Photo-electric particle sensing system

• US 4,422,761 A
• Filed: 09/28/1981
• Issued: 12/27/1983
• Est. Priority Date: 09/28/1981
• Status: Expired due to Fees

• Current Assignee: Joseph C. Frommer
• Original Assignee: Joseph C. Frommer
• Inventors: Frommer, Joseph C.
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): Koren, Matthew W.
• Application Number:
  US06/305,974
• Time in Patent Office: 820 Days
• Field of Search: 356/336, 356/338, 356/339, 356/342, 356/244, 356/246, 356/317, 356/318, 250/573, 250/574, 250/576, 350/503, 350/504, 350/505, 350/294
• US Class Current: 356/338
• CPC Class Codes: G01N 2015/0238 Single particle scatter
• CPC Class Codes: G01N 21/47 Scattering, i.e. diffuse reflection G01N21/25, G01N21/41 take precedence G01N21/55 takes precedence

Abstract

A particle sensing system in which light is concentrated at an inspection zone and deflected light is concentrated at a photosensor. A first reflecting surface is shaped to direct light toward the inspection zone, and a second reflecting surface is shaped to direct light deflected by particles in the inspection zone toward the photosensor. These two reflecting surfaces can be shaped so that an overwhelming part of the directions around the inspection zone are utilized for illuminating it and to direct light deflected toward the photosensor. A third reflecting surface, having spherical curvature with the center of curvature at the inspection zone permits utilization of an overwhelming part of the remaining directions around the inspection zone.

Claims

1. A photoelectric system for sensing light deflected from its direction of propagation by small particles in a fluid comprising a source of light, a photosensor having a light sensitive surface, two spaced light concentration zones and an inspection zone, means for directing the fluid to the inspection zone, a first of the said light concentration zones receiving light from the source of light, the said inspection zone being created by providing a first light concentrating reflecting surface so designed and arranged that it concentrates light from said first of the light concentration zones into the inspection zone and a second light concentrating reflecting surface so designed and arranged that it concentrates light deflected by particles at the inspection zone from the inspection zone toward a second of the light concentration zones, the said light sensitive surface being so placed that it intercepts light concentrated by the said second light concentrating reflecting surface toward the second of the light concentration zones, one of the said reflecting surfaces being located wholly outside a full cone having its apex at the inspection zone and the other of the said reflecting surfaces being located wholly inside the said full cone, the first light concentrating reflecting surface being of annular shape, whereby the space traversed by rays that the annular reflecting surface can reflect from one of the zones associated therewith to the other of the zones associated therewith encloses a free space not traversed by these rays and the second light concentrating reflecting surface is positioned between the two zones associated with the annular reflecting surface inside the said free space.

2. A photoelectric system for sensing light deflected from its direction of propagation by small particles in a fluid comprising a source of light, a photosensor having a light sensitive surface, two spaced light concentration zones and an inspection zone, means for directing the fluid to the inspection zone, a first of the said light concentration zones receiving light from the source of light, the said inspection zone being created by providing a first light concentrating reflecting surface so designed and arranged that it concentrates light from said first of the light concentration zones into the inspection zone and a second light concentrating reflecting surface so designed and arranged that it concentrates light deflected by particles at the inspection zone from the inspection zone toward a second of the light concentration zones, the said light sensitive surface being so placed that it intercepts light concentrated by the said second light concentrating reflecting surface toward the second of the light concentration zones, one of the said reflecting surfaces being located wholly outside a full cone having its apex at the inspection zone and the other of the said reflecting surfaces being located wholly inside the said full cone, the second light concentrating reflecting surface being of annular shape, whereby the space traversed by rays that the annular reflecting surface can reflect from one of the zones associated therewith to the other of the zones associated therewith encloses a free space not traversed by these rays and the first light concentrating reflecting surface is positioned between the two zones associated with the annular reflecting surface inside the said free space.

3. In a system for sensing light deflected from its direction of propagation by small particles in a fluid comprising means to send the fluid along a predetermined fluid path, a source of illumination, a photosensor having a light sensitive surface, a first optical means so designed and arranged that it can direct illumination from the said source of illumination toward an inspection zone in the said fluid path, the said first optical means comprising a reflecting surface facing the inspection zone so designed and arranged that it concentrates light at the inspection zone, a second optical means so designed and arranged that it can direct light deflected by particles in the inspection zone toward the said light sensitive surface, the said second optical means comprising a second reflecting surface facing the inspection zone so designed and arranged that it can direct toward the said light sensitive surface light deflected by particles in the inspection zone and falling on it, one of the two said reflecting surfaces being located wholly outside a full cone comprising two half cones that may be drawn with its apex at the inspection zone, the other of the two said reflecting surfaces being located wholly inside one of the two said half cones, the said reflecting surface located outside the said full cone having an annular shape, the said reflecting surface located inside the said half cone being saucer shaped, the said two reflecting surfaces having elliptical curvature and being so designed and arranged that each reflecting surface conjugates the inspection zone with one of two light concentration zones, a spherical reflecting surface having its center of curvature at the inspection zone facing the inspection zone in a direction opposite to the direction in which the said saucer shaped reflecting surface faces the inspection zone, a transparent opening in the said spherical reflecting surface forming the light concentration zone with which the said saucer shaped reflecting surface conjugates the inspection zone.

4. In a system for sensing light deflected from its direction of propagation by small particles in a fluid comprising means to send the fluid along a predetermined fluid path, a source of illumination, a photosensor having a light sensitive surface, a first optical means so designed and arranged that it can direct illumination from the said source of illumination toward an inspection zone in the said fluid path, the said first optical means comprising a reflecting surface facing the inspection zone so designed and arranged that it concentrates light at the inspection zone, a second optical means so designed and arranged that it can direct light deflected by particles in the inspection zone toward the said light sensitive surface, the said second optical means comprising a second reflecting surface facing the inspection zone so designed and arranged that it can direct toward the said light sensitive surface light deflected by particles in the inspection zone and falling on it, one of the two said reflecting surfaces being located wholly outside a full cone comprising two half cones that may be drawn with its apex at the inspection zone, the other of the two said reflecting surfaces being located wholly inside one of the two said half cones, the said reflecting surface located outside the said full cone having an annular shape, the said reflecting surface located inside the said half cone being saucer shaped, the said two reflecting surfaces having elliptical curvature and being so designed and arranged that each reflecting surface conjugates the inspection zone with one of two light concentration zones, and a spherical reflecting surface having its center of curvature at the inspection zone facing the inspection zone in a direction opposite to the direction in which the said saucer shaped reflecting surface faces the inspection zone, a transparent opening in the said spherical reflecting surface clearing the path of rays between the said saucer shaped reflecting surface and the light concentration zone with which it conjugates the inspection zone.

5. In a system for sensing light deflected from its direction of propagation by small particles in a fluid comprising means to send the fluid along a predetermined fluid path, a source of illumination, a photosensor having a light sensitive surface, a first optical means so designed and arranged that it can direct illumination from the said source of illumination toward an inspection zone in the said fluid path, the said first optical means comprising a reflecting surface facing the inspection zone so designed and arranged that it concentrates light at the inspection zone, a second optical means so designed and arranged that it can direct light deflected by particles in the inspection zone toward the said light sensitive surface, the said second optical means comprising a second reflecting surface facing the inspection zone so designed and arranged that it can direct toward the said light sensitive surface light deflected by particles in the inspection zone and falling on it, one of the two said reflecting surfaces being located wholly outside a full cone comprising two half cones that may be drawn with its apex at the inspection zone, and the other of the two said reflecting surfaces being located wholly inside one of the two said half cones, the said reflecting surface located outside the said full cone having an annular shape, the said reflecting surface located inside the said half cone being saucer shaped, the said two reflecting surfaces having elliptical curvature and being so designed and arranged that each reflecting surface conjugates the inspection zone with one of two light concentration zones, the two said light concentration zones being located on a straight line traversing the inspection zone, creating thereby a common optical axis for the two reflecting surfaces.

6. A system as in claim 5 in which there is means that cause the fluid to be tested to traverse the said inspection zone in a stream centered around the said optical axis.

7. In a system for sensing light deflected from its direction of propagation by small particles in a fluid comprising means to send the fluid along a predetermined fluid path, a source of illumination, a photosensor having a light sensitive surface, a first optical means so designed and arranged that it can direct illumination from the said source of illumination toward an inspection zone in the said fluid path, the said first optical means comprising a reflecting surface facing the inspection zone so designed and arranged that it concentrates light at the inspection zone, a second optical means so designed and arranged that it can direct light deflected by particles in the inspection zone toward the said light sensitive surface, the said second optical means comprising a second reflecting surface facing the inspection zone so designed and arranged that it can direct toward the said light sensitive surface light deflected by particles in the inspection zone and falling on it, one of the two said reflecting surfaces being located wholly outside a full cone comprising two half cones that may be drawn with its apex at the inspection zone, and the other of the two said reflecting surfaces being located wholly inside one of the two said half cones, at least one of the said reflecting surfaces being a reflecting coating on the outside of a transparent body, in which an interior path is provided for sending the fluid to be tested through the said inspection zone, another part of the outside of the said transparent body being shaped spherically with the center of its curvature at the inspection zone and being covered at least partly with a reflecting coating.

8. In a photoelectric particle sensing system comprising a light source, a photosensor having a light sensitive surface, means to conduct a fluid to be tested on a predetermined path, a first reflecting surface suitable for directing light of the said light source toward an inspection zone which is a selected region of the said path, and a second reflecting surface suitable to direct toward the said light sensitive surface light leaving the said inspection zone in directions different from the directions in which the said first reflecting surface directs light toward the inspection zone, the improvement that one of the said two reflecting surfaces is of annular shape and faces the inspection zone from the outside of a full cone consisting of two half cones and having its apex at the said inspection zone, so that this reflecting surface can face the inspection zone from essentially all directions outside the said full cone, and the other of the said two reflecting surfaces is saucer shaped and faces the inspection zone from the inside of one of the said half cones, so that this other of the said two reflecting surfaces can face the inspection zone from essentially all directions inside the said half cone, the location of the said two reflecting surfaces facing the inspection zone being further limited to one side of a plane traversing the apex of the said full cone, and the system includes a third reflecting surface facing the inspection zone having spherical curvature with its center of curvature at the said inspection zone and facing the inspection zone from the other side of said plane.

9. In a system for sensing light deflected from its direction of propagation by small particles in a fluid comprising means to send the fluid along a predetermined fluid path, a source of illumination, a photosensor having a light sensitive surface, a first optical means so designed and arranged that it can direct illumination from the said source of illumination toward an inspection zone in the said fluid path, the said first optical means comprising a reflecting surface facing the inspection zone so designed and arranged that it concentrates light at the inspection zone, a second optical means so designed and arranged that it can direct light deflected by particles in the inspection zone toward the said light sensitive surface, the said second optical means comprising a second reflecting surface facing the inspection zone so designed and arranged that it can direct toward the said light sensitive surface light deflected by particles in the inspection zone and falling on it, one of the two said reflecting surfaces being located wholly outside a full cone comprising two half cones that may be drawn with its apex at the inspection zone, and the other of the two said reflecting surfaces being located wholly inside one of the two said half cones, the said reflecting surface located outside the said full cone having an annular shape, the said reflecting surface located inside the said half cone being saucer shaped, the location of the said two reflecting surfaces facing the inspection zone being further limited to one side of a plane traversing the apex of the said full cone, the system including a third reflecting surface facing the inspection zone having spherical curvature with its center of curvature at the said inspection zone and facing the inspection zone from the other side of the said plane, the said plane traversing the apex of the said cone being located outside the said full cone the said full cone having a centerline, and the said plane being perpendicular to the said centerline.

10. In a system for sensing light deflected from its direction of propagation by small particles in a fluid comprising means to send the fluid along a predetermined fluid path, a source of illumination, a photosensor having a light sensitive surface, a first optical means so designed and arranged that it can direct illumination from the said source of illumination toward an inspection zone in the said fluid path, the said first optical means comprising a first reflecting surface facing the inspection zone so designed and arranged that it concentrates light at the inspection zone, a second optical means so designed and arranged that it can direct light deflected by particles in the inspection zone toward the said light sensitive surface, the said second optical means comprising a second reflecting surface facing the inspection zone so designed and arranged that it can direct toward the said light sensitive surface light deflected by particles in the inspection zone and falling on it, one of the two said reflecting surfaces being located wholly outside a full cone comprising two half cones that may be drawn with its apex at the inspection zone, and the other of the two said reflecting surfaces being located wholly inside one of the two said half cones, the said reflecting surface located wholly outside the said full cone conjugating the inspection zone with a light concentration zone by rays which surround a space not traversed by these rays and the said reflecting surface located inside one of the said two half cones being arranged also inside the said space.

11. In a photoelectric system for sensing light deflected from its direction of propagation by microscopic or sub-microscopic particles in a fluid comprising means for sending the fluid along a predetermined fluid path, a light source, a non-transparent surface having a transparent opening therein between the light source and a zone of the fluid path, a photosensor having a light sensitive surface, a first reflecting surface so designed and arranged that it reflects rays reaching it from the said light source toward the transparent opening in the non-transparent surface, a second light reflecting surface so designed and arranged that it reflects light reaching it from the said transparent opening toward the said zone of the said fluid path, and a third light reflecting surface so designed and arranged that it reflects light reaching it from the said zone of the said fluid path toward the said light sensitive surface, the said third reflecting surface being of annular shape so that rays reflected by it from said zone toward the said light sensitive surface surround a space not traversed by these rays, and the said second reflecting surface being arranged inside this space not traversed by these rays.

12. In a photoelectric system for sensing light deflected from its direction of propagation by microscopic or sub-microscopic particles in a fluid comprising means for sending the fluid along a predetermined fluid path, a light source, a non-transparent surface having a transparent opening therein between the light source and a zone of the fluid path, a photosensor having a light sensitive surface, a first reflecting surface so designed and arranged that it reflects rays reaching it from the said light source toward the transparent opening in the non-transparent surface, a second light reflecting surface so designed and arranged that it reflects light reaching it from the said transparent opening toward the said zone of the said fluid path, and a third light reflecting surface so designed and arranged that it reflects light reaching it from the said zone of the said fluid path toward the said light sensitive surface, the said second reflecting surface being of annular shape so that rays reflected by it from the said transparent opening toward the said zone surround a space not traversed by these rays, and the said third reflecting surface being arranged inside this space not traversed by these rays.

13. In a photoelectric system for sensing light deflected from its direction of propagation by microscopic or sub-microscopic particles in a fluid comprising means for sending the fluid along a predetermined fluid path, a light source, a non-transparent surface having a transparent opening therein between the light source and a zone of the fluid path, a photosensor having a light sensitive surface, a first reflecting surface so designed and arranged that it reflects rays reaching it from the said light source toward the transparent opening in the non-transparent surface, a second light reflecting surface so designed and arranged that it reflects light reaching it from the said transparent opening toward the said zone of the said fluid path, and a third light reflecting surface so designed and arranged that it reflects light reaching it from the said zone of the said fluid path toward the said light sensitive surface, the system including a fourth reflecting surface having spherical curvature with the center of its curvature at the said zone of the fluid path so that it reflects light reaching it from the said zone back toward the said zone, the said second and third reflecting surfaces facing the said zone of the fluid path from one side of a plane through the said zone and the said fourth reflecting surface facing it from the other side of this plane.

14. In a photoelectric particle sensing system comprising a light source, a photosensor having a light sensitive surface, means to conduct a fluid to be tested on a predetermined path, a first reflecting surface suitable for directing light of the said light source toward an inspection zone which is a selected region of the said path, and a second reflecting surface suitable to direct toward the said light sensitive surface light leaving the said inspection zone in directions from the directions in which the said first reflecting surface directs light toward the inspection zone, the improvement that one of the said two reflecting surfaces is of annular shape and faces the inspection zone from the outside of a full cone consisting of two half cones and having its apex at the said inspection zone, so that this reflecting surface can face the inspection zone from essentially all directions outside the said full cone, and the other of the said two reflecting surfaces is saucer shaped and faces the inspection zone from the inside of one of the said half cones, so that this other of the said two reflecting surfaces can face the inspection zone from essentially all directions inside the said half cone, the two said reflecting surfaces having elliptical curvature and being so designed and arranged that both of the said two reflecting surfaces conjugate the inspection zone with one of two light concentration zones, and the system includes a third spherical reflecting surface having its center of curvature at the inspection zone facing the inspection zone in a direction opposite to the direction in which the said saucer shaped reflecting surface faces the inspection zone, and a transparent opening in the said spherical reflecting surface forming the light concentration zone with which the said saucer shaped reflecting surface conjugates the inspection zone.

15. In a photoelectric particle sensing system comprising a light source, a photosensor having a light sensitive surface, means to conduct a fluid to be tested on a predetermined path, a first reflecting surface suitable for directing light of the said light source toward an inspection zone which is a selected region of the said path, and a second reflecting surface suitable to direct toward the said light sensitive surface light leaving the said inspection zone in directions different from the directions in which the said first reflecting surface directs light toward the inspection zone, the improvement that one of the said two reflecting surfaces is of annular shape and faces the inspection zone from the outside of a full cone consisting of two half cones and having its apex at the said inspection zone, so that this reflecting surface can face the inspection zone from essentially all directions outside the said full cone, and the other of the said two reflecting surfaces is saucer shaped and faces the inspection zone from the inside of one of the said half cones, so that this other of the said two reflecting surfaces can face the inspection zone from essentially all directions inside the said half cone, the two said reflecting surfaces having elliptical curvature and being so designed and arranged that both of the said two reflecting surfaces conjugate the inspection zone with one of two light concentration zones, and the system includes a third spherical reflecting surface having its center of curvature at the inspection zone facing the inspection zone in a direction opposite to the direction in which the said saucer shaped reflecting surface faces the inspection zone, and a transparent opening in the said third spherical reflecting surface clearing the path of rays between the said saucer shaped reflecting surface and the light concentration zone with which it conjugates the inspection zone.

16. In a photoelectric particle sensing system comprising a light source, a photosensor having a light sensitive surface, means to conduct a fluid to be tested on a predetermined path, a first reflecting surface suitable for directing light of the said light source toward an inspection zone which is a selected region of the said path, and a second reflecting surface suitable to direct toward the said light sensitive surface light leaving the said inspection zone in directions different from the directions in which the said first reflecting surface directs light toward the inspection zone, the improvement that one of the said two reflecting surfaces is of annular shape and faces the inspection zone from the outside of a full cone consisting of two half cones and having its apex at the said inspection zone, so that this reflecting surface can face the inspection zone from essentially all directions outside the said full cone, and the other of the said two reflecting surfaces is saucer shaped and faces the inspection zone from the inside of one of the said half cones, so that this other of the said two reflecting surfaces can face the inspection zone from essentially all directions inside the said half cone, the two said reflecting surfaces having elliptical curvature and being so designed and arranged that both of the said two reflecting surfaces conjugate the inspection zone with one of two light concentration zones, the two said light concentration zones being located on a straight line traversing the inspection zone, creating thereby a common optical axis for the two reflecting surfaces.

17. In a photoelectric particle sensing system comprising a light source, a photosensor having a light sensitive surface, means to conduct a fluid to be tested on a predetermined path, a first reflecting surface suitable for directing light of the said light source toward an inspection zone which is a selected region of the said path, and a second reflecting surface suitable to direct toward the said light sensitive surface light leaving the said inspection zone in directions different from the directions in which the said first reflecting surface directs light toward the inspection zone, the improvement that one of the said two reflecting surfaces is of annular shape and faces the inspection zone from the outside of a full cone consisting of two half cones and having its apex at the said inspection zone, so that this reflecting surface can face the inspection zone from essentially all directions outside the said full cone, and the other of the said two reflecting surfaces is saucer shaped and faces the inspection zone from the inside of one of the said half cones, so that this other of the said two reflecting surfaces can face the inspection zone from essentially all directions inside the said half cone, at least one of the said reflecting surfaces being a reflecting coating on the outside of a transparent body in which an interior path is provided for sending the fluid to be tested through the said inspection zone, another part of the outside of the said transparent body being shaped spherically with the center of its curvature at the inspection zone and being covered at least partly with a reflecting coating.

18. In a photoelectric particle sensing system comprising a light source, a photosensor having a light sensitive surface, means to conduct a fluid to be tested on a predetermined path, a first reflecting surface suitable for directing light of the said light source toward an inspection zone which is a selected region of the said path, and a second reflecting surface suitable to direct toward the said light sensitive surface light leaving the said inspection zone in directions different from the directions in which the said first reflecting surface directs light toward the inspection zone, the improvement that one of the said two reflecting surfaces is of annular shape and faces the inspection zone from the outside of a full cone consisting of two half cones and having its apex at the said inspection zone, so that this reflecting surface can face the inspection zone from essentially all directions outside the said full cone, and the other of the said two reflecting surfaces is saucer shaped and faces the inspection zone from the inside of one of the said half cones, so that this other of the said two reflecting surfaces can face the inspection zone from essentially all directions inside the said half cone, the two said reflecting surfaces facing the inspection zone only from one side of a plane traversing the apex of the said cone and situated outside of the said cone, and the system includes a third spherical reflecting surface having its center of curvature at the inspection zone facing the inspection zone from the other side of the said plane.

19. In a photoelectric particle sensing system comprising a light source, a photosensor having a light sensitive surface, means to conduct a fluid to be tested on a predetermined path, a first reflecting surface suitable for directing light of the said light source toward an inspection zone which is a selected region of the said path, and a second reflecting surface suitable to direct toward the said light sensitive surface light leaving the said inspection zone in directions different from the directions in which the said first reflecting surface directs light toward the inspection zone, the improvement that one of the said two reflecting surfaces is of annular shape and faces the inspection zone from the outside of a full cone consisting of two half cones and having its apex at the said inspection zone, so that this reflecting surface can face the inspection zone from essentially all directions outside the said full cone, and the other of the said two reflecting surfaces is saucer shaped and faces the inspection zone from the inside of one of the said half cones, so that this other of the said two reflecting surfaces can face the inspection zone from essentially all directions inside the said half cone, the said annular reflecting surface conjugating the inspection zone with a light concentration zone by rays which surround a space not traversed by these rays, the said saucer shaped reflecting surface being arranged inside the said space.