Variable Pitch Propeller Automatic Control via Venturi Effect
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Solution Overview
Problem
Existing variable pitch propeller control systems are complex, expensive, and often fail to provide satisfactory pitch control across the entire speed range of a boat, with manual systems requiring delicate adjustments and being difficult to use.
Innovation Solution
A device using the Venturi effect to modify propeller pitch by creating a depression in a chamber with non-parallel orifices, which moves a movable partition to activate a mechanism for adjusting the propeller pitch, allowing automatic control based on fluid flow speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If hydraulic, electrical, mechanical, or hydrodynamic control systems are used, then pitch control precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses hydrodynamic forces generated by water flow through strategically positioned orifices to automatically adjust propeller pitch. The flow-induced pressure differences move the propeller blades without requiring complex hydraulic actuators, electrical motors, or mechanical linkages, thereby achieving precise pitch control while simplifying the overall system.
Solution Approach 2:
The control system utilizes the natural hydrodynamic forces of the surrounding water flow to automatically regulate propeller pitch based on the boat's speed. The system self-adjusts without external control inputs, eliminating the need for complex control electronics, sensors, and actuators while maintaining optimal pitch across the entire speed range.
2Device complexity
If manual pitch control systems are used, then device complexity is reduced, but ease of operation deteriorates due to delicate adjustments required
Solution Approach 1:
The system automatically adjusts propeller pitch by exploiting hydrodynamic forces from water flow through orifices positioned on the propeller hub. This self-regulating mechanism eliminates the need for manual intervention entirely, making operation trivial while keeping the device mechanically simple with no complex linkages or adjustment mechanisms.
3Measurement precision
If conventional control systems are used, then pitch control is improved at certain speeds, but adaptability across the entire speed range deteriorates
Solution Approach 1:
The patent employs hydrodynamic pressure differences created by water flow through multiple orifices positioned at different locations and orientations on the propeller hub. As boat speed varies, the flow characteristics change, automatically generating appropriate pitch adjustments across the entire speed range without requiring multiple control systems or complex adaptive algorithms.
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 solution simplifies the design and operation of variable pitch propeller control, enabling efficient and automatic pitch adjustment over a range of 15°, improving control across various speeds without the need for complex and expensive systems.
Implementation Method 1
an external flow of a fluid generates, by Venturi effect, a depression in a first compartment of a chamber comprising one or more first orifices not parallel to an axis of rotation of the propeller
Data Source
Figure 1~2
Figure 3(A)~3(B)
Figure 4(A)~4(B)
AI summary
The present invention relates to a device comprising a variable pitch propeller (11) and means adapted to modify the pitch of the propeller by Venturi effect.