A MARKER BEACON

Abstract: A marker beacon comprising one or more planar surfaces and intended to be seen by those at sea which is characterized by the combination in which the surfaces (2, 3, 4) are provided with a fluorescent paint which transmits light in the visible waveband when irradiated with ultraviolet light, and in which a lighting arrangement (7, 8) is provided for illuminating the surfaces (2, 3, 4) with light containing a high proportion of ultraviolet light.

Description: A Marker Beacon The present invention relates to a marker beacon, and more / particularly to an illuminated marker beacon. There are many kinds of beacons . A marker beacon is a type of beacon which in recent years has been standardized in Sweden to the form of pyramidal box having a height of about 1 . 5 meter s. Certain beacons , such as pyramidal marker beacons, are illuminated at night, so as to be more readily seen by those at sea. In Sweden newly erected marker beacons are painted with a so-called daylight luminous paint, i. e. a paint which transmits light of visible wavelength when irradiated with ultraviolet light. Thus, the ultraviolet light present in the sunlight falling on the beacon will cause the beacon to fluouresce, so that it can be readily seen in daylight. Red is the most commonly used daylight luminous paint employed in this respect. In order to make the marker beacon visible at night, it is illuminated with the aid of a lighting arrangement or lamp unit, such as a halogen lamp, which shines with a relatively white light. A beacon which is illuminated i this way, however, can only be seen from a distance of about 1 . 5 nautical miles . When drawing away from such a beacon at night, the naked eye sees pro¬ gres sively more and more white in the light emanating from the beacon, and consequently progressively less red light. At a distance of about 1 . 5 nautical miles, the beacon is seen as a white lamp, resembling approximately a stationary street lamp or some other source of white light. One of the reasons for this is that the light cast by the lamp unit onto the surroundings in the vicinity of the beacon illuminates an area which is far greater than the surface area of the beacon itself, while the solid angle included by the beacon, measured from the eye, is extremely small at a distance of 1 . 5 nautical miles . Consequently, at distances such as these, the light which illuminates the surroundings dominates over the light reflected by the beacon. This means that in practice it is not possible with the naked eye to distinguish an illuminated marker beacon from a street lamp, an outdoor lamp attached to a house or like building, or a correspond¬ ing light sour ce. Consequently, in order to be able to identify a marker beacon with the naked eye at greater distances , it is necess ¬ ary to know the bearing of the beacon concerned. This is a most unsatisfactory condition, since the concept of a beacon is conversely that it should be pos sible to identify first the beacon and then to establish one 's own position, inter alia by - taking a bearing on the beacon. It is practically impossible to descern an illuminated marker beacon at distances greater than 1. 5 nautical miles in fairways which include many buildings and where other stationary lighting is to be found. These problems are solved by means of the present invention. Accordingly, the present invention relates to a marker beacon which includes one or more planar surfaces and is intended to be seen by those at sea, characterized by the combination in which said sur ¬ faces are provided with a fluourescent paint which when irradiated by ultraviolet light transmits light of visible wavelength; and in which a lighting arrangement is provided to irradiate said surfaces with light containing a high proportion of ultraviolet light. An examplifying embodiment of a marker beacon according to the invention will now be described in more detail with reference to the accompanying drawing, in which Figure 1 is a side view of a marker beacon according to the invention; and, Figure 2 illustrates the marker beacon of Figure 1 from above. Figure 1 shows a marker beacon 1 as seen from one side, i. e. as seen by thos e on the seaward side of the beacon. Figure 2 shows the beacon 1 f rom above. According to one preferred embodiment there is used a - marker beacon 1 of substantially pyramidal configuration and having a square cross -sectional shape in the horizontal plane, as shown in Figure 2. The beacon suitably comprises three sheet-metal side- panels 2, 3 , 4. Each of the panels has the shape of an equilateral triangle, with a side length of 1 . 8 meters . This construction is used in those cases when the side 5 to which no panel is fitted faces inland. Naturally, the beacon may be fitted with two or four side panels . The outer surfaces of respective panels 2, 3 , 4 are coated with a paint which fluouresces when irradiated with ultraviolet light and reflects light having a wavelength which lies within the visible spectrum, i. e. a so-called daylight luminous paint. The paint used is preferably one which when irradiated with ultraviolet light, trans ¬ mits light within the red region of the spectrum. The illustrated beacon incorporates a lighting arrangement 6, 7, 8 for the transmis sion of ultraviolet light. The lighting includes, for example, two lamp units 7, 8 , each of which comprises a light source in the form of a mercury lamp. The lighting arrangement is preferably constructed to transmit light in the wavelength band of 360 - 370 nanometer s . According to one preferred embodiment, the lighting arrangement is so constructed that the light source, optionally in combination with the cover glas s of the lamp units , transmits no light within the visible spectrum. This means that no part of the surroundings will be illuminated in a manner discernible to the eye . The lamp units are suitably carried by a frame 6 and are so mounted that the light pas sing through respective light apertures illuminates all the side panels 2, 3 , 4 of the beacon. In this regard, an advantage is gained when the lamp units are constructed so that substantially all light transmitted falls within the sector s indicated in broken lines in Figure 1 , since ultraviolet light which falls outside the beacon serves no useful purpose. A marker beacon constructed in accordance with the in¬ vention is a remarkable improvement on beacons illuminated with white light, especially during the dark hours . Practical tests have shown that when a marker beacon constructed in accordance with the invention and having the aforesaid dimensions is illuminated by two lamp units each of 125 W and transmitting ultraviolet light, there is seen solely an. intensive red light, even at distances of up to about 5 nautical miles . Since the surroundings are not illuminated in a manner to be visible to the eye, the beacon is seen only as an intensive red light. In addition to being visible over distances which are four times greater than those pos sible when using visible light, the beacon can be readily distinguished from other fixed land lighting. A marker beacon according to the invention thus constitutes a remarkable improvement for those at sea. In the aforegoing the marker beacon has been described by way of an example as having a pyramidal form, although it will be understood that beacons of other configurations and other types also fall within the scope of the invention. The present invention is therefore not restricted to the - aforedescribed embodiments, and modifications thereto can be carried out within the scope of the following Claims .

Claims: CLAIMS 1 . A marker beacon which incorporates one or more planar surfaces and which is intended to be seen by those at sea, character ¬ ized by the combination in which said surfaces (2, 3 , 4) ar e coated with a fluourescent paint which transmits light of visible wavelength when irradiated with ultraviolet light, and in which a lighting arrange ¬ ment (7 , 8 ) is provided for irradiating said surfaces (2, 3 , 4) with light containing a high proportion of ultraviolet light. 2. A marker beacon according to Claim 1 , characterized in that the light source of the lighting arrangement (7 , 8) , optionally in combination with a cover glas s, is arranged so as to transmit substantially no light within the visible light spectrum. 3. A marker beacon according to Claim 1 or 2, character ¬ ized in that said surfaces (2, 3 , 4) ar e provided in a known manner with a paint which when irradiated with ultraviolet light transmits a visible wavelength within the red ar ea; and in that the lighting arrangement (7, 8) is arranged to transmit light of a wavelength of about 360 - 370 nanometer s . 4. A marker beacon according to Claim 1 , 2 or 3 , characterized in that the beacon (1 ) has a pyramidal configuration and a square cros s section in the horizontal plane .

Inventors: BERGKVIST LARS ANDERS, BERGKVIST, LARS, ANDERS
Applicants: BERGKVIST LARS A, BERGKVIST, LARS, ANDERS
Application year: 1985
Main classification: B63B51
IPC codes: B63B51, E01F9, G09F13