Adjustable Pressure Limiting Valve With Locking Cap Stops
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Solution Overview
Problem
Existing adjustable pressure limiting (APL) valves in anaesthesiology face challenges in achieving accurate and consistent maximum limit pressure due to variations in spring force and manufacturing tolerances, leading to potential under or over-opening issues.
Innovation Solution
The design incorporates a first valve cap that adjusts the spring force and a second cap that locks in place to prevent further adjustment, allowing for precise setting and adjustment of the maximum pressure during assembly while enabling pressure reduction during use, using a screw thread mechanism and abutment stops for secure engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a slightly stronger spring is used to ensure all valves achieve the target pressure, then the reliability of achieving minimum pressure is improved, but the maximum limit pressure becomes excessively high and the valve may not open at all
Solution Approach 1:
The valve cap is divided into a first valve cap for adjustment and a second valve cap for limiting, allowing the spring force to be segmented into adjustable components and fixed limit components. This enables independent optimization of minimum pressure reliability and maximum pressure limitation without compromising either function.
2Manufacturing precision
If the spring force is increased to accommodate manufacturing tolerances, then the consistency of maximum limit pressure is improved, but the valve opening pressure at the low end of the operating range increases undesirably
Solution Approach 1:
The valve cap segmentation allows the spring force to be distributed such that the first valve cap handles low-end opening pressure requirements while the second valve cap handles maximum limit pressure consistency, eliminating the need to increase overall spring force.
Solution Approach 2:
Different regions of the valve mechanism are assigned different functional qualities: the first valve cap region provides ease of operation at low pressures, while the second valve cap region provides manufacturing precision at maximum pressure, allowing each region to be optimized independently.
3Device complexity
If the maximum pressure threshold is fixed during manufacture, then the device complexity is reduced, but the manufacturing precision and reliability of threshold pressure are compromised due to spring variations
Solution Approach 1:
The valve cap is segmented into two functional parts that can be assembled in different configurations, providing a simple structural solution that enables precise pressure threshold adjustment while accommodating spring variations without increasing overall device complexity.
Solution Approach 2:
The valve transitions from a static fixed-pressure design to a dynamic adjustable-pressure design, where the two-valve-cap configuration allows the pressure threshold to be adjusted during assembly or use, providing both simplicity and precision.
4Manufacturing precision
If a second valve cap is added to lock the first valve cap, then the manufacturing precision of maximum pressure is improved, but the device complexity increases
Solution Approach 1:
The valve cap is segmented into two functional units that work together: the first valve cap for pressure adjustment and the second valve cap for precision locking. This segmentation achieves high manufacturing precision while keeping the overall structure relatively simple through functional division.
Solution Approach 2:
The second valve cap is nested over the first valve cap, with the smaller first valve cap contained within the larger second valve cap structure. This nesting arrangement achieves precise pressure control while minimizing the increase in device complexity through space-efficient design.
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
This solution ensures consistent maximum pressure setting across valves, accommodating spring and manufacturing variations, while allowing for adjustable pressure delivery, ensuring reliable operation and accuracy.
Implementation Method 1
the spring force provided by springs, in particular light springs, can vary
Implementation Method 2
rotating a part of the valve top to compress the spring
Data Source
AI summary
The present invention relates to adjustable flow control valves, for example to an Adjustable Pressure Limiting (APL) valve. The adjustable valve (2) described comprises a valve body (4) comprising a valve seat (6), a valve member (10) movable relative to the valve seat (6), a first valve cap (20), a second valve cap (50) and a biasing element (30) to bias the valve member (10) away from the first valve cap (20). The first valve cap (20) is movable to increase the biasing force applied by the biasing element (30). The second valve cap (50) is engageable with the first valve cap (20) to prevent such movement of the first valve cap (20) beyond a selected position, but to allow movement of the first valve cap (20) in an opposite direction, way from said position.