Illumination – With static structure – Wall or ceiling
Reexamination Certificate
1999-10-21
2001-01-30
O'Shea, Sandra (Department: 2875)
Illumination
With static structure
Wall or ceiling
C362S375000, C362S376000
Reexamination Certificate
active
06179435
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a lighting assembly which extends through a wall particularly, though not exclusively, for illuminating an un-manned area.
2. Description of the Prior Art
In un-manned areas such as, for example, so-called “caves” where radioactive materials are being remotely handled, it is necessary to provide a high level of illumination. Two principal types of lighting systems are used for lighting nuclear processing areas. The first is by sealed lighting units hung at stations within the cave and which are capable of being remotely disconnected and removed from the facility for maintenance as indicated schematically in FIG.
12
. The second type are units inserted through the wall of the facility and have the lighting means emerging into an enclosed section with a window on the un-manned side to allow the light to shine on the area or objects to be viewed and as indicated schematically in FIG.
13
.
The first type has the disadvantage that that the unit has to be removed from the radioactive area using remote handling equipment, potentially tying up scarce resources such as the in-cell crane and operators time for example. The removed unit then has to be transferred to a maintenance area for decontamination before it can be repaired, then to be reinstalled in its position within the cave using the crane again.
The second type of lighting system has an advantage over the first type in that the maintainable parts are located outside of the cave environment and there is no requirement for the use of cranes or manipulators within the cave so that processing is not interrupted nor is there any decontamination of the lighting device required which saves cost due to there being no waste arisings to be further processed. However, current designs of through-wall lighting systems of the second type have their own particular disadvantages which relate mainly to weight and safety aspects. Current designs of throughwall lights necessitate the removal of a large shielding wall plug comprising mainly concrete grout and which weighs in the region of 700 kgs. The wall plug is unwieldy and awkward to extract as the wall has a thickness of some 1-1.5 m and requires special equipment by way of a handling device weighing about 1000 kgs and specially trained personnel using a procedure which ensures that no radiation hazard is produced.
When nuclear processing facilities are built, many additional lighting units are initially installed to provide for redundancy and the fact that new light tubes will all be installed simultaneously and hence likely to fail at about the same time.
Currently, about 20 man hours are required to change a light tube in known through-wall lighting designs.
A further disadvantage of current designs is that although they have a closed cover into which the light tube emerges in use, this cover is sometimes broken accidentally by a manipulator or in-cell crane for example. Thus, when the light tube is to be replaced, it is necessary for a much more rigorous and hence time consuming and expensive procedure due to the safe-side of the wall being open to contamination by radioactive dust and debris for example.
SUMMARY OF THE PRESENT INVENTION
It is an object of the present invention to provide a through-wall lighting unit which allows easier, more economic and safer maintenance and replacement of failed lights than existing systems.
According to the present invention, there is provided a lighting assembly which extends through the thickness of a wall having a first side and a second side, the assembly having at least one light source to illuminate an area on the first side of said wall and means being included to enable replacement of said light source from the second side of said wall wherein said means includes at least one duct extending at least part of the way from the first side of the wall to the second side of the wall; light source carrier means on which said light source is mounted, said light source carrier means and said light source being movable through said at least one duct from said second side to said first side; moving means to move said light source and said carrier means through said at least one duct; and, power supply means to said light source.
In the present invention, the light source may be any required light source for the purpose intended. Examples of light sources may include generally rounded light bulbs, quartz-halogen bulbs, light tubes such as high-intensity sodium tubes or any other desired light source. The main requirement is that the shape of the passage through the duct and the carrier means may be adapted to the type and shape of light source in question.
Furthermore, the method and apparatus of the present invention for deploying a light source may also be used to locate and deploy other lighting and surveillance means such as cameras, fibre optics for lighting or lasers or cameras or video recording apparatus for example. Therefore, any reference to ‘light sources’ should be taken to include such alternative devices and apparatus.
The lighting assembly according to the present invention may also include location means at the first side to locate the light source in a desired position.
The number of ducts within the lighting assembly may be partially dependent upon the shape of the light source itself. In the case where the light source is of generally rounded form, there may be a plurality of ducts. Where the shape of the light source is of generally elongate tubular form, there may be only one duct.
The lighting assembly according to the present invention may be intended for a nuclear processing facility. However, the lighting assembly of the present invention may equally well be employed in other special environments such as clean rooms, sterile areas and explosive atmospheres for example.
The component parts of the lighting assembly of the present invention may be contained within a container housing which is adapted to fit closely within a shaped aperture in the wall through which the assembly is to extend or, in the case of new facilities being built, the shape of the aperture through the wall may be such as to conform to the shape of the lighting assembly housing. The wall aperture may alternatively have a liner therein adapted to seal against said container housing for increased confidence against leakage of contaminants from the first side to the second side.
The end of the container housing adjacent the first side of the wall may include reflector means of a desired shape to enable said light source to illuminate the area on the first side in a particular manner. The shape of the reflector means required will be known to those people skilled in the lighting art and will not be elaborated on further. The location means may locate the light source in a position consistent with the requirements of the reflector means to permit efficient illumination. The location means may contain features which automatically locate the light source in the desired position on being moved to the first side of the duct.
Since there is no need to remove the container housing from the wall during replacement of the light source in the lighting assembly according to the present invention, the container housing may be filled in the free volume about the duct by, for example, concrete grout in the same manner as existing lighting systems but which do need to be removed during light source changes. Thus, in the present invention, materials, such as the grout for example, which are fully characterised and quantified may be used so that confidence in the shielding efficiency of the lighting assembly of the present invention is as high as with prior art systems.
The duct, in the case of a lighting assembly intended for a nuclear processing facility may be non-linear so as to preclude a so-called direct shine path being available from the first side to the second side. In one embodiment of a lighting assembly according to the present invention, the shape of the duct from a side elevat
Alavi Ali
British Nuclear Fuels PLC
Myers Bigel & Sibley & Sajovec
O'Shea Sandra
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