Variable Orifice Rotary Valve for Medical Ventilator Gas Flow Control
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Solution Overview
Problem
Existing medical ventilator valves lack fine control over flow restriction, linear flow control, fast response time, electronic control, wide range of flow rates, lubrication-free operation, and compatibility with low pressures, making them unsuitable for diverse patient needs such as adults and neonates.
Innovation Solution
A variable orifice gas flow control valve with a cylindrical rotary valve element and housing, featuring tapered cutouts and exhaust/bypass openings, allowing precise control of gas flow through rotational alignment and materials like graphite and glass for low friction and sealing without lubrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If globe valves or piston valves are used, then flow control is achieved, but response time is slow and pressure drop is high at low flows
Solution Approach 1:
The valve employs a rotary element that can dynamically adjust its angular position to change the effective flow area. This dynamic configuration allows the valve to transition quickly between different flow states, achieving fast response time while maintaining low pressure drop across the valve body.
Solution Approach 2:
The valve design segments the flow control function into multiple independent pathways with different flow characteristics. This allows the valve to optimize flow control for different operating conditions (low flow vs high flow, adult vs neonate patients) by selectively activating different segments, improving both response time and pressure drop characteristics.
2Ease of operation
If sliding valves or rotating valves are used, then simple on/off control is achieved, but flow control precision is poor and response time is slow
Solution Approach 1:
The rotary valve element can be positioned at any angular location, providing continuous and precise flow control rather than discrete on/off states. This dynamic positioning capability enables proportional flow control with high precision while maintaining fast response time through direct rotational actuation.
Solution Approach 2:
The valve changes the flow parameter by rotating the valve element to different angular positions, which directly alters the effective flow area. This parameter change mechanism provides both precise flow control and fast response, as the flow rate is directly proportional to the angular position of the rotary element.
3Reliability
If conventional valves are used, then flow control is achieved, but lubrication is required for moving parts
Solution Approach 1:
The valve employs homogeneous materials with low friction coefficients for the rotating components, such as PTFE (Teflon) or other self-lubricating materials. This material selection provides both lubrication-free operation and reliable sealing, as these materials inherently combine low friction with good conformability to mating surfaces.
Solution Approach 2:
The valve utilizes composite material construction, combining materials with complementary properties. For example, a rigid body material provides structural strength while a soft sealing material (such as elastomer or PTFE) provides both sealing and low friction characteristics, eliminating the need for external lubrication while maintaining sealing capability.
4Measurement precision
If standard valves are used, then flow control works for high flows, but control resolution is low at low flow rates
Solution Approach 1:
The valve incorporates multiple flow pathways or chambers with different flow coefficients, allowing the system to segment the overall flow range into multiple zones. By switching between or combining these segments, the valve achieves high control resolution at low flows while maintaining the capability to handle high flows, thus providing both precision and versatility.
Solution Approach 2:
The valve is designed with multi-functionality to serve different patient populations (adults and neonates) using the same device. This is achieved through a rotary element with multiple angular positions that can provide appropriate flow control characteristics for different flow ranges, ensuring high resolution control for neonates while maintaining adequate control for adults.
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
Enables flexible, precise control of gas flow with minimal pressure drop, fast response, and long life, accommodating a wide range of flow rates and pressures, suitable for both adult and neonatal applications without the need for lubrication.
Implementation Method 1
The valve element is rotatably received within the interior passage of the valve housing... materials like graphite and glass for low friction and sealing without lubrication
Implementation Method 2
an area of overlap of the housing opening and the valve element opening may be varied by rotating the valve element within the interior passage of the valve housing
Data Source
Figure 1A~2B
Figure 2C~4B
Figure 5~6
AI summary
Gas flow control valves comprising a valve housing including a cylindrical interior passage, and a housing opening extending from the interior passage through the housing. The gas flow control valve further comprises a cylindrical rotary valve element including a sidewall, and a rotary valve element opening extending through the sidewall. The valve element is rotatably received within the interior passage of the valve housing, such that the housing opening may be selectively aligned with the rotary valve element opening, and an area of overlap of the housing opening and the valve element opening may be varied by rotating the valve element within the interior passage of the valve housing.