Emissions – Flammability Monitoring
Many industrial processes, such as large scale coating of thin films for food packaging, coating of metal coils for building construction, and indeed many printing processes use organic solvents as part of the production coating process. In such processes, industrial ovens (dryers) are invariably used to evaporate the solvents used in the coating precursors. The solvents used are usually flammable liquids which, when evaporated in hot air, form potentially explosive vapours within the oven. Depending on the design, it is a requirement of safety standard EN1539 that flammability monitors (often called explosion monitors) be installed on the oven to monitor the flammability of the atmosphere within the oven, thereby minimising the risks of fire or explosion.
There are a number of challenges that must be overcome when monitoring flammability levels. One recurring problem is that the majority of industrial coating processes use more than one solvent and often the stoichiometric ratio of the solvents changes as the coating process cycles: this presents a very real problem of how to calibrate the monitor. Orbital have a solution to this calibration problem by using a unique design of monitor which extracts a sample of the flammable gas from within the oven and burns the gas in a special chamber protected by flame arrestors. The more flammable the sampled gas, the hotter the flame in the chamber will be. In this way, by measuring the flame temperature, a direct measurement of flammability is achieved. A key feature of making a direct measurement of flammability is that calibration can be made for all solvents present with a single reference solvent, this method is often called a universal calibration.
By their design, industrial hot air dryers require the heating of large quantities of air within the oven. Clearly there is a substantial production cost associated with heating of the air and as such, any method which gives tighter control of the air flow can result in significant cost savings. The unique design of our flammability monitor results in the most accurate and fastest responding monitor available on the market today. This allows the oven to be run very close to the legal maximum % of LEL allowed, resulting in less energy usage and/or allows product throughput to be optimised at a maximum.
Orbital are the sole UK distributors for Control Instrument Corporation flammability monitors. Orbital not only supply the CIC range of flammability monitors, but we have a team of trained technicians experienced in the installation, commissioning and servicing of the monitors allowing us to provide our customers with a complete safety monitoring solution.