Directly Piloted Valve Assembly Spool Design
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Solution Overview
Problem
Direct acting pneumatic valve designs face challenges with tight manufacturing tolerances, high solenoid power requirements, and limited flow capacity due to short spool stroke, while piloted designs have higher part counts, larger size, and slower response times. Additionally, piloted valves require minimum operating pressure and are not suitable for vacuum applications.
Innovation Solution
A directly piloted valve assembly that integrates a spool and actuator with a shuttle seal channel, allowing for simultaneous movement of the spool and shuttle seal, eliminating the need for a separate pilot valve and reducing the number of seals, thus achieving lower operating pressure and higher flow capacity with reduced component costs and faster response times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a direct acting solenoid design is used, then the total part count is low and there is no minimum operating pressure limitation, but the spool stroke must be short which increases manufacturing difficulty and requires tight tolerances
Solution Approach 1:
The valve is segmented into a direct-acting solenoid portion and a pilot portion, allowing the spool stroke to be divided into two stages: initial movement by the solenoid and completion by the pilot pressure, enabling longer overall stroke without increasing solenoid power requirements
Solution Approach 2:
The pilot valve is integrated within the main valve body, with the pilot spool nested inside the main spool assembly, allowing compact arrangement while maintaining separate functional zones for direct-acting and pilot-acting mechanisms
2Use of energy by moving object
If a direct acting design with short spool stroke is used, then solenoid power is kept low, but sliding seals cannot be used which requires metal to metal fits that always leak
Solution Approach 1:
The spool stroke is made dynamic with two distinct phases: initial rapid movement driven by solenoid force for low power consumption, and completion movement driven by pilot pressure differential, allowing the use of sliding seals that require longer stroke while maintaining low solenoid power requirements
Solution Approach 2:
Pilot pressure acts as an intermediary force that assists the solenoid in completing the spool stroke, enabling the use of sliding seals with longer stroke without requiring proportionally higher solenoid power
3Quantity of substance
If a piloted valve design is used, then flow capacity is high and solenoid power is low, but the part count is high, size is large, and response time is slow
Solution Approach 1:
The pilot valve and main valve are merged into a single integrated assembly, sharing common components such as the valve body, spool, and sealing elements, reducing part count while maintaining the high flow capacity benefits of piloted design
Solution Approach 2:
The integrated design allows components to serve multiple functions: the pilot spool controls both pilot pressure and main spool positioning, and the valve body accommodates both direct-acting and pilot-acting mechanisms, reducing overall component count
4Quantity of substance
If a piloted valve design is used, then flow capacity is high, but the valve requires minimum operating pressure and is not suitable for vacuum applications
Solution Approach 1:
The valve operates dynamically across different pressure regimes: in vacuum applications, the direct-acting solenoid portion handles low-pressure operation, while in pressure applications, the pilot portion activates to provide high flow capacity, enabling universal applicability across vacuum and pressure ranges
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 directly piloted valve design achieves lower component costs, faster response times, and higher flow capacity with reduced solenoid power requirements, while maintaining a compact size and being suitable for both pressure and vacuum applications, overcoming the limitations of both direct and piloted valve designs.
Implementation Method 1
A solenoid is connected to the valve body. The solenoid is capable of moving the actuator between a first actuator position and a second actuator position.
Implementation Method 2
When the actuator is moved by a solenoid or return spring, the fluid pressures acting on the spool and actuator shuttle seal are changed, forcing the shuttle seal to move from one end of the shuttle seal channel to the other and the spool to shift from a first position to a second position
Implementation Method 3
A return spring is disposed within the spool. The return spring is capable of moving the actuator between the first actuator position and the second actuator position.
Data Source
AI summary
A directly piloted valve assembly has a valve body including a bore, at least one inlet port, at least one outlet port and at least one exhaust port or second outlet port wherein the ports are all in fluid communication with the bore. A spool is received in the bore. The spool includes a wall defining a lumen. An actuator is received in the lumen. The actuator includes a shuttle seal channel. A shuttle seal is received in the shuttle seal channel. A solenoid is connected to the valve body. The wall of the spool includes at least one pilot hole in fluid communication with the lumen defined by the spool and the bore of the valve body.