Optimum Design Of Pneumatic Valve System For Continuous Non-invasive Blood Pressure Monitoring

Blood pressure is one of the important parameters to monitor vital signs.It is an important parameter to reflect the function of cardiovascular and cerebrovascular function.It is also an important physiological index reflecting the circulatory system.Blood pressure provides a basis for many important decisions in health care,including the diagnosis of various diseases,monitoring of rehabilitation,observation of treatment and prognosis of surgery.Continuous noninvasive blood pressure monitoring can monitor the blood pressure generated by the stroke pulse and the resulting blood pressure waveform,and the advantages are obvious during the procedure,the care ward and other special circumstances.Continuous noninvasive blood pressure monitoring system can accurately provide absolute value and trend of blood pressure changes in the clinical use of a high value.The pressure control module of continuous noninvasive blood pressure monitoring system need to quickly adjust the pulse wave with the pulse pressure gas.The piezoelectric valve as a pressure control module in the active control of the core pressure of gas components,it performance directly affect the accuracy of blood pressure measurement system measurement.Piezoelectric valve with high precision,fast response,the basic no power consumption,small size,easy to damage,energy saving and environmental protection,fully meet the pressure control module requirements.The main work done in this paper:1)Compared with the performance of a variety of piezoelectric valves,and ultimately selected and the original structure similar to the miniature direct acting type piezoelectric valve design.The working principle and characteristics of the piezoelectric bimorph are studied,and the piezoelectric piezoelectric system is constructed.2)The choice of a suitable performance of the piezoelectric double wafer structure piezoelectric valve.The stress of the piezoelectric bimorph in the piezoelectric valve is analyzed,and the relationship between the gas flow rate and the airway diameter is established.3)The overall structure of the piezoelectric valve was designed,the use of two piezoelectric dual-chip structure of a piezoelectric valve,to achieve the original two piezoelectric valve function,effectively reducing the overall gas structure.Optimized ventilation pore size.Ansys were used for fluid analysis to obtain changes in gas flow and gas pressure in the valve body in both inlet and exhaust conditions.4)The conditions of influencing the flow rate of the piezoelectric valve are tested,and the influence of the free length of the piezoelectric double wafer,the thickness of the gasket and the size of the vent hole on the flow rate is obtained.In the piezoelectric valve performance and the original piezoelectric valve performance equivalent circumstances,effectively reduced the size of the piezoelectric valve.In accordance with the design of a self-made piezoelectric valve,fully meet the requirements.In this paper,the piezoelectric valve structure is optimized and a new piezoelectric valve structure is provided,and a better method is proposed for the sealing of the piezoelectric valve.The new design of the piezoelectric valve compared with the original piezoelectric valve,traffic and other key performance is higher,the size of the basic remain unchanged.But the new design of the piezoelectric valve can replace the original two piezoelectric valve work,effectively reducing the pressure control module volume.