LAMP FOR TRANSMITTING ULTRAVIOLET LIGHT

Abstract: A lamp for emitting ultraviolet light and illuminating objects for inspection purposes, such as detecting oil leakages in jet engines. The lamp comprises a reflector (1), a light source (2) for emitting ultraviolet light, and a filter (3) for filtering-out light within the visible spectrum. The invention is characterized in that the light source (2) is comprised of a gas discharge tube having an electrode distance of less than 5 mm.

Description: Lamp for Transmitting Ultraviolet Light The present invention relates to an ultraviolet lamp. • I 5 More specifically, the invention relates to a lamp of the kind used to detect oil leakages in jet engines, among other things. Oil will fluoresce when illuminated with ultraviolet 10 light and such lighting is therefore used to detect oil leakages in jet engines, among other things, oil leakages from other sources are also traced with the aid of ultraviolet lighting. 15 Ultraviolet light is also used in other determining contexts, for instance to determined between different types of rock. A known oil leakage detecting lamp includes a parabol- 20 ic reflector and a conventional gas discharge tube or bulb, which has an electrode distance of 30 to 70 mm. The use of such a tube renders the lamp very large and awkward. 25 One problem with the known lamp is that focusing of the light becomes poor because of the large electrode distance. In turn, this means that the wattage of the tube must be as high as 110 W. Despite this high wattage, it is necessary to hold the lamp close to the 30 object concerned, as close as 30 cm or even closer, in order to enable oil leakages in jet engines to be " * detected, for instance. This makes it very difficult > to handle the lamp, particularly when the inspection i or control needs to be carri.ed out i.n confi.ned spaces. 35 The present invention solves these problems and pro¬ vides a lamp which is compact, easy to operate and effective. The present invention thus relates to a lamp which emits ultraviolet light and is intended for illuminat¬ ing objects for inspection purposes, such as for detecting oil leakages in jet engines, said lamp including a reflector, a light source which emits ultraviolet light, and a filter for filtering-out light within the visible spectrum, said lamp being characterized in that the light source is comprised of a gas discharge tube having an electrode distance of less than 5 mm. The invention will now be described in more detail with reference to an exemplifying embodiment thereof and also with reference to the accompanying drawing, the Figure 1 of which is a schematic longitudinal section view of an inventive lamp. Figure 1 illustrates a lamp for emitting ultraviolet light and intended for irradiating objects for inspec- tion purposes, such as to detect oil leakages in jet engines. The lamp includes a reflector 1, a light source 2 for emitting ultraviolet light, and a filter 3 for filtering-out light within the visible spectrum. The filter 3 is suitably comprised of so-called Wood's glass. The filter may be included in a lamp-covering glass, or may alternatively be placed in some other location in the beam path, for instance around the light source. According to the invention, the light source 2 is com¬ prised of a gas discharge tube which has an electrode distance of less than 5 mm. This enables the reflector to focus the light generated by the light source to an area corresponding to the light aperture of the re- fleeter, for instance. The reflector may, for ins¬ tance, have an aperture diameter of 135 mm, although said diameter may, of course, be both larger and smaller. The reflector is suitably a parabolic round reflector. A light source developed by Philips under the designa¬ tion 35 DI UV -constitutes one example of a light source that can be used with the inventive lamp. This tube is a mercury discharge tube of the gas discharge 5 type having an electrode distance of 4.2 mm. The % discharge tube has a wattage of 35 W. Surprisingly, it has been found that when using the inventive lamp fitted with the aforesaid discharge 10 tube, it is possible to detect oil leakage at a dis¬ tance as far away as roughly 25 metres, when irradiat¬ ing the object concerned, which shall be compared with the known lamp which must be held as close as 30 centimetres to the object to be inspected. 15 It is quite evident that the inventive lamp provides completely different possibilities of detecting oil leakages to those afforded by the known lamp, particu¬ larly when the space available is limited. 20 According to one preferred embodiment, the lamp is supplied with a high frequency voltage from a power means 4. The power means is intended to deliver in a discharge tube ignition phase a high frequency voltage 25 at high voltage, preferably exceeding 10 kHz at a voltage higher than 10 kV. The power means may be of any known kind and may, for instance, deliver 15 kV at 11.5 kHz during the igni- 30 tion phase. The discharge tube will then ignite imme¬ diately. The known lamp is connected directly to the ^ mains supply through the agency of a reactor, although without the provision of the aforesaid power means, resulting in an ignition time of about 5 minutes. 35 While the lamp is in operation, the power means can supply the discharge tube with 85 V at 11.5 kHz, i.e. with a much lower voltage. Reference numeral 7 identifies the lamp housing, while reference numeral 8 identifies a cable for connecting the lamp to the mains supply network. According to one preferred embodiment of the inven¬ tion, the power means 4 is integrated with the lamp. ' It is also possible for the lamp to include a battery 5, so that the lamp can be run on battery power. In this case, the battery will preferably be a compact lead accumulator or an Ni/Cd-battery. The use of a battery powered lamp provides a complete¬ ly different degree of flexibility in investigatory work than when the lamp must be connected to a mains supply source and provided with the cables to this end. The present invention may be varied as regards the aforesaid voltages and frequencies and structural configuration of the lamp. The present invention is not therefore considered to be restricted to the aforedescribed embodiments, since variations can be made within the scope of the following Claims.

Claims: Claims 1. A lamp for emitting ultraviolet light and irradi¬ ating objects for inspection purposes, such as for 5 detecting oil leakages in jet engines, said lamp comprising a reflector (1), a light source (2) for emitting ultraviolet light, and a filter (3) for filtering-out light within the visible spectrum, c h a r a c t e r i z e d in that the light source 10 (2) is comprised of a gas discharge tube having an electrode distance of less than 5 mm. 2. A lamp according to Claim 1, c h a r a c ¬ t e r i z e d by a power means (4) which functions to 15 supply the lamp with high frequency voltage and which is intended to deliver in a discharge tube ignition phase a high frequency voltage at high voltage, pref¬ erably exceeding 10 kHz at a voltage higher than 10 kV. 20 3. A lamp according to Claim 2, c h a r a c ¬ t e r i z e d in that the power means (4) is integral with the lamp; and in that the lamp includes a facili¬ ty for including a battery (5) so as to enable the 25 lamp to be operated on battery power. - /

Inventors: BERGKVIST LARS A, BERGKVIST, LARS, A.
Applicants: BERGKVIST LARS A, LABINO PATENT AB
Application year: 1993
Main classification: G01M3
IPC codes: F21V9, G01M3, H01J61