At present, the most commonly used liquid level switches in the raw material warehouse (wheat) and finished product warehouse (flour) of flour mills are the stop rotation liquid level switch and the radio frequency admittance liquid level switch. Radar level gauges and ultrasonic level switches are also rarely used.

Anti-rotation level switches were favored by many manufacturers in the early days due to their low price and simple installation. However, many manufacturers have found that after using the liquid level switch, their motors are easily damaged, causing normal operation to fail, affecting production efficiency, and even causing production to fail to proceed normally. In addition, because it contains lubricated moving parts, it is easy to contaminate materials in raw material warehouses, wet wheat warehouses, and finished product warehouses, causing economic losses.

Due to the different humidity of wheat and flour after humidification, the dielectric constant often changes, which can easily lead to the failure of the RF admittance level switch in normal use. In addition, the probe of the RF admittance level switch is an embedded structure (long and thin), which can easily cause the probe to bend or break, causing damage to the RF admittance level switch and affecting normal production.

Although radar level gauges have good measurement results in raw material bins, they are not cost-effective due to their high price; ultrasonic level switches are reasonably priced, but due to the large amount of dust in flour mills, the measurement of finished product bins is often inaccurate, and false alarms often occur.

How to reasonably select the material level switch in the material level measurement of flour mills to ensure safe and reliable storage of materials and ensure continuous and stable production has become a major problem for flour mills to solve.