# US 4,392,746 A · Portable photometer

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- Number: US 4,392,746 A
- Document ID: US4392746A
- Status: Granted
- Kind: A
- Application number: 06/214,530
- Filed: 1980-12-08
- Granted: 1983-07-12
- Earliest claimed: 1980-12-08
- Assignees: Portalab Instruments Limited
- Inventors: Graham A. W. Rook; Colin H. Cameron
- Web page: https://patentgrep.com/patent/US4392746A

## CPC

- G01N 21/253: {for batch operation, i.e. multisample apparatus (analytical automats G01N35/00)}
- G01N 33/53: Immunoassay; Biospecific binding assay; Materials therefor
- G01N 35/02: using a plurality of sample containers moved by a conveyor system past one or more treatment or analysis stations {(G01N35/0098 and G01N35/0099 take precedence)}
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

A portable photometer for measuring the transmission properties of a fluid contained in a container having a transparent bottom is disclosed which is characterized in that there is provided: a monochromatic light source and a collimator assembly, both of which are contained within the base of a moveable member; a locating member arranged to contact the top of the container to thereby locate the end of the tubular member at a predetermined position with respect to the bottom of the container; and a photodetector device positioned beneath the container to receive the light from the collimator.

## Claims

### Claim 1

A photometer for measuring the transmission properties of a fluid contained in a container having a transparent bottom, said photometer comprising:
a monochromatic light source of a fixed wavelength;
a source of direct current connected to said monochromatic light source;
a collimator assembly for said light source to form a collimated, narrow beam of light;
a moveable tubular member having a base containing said light source and said collimator assembly;
a locating member arranged to contact the top of the container and to thereby locate the end of the tubular member at a predetermined position with respect to the transparent bottom of said container;
a photodetector device positioned beneath said container and arranged to receive said collimated, narrow beam of light.

### Claim 2 (depends on 1)

A photometer according to claim 1, wherein the light source is a light emitting diode.

### Claim 3 (depends on 2)

A photometer according to claim 2, wherein the diode emits red light.

### Claim 4 (depends on 1)

A photometer according to claim 1, wherein said lid is provided with a depending member arranged to cause movement of said moveable tubular member.

### Claim 5 (depends on 1)

A photometer according to claim 1, wherein the photodetecting device is provided with a diffuser, the diffuser and the photodetecting device being mounted in an assembly so that the diffuser is spaced from the photodetecting device.