Spool Valve Neutral Position Accuracy via Segmented Contact
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Solution Overview
Problem
Existing spool valves fail to efficiently remove elemental mercury (Hg0) from flue gas and oxidized mercury (Hg0) from waste liquid, with activated carbon injection technology being costly and its mercury removal efficiency is affected by NOx and SO2.
Innovation Solution
Utilization of metal sulfides (e.g., FeS2, CuS, CuFeS2) as mercury removal efficiency is affected by NOx and SO2.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the first end face and stopping surface are brought into close contact to ensure positional accuracy, then the neutral position accuracy is improved, but hydraulic fluid supply between the surfaces becomes difficult and hydraulic load balance deteriorates
Solution Approach 1:
The first end face or stopping surface is divided into multiple contact regions rather than a single flat contact area. This segmentation allows hydraulic fluid to access gaps between segments while maintaining sufficient contact area for positional accuracy, thus balancing both requirements
Solution Approach 2:
A shim or intermediate component is introduced between the first end face and stopping surface. This intermediary element creates controlled gaps that facilitate hydraulic fluid supply while maintaining the required positional accuracy through precise thickness control of the shim
2Stability of the object's composition
If the gap between first end face and stopping surface is made extremely small for positional accuracy, then the neutral position stability is improved, but hydraulic fluid supply time increases and spool movement reliability deteriorates
Solution Approach 1:
The contact interface between the first end face and stopping surface is designed to be dynamically adjustable. The spool can maintain stable neutral position through controlled contact while allowing dynamic gap formation during movement to facilitate hydraulic fluid supply and ensure reliable operation
3Device complexity
If an electric device is used to move the spool instead of hydraulic operation, then the device complexity is reduced, but the risk of spool non-movement due to unbalanced hydraulic loads increases
Solution Approach 1:
The hydraulic circuit is designed with beforehand cushioning measures including pressure balancing channels and flow control mechanisms that prevent unbalanced hydraulic loads from occurring in the first place. This ensures the electric device can reliably move the spool without encountering unexpected resistance
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
Achieves efficient, cost-effective, and environmentally friendly simultaneous removal of Hg0 from flue gas and Hg2+ from waste liquid, avoiding secondary pollution and reducing operational costs.
Implementation Method 1
an electric device connected to the spool and switching the hydraulic fluid path by moving the spool along the axis
Implementation Method 2
When hydraulic fluid is supplied to a pressure regulating port connected to a pressure regulating circuit, the spool moves from the neutral position to a second position against the biasing force of the spring
Implementation Method 3
The spool of the spool valve is biased toward a neutral position by a spring
Implementation Method 4
it is difficult for hydraulic fluid to be supplied between the first end face and the stopping surface or it takes a long time for the hydraulic fluid to be supplied therebetween
Data Source
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AI summary
A spool valve (1) includes: a spool (2); a housing (3) that houses the spool so as to allow the spool to reciprocate along an axis (X); and an electric device (4) that switches the hydraulic fluid path by moving the spool along the axis. The spool includes a first end face (24) that is perpendicular to the axis. The housing includes a stopping surface (35) that positions the spool in a neutral position by abutting against the first end face of the spool. Either one or both of the first end face and the stopping surface have one or more projections or recesses.