Colorimeter

Claim 2

A colorimeter for analyzing a given sample by producing an output voltage which is a direct measurement of the concentration of the sample, comprising: a. container means for holding the sample to be analyzed; b. a source of radiant energy positioned on one side of the sample to be analyzed; c. a reference photoconductive cell positioned between the source of radiant energy and the sample, said photoconductive cell having a resistance which varies as a function of the radiant energy impinging thereon; d. a sample photoconductive cell positioned on the opposite side of the sample from the light source, said photoconductive cell having a resistance which varies as a function of the light which reaches said sample photoconductive cell after passing through the sample; e. amplifier means having an input and an output, said sample photoconductive cell being electrically connected to the input of the amplifier means and said reference photoconductive cell being electrically connected across the input and output of the amplifier means, the output of said amplifier being a function of the ratio of the intensity of radiant energy directed onto said reference photoconductive cell to the intensity of radiant energy directed onto said sample photoconductive cell; f. measuring means connected to the output of said amplifier means; g. a filter positioned between the source of radiant energy on one side of the filter and the reference photoconductive cell, sample containing means, and sample photoconductive cell on the opposite side of the filter; and h. a housing to contain the source of radiant energy, reference photoconductive cell, sample containing means, sample photoconductive cell, amplifier means, measuring means and filter; i. wherein the radiant energy from said source of radiant energy falls directly on said reference photoconductive cell, but is transmitted through the sample to be analyzed before said radiant energy falls on said sample photoconductive cell.

Claim 3

The colorimeter of claim 1 wherein the amplifier means is a high gain dc operational amplifier.

Claim 4

The colorimeter of claim 1 wherein said measuring means is a meter.

Claim 5

The colorimeter of claim 1 further comprising a logarithmic amplifier which is connected between the output of said amplifier means and said meter to produce an output which is the logarithm of the output of said amplifier means to give a direct reading of optical density on said meter.

Claim 6

The colorimeter of claim 1 wherein said measuring means is a recorder.

Claim 7

The colorimeter of claim 1 wherein said measuring means comprises a meter and a recorder, both being connected to the output of said amplifier means.

Claim 8

The colorimeter of claim 6 further comprising a source of variable voltage which is applied as an input to said amplifier means to enable an expanded scale of values to be displayed on said meter.

Claim 9

The colorimeter of claim 7 wherein said source of variable voltage comprises a source of fixed voltage and variable resistanCe connected across said source of fixed voltage and connected to the input of said amplifier means.

Claim 10

The colorimeter of claim 1 wherein the container means for holding the sample to be analyzed is a transparent cuvette.

Claim 11

The colorimeter of claim 9 further comprising a switch which is positioned in the electrical circuit between the sample photoconductive cell and said amplifier means, said switch being normally open and said switch being adapted to be closed by said cuvette.

Claim 12

The colorimeter of claim 1 wherein the container means for holding the sample to be analyzed is a fluid flow cell. 12. A colorimeter for determining the quantitative difference in transmittance between two solutions, comprising: a. two container means, one for holding each of the two solutions; b. a source of radiant energy positioned on one side of the two solutions to be analyzed; c. a reference photoconductive cell positioned adjacent to the first of the two solutions to be analyzed and positioned on the opposite side of said solution from the source of radiant energy, said photoconductive cell having a resistance which varies as a function of the radiant energy impinging thereon; d. a sample photoconductive cell positioned adjacent to the second of the two solutions to be analyzed and positioned on the opposite side of said solution from said source of radiant energy, said photoconductive cell having a resistance which varies as a function of the radiant energy impinging thereon: e. amplifier means having an input and output, said sample photoconductive cell being electrically connected to the input of said amplifier means and said reference photoconductive cell being electrically connected across the input and output of said amplifier means; f. a measuring means connected to the output of said amplifier to indicate the difference in transmittance of the two solutions: g. a filter positioned between the source of radiant energy and the two solutions to be analyzed; and h. a housing to contain the source of radiant energy, the two samples to be analyzed, the reference photoconductive cell, the sample photoconductive cell, the amplifier means, the measuring means and the filter; i. wherein radiant energy from said source of radiant energy is transmitted through the first of the two solutions to be analyzed onto said reference photoconductive cell and radiant energy from said source of radiant energy is transmitted through the second of the two solutions to be analyzed onto said sample photoconductive cell.

Claim 13

The colorimeter of claim 12 wherein the amplifier means is a high gain dc amplifier.

Claim 14

The colorimeter of claim 12 wherein the measuring means is a meter.

Claim 15

The colorimeter of claim 12 wherein a logarithmic amplifier is connected to the output of said amplifier means to produce which is the logarithm of the output of said amplifier means to give a direct reading of optical density on said meter.

Claim 16

The colorimeter of claim 12 wherein said measuring means is a recorder.

Claim 17

The colorimeter of claim 12 wherein said measuring means comprises a meter and a recorder, both being connected to the output of said amplifier means.

Claim 18

The colorimeter of claim 12 wherein the container means for holding each of the solutions is a transparent cuvette. 19. The colorimeter of claim 12 wherein the container means for holding each of the solutions is a fluid flow cell.

Claim 19

A colorimeter for analyzing a given sample by measuring the light reflected from the sample, comprising: a. container means for holding the sample to be analyzed; b. a source of radiant energy positioned on one side of the sample to be analyzed to emit a light on the sample; c. a reference photoconductive cell positioned adjacent to the source of radiant energy to receive radiant energy directly from said source, said photoconductive cell having a resistance which varies as a function of the light impinging thereon from the light soUrce; d. a sample photoconductive cell positioned adjacent to the source of radiant energy and adjacent to the sample to be analyzed to receive radiant energy reflected from the sample, said photoconductive cell having a resistance which varies as a function of the light which reaches said sample photoconductive cell after passing through the sample; e. amplifier means having an input and an output, the sample photoconductive cell being electrically connected to the input of the amplifier means and the reference photoconductive cell being electrically connected across the input and output of the amplifier means, the output of said amplifier being a function of the ratio of the intensity of radiant energy directed onto said reference photoconductive cell to the intensity of radiant energy directed onto said sample photoconductive cell; f. measuring means for measuring the output of said amplifier means; g. a filter positioned between the source of radiant energy on one side of the filter and the reference photoconductive cell, sample containing means, and sample photoconductive cell on the opposite side of the filter; and h. a housing to contain the light source, reference photoconductive cell, sample containing means, amplifier means, measuring means and filter.

Claim 20

A colorimeter for analyzing a given sample by measuring the light reflected from the sample, comprising: a. container means for holding the sample to be analyzed; b. a source of radiant energy positioned on one side of the sample to be analyzed to emit a light on the sample; c. a reference photoconductive cell positioned adjacent to the source of radiant energy to receive radiant energy directly from said source, said photoconductive cell having a resistance which varies as a function of the light impinging thereon from the light soUrce; d. a sample photoconductive cell positioned adjacent to the source of radiant energy and adjacent to the sample to be analyzed to receive radiant energy reflected from the sample, said photoconductive cell having a resistance which varies as a function of the light which reaches said sample photoconductive cell after passing through the sample; e. amplifier means having an input and an output, the sample photoconductive cell being electrically connected to the input of the amplifier means and the reference photoconductive cell being electrically connected across the input and output of the amplifier means, the output of said amplifier being a function of the ratio of the intensity of radiant energy directed onto said reference photoconductive cell to the intensity of radiant energy directed onto said sample photoconductive cell; f. measuring means for measuring the output of said amplifier means; g. a filter positioned between the source of radiant energy on one side of the filter and the reference photoconductive cell, sample containing means, and sample photoconductive cell on the opposite side of the filter; and h. a housing to contain the light source, reference photoconductive cell, sample containing means, amplifier means, measuring means and filter.

Claim 21

The colorimeter of claim 20 wherein the amplifier means is a high gain dc operational amplifier.

Claim 22

The colorimeter of claim 20 wherein said measuring means is a meter.

Claim 23

The colorimeter of claim 20 wherein a logarithmic amplifier is connected to the output of said amplifier means to produce an output which is a logarithm of the output of said amplifier means to give a direct reading of optical density on said meter.

Claim 24

The colorimeter of claim 20 wherein said measuring means is a recorder.

Claim 25

The colorimeter of claim 20 wherein said measuring means comprises a meter and a recorder, both being connected to the output of said amplifier means.

Claim 26

The colorimeter of claim 20 wherein the container means for holding the sample to be analyzed is a transparent cuvette.

Claim 27

The colorimeter of claim 20 wherein the container means for holding the sample to be analyzed is a fluid flow cell.