Patent Number: 062781251
Section: description

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The shielding assembly of the present invention protects a person from the harmful effects of radiation that is used to irradiate a radiation space, while permitting easy access to the space. The shielding assembly includes a radiation emitting device and a radiation shield that encloses the radiation space to prevent the leakage of radiation. Referring to the drawings, a shielded radiation assembly 100 includes a radiation shield 120, a radiation emitting device 160 and a support structure 115. The support structure 115 supports radiation emitting device 160 and radiation shield 120. The area enclosed by the radiation shield 120 defines a radiation space 190. Support structure 115 includes a generally planar base 150, an elongate upright support member 130 extending from the base 150, and a shield support frame 110. Shield support frame 110 is a rectangular frame-like member having four sides which define interiorly thereof radiated space 190. While a rectangular structure is shown in the drawings, support frame 110 may take any shape which forms a full or partial enclosure. The shield support frame 110 is attached to the upright support member 130 at one side 110a thereof by a frame fastening member 170 so as to overlie base 150. Preferably, the frame fastening member 170 is adjustable so that the shield support frame 110 can be moved to allow access to the base for maintenance or to position an object within the radiation space 190. Radiation shield 120 is preferably a curtain formed by a plurality of elongate, slat-like radiation shielding sections 122 that are vertically suspended from a support frame 110 in side-by-side fashion. FIG. 2 shows a top view of the shielded radiation assembly 100 with shielding sections 122 extending downwardly from the sides of support frame 110 so as to perimeterically enclose the radiated space. Each shielding section 122 is at least partially overlapped by another section 122. The shield sections 122 allow the radiation shield 120 to be manually penetrated at any point between adjacent shield sections 122 and thus provide easy access to the radiation space 190 for positioning and removing articles. The shield sections 122 of the radiation shield 120 allow the shield 120 to conform to the contour of the radiation space 190 and provide a substantially continuous enclosed shield that prevents the leakage of radiation from the radiation space 190. The radiation shield sections 122 can be either rigid or flexible and can be made from several different types of materials, including radiation absorbent materials, radiation reflective materials, metal coated materials, and coated thermoplastic materials. Where the sections 122 contain lead, the lead can be in the form of a layer or the sections 122 can be made of a material impregnated with lead. Other methods for forming radiation shields known in the art can also be used. The radiation shield 120 can be used in combination with various radiation emitting devices, including ultraviolet. In the preferred embodiment, the radiation shield 120 is used with radiation emitting devices that emit actinic radiation. As used herein, "actinic radiation" means radiation that is capable of producing chemical change. When actinic radiation is used to cure resin based adhesive materials, the term refers to electromagnetic radiation having a wavelength of about 700 nm or less which is capable, directly or indirectly, of curing the specified resin component of the resin composition. By indirect curing in this context is meant curing under such electromagnetic radiation conditions, as initiated, promoted, or otherwise mediated by another compound. Actinic radiation includes ultraviolet and visible light. The most common criteria for selecting shielding materials are radiation attenuation, ease of heat removal, resistance to radiation damage, economy and structural strength. Based on the type of radiating emitting device that is used, the intensity of the radiation and the particular application, the selection of the radiation shield can vary. The overall thickness of the material is chosen to reduce radiation intensities outside the shield to levels well within prescribed limits for occupational exposure. The shield 120 can be fabricated from a variety of materials including radiation absorbent materials, radiation reflective materials, metal coated materials and coated thermoplastic materials. In a preferred embodiment, the shield 120 is made of a transparent acrylic copolymer resin. The radiation emitting device 160 is also attached to the support structure 115. Radiation emitting device 160 is adjustably supported to upright support member 130 by a device fastening member 140. The position of the radiation emitting device 160 can be adjusted vertically with respect to base 150 so that it can be moved closer to or further away from the object (not shown in figures) that is being radiated. The adjustable device fastening member 140 also allows the radiation emitting device 160 to rotate around the support structure 115 so that it can be more accessible for service and repair. The radiation emitting device 160 can be adjustably positioned at any point along the upright support member 130, according to how the shielded radiation assembly 100 is to be used. When an object is radiated, the radiation emitting device 160 can be lowered to provide a more intense radiation dosage. It also can be raised to provide a less intense radiation dosage or to accommodate larger objects. As illustrated in FIGS. 3 and 4, the radiation emitting device 160 can be positioned independently so that the position of the radiation emitting device 160 can be adjusted without having to readjust the position of the shield 120. Prior art devices, which use a curtain made up of a plurality of vertical sections to form the radiation shield, attach the curtain to the radiation emitting device 160. When the radiation emitting device 160 is lowered, the curtain bends and openings are formed between the vertical sections. These openings allow radiation to leak out of the enclosed space. The present invention overcomes this problem by maintaining the radiation shield 120 in position while the radiation emitting device 160 is either lowered or raised. Thus, the vertical sections 122 of the curtain do not fold open and the integrity of the shield is continuously maintained. The shielded radiation assembly 100 may also include a fan, radiating fins, liquid cooling system or a combination thereof for dissipating heat generated by the radiation emitting device 160. One or more cooling fans 180, as shown in the drawings, is preferred for dissipating heat. As shown in FIG. 6, cooling fans 180 can be located both above the radiation emitting device 160 and below the work surface defined by base 150. In a preferred embodiment, the radiation emitting device 160 is an ultraviolet lamp which can produce high temperatures. For example, a 300 watt/inch mercury vapor lamp that generates 800 MW/cm.sup.2 ultraviolet energy in the 360 nanometer region can produce temperatures in excess of 480.degree. F. in the radiation space. Over a prolonged period of time, these high temperatures can shorten the life of the lamp and can damage the radiation shield 120. Moreover, these high temperatures can damage the objects that are being irradiated. Many plastics and synthetic materials will begin to melt or deform at these temperatures. Therefore, in preferred embodiments that use an ultraviolet lamp, the shielded radiation assembly 100 includes the cooling fans 180 located above the radiation emitting device 160 and/or adjacent the base assembly 150 to provide convective cooling of the work space. Thus, while there have been described the preferred embodiments of the present invention, those skilled in the art will realize that other embodiments can be made without departing from the spirit of the invention, and it is intended to include all such further modifications and changes as come within the true scope of the claims set forth herein.