Lighting apparatus with forced air circulation Technical Field
The present invention relates to lighting apparatus and, in particular, to lighting apparatus according to the preamble to the first claim. Background Art
Various types of lighting apparatus are commonly used for distributing a luminous flux supplied by suitable lamps in a surrounding environment . Most lamps have an extremely high working temperature so that their operation is associated with the production of a considerable amount of heat; in practice, most of the electrical energy absorbed by the lamps (about 90%) is dissipated in the form of heat whereas only a minimal portion (about 10%) is used to produce the luminous flux. The air heated by the lamps immediately rises in the environment; in cold seasons, this heat does not therefore contribute to the heating of the lower portions of the environment normally used by people. Similarly, the heat supplied by heating systems is concentrated mainly in the upper portions of the environment, creating a non-uniform temperature distribution.
Known lighting apparatus of the type which stands on the ground takes air from the upper portion of the environment, heats it by causing it to pass in the vicinity of the lamp, and readmits it to the lower portion of the environment with a forced circulation, thus recovering some of the heat produced by the lamp and by any heating system, in particular, the air enters the upper portion of a tube, passes through a double glass where it absorbs heat from the lamp, passes through a heating resistor, and is drawn in and forced out by a fan.
A disadvantage of the lighting apparatus described above is that the heat produced by the lamp is not used in an optimal manner; in particular, the hot air outside the double glass is dispersed in the environment and rises directly upwards, only a minimal portion being recovered.
Moreover, the double glass structure causing the air to pass in the vicinity of the lamp greatly limits the freedom of design of the lighting apparatus, affecting its appearance to a large extent . Disclosure of the Invention
The object of the present invention is to prevent the aforementioned problems. To achieve this object, lighting apparatus as described in the first claim is proposed.
The lighting apparatus of the present invention enables substantially all of the heat produced by lamps to be recovered in an optimal manner. Moreover, the system for the forced circulation of the air also returns downwards the hot air produced by any other heat source (for example, by heating systems, by people, by household appliances) , ensuring a more uniform ambient temperature. The lighting apparatus according to the present invention achieves a considerable energy saving with a reduction of up to 50% in heating costs.
The movement of air in the vicinity of the lamps also eliminates unpleasant odours and, in particular, cigarette smoke,- this also prevents overheating of the lamps, extending their life.
Finally, the structure according to the present invention does not adversely affect the external appearance of the lighting apparatus, enabling particularly excellent aesthetic
effects to be achieved. Brief Description of Drawings
Further characteristics and advantages of the lighting apparatus according to the present invention will become clear from the following description of a preferred embodiment thereof, given by way of non-limiting example with reference to the single appended drawing which shows the lighting apparatus in a schematic view. Best Mode of Carrrying out the Invention
The drawing shows lighting apparatus 5, particularly of the standard (or pedestal) type; the present invention may, however, also be implemented with lighting apparatus of other types, such as a ceiling lamp, a wall lamp, or a table lamp. The lighting apparatus 5 is generally used in an inside environment but its external use, for example, in the vicinity of tables in public premises (bars, restaurants) disposed out of doors even in cold seasons is not excluded.
The lighting apparatus 5 includes a tubular duct 10 formed, for example, by a tubular element having a height of about 2m, with funnel-shaped upper and lower ends having an intake opening 15 and an outlet opening 20, respectively; when the lighting apparatus 5 is in use, the tubular element 10 is arranged vertically so that the intake opening 15 is arranged above the outlet opening 20, which is generally disposed close to the floor.
The lighting apparatus 5 is suitable for use with one or more lamps 25, preferably halogen lamps; alternatively, incandescent lamps, neon lamps, or other equivalent artificial light sources may be used. An upper portion of the tubular
element 10 has an external threaded structure onto which an element 30 for the mechanical support and electrical connection of the lamp 25 is screwed (for example 50cm from the upper end) ; typically, the support element 30 comprises three seats 35, for example, threaded sockets, spaced at 120° intervals about an axis of the tubular element 10 and each housing a corresponding lamp 25.
The tubular element 10 is engaged, in the vicinity of its lower end, in a base 40 which bears on the ground and acts as a support for the entire lighting apparatus 5. One or more slots 45 formed in the base 40 in the region of the outlet opening 20 put the tubular element 10 into communication with the surrounding environment. In the vicinity of the outlet opening 20 there is a fan 50 (with a flow rate, for example, of 80m3/h) having a respective drive motor and conveying air from the intake opening 15 to the outlet opening 20. Alternatively, the fan 50 is disposed in a different position, for example, in the vicinity of the intake opening 15, or other equivalent devices are used. A supply cable 55 extending from the base 40 terminates in a connector 60 for connecting the lighting apparatus 5 to an electrical mains supply. A control unit 63 which includes a device (for example a switch) for selectively activating the lighting apparatus 5 is connected in series with the supply cable 55.
A protection element 65 disposed around the lamps 25 includes a glass diffuser 70 with a substantially frusto- conical lateral surface; a smaller rim of the diffuser 70 terminates in an inwardly-facing lip 75 which is fixed to the upper end of the tubular element 10 by means of a clamping ring
80. A support ring 76 terminating in a step 81 is screwed onto the tubular element 10 in the region of a larger-diameter rim of the diffuser 70; a disc-shaped element 85, preferably of Pyrex glass, (in which a radial mounting slot is formed) abuts the step 81 and is fixed to the support ring 76 by means of suitable screws (not shown in the drawing) . The radius of the disc-shaped element 85 is smaller than the radius of the larger rim of the diffuser 70 so that the disc-shaped element 85 is separated from the diffuser 70 in order to define an annular intake opening 87. The protection element 65 may, however, be formed with a different structure (for example, with a larger disc positioned below the larger rim of the diffuser or with a spherical shape with a lower circular opening) or even of different materials (for example, of transparent glass, with a reflecting parabola) .
The interior of the protection element 65 and of the tubular element 10 communicate with one another in a region above the intake opening 87. In particular, one or more slots 89, are formed in the lateral surface of the funnel disposed in the region of the intake opening 15, for example, six slots are disposed longitudinally and spaced at 60° intervals about the axis of the tubular element 10. In alternative embodiments of the present invention, the tubular element 10 extends further above the protection element 65 so that the intake opening 15 is in a higher position, or the protection element 65 is fixed below the intake opening 15 and is spaced from the tubular element 10 in order to define a further opening through which the air leaves the protection element 65; alternatively, the intake opening 15 is disposed inside the protection element
When the lighting apparatus 5 is switched on by the operation of the switch of the control unit 63, the lamps 25 are lit and the fan 50 is set in operation. The air taken into the protection element 65 by convection through the lower opening 87 is heated by the lamps 25 (and by the tubular element 10) so as to define a "reservoir", for example, of 30 1, of hot air at a substantially constant temperature of 70°. This hot air is admitted to the tubular element 10 through the slots 89 and is mixed with the external air forced through the intake opening 15 by the fan 50. The air in the tubular element 10, further heated by the tubular element upon passing in the vicinity of the lamps 25, is then drawn towards the outlet opening 20 where it is finally readmitted to the environment through the slots 45.
In a preferred embodiment of the present invention, the lighting apparatus 5 includes a resistor 90 (for example, a 200 Ω resistor) disposed in the tubular element 10, for example, just below the intake opening 15, for further heating the air forced towards the outlet opening 20.
The control unit 63 is preferably constituted by a central control unit for controlling the operation of the lighting apparatus 5. For example, the control unit 63 includes a variator for controlling the intensity of the luminous flux emitted by the lamps 25, and/or a timing device (a timer) for programming the automatic switching on and/or off of the lighting apparatus 5 at predetermined times. In a preferred embodiment of the present invention, the control unit 63 includes an electronic device for activating various modes of
operation of the lighting apparatus 5. For example, there may be a "winter day-time" type of operation in which only the lamps 25 and the fan 50 are switched on (with the resistor 90 switched off) , a "winter night-time" type of operation in which only the resistor 90 and the fan 50 are switched on (with the lamps 25 switched off) , and a "summer" type of operation in which only the lamps 25 are switched on. Moreover, the control unit 63 preferably includes a thermoregulation device for keeping the ambient temperature, shown by means of a suitable display, at a predetermined value; in particular, if the temperature detected is above the predetermined value, the control unit 63 interrupts the operation of the fan 50, whereas in the opposite situation the control unit switches on the resistor 90.
The control unit 63 is disposed outside the base 40; alternatively, however, the unit 63 may be housed inside the base 40 and the lighting apparatus 5 may be provided with a remote control for controlling the functions provided for.
The lighting apparatus 5 preferably includes further, emergency lamps 93, typically of lower power than the main lamps 25 and supplied by a buffer battery 95 which is disposed in the base 40 and is activated in the event of an interruption of the electrical supply. The emergency lamps 93 are preferably disposed on the support element 30 and housed in further seats 97, for example, threaded sockets, spaced at 120° intervals and offset by 60° relative to the seats 35 of the main lamps 25.
An ionizer of known type may possibly be associated with the lighting apparatus 5. The ionizer comprises one or more
electrodes 100 disposed inside the lower portion 101 of the tubular element 10 and a high-voltage (4000V) current generator or other equivalent ionization means.
Naturally, in order to satisfy contingent and specific requirements, an expert in the art may apply to the above- described lighting apparatus many modifications and variations all of which, however, are included within the scope of protection of the invention as defined by the following claims.