Dual-beam fluid monitor for measuring transmitted and scattered light

Claim 1

Apparatus for testing a sample of material to determine at least one characteristic correlated to the affect the material has on light, comprising: means for holding a sample material; separate means for holding a reference material having known light-affecting characteristics; alternate light-directing means for passing light alternately through each of said means for holding to alternately pass the light through the sample and reference material respectively and including only a single light source; single attenuated light-responsive means for intercepting the attenuated light after it has passed through said means for holding a sample material and after it has passed through said means for holding a reference material respectively to produce an attenuation electrical output having correspondingly alternating sample and reference electrical signals in response to the light intercepted; single scattered light-responsive means mounted with respect to said holding means and said means for passing light so that it receives the light scattered by said materials to produce a single scattering electrical output correspondingly alternating between sample and reference signals; a wall means forming a sealed chamber separate from a fluid sample to be tested; said light source being mounted in said chamber; each of said lightresponsive means being mounted in said chamber; first optical fiber means sealingly extending through said wall means from said light source; second and third optical fiber means sealingly extending through said wall means respectively from each of said light-responsive means to spaced branched inlets; said spaced branch inlets of said second optical fiber means are positioned to receive light which has passed through said means for holding a sample material and means for holding a reference material respectively; said spaced branch inlets of said third optical fiber means are positioned to receive light which has been scattered by a material in said means for holding a sample material and means for holding a reference material respectively; said means for holding a reference material being outside of said chamber; branch optical fiber means conducting light from said first optical fiber means substantially only through said means for holding a reference material on a path to one branch of said second optical fiber meaNs and at intersecting right angles to one branch of said third optical fiber means; and separate branch optical fiber means for passing light from said first optical fiber means through said sample of material on a separate path to another branch of said second optical fiber means and at intersecting right angles to another branch of said third optical fiber means.