Fluidic Oscillator Pulse Generation Without Moving Parts
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Solution Overview
Problem
Existing systems for generating periodic pulses of pressurized liquids or gases are costly, require maintenance, and lack control over pulse repetition frequency, pulse duration, and peak flow rate, especially for applications like micro-irrigation and therapeutic uses.
Innovation Solution
A fluidic oscillator with no moving parts, powered solely by an inlet fluid stream, utilizing a Y-configured fluidic circuit with converging and diverging channels to produce modulated pulses of gas or liquid, allowing control over pulse repetition frequency, pulse duration, and pulse peak pressure without external power or venting to the atmosphere.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical switching systems or pumps with control circuits are used to generate periodic pulses of pressurized fluids, then pulse generation capability is achieved, but device complexity and maintenance requirements increase due to robust switching systems and mechanical valving arrangements
Solution Approach 1:
The patent replaces mechanical switching systems and control circuits with a fluidic oscillator that uses fluid dynamics principles (Coanda effect, pressure differential) to automatically generate periodic pulses. The system eliminates mechanical valving arrangements and electronic control circuits by using a feedback mechanism where pressurized fluid accumulates in a chamber, creates pressure differential that redirects flow, and repeats cyclically.
Solution Approach 2:
The fluidic oscillator is self-regulating and requires no external control. The system automatically generates pulses through its own operation: as fluid accumulates in the chamber, pressure builds until it naturally redirects the flow through the alternative path, creating a self-sustaining oscillation cycle without external intervention.
2Reliability
If check valves with moving components are used to interrupt fluid flow and produce pressure pulses, then pulse generation is achieved, but high input pressures are required and frequency control becomes difficult
Solution Approach 1:
The patent replaces moving valve components with fixed fluidic passages and a flexible diaphragm or membrane that responds to pressure differential. The flow redirection is achieved through fluid dynamic effects (Coanda effect) rather than mechanical valve movement, eliminating the need for high input pressures and enabling precise frequency control through geometric parameters.
Solution Approach 2:
The pulse frequency and characteristics are controlled by changing geometric parameters of the fluidic circuit (passage dimensions, chamber volume, orifice size) rather than adjusting operating pressure or using mechanical controls. This allows precise frequency control without requiring high input pressures or complex adjustment mechanisms.
3Reliability
If atmospheric venting is used in fluidic circuits to recover pressure, then pressure recovery is achieved, but fluid loss to ambient occurs
Solution Approach 1:
The patent introduces a flexible diaphragm or membrane as an intermediary between the pressurized chamber and the atmosphere. This diaphragm allows pressure recovery by deforming in response to pressure differential while preventing direct fluid communication with the atmosphere, thus eliminating fluid loss while maintaining pressure recovery functionality.
Solution Approach 2:
The patent replaces atmospheric venting with a closed-loop fluidic system where pressure recovery is achieved through elastic deformation of a diaphragm or membrane. The system recovers pressure by allowing the diaphragm to return to its original shape, eliminating the need to vent fluid to the atmosphere while maintaining effective pressure cycling.
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 solution provides a reliable, adjustable, and cost-effective method for generating pulsed pressure effects, capable of varying output frequency from 1 to 100 Hz and flow rates from 0.25 to 100 liters per minute, suitable for both liquids and gases, with no moving parts and no fluid venting to the ambient, enhancing applications in micro-irrigation and therapeutic uses.
Implementation Method 1
receive the input fluid flow to increase pressure in the chamber
Implementation Method 2
a flexible diaphragm or membrane in the flow path that deflects in response to pressure differential
Implementation Method 3
the jet initially tries to attach to the chamber's right wall where a Coanda bubble forms, thereby producing a lower pressure area on the jet's right side
Implementation Method 4
where a Coanda bubble forms, thereby producing a lower pressure area on the jet's right side
Data Source
AI summary
A fluidic device which produces fluid pulses having a selected pulse repetition frequency, pulse duration, pulse peak pressure and pulse peak flow rate includes first, second and third fluid flow controlling channels or lumens which converge in a junction, defining a “Y” configuration having a base leg and right and left diverging arms. The first leg portion has a fluid input and terminates downstream at the Y junction of the base and the two diverging arms. The first leg has converging walls which reduce the cross sectional area of the flow to thereby increase the fluid velocity to make a fluid jet. The second or right leg, begins at the Y junction and terminates distally in an enclosed, fluid-tight container having a selected blind volume. The third, or left leg, begins at the Y junction and terminates distally in a fluid outlet passage having a selected cross-sectional area.