ABSTRACT
Level meters are classified into two types: a continuous type and a discrete type. Discrete level meters are also called level switches and are usually used to maintain the powder level between the prescribed upper and lower limits by feeding or discharging powder.1 Table 4.1 illustrates the principles of continuous level meters. The electric capacitance method is also utilized in measurement of the powder level. Table 4.2 lists the principles of various level switches.
