Cylindrical mouthpiece for piezoresonance sensor functioning as an alcohol dragger

Abstract

The invention relates to a cylindrical mouthpiece for a quartz piezoelectric resonator based on volumetric electromechanical ("acoustic") vibrations, applicable in the field of physics, chemistry and engineering, and in particular, for qualitative and quantitative analysis of the concentration of alcohol in the blood. According to the proposed configuration of the mouthpiece, plastic and brass are selected as materials for the main mechanical parts. The main parts are four - an inlet pipe, a regulating nozzle, an expansion chamber and an outlet pipe. The inlet pipe (position 1) has dimensions ф12*2 mm and a length of 50 mm and serves for exhaling human breath and its passage through a circular nozzle (position 2) mounted at the end of the pipe with a diameter of 10 mm and a thickness of 2 mm. The nozzle is implemented with two technological holes with a diameter of 1 mm, located symmetrically on the axis at an angle of 65 °, in order to redirect the air (gas) jet along the walls of the pipe, and not directly to its outlet. The expansion chamber (item 3) consists of two identical circular parts (elements 3.1 and 3.3) with a diameter of 50 mm and a technological hole of 12 mm in the center, and a closing tube (element 3.2) with dimensions ф52*2 mm and a length of 50 mm, connecting the chamber with the inlet pipe and the outlet pipe (item 4) with dimensions ф12*2 mm and a length of 30 mm. The design of the chamber is designed to subject the air flow to constant expansion and eliminate vortices. The advantages of the mouthpiece are related to the conversion of the turbulent vortex structures of the exhaled air into plate-like structures, maintaining a constant pressure drop at the outlet and, accordingly, ensuring a constant gas / mass flow rate at the outlet, which guarantees the same number of molecules hitting the sensor surface during each measurement. The cylindrical mouthpiece for a quartz piezoelectric sensor element based on volumetric electromechanical ("acoustic") vibrations can find wide practical application in the field of catering and entertainment business, as an auxiliary element for precise analysis of the alcohol content in the breath / blood, in order to prevent serious road accidents after excessive alcohol consumption and drunk driving.