You have a wide range of industrial process’ that may require the use of level switches in a hazardous environment. In many of these cases, the level switch will need to operate in an environment with flammable materials and combustible fumes. Under these conditions, getting the wrong type of switch could increase the risk of an explosion or fire.
For these hazardous locations, it is necessary to look for specially designed level switches that are explosion proof. With these level sensors, you have switches that are engineered to work in these hazardous conditions while limiting the risk of having electrical equipment operating around combustible fumes or liquids.
When it comes to finding level switches that are safe for use in this type of hazardous location, you have two broad categories. You have switches that meet the Intrinsic Safety standard and then there are those that meet the standards for being called explosion proof. In both cases, the switch would be designed to eliminate the possibility of the switch being an ignition source for the flammable or combustible materials in the environment.
In both cases, you have different designs that might be needed to meet different standards or to work for different applications, but there is one key difference between these two categories. A switch that meets the standards for Intrinsic Safety is designed to operate on voltages that are low enough to prevent ignition. An explosion proof switch is one that cannot be designed to work at these low voltages, so it has to apply different engineering principles to prevent the possibility of ignition.
For some applications, going with a low voltage switch is just not an option. Some types of sensors cannot work on low voltage or you might need a level switch that is going to work with a piece of equipment that requires more energy. These would be some of the reasons that you would have to go with an explosion proof level switch over one that is intrinsically safe.
In general, there are two key ways that explosion proof switches are designed to prevent the possibility of ignition. To start, the switch would have conduit and seals to prevent things like fumes or flammable materials for coming in contact with the electrical components of the switch. This essentially isolates the circuit from the hazardous material, and in doing so, it helps to eliminate the circuitry as a source of ignition.
In addition to that, the switch would also have an explosion proof housing. Even with the seals, there is always the possibility that fumes or hazardous materials could come in contact with the circuitry of the switch. In the event that a flammable material did get into the switch, the explosion proof housing would contain the ignition, and this would prevent the ignition of materials that are outside the switch.
Under hazardous conditions, getting the right type of level sensor can be the difference between operating safely and the potential for disaster. Whether you need switches that are explosion proof or intrinsically safe, it is of the highest importance that you get a switch that is design to operate safely in the work environment.