As suggested by the name, level gauges are the type of level measurement devices which are mainly employed in the industrial instrumentation field to detect the level of liquids or fluids contained by a storage tank or process vessel. These level sensing devices are considered to be very simple and fast means to inspect level. They can detect any type of vapor leakage also.
They are available in various types and made up of different materials like glass tube, plate glass or reflex plate glass etc. depending upon the use. Level gauges prepared from glass tubes are particularly employed for boiler applications involving low pressures whereas level gauges constructed out of clear plate glasses are utilized for higher pressure boiler applications. Some of the major types of level gauges include magnetic level gauges, tank level gauges, reflex level gauges, transparent level gauges and bi-color level gauges etc.
Gauges used for measurement and control of level may be applied in variety of applications such as domestic, industrial, environmental etc. Major application areas of level gauges include:
- Chemical and petrochemical refinery units,
- Water treatment divisions
- Waste material handling units
- Pulp and paper manufacturing units
- Power generation plants
- Pharmaceutical processing systems
- Food and beverage processing units
- Oil making plants
“They are also used in tanks such as boiler feed water tanks, ammonia tanks, scrubber tanks, storage tanks, and acid tanks. In the above industries, level gauges are used in some form or another to measure the level of the fuels and solvents, oil production and refining, lubrication oils, detergents and soaps, boiler feedwater tanks, fertilizers and pesticides, ammonia tanks.”1
Key features of level gauges are listed below:
- The types of gauges which are brought into use for measurement of level in boilers include bi-color level gauges and magnetic level gauges.
- “Illuminators are provided with most of the level gauges, except magnetic gauges. The illuminators enable easier viewing of the water level even from long distances either using the naked eye or through a closed circuit television (CCTV) camera.”2
These kinds of illuminators find their best use in boilers which work across multiple floors and involve longer lengths.
- Magnetic level gauges devoid of glass plate constructions are considered ideal for high pressure conditions and dangerous locations.
- A typical level gauge generally consist of elements such as “head, float, measuring tape, bottom anchored bracket, guide wires, elbows, anchors, coupling, pipe support brackets, and pipe work”.3