Jet Pipe Servovalve Spool Layout for High Flow and Low Leakage
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Solution Overview
Problem
Existing servovalves face challenges in handling large fluid flows while maintaining a compact design, being vulnerable to contamination and leakage, and requiring complex external fluid supply systems.
Innovation Solution
A servovalve design with a spool that isolates control fluid and regulated fluid pathways, incorporating internal fluid supply and filtration within the spool, eliminating external supply pipes and filters, and using a steerable nozzle for precise fluid control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If large valve orifice areas are used to handle large fluid flows, then fluid flow capacity is improved, but valve size increases
Solution Approach 1:
The valve system is divided into two independent fluid pathways: a first pathway for regulated fluid flow with large orifices for high flow capacity, and a second pathway for control fluid with smaller orifices for precise control. This segmentation allows each pathway to be optimized independently, enabling large fluid flow handling without proportionally increasing overall valve size.
2Ease of operation
If external fluid supply pipes are used to provide pressurised fluid to the jet pipe, then fluid supply is simplified, but vulnerability to damage and leakage increases
Solution Approach 1:
The jet pipe is integrated within the spool structure, merging the control fluid pathway with the regulated fluid pathway. The spool's interior passage serves as both a structural component and a fluid conduit, eliminating the need for separate external supply pipes and reducing vulnerability to damage and leakage.
3Ease of operation
If the jet pipe is mounted outside the servovalve body in the torque motor chamber, then fluid supply to the nozzle is enabled, but external leakage risk and overall size increase
Solution Approach 1:
The jet pipe is nested within the spool's interior passage, with the nozzle positioned inside the servovalve body. This nested arrangement allows the control fluid to be supplied internally through the spool to the nozzle, eliminating external mounting and associated leakage risks while maintaining compact overall size.
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 design enables efficient handling of large fluid flows with reduced size, vulnerability, and contamination resistance, ensuring reliable operation and improved accuracy.
Implementation Method 1
a torque motor arranged to steer the nozzle by means of an induced current
Implementation Method 2
a steerable nozzle from which fluid is directed to the ends of the spool
Data Source
AI summary
A servovalve includes a fluid transfer valve assembly comprising a primary fluid supply port and a control port, a moveable valve spool arranged to regulate flow of fluid through a first fluid pathway from the primary fluid supply port to the control port, and a jet pipe assembly configured to axially move the spool relative to the fluid transfer valve assembly in response to a control signal to regulate the fluid flow along the first fluid pathway. The jet pipe assembly comprises a steerable nozzle from which fluid is directed to the ends of the spool in an amount determined by the control signal. The spool comprises an opening and an interior passage fluidly coupling the opening to the jet pipe assembly via a second fluid pathway. The first fluid pathway is fluidly isolated from the second fluid pathway within the spool.