Detector for meniscus of sample of petroleum product in analysis tube, has axes offset by specific angle

摘要

The axes of the beam of light and the axes of the detector are offset by an angle of 110-160 deg , preferably 135 deg , so that in the absence of the sample part of the light beam is reflected from the wall of the analysis tube to the detector and in the presence of the sample the beam passes through the tube and the detector does not receive any light. The physical detector for petroleum products is adapted for the detection of the meniscus of a sample to be analyzed circulating in a glass analysis tube (1). The sample passes vertically across a horizontal measuring plane (A) placed at a set height and carrying at least one emitter (91) mounted in the measuring plane and emitting a light beam in the direction of the analysis tube. There is also an associated detector (92) of light also in the measuring plane as well as analyzers. Detecting the passage of the meniscus is consecutive with modifying the light intensity received by the detector. The light beam is in the near infrared. The detector acts with a diaphragm placed to its right. A second measuring plane (B) with its own light source (81) and detector (82) allows the time to be calculated for the meniscus to pass from one measuring plane to the other. The device is designed for an installation to determine the temperature limit for filtration of petroleum products, with a cooling chamber containing a glass analysis pipette and two measuring planes as described above.