Two-Stage Valve with Shape-Memory Alloy Actuator
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Solution Overview
Problem
Conventional two-stage valves are bulky, heavy, and energy-intensive, lacking the ability to autonomously interrupt flow without electrical power and efficiently manage fluid parameters in hydraulic circuits.
Innovation Solution
A two-stage valve utilizing a shape-memory alloy (SMA) actuator device with a pilot stage that integrates seamlessly into the main valve body, allowing for precise control of fluid flow and pressure with minimal electrical power consumption, and includes an electronic control board for parameter detection and wireless communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a conventional two-stage valve is used, then the valve can control high pressure hydraulic circuits, but the valve becomes bulky and heavy
Solution Approach 1:
The patent integrates the pilot valve and main valve into a single compact valve body, merging two previously separate components. The pilot stage and main stage share a common valve body structure, eliminating the need for separate valve housings and reducing overall size and weight while maintaining high pressure control capability
Solution Approach 2:
The pilot valve is nested within the main valve structure. The pilot stage components (pilot shutter, pilot solenoid) are positioned inside the main valve body, with the pilot shutter moving within the main valve's flow path. This nested arrangement allows the smaller pilot valve to control the larger main valve without requiring separate external mounting
2Stress or pressure
If a conventional two-stage valve is used, then the valve can operate in high pressure circuits, but the valve consumes substantial electrical energy
Solution Approach 1:
The valve utilizes the hydraulic circuit's own fluid pressure to actuate the main shutter through the pilot stage. The pilot solenoid only needs to move the small pilot shutter, which then uses hydraulic pressure from the circuit fluid to automatically open or close the main shutter. This self-service mechanism eliminates the need for a large electrical actuator on the main valve, dramatically reducing electrical energy consumption
Solution Approach 2:
The invention employs hydraulic amplification where a small pilot shutter controls a larger main shutter through fluid pressure. The pilot stage modulates hydraulic flow to create pressure differential that actuates the main valve shutter, converting small pilot valve movements into large main valve movements using the circuit's hydraulic energy rather than electrical energy
3Ease of operation
If a conventional two-stage valve is used, then the valve can control fluid flow, but the valve lacks the ability to autonomously interrupt flow without electrical power
Solution Approach 1:
The valve is designed with a normally closed main shutter that requires active hydraulic pressure to open, rather than a normally open shutter that requires active pressure to close. The pilot solenoid controls a pilot shutter that, when energized, opens a pilot passage allowing hydraulic pressure to act on the main shutter and open it. When power is removed, the pilot shutter returns to closed position, automatically blocking the pilot passage and causing the main shutter to close. This inverted logic provides inherent fail-safe autonomous flow interruption
Solution Approach 2:
The valve incorporates a return spring in the pilot stage that pre-positions the pilot shutter in the closed position, ready to block the pilot passage. This spring-loaded reset mechanism ensures that upon loss of electrical power, the pilot shutter automatically returns to its cushioning closed position, preventing uncontrolled hydraulic pressure buildup and ensuring autonomous flow interruption before any potential damage can occur
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 SMA actuator enables a compact, energy-efficient valve that can autonomously manage fluid flow and parameters, reducing size and weight while providing precise control and wireless communication capabilities.
Implementation Method 1
The actuator device (28) comprises at least one wire (30) made of a shape-memory alloy, which is able to apply a force onto the shutter element (26) of the pilot valve by means of the temperature variation (heating) determined by Joule effect by the passage of an electric current through the wire (30) itself
Implementation Method 2
The actuator device (28) comprises at least one wire (30) made of a shape-memory alloy, which is able to apply a force onto the shutter element (26) of the pilot valve by means of the temperature variation (heating) determined by Joule effect by the passage of an electric current through the wire (30) itself
Implementation Method 3
Between the fluid inlet duct (14) of the main valve and the fluid outlet duct (16) of the main valve at least one shutter element (18) of the main valve is interposed, configured to put selectively in fluid communication such a fluid inlet duct (14) of the main valve with such a fluid outlet duct (16) of the main valve
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
The present invention describes a two-stage valve comprising a first stage constituted by a main valve body provided with at least one fluid inlet duct and with at least one fluid outlet duct, between which is interposed at least one shutter element configured to put selectively in fluid communication such ducts. The valve comprises a second stage constituted by a pilot valve body provided with at least one fluid inlet duct and with at least one fluid outlet duct, between which is interposed at least one shutter element configured to put selectively in communication such ducts. The opening of the shutter element of the pilot valve generates a fluid flow passing through the fluid inlet duct of the pilot valve and the fluid outlet duct of the pilot valve, the pressure of such a fluid flow generating the opening of the shutter element of the main valve. The shutter element of the pilot valve is actuated by an actuator device comprising at least one wire made of a shape-memory alloy, capable of applying a force onto the shutter element of the pilot valve as a consequence of a temperature variation determined by the Joule effect by the flow of an electric current through such a wire.