Detector with coated lens assembly

• US 7,026,619 B2
• Filed: 09/30/2004
• Issued: 04/11/2006
• Est. Priority Date: 02/20/2004
• Status: Active Grant

• Current Assignee: Suppression Technologies Incorporated
• Original Assignee: Suppression Technologies Incorporated
• Inventors: Cranford, Ronald D.
• Primary Examiner(s): Hannaher, Constantine
• Application Number:
  US10/954,324
• Publication Number:
  US 20050184240A1
• Time in Patent Office: 558 Days
• Field of Search: 250/353
• US Class Current: 250/353
• CPC Class Codes: G01J 5/0022 for sensing the radiation of moving bodies
• CPC Class Codes: G01J 5/02 Constructional details
• CPC Class Codes: G01J 5/0205 Mechanical elements; Supports for optical elements
• CPC Class Codes: G01J 5/04 Casings
• CPC Class Codes: G01J 5/042 High-temperature environment G01J5/0007, G01J5/0044, G01J5/0088 and G01J5/004 take precedence
• CPC Class Codes: G01J 5/046 Materials; Selection of thermal materials
• CPC Class Codes: G01J 5/068 by controlling parameters other than temperature
• CPC Class Codes: G01J 5/08 Optical arrangements
• CPC Class Codes: G01J 5/0802 Optical filters
• CPC Class Codes: G01J 5/0806 Focusing or collimating elements, e.g. lenses or concave mirrors

Abstract

A spark detector lens assembly is adapted to block energy from static electric discharges. The lens assembly includes a housing which receives a lens. The lens is adapted to pass infrared frequency energy therethrough. A conductive coating is disposed on one side of said lens, which is effective to block radio frequency energy but pass infrared frequency energy. The conductive coating may be electrically connected to an electrical ground path. The lens assembly is especially effective for preventing false alarms by shielding a spark detector from radio frequency energy radiated by static electric discharges.

Claims

1. A spark detector comprising:

a duct adapted to pass a flow of flammable material therethrough;

a spark sensor responsive to the impingement of radiation thereon;

a lens adapted and positioned to receive infrared energy from said duct and pass said energy therethrough to said spark sensor;

a conductive coating disposed on one side of said lens, said coating effective to block radio frequency energy but pass infrared energy therethrough; and

an electrical ground path connected to said coating.

2. The spark detector of claim 1 further comprising an electrically conductive housing which receives said lens.

3. The spark detector of claim 2 wherein said conductive coating is electrically connected to said housing.

4. The spark detector of claim 3 wherein a conductive epoxy is disposed in contact with said conductive coating and said housing.

5. The spark detector of claim 2 wherein said conductive coating comprises indium-tin-oxide.

6. The spark detector of claim 2 wherein the thickness of said coating is from about 1 micrometer to about 4 microns.

7. The spark detector of claim 6 wherein the thickness of said coating is about 1 micrometer.

8. The spark detector of claim 2 wherein said housing is mounted in a casing.

9. The spark detector of claim 8 wherein said casing is electrically conductive and said casing is connected to an electrical ground path.

10. The spark detector of claim 8 wherein said casing comprises high temperature plastic.