Rotary Piston Sealing via Offset Shutter Disc
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Solution Overview
Problem
Rotary piston and cylinder devices face challenges in achieving effective sealing at high speeds, leading to leakage issues due to the use of reciprocating components and complex geometries that are difficult to manufacture and inspect.
Innovation Solution
The design incorporates a shutter disc with a circumferential surface that forms a seal with the rotor, featuring a close-running line offset from the rotor's radial plane, which minimizes clearance and leakage by using a simpler geometry approximated by single-radius curves or radiused portions, and is preferably rotary with apertures aligned for piston passage, reducing fluid transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reciprocating components are used for shutter means, then sealing can be achieved, but device complexity increases and reliability decreases at high speeds
Solution Approach 1:
Instead of using reciprocating shutter means that move back and forth to seal, the invention uses a rotary shutter disc that rotates continuously. The close-running line is offset from the radial plane, creating an asymmetric geometry that provides sealing during rotation without requiring reciprocating motion. This inversion from reciprocating to rotary motion simplifies the mechanism and improves reliability at high speeds.
Solution Approach 2:
The shutter disc features a curved close-running line that is offset from the radial plane, creating an asymmetric curved geometry. This curved profile allows the shutter disc to maintain continuous contact with the rotor surface during rotation, providing effective sealing without the need for reciprocating components. The curvature enables smooth rotation while maintaining seal integrity.
2Reliability
If complex geometries are used for sealing, then sealing effectiveness improves, but manufacturing precision requirements increase
Solution Approach 1:
The invention uses an asymmetric close-running line geometry where the sealing line is offset from the radial plane of the rotor. This asymmetric configuration provides effective sealing by maintaining optimal contact between the shutter disc and rotor surfaces during rotation. The asymmetric geometry is simpler to manufacture than complex symmetric profiles because it can be defined by a single offset distance from the radial plane, reducing manufacturing precision requirements while maintaining sealing effectiveness.
3Reliability
If close-running lines are positioned on the radial plane, then sealing contact is maximized, but clearance and leakage increase
Solution Approach 1:
The invention offsets the close-running line from the radial plane, introducing a dimensional offset that creates an asymmetric sealing configuration. This offset positioning changes the spatial relationship between the shutter disc and rotor surfaces, allowing the sealing line to intersect the rotor at an angle rather than along the radial plane. This dimensional change reduces clearance and minimizes leakage paths while maintaining effective sealing contact during rotation.
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
This configuration enhances sealing efficiency, reduces leakage, and simplifies manufacturing and inspection by using offset close-running lines and radiused surfaces, improving the overall performance and packaging of rotary piston and cylinder devices.
Implementation Method 1
the circumferential surface arranged to form a seal with a surface of the rotor, the circumferential surface defining a profile which forms at least one close running line with said rotor surface, and the at least one close-running line offset from a plane which lies on a radius of the rotor
Data Source
Figure 1
Figure 2
Figure 2a
AI summary
A rotary piston and cylinder device (1) comprising a rotor (2), a stator and a shutter disc (3), the rotor comprising a piston which extends from the rotor into the cylinder space, the rotor and the stator together defining the cylinder space, the shutter disc passing through the cylinder space and forming a partition therein, and the disc comprising a slot (3a) which allows passage of the piston therethrough, the shutter disc comprising a circumferential surface (30) arranged to form a seal with a surface of the rotor, the circumferential surface defining a profile which forms at least one close running line (13b) with said rotor surface, and the at least one close-running line offset from a rotor plane (13) which lies on a radius of the rotor and which includes the axis of rotation of the rotor.