Double beam optical absorption photometer having sample and reference chambers positioned along a single optical axis

Claim 2

The apparatus of claim 2 wherein said chambers are substantially cylindrical.

Claim 3

The apparatus of claim 2 wherein said chambers are contained within a single member.

Claim 4

The apparatus of claim 2 wherein said means for placing comprise inlet and outlet fluid lines communicating with each of said first and second chambers.

Claim 5

The apparatus of claim 1 wherein said comparing means comprise first and second photosensitive detectors positioned, respectively, in said first and second beams.

Claim 6

The apparatus of claim 6 wherein said radiation is ultraviolet and wherein each of said detectors comprises a photosensitive portion responsive to visible radiation and having a coating of a material which fluoresces in the visible region when excited by ultraviolet radiation.

Claim 7

The apparatus of claim 6 wherein said detectors are of the solid state type mounted on a common substrate.

Claim 8

The apparatus of claim 6 wherein said comparing means comprises: a Wheatstone bridge including said detectors therein; power supply means connected to energize said bridge; and indicating means responsive to the output of said bridge.

Claim 9

The apparatus of claim 1 wherein said single means is an optical lens.

Claim 10

The apparatus of claim 1 wherein said single means is a planoconvex optical lens; said lens being disposed between said source and said material placing means, and being positioned so that the Convex surface of said lens faces said source of radiation.

Claim 11

Apparatus for double beam absorption photometry which comprises: a single source of electromagnetic radiation; single means for collimating said radiation along a single optical axis; means for defining first and second parallel beams of such collimated radiation, the respective fields and apertures of said beams being of substantially equal size; means for placing in said first and second beams respective first and second materials; and means for comparing the intensity of radiation transmitted through said first and second materials to indicate their relative absorption; said comparing means comprise first and second photosensitive detectors positioned, respectively, in said first and second beams; a Wheatstone bridge including said detectors therein; power supply means connected to energize said bridge; and indicating means responsive to the output of said bridge; a voltage divider connected across the output of said bridge; and a feedback line connected between a preselected point of said voltage divider and said power supply, said power supply being responsive to the voltage at said preselected point to maintain said voltage at a substantially constant value.

Claim 12

The apparatus of claim 12 wherein said preselected point is at substantially the midpoint of said voltage divider.

Claim 13

Apparatus for comparing the electrical resistances of first and second variable resistors which comprises: a Wheatstone bridge including said resistors in adjacent arms therein; a voltage divider connected across the output of said bridge; a power supply connected to energize said bridge and having a feedback voltage input, the output of said power supply being variable in response to a feedback voltage to maintain said feedback voltage at a substantially constant value; a feedback line connected to apply the voltage at a preselected point on said voltage divider to said powersupply feedback voltage input; and indicating means responsive to the output of said bridge.

Claim 14

The apparatus of claim 14 wherein said preselected point is substantially at the midpoint of said voltage divider.

Claim 15

Apparatus for double beam absorption photometry which comprises: a single source of electromagnetic radiation; collimating means for developing two collimated beams of radiation from the radiation emanating from substantially each position on said source along a single optical axis; the respective fields and apertures of said beams being of substantially equal size; means for placing in said first and second beams respective first and second materials; and means for comparing the intensity of radiation transmitted through said first and second materials to indicate their relative absorption.

Claim 16

The apparatus of claim 16 wherein said collimating means is an optical lens.

Claim 17

The apparatus of claim 16 wherein said single means is a planoconvex optical lens; said lens being disposed between said source and said material placing means, and being positioned so that the convex surface of said lens faces said source of radiation.