Optical scanner with self contained standardization means
AssigneeABB Process Automation Inc.
InventorAke A. Hellstrom
Life of this patent
Estimating the term…
Abstract
An apparatus for optically scanning and measuring the physical parameters of a sheet material by means which are fully enclosed within an air purged cross-machine box-beam structure to protect the radiation source, the radiation detector and the optics from the harsh machine environment. The apparatus may involve a single beam enclosing a combined source/detector module for reflection measurement or dual beams on opposite sides of the sheet for transmission measurement with one enclosing a source module and the other enclosing a detector module. Standardization means are also provided either in the module itself or as an extension of the beam. Means are also disclosed for sealing the opening in the beams through which the radiation passes.
Claims20
In a system for measuring optical properties of a moving web of sheet material by projecting electromagnetic radiation onto the moving web and detecting the electromagnetic radiation after interaction with the moving web comprising:
- a first beam mounted to extend parallel to one face of the moving web in a cross-machine direction, said beam being generally hollow and including an elongated opening through the side of said first beam adjacent the moving web;
- an electromagnetic radiation source module mounted entirely inside of said first beam adjacent said elongated opening;
- and
- means for traversing said source module back and forth within said first beam along said elongated opening, and wherein said source module comprises:
- a. a housing having an aperture adjacent said elongated opening for passing electromagnetic radiation through said aperture and said elongated opening;
- b. a source of electromagnetic radiation within said housing;
- and
- c. optical means within said housing including an elliptical mirror to receive and focus said radiation from said source through said aperture and through said elongated opening onto the moving web.
A system for measuring optical properties of a moving web of sheet material comprising:
- a beam mounted to extend parallel to one face of the moving web in a cross-machine direction, said beam having a generally rectangular cross section, being generally hollow and including an elongated opening through the side of said beam adjacent the moving web, and
- a sensor module mounted entirely inside of said hollow beam, said sensor module and means for traversing said source module back and forth within said beam along said elongated opening, said sensor module comprising:
- a. a housing having first and second apertures adjacent said elongated opening for passing electromagnetic radiation through said apertures and said elongated opening;
- b. a source of electromagnetic radiation within said housing;
- c. a fixed elliptical mirror within said housing to receive and reflect a first portion of said radiation from said source through said first aperture and through said elongated opening and to focus said radiation onto the moving web;
- d. a second elliptical mirror within said housing pivotally mounted to move between a first and second position to receive said radiation reflected from said web through said elongated opening and said second aperture;
- e. detector means within said housing to receive radiation from said second elliptical mirror in said first position and convert said received radiation to a signal indicative of said optical property;
- and
- f. a standardization sample mounted within said housing to receive a second portion of said radiation from said source and reflect said radiation onto said detector when said second elliptical mirror is pivoted to said second position, and means for pivoting said second elliptical mirror between said first and second positions.
Dependencies are inferred from the claim text.