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ABSTRACT. A DEVICE FOR CALIBRATING EQUIPMENTS FOR LOW FLOW RATE MEASUREMENTS (VENTURI TUBE, ORIFICE FLOWMETER), IN A RANGE BETWEEN 0.4 AND 5 L/S, IS DESCRIBED IN THIS WORK. IMPORTANT DETAILS, RELATIVE TO THE DEVICE CONFIGURATION AND TO THE EXPERIMENTAL TECHNIQUE, ARE PRESENTED AND THEIR IMPACT ON THE EXPERIMENTAL RESULT PRECISION IS DISCUSSED. IN ORDER TO ACCESS THE ACCURACY OF THE DEVICE DEVELOPED IN THIS WORK, EQUIPMENT FOR DETECTING THE PASSAGE OF A SOAP BUBBLE, WHICH IS MOVING INSIDE A GLASS TUBE, WAS DEVELOPED. TWO LIGHT DIODES ARE USED IN THIS EQUIPMENT, ONE EMITTER AND THE OTHER RECEPTOR, AND ITS FUNCTIONING PRINCIPLE IS BASED ON THE LIGHT REFLECTION ON THE CURVED SURFACE OF THE BUBBLE. THE CALIBRATION DEVICE WAS USED TO CALIBRATE A VENTURI TUBE AND GOOD RESULTS WERE OBTAINED, MAINLY FOR THE LOW VALUES OF FLOW RATE. FOR THE GREATER VALUES, A SCATTERING FOR THE DISCHARGE COEFFICIENT WAS OBSERVED, INDICATING THAT ADDITIONAL IMPROVEMENTS ARE STILL REQUIRED.
KEY-WORDS: LOW FLOW RATE, CALIBRATION DEVICE, DISCHARGE COEFFICIENT, INSTRUMENTATION.
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