Technology of Echotel Model 940/941 Ultrasonic Level Switch
Ultrasonic energy detects the presence or absence of liquid in a tip sensitive transducer gap. The principle behind contact ultrasonic technology is that high frequency sound waves are easily transmitted across a transducer gap in the presence of liquid, but are attenuated when the gap is dry.The transducer uses a pair of piezoelectric crystals that are encapsulated in epoxy at the tip of the transducer. The crystals are made of a ceramic material that vibrates at a given frequency when subjected to an applied voltage. The transmit crystal converts the applied voltage from the electronics into an ultrasonic signal. When liquid is present in the gap, the receive crystal is able to sense the ultrasonic signal from the transmit crystal and convert it back to an electrical signal. This signal is sent to the electronics to indicate the presence of liquid in the transducer gap. When there is no liquid present, the ultrasonic signal is attenuated and is not detected by the receive crystal.
Features of Echotel Model 940/941 Ultrasonic Level Switch
- Pulsed electronics for excellent performance in difficult process conditions and superior immunity from sources of electromagnetic noise
- Tip-sensitive transducer gap provides reliable operation by draining viscous liquids and shedding foam in turbulent applications
- Safety Integrity Level (SIL) data (FMEDA analysis) is available. Model 940 is suitable for SIL 2 loops.Model 941 is suitable for SIL 1 loops.
- Extremely compact unit is easily installed in areaswhere access space is limited
- 1-amp SPDT relay output (940), or mA current shift (941) output
- No calibration required
Applications of Echotel Model 940/941 Ultrasonic Level Switch
The Model 940/941 can be applied in a wide variety of high or low liquid level applications, pump protection,and fill line monitoring as shown in the diagram at the left. These compact units can also be installed in the interstitial space between two tank walls for fluid leak detection.Small size and simplicity of installation make these units ideal for OEM skids as a low cost, yet high performance level measurement solution. They are also the perfect replacement for older floats, conductivity switches, and tuning forks.