an opening, the device comprising: an observation or measuring instrument; an observation orifice: a plurality of light path deflectors arranged so that radiation from the interior of the enclosure passing through the observation orifice is transmitted to the instrument along a folded optical path which lies in a plane, the end part of the said path adjacent the instrument coinciding with the sighting axis of the instrument; means for rotating one of the deflectors about an axis perpendicular to the said plane containing the sighting axis and the said path so as to vary the angle of the end part of the said path adjacent the orifice; and means for rotating the assembly of deflectors relative to the instrument about an axis contained in the said plane and coinciding with the sighting axis.

2. A device as claimed in claim 1, in which the deflectors are mirrors.

3. A device as claimed in claim 2, in which the mirrors are plane mirrors, one of which is rotatable about the said axis perpendicular to the plane of the optical path, the axis of rotation of the rotatable mirror being located outside the path followed by radiation from the orifice to the instrument.

4. A device as claimed in claim 2, in which one of the mirrors is a fixed, curved mirror which is located on the optical path between the orifice and the movable mirror.

5. A device as claimed in claim 4, in which the curved mirror is concave.

6. A device as claimed in any of claims 1 to 5, including a diaphragm which ensures a constant aperture for the optical system.

7. A device as claimed in any of claims 1 to 6, including means for focusing onto the instrument the radiation passing through the diaphragm or the observation orifice.

8. A device as claimed in any of claims 1 to 7, in which the movement given to the rotatable deflector is controlled by a cam or a rack.

9. A device as claimed in any of claims 1 to 8, in which the movement of the rotatable deflector and the rotary movement of the assembly of deflectors are controlled by a single motor by way of a drive system which is arranged to driven them at predetermined relative speeds.

10. A device as claimed in any of claims 1 to 9, in which the instrument, the assembly of deflectors, and the means for rotating this assembly are mounted on a support movable towards and away from the enclosure whose interior is to be inspected.

11. A device as claimed in any of claims 1 to 10, including a shield protecting the deflectors from the internal atmosphere of the enclosure to be inspected.

12. A device as claimed in claim 11, in which the shield is rigid with the assembly of deflectors.

13. A device as claimed in any of claims 1 to 12, in which the instrument and the deflectors are contained in a sealed casing.

14. A device as claimed in claim 1, substantially as described herein with reference to, and as shown in, any of Figures 1 to 3 of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. internal temperatures are to be measured, the said components are mounted on a support 65 which is displaced along guides 66 and 67 by a jack 68. The components 61 to 68 are located in an enclosure 69 under pressure, which encloses the outer end of a conduit 70 attached to a support plate 71 fixed to the plating of the blast furnace. This movement makes it possible to obtain an extremely large observation field 73 independently of the ratio of thickness of useful diameter of the conduit 70. One end position of the movement within the enclosure 69 is determined by the value of the said observation field 73, whereas the other end position is chosen so as to completely withdraw the components 61 to 64 from the conduit. The stroke limit 72 for the downward movement of the components 61 to 64 relative to the isolation enclosure 69 coincides with the closing of a seal 74 of a circular space 75 fed with air. Consequently the air contained in the circular space 75 is discharged from this space and enters the assembly 61 and the shaft 70 and thus assists in keeping these in good working condition. WHAT WE CLAIM IS:-

1. A device for inspecting from outside the interior of an enclosure through an opening, the device comprising: an observation or measuring instrument; an observation orifice: a plurality of light path deflectors arranged so that radiation from the interior of the enclosure passing through the observation orifice is transmitted to the instrument along a folded optical path which lies in a plane, the end part of the said path adjacent the instrument coinciding with the sighting axis of the instrument; means for rotating one of the deflectors about an axis perpendicular to the said plane containing the sighting axis and the said path so as to vary the angle of the end part of the said path adjacent the orifice; and means for rotating the assembly of deflectors relative to the instrument about an axis contained in the said plane and coinciding with the sighting axis.

2. A device as claimed in claim 1, in which the deflectors are mirrors.

5. A device as claimed in claim 4, in which the curved mirror is concave.