FIELD OF THE INVENTION

This invention relates to lighting apparatus, More particularly, although not exclusively it discloses improvements in fluorescent lamps used in street lamps and other applications such as offices, factories, shops, schools etc.

BACKGROUND TO THE INVENTION

Examples of prior art fluorescent lamps which are currently in use are known in the industry as the T8 (25 mm diameter), the T9 (29 mm diameter), the T10 (32 mm diameter), the T12 ( 38 mm diameter ) the T5 (16 mm in diameter) and the T4 ( 12 mm diameter). Most of the T8, T9, T10 and T12 lamps are driven by magnetic iron core ballasts and are assisted in starting by either a starter or a rapid start transformer. They often have a power factor correcting capacitor (PFCC) added in parallel to the input power active and neutral lines to adjust the power factor. Although many of the older T9, T10 and T12 lamps are often replaced by the more efficient T8 lamps the T8 lamps still do not provide satisfactory energy saving. When driven by magnetic iron core ballasts plus starters and PFCC, they usually consume a total of about 46W to 48W power (for a T8-36W lamp) depending on efficiency of the magnetic ballasts. While new luminaires are starting to use electronic ballasts and more efficient reflectors for these T8 lamps power consumption is still approximately 37W to 38W total per lamp for a 1200 mm long T8-36W lamp depending again on efficiency of the electronic ballasts used. It is also known to replace the older magnetic ballasted T8, T9, T10 or T12 lamps with a T8 to T5 conversion device . This includes a batten or adaptors which incorporates a more efficient T5 or T4 fluorescent lamp tube usually coated with Triphosphor or Quadphosphor or other types of fluorescent powder, an electronic ballast, plus in some cases an integral or independent reflector. This saves a lot of energy compared to the original T8, T9, T10 or T12 lamps driven by magnetic ballasts. However, because of the narrow spacing of the pins 1 of the standard T5 lamp relative to the pins 2 of the T8 lamp as shown in figure 1, and the fact that the T5 lamps are much harder to ignite by the starter and magnetic core ballast, a direct

substitution is not possible and a converter, usually including an electronic ballast or special starter, is required. Also, such conversions can only operate well in the case of magnetic ballasts with starter or rapid start transformers. When there are PFCC units in circuit , the resultant PF will be over

compensated and become low, resulting in higher current which may overload the current overload protection circuit breakers. Therefore during installation where PFCCs are installed in individual luminaires, these PFCCs have to be either removed or alternatively tolerated provided that the total current is calculated to ensure that the current overload circuit breakers do not trip and the cables are large enough. For newer installations where the T8 lamps are driven by electronic ballasts, these T8 to T5 conversion units cannot be used.

In Australia and particularly in European Union countries and Japan, there are quite a large proportion of installations where the T8 lamps are driven by electronic ballasts. In Australia, it is estimated about 10% to 20% of all fluorescent lamps installed use electronic ballasts. In Germany, it is estimated about 30% to 40% or more of fluorescent lamps are driven by electronic ballasts due to the colder climate which makes the magnetic ballasted fluorescent lamps harder to start in winter. In Japan this

proportion is even higher.

SUMMARY OF THE INVENTION

It is therefore an object of this invention to ameliorate the aforementioned disadvantages and accordingly an improved fluorescent lamp assembly is disclosed for illuminating streets or other areas such as offices, factory buildings, shops, schools etc. , said lamp assembly including a tube coated with Triphosphor or Quadphosphor or other types and mixes of powder which is adapted to be driven by a known standard electronic ballast, has pin dimensions spacings and lengths corresponding to prior art lamps to enable direct replacement and further includes a clip-on reflector for attachment to the outside of said tube or using an integral reflector assembly to said tube. Preferably said tube includes end caps to which said reflector attaches at least in part.

It is further preferred that said tube has a diameter of about 17 to 18 mm or more to provide higher efficiency, ease of starting and to allow easy installation of the reflector unit for matching and clearing the height of the lamp receptacles at the two ends. In some instances the inert powder mix inside the fluorescent tubes is changed so that the lamps are easier to start. And the tube power is specially made and adjusted to be about 11W for the 600 mm length lamp, 22W for the 1200 mm length lamp, 26W for the 1500 mm length lamp, and proportionately higher for longer lamps. These wattages are selected to ensure that the light output of the new lamp assembly are approximately the same as the original T8 or other diameter lamps.

It is further preferred that said reflector is disposed so that in a position of use of the lamp a maximum amount of light is reflected downward toward an area below said lamp assembly. And, if so desired, the reflector can be rotated to direct the light to any other direction in the overall downward direction.

It is further preferred that the surface of said reflector is approximately parabolic or other shapes in order to throw light more accurately to a narrower or wider area to be illuminated.

It is further preferred that said reflector is releasably held in place on the lamp tube by spring clips.

BRIEF DESCRIPTION OF THE DRAWINGS

One currently preferred embodiment of the invention (hereinafter called the T6S lamp) will now be described with reference to the aforementioned figure 1 as well as:- figure 2 showing an end view of a clip-on reflector according to said invention, figure 2A shows a perspective view of the reflector of figure 2 figure 3 showing a cross-sectional view the reflector of figure 2 when attached to a T6S fluorescent lamp tube in accordance with this invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The reflector may comprise a plastic shell 3 of any required length formed polycarbonate or similar material. The reflector is elongated in shape and would preferably extend the length of the T6S fluorescent lamp tube. The inner surface 4 of the reflector which in a position of use faces said lamp tube is preferably fitted with a cut piece of highly reflective sheet material. To enable this sheet to be pressed into place and held against the surface the edges of the shell 3 are preferably formed with inwardly directed hooks 5. Alternatively the surface 4 may be electroplated with a highly reflective known type of mirror material. It is envisaged that up to 96% reflectivity could be obtained in this manner. As shown in figures 2A and 3 there are also pairs of holes 6 in the reflector shell. These are formed adjacent each end of the reflector. For long T6S lamps these holes may also be formed at one or more intermediate positions. There is a respective spring fastener 7 associated with each pair of holes. With this embodiment each fastener is preferably but not essentially in the shape of a conduit clip. The central portion 7A of the clip extends partly around the outside of the reflector and the curved legs 7B pass through the holes 6 to straddle and securely clamp the T6S lamp end cap 8 (see figure 3) whereby the T6S lamp is held about 4 to 6mm above the bottom of the reflector as shown. In the case of long lamps clips at positions intermediate the ends would clamp the tube 9 directly. The spring clips are preferably made of nickel plated spring steel, phosphor bronze or other suitable strong and springy material such as high temperature engineering plastics such as Polycarbonate. For long T6S lamps a central stiffening rib 10 may also be formed along the outside of the reflector. This includes a hole 11 through which the central portion of the clip passes. The material of the reflector can be any strong engineering plastic material such as ABS or Polycarbonate PC, or a plastic mixture of appropriate fire retardant rating such as 94V0, with sufficient hardness and strength.

Using the aforementioned T6S lamp and clip-on reflector replacement of the inefficient prior art T8, T9, T10 and T12 lamps is relatively straightforward. As the T6S pins 12 (see figure 1) are spaced the same this simply involves replacing said prior art lamp tubes with the T6S lamp tube and clipping on the reflector.

Alternatively, this reflector can be moulded or prefixed to the T6S lamp as part of the T6S lamp tube assembly. This alternative is useable but not as flexible as the clip on separate reflector, since the direction of the reflected light is fixed in one direction and cannot be rotated.

These T6S lamps are preferably designed to have better efficiency and better starting characteristics than the T5 prior art lamps because of a larger internal diameter and hence internal powdered surface, and extra length plus use of better inert gas mix consisting of Krypton, Argon and other inert gases in different proportions.

Preferably the T6S lamps will be set to operate typically at about 25% to 30% lower wattages than the prior art T5 replacement lamps or the T8 ,T9, T10, T12 equivalent lamps with even lower wattages and with the same lengths.

In accordance with this invention the reduced lumen output from this lower wattage is compensated for by the novel clip-on reflector.

For example, typically, for the T8-36W lamp, the current prior art T5 replacement is a T5-28W lamp. For T8-18W, the T5 replacement is T5-14W. For T8-58W, the T5 replacement is T5-35W.

However with the T6S lamps according to the invention the equivalent units will be typically T6S-11W, T6S-20W, and T6S-26W respectively for the T8- 18W, T8-36W, and T8-58W. The reflector according to this invention is preferably shaped and configured to have the maximum amount of light reflected towards the area below the lamps with minimal loss to the standard type of reflector systems or other surfaces of the original luminaires. Indeed photometric tests have shown that these lower wattages of the T6S lamp systems (complete with reflectors in accordance with this invention) can provide the same or better lux levels at the area to be illuminated compared to the prior art T8 lamps or T9, T10, T12 lamps they are intended to replace. The original electronic ballasts are not affected or removed, hence the installation cost is extremely low, similar to the cost of replacing a lamp tube.

The total savings when the T6S lamps are used to replace the prior art T8 lamps driven by electronic ballasts is estimated to be between 40% to 55 % or more without reduction in light levels at the areas to be illuminated. The variation in savings is due to variation in efficiency of the electronic ballasts used and the quality of the original T8 lamps or other lamps used.

The T6S lamp plus reflector system can also in accordance with the invention be used to replace the prior art T8, T9, T10 or T12 lamps driven by magnetic iron core ballasts with starters or rapid start transformers, and with or without the PFCC to obtain even better savings close to 60%.

While this has the disadvantage of retaining the original starter in circuit which still requires regular replacement, when the lamp is operated with the rapid start transformers the transformer life is much longer and usually does not require replacement. The fact that the T6S lamps are under- run at much lower wattages than the equivalent T5 lamps, their life is considerably increased. Tests have shown that this increase in lamp life as implemented in this embodiment can be up to 50% or more to reach a maximum of up to 50,000 hours.

It will thus be appreciated that this invention at least in the form of the embodiment described provides a novel and improved form of replacement fluorescent lamp which can achieve substantial energy savings and much longer life over prior art lamps. Clearly however the example disclosed is only the currently preferred form of the invention and a wide variety of modifications may be made which would be apparent to a person skilled in the art. For example the shape and configuration of the reflector and the design of the clips for fastening the lamp assembly together may be modified according to installation requirements. The invention also extends to the use of suitable materials other than those specifically referred to.