Variable-Orifice Rotary Valve for Precise Low-Pressure Gas Flow
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Solution Overview
Problem
Existing gas flow control valves lack fine control over flow restriction, linear control, fast response time, electronic control, and wide range of flow rates, especially at low pressures, and often require lubrication, which is not suitable for ventilation applications involving blowers and medical devices.
Innovation Solution
A variable orifice rotary valve with a rotatable valve element featuring slots of varying depth and width, allowing precise control of gas flow rates through gradual changes in slot depth and width, and electronic rotation for fast and precise adjustments, functioning without lubrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional valve design is used, then the structure is simple, but the ability to provide fine control over flow restriction is limited
Solution Approach 1:
The valve element is segmented with multiple slots of varying depths and widths arranged circumferentially. Each slot can be independently positioned to control flow, allowing fine-grained adjustment of flow restriction without requiring a complex multi-component structure. The segmentation of the valve element into distinct flow control features enables precise flow management.
Solution Approach 2:
The invention introduces depth as an additional dimension for flow control beyond the traditional width/area adjustment. Slots with varying depths create a three-dimensional flow control mechanism where both the circumferential position and depth of slots determine the effective flow area. This dimensional addition enables finer control resolution without increasing structural complexity.
2Speed
If a conventional valve design is used, then the mechanism is simple, but the response time from fully closed to fully open is slow
Solution Approach 1:
The valve element is designed to rotate dynamically about its axis, allowing rapid transition between closed and open positions. The rotational degree of freedom enables quick repositioning of the slots relative to the housing opening, achieving fast response times. The dynamic rotation mechanism is driven by a low-power actuator that can quickly change the valve element's angular position.
Solution Approach 2:
The invention replaces traditional mechanical lever or plug movement with a rotational mechanism. This substitution allows for faster response times because rotation can be achieved more quickly than linear displacement of comparable magnitude. The rotational system also reduces the mechanical inertia and friction compared to sliding or pivoting mechanisms.
3Extent of automation
If a conventional valve design is used, then the control mechanism is mechanical, but electronic control capability is poor
Solution Approach 1:
The valve element incorporates slots with defined geometries that can be precisely manufactured, enabling deterministic flow control characteristics. This geometric precision allows the mechanical valve to respond predictably to electronic control signals, achieving effective electronic control without requiring complex sensors or feedback mechanisms. The controlled rotation of the valve element can be driven by stepper motors or other electronically controllable actuators.
4Adaptability or versatility
If a conventional valve design is used, then the orifice size is fixed, but the ability to control flow over a wide range of flow rates is limited
Solution Approach 1:
The valve element features multiple slots with different depths and widths, creating a segmented flow control system. By rotating the valve element to different positions, different combinations of slots align with the housing opening, enabling control over a wide range of flow rates. The segmentation allows for both large flow adjustments (by opening/closing multiple slots) and fine flow adjustments (by partially opening individual slots).
Solution Approach 2:
The dynamic rotation of the valve element allows the effective orifice area to change continuously from fully closed to fully open positions. The varying depths of slots create a non-linear flow characteristic that provides fine control at low flow rates and broader control at high flow rates, achieving wide range adaptability while maintaining control resolution throughout the entire flow range.
5Reliability
If a conventional valve design is used, then lubrication is required for smooth operation, but this is not suitable for ventilation applications
Solution Approach 1:
The valve element and housing are designed with self-lubricating surfaces or low-friction materials that enable smooth rotation without external lubrication. The rotational interface is engineered to minimize friction and wear through surface treatments, material selection, or geometric design features such as rounded edges and optimized contact surfaces. This self-service approach ensures reliable operation in ventilation applications where lubrication is prohibited.
Data Source
AI summary
A variable orifice rotary valve for controlling gas flow has a housing with a cylindrical interior passage, a housing opening extending from the interior passage through the housing and a rotatable valve element including a sidewall having a cylindrical external sidewall surface. A slot in the sidewall varies in depth linearly or nonlinearly along at least a portion of a circumferential length of the slot and terminates in an opening in the sidewall. The valve element is rotatably received within the interior passage such that rotation of the valve element determines a length and depth of the portion of the slot that overlaps with the housing opening. That portion of the slot comprises part of the fluid channel. A gas flow rate through the fluid channel is determined by the width, length and depth of the portion of the slot that overlaps with the housing opening.