Pneumatic Cylinder-Piston Ventilator for Precise Gas Delivery
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Solution Overview
Problem
Traditional ventilators struggle with precise control of both pressure and volume of ventilation gas, leading to issues like barotrauma, hypoventilation, volotrauma, and contamination risks, while being bulky and requiring frequent calibration.
Innovation Solution
A pulmonary ventilator with a cylinder-piston unit, magnetized piston, and integrated sensors and control systems to adjust gas flow and pressure dynamically, ensuring accurate delivery of a desired volume at a desired pressure, while minimizing contamination and size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If volume-controlled ventilation is used, then tidal volume is regulated, but interalveolar pressure becomes disproportionate causing barotrauma or hypoxia
Solution Approach 1:
The ventilator incorporates pressure sensors that continuously monitor interalveolar pressure and provide feedback to the control system. The control system adjusts the tidal volume in real-time based on pressure feedback, ensuring pressure remains within safe limits while delivering appropriate ventilation volumes.
Solution Approach 2:
The system dynamically adjusts ventilation parameters based on real-time pressure measurements. The tidal volume is not fixed but adaptively modified according to the patient's instantaneous respiratory system compliance and resistance, preventing barotrauma while maintaining adequate ventilation.
2Stress or pressure
If pressure-controlled ventilation is used, then interalveolar pressure is controlled, but tidal volume varies significantly causing hypoventilation or volotrauma
Solution Approach 1:
The system uses flow sensors and volume sensors to continuously monitor actual tidal volume delivery and provides feedback to the control system. When volume deviation is detected, the control system adjusts pressure parameters to maintain the prescribed tidal volume, preventing both hypoventilation and volotrauma.
Solution Approach 2:
The ventilator dynamically transitions between pressure and volume control modes based on real-time sensor data. The system adapts pressure support levels and inspiratory time to maintain consistent tidal volume delivery despite variations in patient respiratory mechanics.
3Measurement precision
If traditional sensors are used for volume measurement, then volume can be measured, but periodic calibration is required due to time drift
Solution Approach 1:
The system replaces traditional volumetric/mass type sensors with a combination of flow sensors and pressure sensors. Volume is calculated by integrating flow measurements over time, where flow is derived from pressure differential across a known resistance. This electronic/optical measurement system eliminates time drift issues inherent in mechanical sensors, removing the need for periodic calibration.
Solution Approach 2:
The system performs self-verification using the known geometry of the cylinder-piston unit and integrated sensors. The control system continuously monitors sensor readings against expected values based on piston position and chamber volume, automatically compensating for any drift without external calibration intervention.
4Stress or pressure
If electric motor and shaft connected to piston are used, then accurate pressure control is achieved, but device size increases and contamination risk arises
Solution Approach 1:
The system replaces the electric motor and shaft mechanical drive with a pneumatic actuation system. A second gas chamber with controlled pressure differential acts directly on the piston, eliminating the need for external mechanical drive components. This reduces device size and eliminates contamination pathways associated with shaft seals and motor housings.
Solution Approach 2:
The piston is actuated purely by pneumatic pressure differential between two sealed gas chambers. The first chamber receives ventilation gas and the second chamber receives reference pressure, creating a clean, sealed pneumatic actuation system that maintains pressure control accuracy without mechanical transmission components.
5Ease of operation
If shaft connected to piston moves in and out of cylinder, then piston actuation is achieved, but ventilation gas is exposed to contamination
Solution Approach 1:
The system replaces mechanical shaft actuation with direct pneumatic actuation. The piston responds to pressure differential between two sealed chambers without requiring mechanical connection to external drive mechanisms. This eliminates shaft seals and bearing interfaces that could allow contamination, maintaining complete gas isolation.
Solution Approach 2:
The system uses flexible diaphragms or membranes to seal the gas chambers while allowing piston movement. These flexible barriers maintain complete gas isolation between the ventilation gas chamber and the reference pressure chamber, preventing contamination while enabling smooth piston actuation through pressure differential.
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 ventilator provides precise and reliable control of gas pressure and volume, reduces contamination risk, and allows portability with an auxiliary supply system, overcoming limitations of traditional models.
Implementation Method 1
said piston being moved inside said cylinder due to the pressure difference between said first gas in said actuation chamber and said ventilation gas in said ventilation chamber
Implementation Method 2
one position detector, configured for detecting the position of said piston inside said cylinder
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A pulmonary ventilator for delivering to a patient a desired volume of a ventilation gas at a desired pressure, comprising: - a cylinder-piston unit (21) having a cylinder (211) and a piston (212) which delimit: an actuation chamber (3) for selectively receiving a first gas under pressure; and a ventilation chamber (4) for selectively receiving said ventilation gas under pressure to be provided to said patient; - devices for adjusting the flow entering into and leaving said actuation and ventilation chambers; - sensors for detecting in use the pressure in said actuation and ventilation chambers; - one position detector (29) configured for detecting the position of said piston inside said cylinder; and - one acquisition and processing unit (6) for controlling said flow adjusting devices based on the piston position and the pressure in the chambers, so as to deliver to the patient said desired volume of said ventilation gas at said desired pressure.