Piezoelectric Pump Backflow Prevention for Blood Pressure Measurement
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Solution Overview
Problem
Piezoelectric pumps used in blood pressure measurement devices suffer from limited pressurization capability due to fluid backflow through the connecting hole during the discharging operation, leading to insufficient pressure force and prolonged pressurization times.
Innovation Solution
A piezoelectric pump design featuring an actuator with a piezoelectric element and vibrating sheet, a first diaphragm with a connecting hole, and a backflow prevention mechanism, such as an opposing wall portion on a second diaphragm or a thin-film valve body, to prevent fluid from flowing back during discharging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a piezoelectric pump with a connecting hole in the diaphragm is used for pressurization, then the pump can be compact and suitable for blood pressure measurement devices, but fluid backflow occurs during discharging operation reducing pressurization capability
Solution Approach 1:
The pump is divided into separate suction chamber and discharge chamber with a common wall, and the diaphragm is segmented with a connecting hole that is selectively openable/closable to control fluid flow between chambers while maintaining compact structure
Solution Approach 2:
The valve body is positioned in advance at the connecting hole to prevent backflow before it occurs during the discharging operation, ensuring pressurization capability is maintained from the start of each pumping cycle
2Productivity
If the piezoelectric pump operates with a diaphragm connecting hole, then fluid can pass through during pumping cycles, but backflow causes insufficient pressure force and prolonged pressurization time
Solution Approach 1:
The valve body is pre-positioned at the connecting hole to close the passage before backflow can occur, preventing pressure loss and ensuring rapid pressurization without prolonged operation time
Solution Approach 2:
The valve mechanism converts the potential harmful backflow into a controlled flow path, where the valve body directs fluid flow appropriately during different phases of the pumping cycle, turning the connecting hole from a source of backflow into an efficient flow pathway
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design enhances pressurization efficiency, preventing backflow and enabling high-pressure, large-flow operation, ensuring sufficient pressure force for speedy blood pressure measurement.
Implementation Method 1
an actuator including a piezoelectric element and a vibrating sheet to which the piezoelectric element is attached, wherein the actuator is vibrated by the piezoelectric element being resonantly driven
Implementation Method 2
the actuator is vibrated by the piezoelectric element being resonantly driven
Data Source
AI summary
A piezoelectric pump is provided with an actuator containing a piezoelectric element and a vibrating sheet; a first diaphragm, positioned opposite the actuator, with a first connecting hole provided therein; a pump chamber formed by the space between the actuator and the first diaphragm; and a second diaphragm positioned opposite the first diaphragm. The part of the second diaphragm opposite the first connecting hole is provided with an opposing wall portion that prevents a fluid that has been introduced into the pump chamber via the first connecting hole from flowing back towards a suction side via the first connecting hole.