Diaphragm Pump Acoustic Filter for Pressure Ripple Reduction
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Solution Overview
Problem
Conventional diaphragm pumps in blood pressure monitors generate significant pressure ripple noise, leading to increased pump noise and complexity in existing solutions, which are not effective in reducing the pressure ripple itself and often require additional components like acoustic filters and comparators.
Innovation Solution
A diaphragm pump design incorporating an air chamber and a partition wall with a through hole portion to regulate the flow rate of gas, acting as an acoustic filter to reduce pressure ripple, eliminating the need for external acoustic filters and simplifying the pump structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional diaphragm pump is used for pressurization, then the pump can transfer air to the bladder, but pressure ripple is generated causing increased pump noise
Solution Approach 1:
An acoustic filter is introduced as an intermediary component between the pump chamber and the air valve. The acoustic filter includes a tank and a thin pipe that allows air to pass through while filtering out pressure ripple and noise, thus enabling the pump to transfer air effectively without generating harmful pressure ripple noise
Solution Approach 2:
The harmful pressure ripple component is extracted and separated from the air flow using the acoustic filter. The filter isolates the unwanted pressure ripple from the main air stream, allowing the pump to maintain its air transfer function while removing the harmful noise component
2Object-generated harmful factors
If an acoustic filter is added to reduce pressure ripple, then pump noise decreases, but the number of parts and device complexity increase
Solution Approach 1:
The acoustic filter is integrated into the existing pump structure by combining the filter tank and thin pipe with the pump chamber and air valve assembly. This merging approach allows the acoustic filter to function as part of the pump system rather than a separate external component, reducing overall device complexity while maintaining noise reduction effectiveness
3Measurement precision
If an acoustic filter is provided at the pressure sensor inlet, then pressure ripple is reduced, but the air pipe arrangement becomes complicated and cost increases
Solution Approach 1:
The acoustic filter is installed at the pump outlet before the air enters the bladder and pressure sensor, performing the noise filtering action preliminarily. This preliminary action prevents pressure ripple from reaching the pressure sensor in the first place, eliminating the need for complex air pipe arrangements and additional filtering components elsewhere in the system
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 solution effectively reduces pressure ripple and associated noise, improving the accuracy of blood pressure measurements and reducing the size and complexity of the blood pressure monitor while lowering costs.
Implementation Method 1
a partition wall portion for partition between the air chamber and the exhaust path. In the partition wall portion, a through hole portion for communication between the air chamber and the exhaust path is formed. The through hole portion restricts a flow rate of the gas that flows from the air chamber to the exhaust port
Implementation Method 2
The through hole portion restricts a flow rate of the gas that flows from the air chamber to the exhaust port, acting as an acoustic filter to reduce pressure ripple
Data Source
AI summary
A diaphragm pump for achieving reduced pressure ripple of an exhausted gas is provided. The diaphragm pump is a pump for transporting a gas in accordance with change in volume of a pump chamber, and the diaphragm pump includes an exhaust valve permitting flow of the gas that flows out of the pump chamber and prohibiting a flow thereof in a reverse direction, an air chamber in which the gas that has flowed out of the pump chamber through the exhaust valve flows, an exhaust port through which the gas is exhausted to the outside of the diaphragm pump, and a through hole portion for restricting a flow rate of the gas that flows from the air chamber to the exhaust port.