Abstract: An optical measuring device, particularly using spectrophotometry, which comprises at least one group of optical fibers (24) connected to measuring cells, at least one auxiliary optical fiber (30) and at least one selection member connecting the latter to the group. The selective member establishes a link between the auxiliary fiber and one of the fibers of the group. The selection member comprises fixed optical means (32, 34 ) for establishing the link between the group and the auxiliary fiber and retractable seals (36) associated with the fibers of the group and which seal the ends of auxiliary fibers leading to said member.

Abstract: An improved optical fiber monitoring system using a light-emitting diode which is controlled by a module 12 having an oscillator 40, a first JK trigger 42, two univibrators 44, 46 and a second JK trigger 48 with an output stage 43 being connected to one or the other of the two outputs of the first trigger. A synchronization selector 50 is also a part of the module and has four inputs connected to the four output of the two JK triggers and to an output supplying one of the four signals which are received. The photoreceiver is connected to a synchronous detector module which uses the signal supplied by the selector 50 as a synchronization signal. The system also utilizes a inhibit circuit 83 and the control system incorporates a means for detecting the possible failure of the light emitting diode 10 with the controlling means inhibiting the input 83.

Abstract: The present invention relates to a photometric measuring device making it possible to automatically study complex solutions with variable "background noise."This device comprises a light source (2) making it possible to illuminate a measuring cell, means for splitting the light beam (20, 22) from source (2) into a plurality of individual beams, balancing means (24), means (26) for selecting each wavelength associated with each of the light beams, a discriminator (28) making it possible to distinguish the different wavelengths, means (26) for making the light beams monochromatic, detection means (46) and an analog computing system (44) making it possible to calculate the concentration of several dissolved chemical species.Application to the following or monitoring of chemical reactions.