The Latest in Vibe Level Control

Dwyer Instruments, Inc. and Proximity Controls have both been well-recognized manufactures of sensors used for powder and bulk material handling systems. Our most popular powder and bulk product lines include the: DCT Timer Control Boards, DCS/RDCS Diaphragm Pulse Valves, PLS Paddle Level Switch, and CLS2 Capacitive Level Switch.  These products are most often seen in dust collection cartridge or bag house filter systems, concrete batch plants, or pneumatic conveying systems. While these products are all reliable, user-friendly, and cost-effective, they may not be best suited for your particular application. A new product Dwyer offers that is often times better suited for certain applications is the tuning fork level switch.

What is a Tuning Fork Level Switch and how does it work?
A tuning fork level switch is a single point level switch used for indication of material at either a high or low point in the process depending on user settings. Dwyer’s tuning fork level switches create a vibration frequency that changes when the forks come in contact with a solid material. Through the use of piezoelectric crystals in a vibration tube, vibrations/resonations are produced at specific frequencies. One element acts as a transmitter of the signal and the other receives the signal and converts it to an electrical output.  Once the fork comes in contact with material, the vibration is dampened, which results in a frequency change triggering the switch.

When to use a Tuning Fork Level Switch?
Tuning fork level switches are great for applications with process media that may have a changing consistency or die electric constant due to humidity/moisture content. Tuning forks are frequently used as an alternative to capacitive level switches when the process media has a low dielectric constant, such as hydrated lime for flue gas desulfurization. Lighter bulk density materials, such as flours or sugars that may not be detected by paddle style switches, can be detected with tuning fork switches and are frequently used in these pneumatic conveying systems.  Tuning forks are not recommended for applications where the process material is sticky and could buildup on the forks. This buildup leads to disruption of the natural frequency of the switch leading to a premature switch.

What types of Tuning Fork Level Switches does Dwyer Instruments offer?
Dwyer offers three different tuning fork switches, the TFLS, TFLS2, and CTF models. All three models use a standard two fork design and integrate weather proof housings. The TFLS Tuning Fork Level Switch and TFLS2 Tuning Fork Level Switch designs allow for the use of low bulk solid densities of 1.8 and 4.4 pounds per cubic foot respectively.  The CTF Compact Tuning Fork Level Switch is a small compact unit great for tight spaces and the integral DIN electrical connection allows for quick installation and future serviceability.

To learn more about the versatility of Dwyer’s complete line of tuning fork level switches and how they can be best suited in your application, please visit us at or call  1.800.872.9141.