Transmitted light measurement systems for spray jet monitoring (Ex area)

In transmitted light measurement within the visible wavelength range, the spray jet is continuously monitored in the optical path between transmitter and receiver. Single channel, two channel, three channel, and multi channel systems are available for this purpose. Changes in the spray pattern, nozzle wear, or blockages can thus be reliably detected in real time.

For use in the Ex zone, fiber optic cables are employed, enabling safe measurement while the electronics are installed outside the Ex zone. In addition, both the transmitter and receiver sides provide a compressed air connection. Even a slight overpressure is sufficient to keep the optics clean and ensure long term stable measurement.

See also our brochure on inline spray jet monitoring: 




For the Ex zone, a fiber optic version is available for spray jet monitoring in transmitted light operation. A so called transmitted light fiber, for example a D-S-Q3-(18x0.3)-1200-67°, is connected to a control unit of type SPECTRO-1-FIO-JC. In principle, fiber optic cross sections with diameters from 0.6 mm to 3.0 mm as well as rectangular cross sections from 3 mm × 0.5 mm to 48 mm × 0.15 mm can be used. For most fiber optic cables, adapter optics are available that allow the distance between transmitting and receiving fibers to be increased.
Relatively large spray cones can also be monitored using a corresponding light curtain, provided by a cross section converter such as a Q3 (18 mm × 0.3 mm). When the spray jet is active, part of the light in the light curtain is absorbed or scattered, reducing the received signal accordingly.
At the output of the electronics, both digital signals (0 V / +24 V) and an analog signal are available, the latter representing the progression of signal attenuation caused by the spray jet.