Application of Tuning Fork Liquid Level Switch in White Oil Storage Tanks

Liquid level sensors are widely used in petroleum, chemical, food and other industrial field. Liquid level sensors can be classified into two categories ---- level switches and level meters. Level switches are sensors that detect the presence of liquids, powder, or granulated materials at specific locations. Different from level switches, level meters are devices continuously measure the volume of liquid, powder, or granulated materials.

Few months ago, a lithium battery separator manufacturer had encountered an overfill accident. The absence of liquid level switch and the fault signal of the continuous measuring instrument were the main reasons caused this accident.

The liquid level sensors are mainly used in the production process of lithium battery separator to detect the liquid level of white oil in storage tank. To facilitate on-site observation and send remote signal to a control room, the user selected the magnetic level indicator with remote transmitter (commonly known as remote magnetic level meter). However, the viscosity of white oil had great resistance on the movement of magnetic floats, which resulted in overflow accident.

For safety concerned, the user decided to install a liquid level switch on the top of the storage tanks to alarm the high level overflow.

Among tuning fork liquid level switches and float level indicators, tuning fork liquid level switches were recommended in this case.

Compared with the float level indicators, tuning fork level switches cost higher but also have higher stability and reliability:

1. The fork’s harmonic resonant frequency has been precisely pre-adjusted to achieve high sensitivity so the lowest measurable density can be as low as 0.5g/cm³. With strong disturbance resistance ability, not influenced by foam, bubbles, viscosity, vibration and other liquid characteristics.

2. High reliability due to the detection of vibration frequency. Maintenance free, with durable life.

3. Passed SIL2 / SIL3 Functional Safety Assessment, as well as certified for both Intrinsic Safety (Ex ia IIC T6~T1 Ga) and Flameproof Enclosure (Ex d IIC T6~T1 Gb) explosion protection, with protection rating of IP66/IP67.

Through the above comparison, Ring-11 tuning fork level switch has been selected and applied in the application site. The stable and excellent performance of Ring-11s in the level measurement of white oil storage tanks further highlights the cost-effective.