WO2012054966A1

WO2012054966A1 - Improvements in street lights and high bay light

Info

Publication number: WO2012054966A1
Application number: PCT/AU2011/001358
Authority: WO
Inventors: Thien Siung Yang
Original assignee: Thien Siung Yang
Priority date: 2010-10-26
Filing date: 2011-10-25
Publication date: 2012-05-03

Abstract

There is a light fitting for illuminating an outdoor area such as a roadway or an indoor area such as large factory or the like. The light fitting including a base (1A) with a substantially transparent or translucent cover (2) and a plurality of LEDs (4) mounted therein. When said fitting is in an elevated configuration of use with said base disposed upwardly and the cover below the LEDs illuminate downwardly through said cover and at least some of the LEDS being mounted at a lateral angle relative to the light fitting to direct light onto selected regions of said area adjacent those immediately underneath.

Description

IMPROVEMENTS IN STREET LIGHTS AND HIGH BAY LIGHTS

FIELD OF THE INVENTION

This invention relates to lighting apparatus. More particularly although not exclusively it discloses an improved LED street lamp and High Bay lamp.

BACKGROUND TO THE INVENTION

While it is known to use LEDs for street lighting with existing installations the light emitting diodes all face downward in the same direction. This unduly concentrates the radiance onto a limited area directly below the light fitting to the detriment of adjacent areas of roadway or illuminated areas which are insufficiently lit. This necessitates close spacing and an increased number of street lights which inflates installation and operating costs. Other known types of street lights such as High pressure Sodium (HPS) and other High Intensity Discharge lamps shine outward in a wide hemispherical configuration whereby the light can intrude into adjacent homes and shops. This also wastes a great deal of useful light .

SUMMARY OF THE INVENTION

It is therefore an object of this invention to ameliorate the aforementioned disadvantages and accordingly a light fitting for illuminating an outdoor area such as a roadway and indoor areas such as large factories and warehouses is disclosed, said light fitting including a base with a substantially transparent or translucent cover and a plurality of LEDs mounted therein whereby when said fitting is in an elevated configuration of use with said base disposed upwardly and the cover below said LEDs illuminate downwardly through said cover and at least some of the LEDs being mounted at a lateral angle relative to said light fitting to direct light onto selected regions of said area adjacent those immediately underneath.

Preferably said light fitting is elongated and said selected regions are to the sides of said fitting. It is further preferred that the said LEDS or at least some of them are in one or more rows along printed circuit boards which are fixed to the inclined sides of a V shaped mounting rail, said printed circuit boards are preferred to be of aluminium copper alloy or other good heat conducting material base for better heat dissipation.

It is further preferred that said V shaped rail is adapted to act as a heat sink and is formed with heat dissipation fins.

It is further preferred that said at least some or all of the LEDs are fitted with light directing reflectors and focusing lens.

It is further preferred that said base is adapted for mounting onto the end of a lamp pole or in the case of a High Bay lamp application, is mounted by 2 hooks added to the base of the light fitting hanging from the ceiling.

BRIEF DESCRIPTION OF THE DRAWINGS

Currently preferred embodiments of the invention will now be described with reference to the attached representations in which: figure 1 is a perspective view of the light fitting in a

configuration of use with the base disposed upwardly

and the transparent cover below,

figure 2 is another perspective view of the light fitting of

figure 1 showing the top finned surface of the base,

figure 3 is a cross-section view of the light fitting along the lines

A-A of figure 2,

figure 4 is an end view of the light fitting from the direction of

arrow B in figure 2,

figure 5 is a detailed view of part of the light fitting showing one way

of the mounting for a photocell light switch, figure 6 is a perspective view of a light fitting according to the

invention when in a configuration of use mounted on a

lamp pole extending over a roadway,

figures 7 and 8 show examples of the light distribution along and across a roadway from the light fitting of figure 6 as compared to a prior art light fitting, figure 9 shows a perspective view of a section of an alternative embodiment of the lamp where the finned base is formed as one piece with the V-shaped mounting rail,

figure 10 shows the preferred method of sealing the cover to the base, and

figure 11 shows the complete light assembly according to the embodiment of figure 9 where two moulded caps are fitted to each end of the base and mounting rail with one cap having a boss spigot for mounting on a light pole.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The light fitting may comprise a housing indicated generally as i formed by a base 1 A of die cast aluminium or other suitable waterproof material having good heat dissipation characteristics and a substantially transparent or translucent cover 2 of polycarbonate, acrylic, glass or other suitable material. The cover is removably secured to the underside of the base using spring clips 3. Within the housing are rows of LEDs with reflectors and focusing lenses 4. They are fitted to printed circuit boards 5 which in turn are fixed to the inclined side panels 6 of a V shaped mounting rail 7. With the present embodiment the housing is elongated and the light from these LEDs is directed out from the long sides 8 at a downwardly directed angle of about 45 or SO degrees relative to the horizontal plane of the housing shown in figure 3. Other angles however may be obtained by changing the inclination of the side panels 6 depending upon design and installation requirements depending on roadway width, and spacing between lamp poles. One or more additional rows of LEDs (not shown) may be mounted along the central flat portion 10 of the rail to also illuminate those areas directly below the light fitting.

The mounting rail 7 is also preferably formed from die cast aluminium and comprises a heat sink for the LEDs. It is fastened along its edges by screws to the underside of the base. The heat absorbed by the mounting plate 7 is transferred either directly by conduction or via fins 12 and convection through a hollow 13 to the base where it is dissipated to atmosphere. This dissipation is facilitated by external fins 4 on the base. An alternative embodiment of this invention as shown in figures 9, 10 and 11 is to make the V-shaped mounting rail 7 A as one piece with the finned base 1AA, by extrusion and drawing of aluminium alloys with internal fins on the V-shaped rail. The transparent cover 2A is also drawn and sealed onto the metal base and V-shaped mounting rail in the manner shown in figure 10 whereby a tongue 8A on the base seats between flanges 9A. Two moulded aluminium end plates 10A are fitted to the two ends of this base and main body of the lamp, and one of these has a boss spigot 11 Afor mounting on the light pole. When using this as a High Bay light, the end cap with spigot is replaced by the same end cap without spigot. And two hooks are added to the top of the lamp body for hanging from the ceiling.

Preferably a photocell light switch of any suitable design may be mounted at one end of the row of LEDs directly into a circular hole 15 in the flat portion of the mounting rail 7 as best shown in figure 5. The photocell switch 15A is preferably mounted through this hole 15 from the inside of the plate. When it protrudes through the hole a screw goes over the protruding part and fixes it to said plate. The switch would operate to automatically switch the light on at dusk and off at dawn. In an alternative embodiment this photocell light switch may be mounted on one end cap of the light fitting which has no spigot.

Although not shown in the drawings small, etched grooves may be formed in the transparent cover 2 to difilise the light and reduce glare. Preferably these grooves are very small V-shaped grooves which are moulded on the inside surface of the cover at the vertical edges of the two sides. The function of these grooves is to deflect the light downward towards the road surface to reduce glare to oncoming cars and to provide better illumination of the road way.

The light fitting with this embodiment is adapted for mounting onto the end of a lamp pole. As best shown in figures 2 and 4 there is a boss 15B with spigot hole 16 at one end of the base for receiving said lamp pole. Holes 17 are also provided in the base for bolts to tighten onto the end of the pole to secure it in place. Preferably but not essentially the spigot hole 16 may have a diameter of about 38 mm to suit standard requirements. Preferably there is also a watertight grommet of diameter about 20 mm located at the base of the spigot hole through which a power cable passes from the pole to the interior of the base for connection to a terminal block using known connectors of suitable design. With the currently preferred embodiment there is also a terminal block inside the light fitting where power cable coming into the casing from the light pole is terminated. This may be an IP65 (or other rating) casing. As an option the power cable is preferably supplied with the light fitting and is pre-connected to the terminal block in the light fitting. It then comes through the aforesaid water tight grommet and ends in a plug and socket set of known design. During installation, the source power cable, which usually comes up along the pole centre and is terminated inside the existing street lamps, can be pushed into the female part of the plug & socket set. The end of the light pole is then pushed inside the spigot and tightened in position by the aforementioned bolts on the light fitting.

A schematic illustration of a street light according to this invention mounted to a pole 18 is shown in figure 6. With the elevated light housing 1 extending out lengthwise from the side of the roadway . The distribution of light onto said roadway as compared with a prior art installation is shown in figures 7 and 8. More specifically with respect to figures 7 and 8:-

21' is the horizontal distance in meters along a roadway from a point

21 A' directly under the street lamp.

22' is the lux level reading of light illuminating the roadway surface

from a street lamp.

23' is a typical light distribution of a prior art 250 watt HPS street

lamp along the roadway surface.

24' is a typical light distribution along the roadway surface of the

LED street light of figure 6 constructed in accordance with this

invention.

25' is the minimum average lux level (7 lux) for a PI class road. 26' is the minimum average lux level (3.5 lux) for a P2 class road

27' is the minimum lux level (2 lux) for a P I class road

28' is the minimum lux level (.7 lux) for a P2 class road.

29' is the horizontal distance in meters across the roadway from the

street lamp on the light pole side.

30' is the horizontal distance in meters across the roadway on the

opposite side of the light pole.

3 is a typical light distribution of a prior art 250 watt HPS street

lamp across the roadway surface.

32' is a typical light distribution across the roadway surface of the

LED street light of figure 6 constructed in accordance with this

invention.

As can be seen the light fitting of the current invention, due to the novel placement of the LEDs, substantially increases the light distribution along the length of the roadway. This enables an increase in spacing between light installations and therefore a reduction in installation and operating costs. For example 400w High Pressure Sodium street lamps are normally spaced at between 30 and 50 metres to obtain adequate illumination. LED street lamps constructed in accordance with this invention may be spaced at up to twice that distance.

According to the Standard (for Australia, it is AS/NZS 1 158.3.1-2005), the requirement for a Category PI road is to have minimum average lux level of 7 lux between the light poles. The minimum lux level at any point in the illuminated area must be more than 2 lux. In order to be compliant, the pole spacings are currently between 30 and 40 m. For a light according to this invention the distance can be as far as 60 to 70 m while still compliant.

Preferably a LED light constructed according to this invention distributes the light so that there is no excess light where it is not needed, and distributes excess light as far as possible along the roadway. hile getting better light less energy is consumed. For example the 250W HPS lamp driven by magnetic iron core ballast normally consumes about 300W total power. The equivalent LED light in accordance with this invention consumes approximately 64W, giving an energy saving of approximately 78 %. Using better high light output new style LEDs, the consumption may be reduced to

approximately 45W, saving 85% energy.

If a simple timer is added to cut out the number of LEDs by 30% after midnight, and to 40% after 3 AM, we can save a further 30% energy. Then, overall energy saving using the subject LED street light with timer control is approximately 84 % to 90%.

While light dimming for prior art street lights is also possible this requires very complicated and expensive dimmable ballasts and control circuit to ensure that the HID lamps can remain ignited. With an LED Hght according to this invention required number of lit LEDs can be cut out using simple and reliable known timers.

The much lower energy consumption makes it possible to economically add Solar Panels to each light pole to drive the lamps. For example, a 60W solar panel with matching battery charger and batteries can be added to provide enough light for remote highways in Australia where there is no power lines.

And where there is power line, the solar panel can even feed excess power back to the power grid line during summer time when day light period is long.

The life of the subject lamp according to the subject invention will be approximately 65,000 hours compared to about 15,000 hours for the average HPS lamp. This reduces maintenance and relamping cost to less than one third. For remote highways and roads, this cost can be very significant. This long life is facilitated by the special design of heat dissipating fin arrangements on the V-shaped mounting rail and external fins on the base resulting in a casing temperature of less than 50 Deg C and LED junction temperature of less than 60 Deg C. And by turning off the LEDs in the early hours after midnight by rotation, the number of hours each LED lamp is used per night is only about 7 hours, hence the lamp can last a maximum of 24 years without maintenance. And, the LEDs are designed in such a way with individual protection circuit that when in the rare occasion any individual LED bulb fails, the remaining LED bulbs will continue operating.

If a light fitting in accordance with the invention is used for Minor roads of subcategory P3, P4 and P5, the minimum average hix level required are respectively 1.75 lux, 0.85 lux and 0.5 lux. The point minimum lux levels are respectively 0.3 , 0.14, and 0.07 lux (note:- For comparison, at full moon with a clear sky, the lux level is about 0.2 to 0.22 lux.). The current standard for these minor roads are the Mercury Vapour 80W lamps driven by magnetic iron core ballast consuming a total of between 96W and 110W depending on ballast efficiency. If the current Mercury Vapour lamps are replaced with light fittings according to the present invention using only approximately 24W LEDs consuming a total of 26W the total energy saving can reach approximately 75 %. Using new high output LEDs, this wattage can be reduced further to total 18W, with resulting energy saving of up to 90 %.

Although not essential to the invention, as also shown in figure 6, one or more solar power panels 19 may also be mounted on the lamp pole 18 outside the light housing.

These would charge storage batteries 20 located at the base of the pole 11. These batteries can also be mounted in a watertight box which is buried underground beside the light pole.

For outback roads, the cost of running long cables can be avoided by using a solar panel to drive the lamps. The street lamps and poles plus battery sets can be completely independent with no external power required, and no maintenance required for more than 20 years.

Also, with remotely installed units with solar power a wireless transmitter may preferably be installed inside the casing which can be powered by the solar panel 19 to send wireless signals to a central control centre regarding the On and Off states of the lamp. This wireless signal would save maintenance costs as the expense of checking whether remote lamps are working can be very high for long remote highways, as it has to be carried out at night. The wireless transmitter can be designed to transmit short distances for simplicity and power saving. But each one can also receive signals from the next adjacent units, and transmit signals to it. Then each unit will transmit to the next one along the road. Hence for a long road or highway, transmission may be made a long way along the road with very small transmitters and receivers consuming little power and with very small added cost.

For most outback roads installation cost, maintenance cost and power cost are very high. Line losses due to the long power lines is also very high. As LED street lights constructed according to this invention use less than 20% of the energy of a normal highway light with timed reduction of light levels, it is easy and economical to use solar panels for the power source. For example, instead of using say a 250 W HPS lamp

which consumes 300 W including ballast loss, a 64W ( or 45W ) LED lamp driven by a 120W ( or 90W ) solar panel with storage batteries can be used. The cost saving in power and cabling plus maintenance will make this very worthwhile.

Total installation cost will therefore be much less than normal highway lighting.

Also there is no power cost and no maintenance for more than 20 years except for replacement of batteries every 3 to 5 years or so. Replacing batteries can be done easily using a small standard maintenance truck instead of using expensive "cherry-picker" type trucks with extension ladders.

Street lamps in accordance with this invention have the flexibility of using any number of LEDs from 10 W to 90W (or more if heat sinks are increased in height). This can be done by mounting as many LEDs as needed. For even bigger wattages, the length of the housing can be increased easily if using the extruded and drawn aluminium casing embodiment.

In order to make the length of the lamp flexible , another embodiment of this invention is to make the body of the lamp from extruded and drawn aluminium alloy which may also be joined together with the V-shaped LED mounting base. Then the end caps can be made from moulded aluminium alloy, with one end having a spigot for mounting the lamp on a lamp pole and the other end having the Daylight sensor switch 12A mounted protruding from the end cap.

The current embodiment preferably uses a 1 watt LED bulb which is the most efficient LED with high lumen output presently available. This also provides better spread of light reducing glare .The present LEDs however can be changed to 2W LEDs or 3W or bigger for higher power output (if required) where glare is not a problem. For example, for football fields, road intersections etc. mounted on very tall poles.

Street lamps according to this invention can be used for Minor roads as well as for major highways and expressways. At present Minor roads all use 80W High Pressure Mercury Vapour lamps consuming 96W to 110W including ballast loss. This can be replaced with a 24W LED unit constructed in accordance with this invention consuming just 24W , giving a saving of about 78 % or more. For better LEDs with higher lumen outputs, this wattage can be reduced to about 18W or less resulting in savings of more than 81%.

If automatic reduction of light levels after Midnight and after 3 AM is included there are savings of more than 84% energy, up to 90%.

Light fittings constructed in accordance with this invention are also very light in weight compared to the present High Intensity Discharge lamps (HID) including High Pressure Mercury Vapour (MV), High Pressure Sodium (HPS), Metal Halide (MH), and induction lamps etc. Typical weight of this unit for replacing a 250W HPS street light is about 4 kg complete with power drive and control units compared to about 8 to 10 kg.

The lamp in accordance with this invention may also be dimmed by using simple known timers to reduce number of LEDs lit according to time of day. For example. At Midnight, when there is less traffic, some of the LEDs can be cut out to reduce light level to say 70%. At say 3 AM in the morning there can be further reduction to say 50% or less. And, by rotating the LED lamps turned off after midnight and early morning, the average number of hours each LED lamp is used each night can be reduced by more than 30%. Hence, the average life of the whole lamp can be increased by also more than 30%. That is, from the normal 50,000 to 60,000 hours to about 65,000 to 80,000 hours or more. That means the whole lamp will not need any maintenance for more than 20 years.

The angle of the 2 side panels 6 of the LED mounting rail preferably may also be adjustable to suit the spacing of the lamp poles. For example, for existing main roads where the poles are spaced at 32 m, the angle can be adjusted to 45 or 50 degrees to the horizontal, so that the light is concentrated along the roadway to 16m either side of the pole.

For new roads the poles can be spaced at say 50 m or 60 m to save energy by adjusting the angle to say 65 to 70 degrees.

For places where there is frequent occurrences of fog, the LEDs can be changed to a warm white colour or have a yellowish tint added to the transparent cover to give a fog light.

Another possible modification according to this invention for smaller minor roads is the replacement of the LEDs with 2 or more units of T5 fluorescent lamps each fitted with matching parabolic mirror surface reflectors mounted on similar V-shaped mounting rail , but without heat dissipating fins, plus having a V-shaped mounting plates but no LEDs . The effect will be similar to the LEDs in throwing light where light is needed, but with less output. For example, instead of using 24W LEDs in the lamp, it is possible to use 2 x T5-14W fluorescent lamps mounted on the sides of the V shape plate. Each T5 unit is preferably a complete luminaire with its own integral ballast mounted inside.

It will thus be appreciated that this invention at least in the form of the embodiments described provides a novel and improved form of light installation for illuminating outdoor areas such as roadways parks and car parking areas, and amusement and recreation areas. Clearly however the examples described are only the currently preferred forms 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 light base and cover, the number and arrangement of the LEDs and the means for attachment to the supporting pole may be changed following further development work by the inventor. And, the methods of constructing this lamp can be either by moulded aluminium with fins for heat sinks, or by extruded and drawn aluminium alloy sections with fins and joined together with the V-shaped mounting rail for mounting the LEDs and focusing lens and reflectors. The transparent cover for this type of embodiment can also be made from exstruded and drawn transparent materials such as Acrylic, PC or other suitable materials.

By changing one end cap of the lamp to the one without spigot, and by adding two hooks to the top of the lamp , this light fitting can be hung from the ceiling and used as a High Bay light for replacing the traditional High Bay lamps. Current state of the art High Bay lamps usually use HID lamps such as MV , HPS or MH lamps of 150W, 250W, 400W or 600W, up to 1000 W. These are typically circular in shape and provides a circular shaped light spot on the ground. This invention, when used as a High Bay light, will have the advantage of providing very even rectangular shaped light on the ground with no dark areas typically caused by circular High Bay lamps. And it saves up to 80 % energy by throwing light where light is needed, with very even light distribution.

Claims

The claims:

1. A light fitting for illuminating an outdoor area such as a roadway or the like, said light fitting including a base with a substantially transparent or translucent cover to define an interior cavity and a plurality of light emitting elements mounted within said cavity whereby when said fitting is in an elevated configuration of use with said base disposed upwardly and the cover below said light emitting elements illuminate downwardly through said cover and at least some of said light emitting elements being mounted at a lateral angle relative to said light fitting to direct light onto selected regions of said area adjacent to those immediately underneath said light fitting.

2. The light fitting as claimed in claim 1 wherein said light emitting elements are light emitting diodes.

3. The light fitting as claimed in claim 2 wherein said light emitting diodes are disposed in one or more rows along inclined sides of a V-shaped mounting rail within said cavity.

4. The light fitting as claimed in claim 3 wherein said light emitting diodes are fitted to printed circuit boards which in turn are fixed to the inclined sides of said v-shaped mounting rail.

5. The light fitting as claimed in claim 3 wherein said V-shaped mounting rail is

adapted to act as a heat sink and said mounting rail and base are formed with heat dissipation fins.

6. The light fitting as claimed in claim 3 wherein at least some or all of said light

emitting diodes are fitted with light directing reflectors and focussing lens.

7. The light fitting as claimed in claim 4 wherein said base and cover are elongated and light from said light emitting diodes is directed out through the long sides of said cover at a downwardly directed angle.

8. The light fitting as claimed in claim 7 wherein said downwardly directed angle is between 45 to 50 degrees relative to the horizontal, or at other angle of inclination to suit the spacing of the adjacent lamp poles.

9. The light fitting as claimed in claim 3 wherein there are one or more additional rows of light emitting diodes (LEDs) mounted between the inclined sides of said V- shaped mounting rail to illuminate directly below said light fitting, and LEDs mounted on the flat base of the inverted V-shape rail to provide light directly below the lamp pole.

10. The light fitting as claimed in claim 9 wherein said light fitting

further includes a photocell light switch, said switch being adapted

to antomatically switch the light emitting diodes on or off

depending upon ambient light, with appropriate time delays of up

to about 60 seconds to cater for lightning or light from passing car

head lights.

1 1. The light fitting as claimed in claim 10 wherein grooves are formed

in the cover to diffuse light downward and reduce glare.

12. The light fitting as claimed in claim 1 wherein said fitting is adapted

for mounting onto a lamp pole and said base is formed with a boss

and spigot hole at one end thereof for receiving an end of said lamp

pole.

13. The light fitting as claimed in claim 12 wherein a watertight grommet is

located at the base of the spigot hole through which a power cable can

pass from said lamp pole into said cavity for connection to a terminal

block.

14. The light fitting as claimed in claim 13 wherein said power cable ends in

a plug and socket which is adapted to connect with a source power cable associated with said lamp pole and housed inside the watertight

terminal chamber at one end cap with the spigot..

15. The light fitting as claimed in claim 2 wherein said light fitting includes

timing means for controlling the number of light emitting diodes that are lit during operation of said light fitting, thereby saving energy

and reducing the actual number of hours each LED is lit each night..

16. The light fitting as claimed in claim 1 wherein said light fitting includes

a solar panel, battery and charger-controller for remote installations without a power supply.

17. The light fitting as claimed in claim 1 wherein said light fitting includes

a wireless transmitter to send wireless signals to a central control

regarding the off/on status of said light emitting elements or lamp pole.

18. The light fitting as claimed in claim 1 wherein said wireless transmitter

is adapted to transmit to an adjacent or several adjacent light fitting

whereby said wireless signal is relayed to the central control using

reduced power.

19. The light fitting as claimed in claim 2 wherein each light emitting

diode consumes about 1 watt of power, or higher power as necessary for higher light outputs.

20. The light fitting as claimed in claim 1 wherein said light emitting

elements are fluorescent lamps fitted with parabolic reflectors.

21. The light fitting as claimed in claim 1 wherein it is modified to become a High Bay light fitting for replacing traditional HID High Bay lamps which normally throw a circular spot light, saving up to 80% energy, and providing evenly distributed light to where light is needed.

22. The light fitting as claimed in claim 1 wherein a watertight chamber

with door is provided on one end cap where the power cable can be terminated.