Interchangeable drain disinfecting device with UV source irradiation optimization

1. A disinfecting device for disinfecting the interior of a drain pipe leading from a drain inlet of a sink basin to a U-shaped trap beneath the sink basin, the device comprising a drain pipe section below or downstream of the sink drain inlet, said drain pipe section having a cylindrical tubular wall having a substantially circular cross-section and having a predetermined thickness and defining an interior space and interior surface and formed with a hole in said tubular wall between the sink drain inlet and the U-shaped trap; at least one UV-C LED module positioned to register with said hole and including a UV-C LED that when energized generates a radiation beam having a predetermined radiation angle “θ” to transmit UV-C light into said drain pipe section through said hole to irradiate at least a portion of said interior surface and pathogens contained therein with UV-C light in proximity to said drain inlet; a substantially flat transparent lens having a diameter “D” and at least partially coextensive with said tubular wall thickness and arranged within said hole, said lens having an inwardly facing surface substantially tangent to a point on said interior surface of said tubular wall aligned with said hole; and energizing means for energizing said at least one UV-C LED module, said UV-C LED being spaced a distance from said lens a predetermined distance “s” and a thickness “t” to cause said radiation beam to irradiate said inner surface along at least a portion of said drain pipe proximate to said lens, wherein

s=D/[ 2 tan(θ/2)]− t,

whereby energizing said at least one UV-C LED module maximizes exposure of pathogens on said interior surface and airborne pathogens within said interior space to said UV-C conical radiation beam and reduces the ability of pathogens from entry into the sink basin.

2. A drain disinfecting device as defined in claim 1 , wherein said UV-C LED module is removably attachable to said drain pipe section.

3. A drain disinfecting device as defined in claim 2 , wherein a threaded sleeve is fixedly secured to said drain pipe section and wherein said UV-C LED module comprises a threaded member threadedly engageable with said threaded sleeve and configured to position said UV-C LED at said predetermined distance when said sleeve and said member are fully threadedly engaged.

4. A drain disinfecting device as defined in claim 3 , wherein said sleeve is internally threaded and said member is externally threaded.

5. A drain disinfecting device as defined in claim 4 , wherein said sleeve is a circular cylinder having one axial end fixed to said drain pipe section and having an opposing axial end formed with a first annular surface and said member being formed with a second annular surface; and further comprising an annular washer interposed between said first and second annular surfaces.

6. A drain disinfecting device as defined in claim 5 , wherein said washer has a thickness selected to provide a seal between said sleeve and said member and to position said UV-C LED at said predetermined distance from said lens when said first and second annular surfaces abut against said washer when said sleeve and said member are fully threadedly engaged.

7. A drain disinfecting device as defined in claim 1 , wherein said UV-C LED generates a radiation beam having a radiation angle θ of 120°, said lens having a diameter of D equal to 0.625 inches and a thickness t of 0.08 inches and said UV-C LED is spaced 0.1 inches from said lens.

8. A drain disinfecting device as defined in claim 1 , wherein said UV-C LED module is removably attachable to said drain pipe section.

9. A drain disinfecting device as defined in claim 7 , wherein said distance does not exceed 0.2 inches.