Typical Flexographic Application Examples Include:
- Drying systems for printing lines
- Abatement systems such as oxidizers
Processes that use flammable solvents can develop explosive concentrations due to failure of coating, metering, ventilation or heating systems, adverse chemical reactions, and human error.
LFL monitors are used for safety as well as process efficiency, protecting the system from fire and explosion while also allowing operating at higher vapor concentrations to save costs.
Although several different types of sensors are employed as LFL monitors, each has an appropriate application to which it is best suited.
Fires and explosions in what was thought to be “protected” equipment can occur without warning when a sensor is not capable of doing the job that had been assigned to it.
This is most often caused by a misunderstanding of the different available technologies.
Catalytic-bead sensors are constructed of two small wire coils covered with a catalyst. One coil is “active” while the other is rendered inert and acts as a reference. A flow of electrical current through the internal coils heats the catalytic coating to a temperature at which the active coil will react with many flammable vapors and gases. This reaction occurs in the form of surface combustion which in turn causes an increase in the sensor’s temperature. The resulting temperature change is converted into an LFL reading.