Application Conditions:
Wet conditions, build-up of high dielectric material in the chute, dust, noise, high vibration and shock.
Level Technology Choice:
Tilt Switch, Admittance Probe, Microwave Switch, Pressure Plate, Vibration Switch, Acoustic Low Frequency through Beam Switch.
Blocked chute detection in a Mining process application is crucial to the operational performance of the site. Hours lost to downtime caused by a blockage in a conveyor transfer chute can take hours to clear, which in dollar terms can mean thousands of dollars in lost production and a delay in production schedules. Build-up and blockage problems in chutes have been a very difficult problem to overcome, and the selection of technology for the blocked chute is very important to getting this right.
Not failsafe, so that when it fails, you will only notice when a blocked chute occurs. Intrusive instrument. Build-up of wet material on the Tilt Switch will stop it working. The Tilt Switch cannot be remote tested. It must be installed away from the inflow of product. It must have “on” delays incorporated to overcome intermittent strikes by flying product. It is not suitable for quick operation and it is best suited for dry product and dry weather conditions.
Better than the tilt switch, in that it can provide feedback about build-up. Intrusive instrument. It is also failsafe in its operation. Can be remote tested. Can sustain intermittent strikes with material. Wet sticky material build-up will stop the Admittance Probe from working. Dust is no problem. Best suited for dry product and dry weather conditions. Will work on comms, Foundation FieldBus, ProfiBus PA.etc.
The non-intrusive design is mounted outside the chute looking through wear plate windows,eg: ceramic, UHMW etc. will see through some build-up over the windows. Rugged construction. Failsafe in operation. Remote test capability. Wet sticky build-up over the windows, will stop the instrument working. Best suited for dry product and dry weather conditions, lump or fines. Dust is no problem. Will work on comms, Foundation FieldBus, ProfiBus PA, etc
Not failsafe and prone to sticking in position, because of build-up issues. Non-intrusive. Best suited for dry products and small granular size particles and dry weather conditions.
Intrusive design. Failsafe option. Can be remote tested. Because of the mechanical design, based on a tuning fork principle, the vibration switch is susceptible to mechanical contact and high vibration. Should only be used with dry granular material that is small in particle size. No high impact applications.
This Acoustic switch was developed for Blocked Chute applications that suffered from wet moist sticky build-up environments. It uses the pressure wave cleaning effect, with each transducer (sender and receiver) pulsing, to remove moisture and build-up. Low frequency acoustic switches produce a pressure wave, with each pulse, that atomizes moisture or dust build-up off the diaphragm (see video attachment demo above). The Acoustic switch system is failsafe. It can be remote tested for continuity. The transducers can be supplied with Titanium diaphragms for wear plate resistance. The remote amplifier can be installed up to 700 meters (2300 feet) away from the sender/receivers. The Acoustic switch can be supplied with Foundation FieldBus, ProfiBus PA, HART,etc comms.
