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18.2 Reliable material flow with ultrasound
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n the beverages section of a supermarket, you will find rows of crates with bottles filled with water, soft drinks, or beer. The choice is not easy. Who would imagine that sensors play a key role when those bottles are filled?
Figure 1: Using ultrasonic sensors to count bottles monitors the material flow on a continuous basis. The different colors of the glass or PET bottles and the colorful imprints or shiny labels call for the use of ultrasonic sensors, which work regardless of color and material. While scanning ultrasonic sensors measure the time of flight of a sound packet and calculate the resulting distance, thru-beam ultrasonic sensors work with continuous sound and analyze the interruption. The result is extremely fast response times.
resistant film. In machine areas not affected by cleaning cycles, standard ultrasonic thru-beam sensors, such as the UBE1000-18GM40 Series, can be used. Since ultrasonic sensors from Pepperl+Fuchs can identify the most difficult materials, even transparent glass or plastic bottles are detected in a reliable manner. Detecting and counting the bottles at several places in the machine ensures continuous monitoring of the material flow. The entry and exit of the bottles to and from the filler is optimized, and missing bottles in the chain are reliably detected. Reliable detection of bottles using ultrasonic thru-beam sensors is guaranteed in areas with high levels of water vapor. Sheet Metal Off the Roll The material flow must not slow down in other applications either. Take the example of a hydraulic punch, in which the sheet metal needs to be fed continuously. As a general rule, sheet metal is supplied in the form of large rolls. The sheet metal runs from the winding system to the press via a loop. A scanning ultrasonic sensor measures the loop sag to regulate the winding tension and reports when the material ends, so that the press is not damaged. Whether brass or steel sheet, oiled or coated—none of them will interfere with the ultrasonic sensor. The sensor’s sound packets are reflected. The runtime is converted into distance and output in digital form as a switching signal, or in analog form via current or voltage. Container Empty Container empty—a message that can result in an entire production line being shut down immediately. System shutdown and loss of production—a horror for any production manager. Continuous measurement of the level of production or auxiliary materials is one traditional application of ultrasonic sensors. The analog output of a cylindrical M30-design sensor continually provides the level, and a switching output reports—overfilling or container empty— to prevent something worse happening in the event of an emergency. The ultrasonic sensor is present no matter what media is in the tank: dough for a bakery, fruit juice for a filling system, or drilling emulsion as an auxiliary material in materials processing.
Figure 2: Ultrasonic thru-beam sensors are ideal for counting bottles at high speed Ultrasonic Sensors Ensure Reliable Material Flow In the food and beverages industry, speed and cleanliness set the tone. Short cycle times and minimum machine and/or system downtime are vital in this industry, and hygiene requirements must not be ignored either. The strictest regulations and certifications are needed to produce high-quality end products. In bottling plants used in beverage production, incoming and outgoing bottles must be counted continuously, irrespective of material and liquid. To ensure the material flow, individual bottles are detected at the outlet of PET bottle blow molding machines and automatic bottle rinsers. High Level of Chemical Resistance Passing bottles move too fast to be individually detected by the normal scanning of ultrasonic sensors because the bottles pass the sensor at high speed and often with just a very small gap between two bottles. Ultrasonic thru-beam sensors are perfect for the task of counting bottles. Ultrasound thru-beam sensors with increased chemical resistance are required, since these applications very often involve the use of hot steam and chemicals to clean machines. The IP protection category should therefore be a minimum of IP68/69K. The UBEC30018GM40 Series from Pepperl+Fuchs is ideal. With this sensor series, the transducer surface is specially protected and sealed by a chemically
Figure 3: The analog output of an ultrasonic sensor provides the level in the tank irrespective of the medium. The Pulse of Automation Ultrasonic sensors in pulse mode or continuous thru-beam mode help to ensure and control the material flow in a reliable manner across a wide variety of applications. Ultrasonic sensors are ideal for these applications due to their rugged yet precise measuring method. Simple parameterization - if the application requires it - links measuring ranges from a few centimeters up to 10 m - and ultrasonic sensors rise from being just a problem solver to the sensor for all applications. It is already generally well-known that ultrasonic sensors are used as a parking assist for cars. In the field of factory automation, these sensors are an often underestimated technology for noncontact object detection. mbracco@za.pepperl-fuchs.com