A proposed solenoid-actuated valve would open for a short time to pass a very small quantity of fluid. The valve could be used to meter a specified total quantity of the fluid through repeated actuations.
In the operation of a typical solenoid-actuated, momentary-opening valve of older design, the solenoid is first actuated to magnetically pull a poppet away from a valve seat to effect opening. Shortly thereafter, the current in the solenoid is turned off, allowing a spring to halt the motion of the poppet away from the seat and then push the poppet back into the seat to effect closure. In the proposed valve, there would be no return stroke; instead, to effect momentary opening, the poppet would be toggled between two "closed" positions. One advantage offered by this approach would be that without a return stroke, a shorter opening time could be achieved. Another advantage would be protective redundancy; if a leak were detected with the poppet in one of the two "closed" positions, one could simply switch the valve to the other "closed" position.
In the proposed valve (see figure), a poppet would be spring-loaded and latched into either a rearward or a forward "closed" position. The spring-loading and latching action would be effected by a Belleville spring, which would be stable in either "closed" position and would snap ("oil-can") between the two stable positions when the poppet was moved through the middle position. Two armatures (magnetically permeable plungers) would be mounted on the poppet, separated by an inner yoke. There would be two solenoids; a forward-closing and a rearward-closing coil.
The armatures would be positioned, relative to the solenoids, to configure the magnetic-flux paths to obtain the desired magnetic forces. The configuration would be such that upon application of electric current to the forward-or rearward-closing coil, the resulting magnetic force would pull the poppet toward either the forward or the rearward "closed" position, respectively. When neither coil was ene rgized, the force of the Belleville spring would hold the poppet in whichever "closed" position was reached most recently.
This work was done by George Yankura of Caltech for NASA's Jet Propulsion Laboratory.
NPO-20596
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Closed/Momentary-Opening/Closed Solenoid Valve
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Overview
The document presents a technical support package detailing a proposed solenoid-actuated valve developed by George Yankura at NASA's Jet Propulsion Laboratory (JPL). This innovative valve design aims to improve fluid metering by allowing for momentary openings without a return stroke, which is a departure from traditional solenoid valves.
The valve features a poppet that is spring-loaded and can be latched into either a rearward or forward "closed" position using a Belleville spring. This spring mechanism ensures stability in both positions and allows the poppet to "snap" between them when moved through a middle position. The design incorporates two solenoids—one for forward closure and another for rearward closure—each connected to magnetically permeable armatures mounted on the poppet. When electric current is applied to either solenoid, it generates a magnetic force that pulls the poppet toward the corresponding closed position.
One of the key advantages of this valve design is its ability to achieve a shorter opening time due to the absence of a return stroke. This feature enhances the valve's responsiveness, making it suitable for applications requiring precise fluid control. Additionally, the design offers protective redundancy; if a leak is detected while the poppet is in one closed position, the valve can be switched to the other closed position, ensuring continued operation and safety.
The document emphasizes that the work was conducted under contract with NASA and does not imply endorsement of any specific commercial products or processes. It also includes a disclaimer regarding the accuracy and completeness of the information provided, stating that neither the United States Government nor NASA assumes liability for any damages resulting from the use of the information contained in the document.
Overall, this proposed solenoid-actuated valve represents a significant advancement in fluid control technology, combining efficiency, reliability, and safety features that could benefit various applications in aerospace and other industries. The innovative design reflects ongoing efforts at JPL to develop cutting-edge solutions for complex engineering challenges.
