Probe provides long term maintenance free operation
12 November 2009
Extronics has the iLEL100 Solvent Monitor probe which virtually eliminates maintenance. The iLEL100 Solvent Monitor was conceived and designed as an in situ solution for the continuous measurement of flammability of solvent vapours driven off in ovens and dryers within the coating/converting industries.
Solvent probe provides long term maintenance free operation
Many systems that have been implemented for such measurements have necessitated the use of complex sample extraction systems demanding high levels of maintenance and in many cases becoming a major cost and labour burden rather than a powerful mechanism to assist in the safe operation of the process.
The key objectives that polarised the design of the iLEL100 Solvent Probe were simplicity reliability and long term maintenance free operation.
Once the concept of the probes operation had been established it was important to put the finished product to the test across a wide range of applications. Extronics contacted a local company “Raleigh Coatings” who had previously engaged Extronics services for the supply of equipment utilised in the hazardous areas of the plant.
Raleigh Coatings was established in 1989, located in Staffordshire and provides a confidential contract high quality coating service to industry. The diverse range of markets supplied by Raleigh includes Medical Devices, Aerospace, Security and Electronics.
The clean room coating and laminating equipment on site is designed to handle 100% solids, water-based and solvent-based chemistry applied with precision to films, foils and papers. R&D clean room pilot coating and laminating facilities are also available; hence the site provided the basis for an ideal Test Bed for the iLEL100 Probe.
Raleigh Coatings plant manager Paul Hewitt agreed to allow Extronics to install the iLEL100 solvent probe and initiate the performance trials to put the probe through its paces.
The first location in which the probe was located was in the main oven exhaust. The internal temperature of the Exhaust Duct was approximately 60°C and the vapour velocity between 4-10m/sec. The Exhaust Duct provided a low temperature point of measurement which was of interest as it presented the possibility of particulate deposition within the probe that could be detrimental to its long term operation; upon periodic examination of the probe no deposition was observed.
The probe was trialled in this location for six months before being moved to the more arduous location by being directly inserted into the oven. The internal conditions within the oven at this point of measurement were of a more turbulent nature in terms of the gas streams as the probe was no longer located in a straight run pipe, hence the velocity across the probe was varying and secondly the temperature was much higher at 120°C plus.
The design of the oven was such that it would open up to allow access to the internals for maintenance and service work, it was noticed during one such interval that the internals of the oven were coated with a brown sticky substance.
This particular point of the oven was the chosen location of installation as it also provided an opportunity for comparative measurements to be made as another semi-extractive monitor was located within close proximity of the selected point of entry.
Across the two year period that the iLEL100 was “trialled” the measured values of the %LEL of the Probe and the reference device were downloaded to a data logger for analysis and comparison. A detailed analysis of the results revealed that the two devices paralleled each other in performance with respect to the measured values of the %LEL.
After the conclusion of the trials the iLEL100 probed was reinstalled on the feed to the Oxidiser where it has been operating for the last three years, providing continuous maintenance free operation.
The iLEL100 Solvent Probe has been successfully tested at operating temperatures up to 240°C and the simplicity of the operational philosophy has been widely accepted on a variety of applications across a broad spectrum of industry.
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