Gems Sensors - PRODUCT NEWS
       

Non-contact Sensor has lots of bottle. A US company has developed a sensor that detects the presence or absence of liquid at a specified fill level inside a plastic bottle or container, without it having to be opened. Developed for the in-vitro diagnostics market, it is ideally suited for systems filling and handling bottles of aggressive chemicals, those containing liquids deemed to be potential biohazards, and situations where it is essential to avoid the possibility of contamination. The 'ExOsense' is a PVDFbased ultrasonic piezoelectric transducer with a 'Rexolite' lens that sticks to the outside of a bottle when an adhesive cover is removed. The amount of acoustic signal that is reflected from the inside surface of the bottle depends on the impedance mismatch between the bottle material and whatever is inside it. If the bottle contains liquid, the acoustic impedances are similar, 1.8 and around 1.5, and most of the ultrasound signal passes into the liquid without being reflected. Whereas if there is no liquid, the acoustic impedances of the bottle and air are sufficiently different, 1.8 and 0, that most of the ultrasound energy is reflected back to the transducer. The transducers are sufficiently low cost that they can be considered disposable in some applications. They are separate from the electronic switch units, and are attached by a cable fitted with a miniature USB connector, which plugs into the transducer head. The lens focuses the ultrasonic signal to a point on the inside of the bottle. The system requires no calibration: it is 'plug and go'. It works with bottles made of polyethylene, polypropylene, polysulfone and polycarbonate but not those made of PTFE or any foamed core plastics. Heads are available for flat-sided and round bottles and containers with a minimum bottle diameter of 50.8mm. WaIl thickness can be from 0.5mm to 3.8mm. Response time is less than 100ms and the transducer works over the temperature range 0°C to 70°C. Sealing is to 1P65. Power requirements are 4.75 to 5.25V DC or 6 to 32V DC. Power consumption is 50mA max and output configuration is open collector, 40mA max. Fluids whose levels can be detected include: reagents; wastes; diluents; detergent washes; coolants; saline; or pure water. The device is used in equipment for clinical chemistry, haematology, immuno-chemistry, histology, medical laser systems, haemodialysis and cytology. The device is available worldwide from Gems Sensors. ______________________________________________ For more information, please contact :- For more information, click here... April 2006
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