Medical Pin Index Valve With Nested Springs for Residual Pressure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing medical pin index valves face challenges in incorporating a residual pressure device due to limited space, stability issues with single spring designs, and material limitations that affect performance with gases like oxygen.
Innovation Solution
A medical pin index valve with a nested biasing mechanism using a dual spring system, where a smaller diameter spring is nested inside a larger diameter spring, providing a stiffer spring effect in less space and ensuring stability and accurate pressure control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single spring is used in the residual pressure device, then the device complexity is reduced, but the stability and reliability deteriorate due to vibration and material limitations
Solution Approach 1:
The patent employs a nested spring configuration where an inner spring is placed inside an outer spring. This nested arrangement allows both springs to work together in a compact space, providing cumulative biasing force while maintaining stability. The inner spring engages with the diaphragm assembly and outer spring engages with the valve body, creating a redundant system that resists vibration and ensures reliable residual pressure maintenance.
2Force
If a single spring with large diameter is used to provide sufficient biasing force, then the biasing force is adequate, but the volume of the valve increases
Solution Approach 1:
By nesting the inner spring within the outer spring, the patent achieves a compact arrangement where both springs contribute to the biasing force without requiring a large single spring. The cumulative effect of both springs provides sufficient biasing force to maintain residual pressure between 0.5-5.0 psig, while the nested configuration keeps the overall valve volume small and suitable for medical applications.
Solution Approach 2:
The patent combines the biasing functions of two separate springs into a single integrated system. The inner and outer springs work together to provide the required biasing force on the diaphragm assembly, merging their effects to achieve the desired residual pressure control in a compact package.
3Volume of stationary object
If Inconel or Phosphorus Bronze or Beryllium Copper is used for the spring, then the spring can be made smaller, but the stability deteriorates due to repeated compression
Solution Approach 1:
The nested spring configuration allows the use of smaller-diameter springs that would individually be unstable, but when nested and working together, they provide cumulative biasing force with improved stability. The inner spring (0.020-0.040 inch diameter) and outer spring (0.030-0.050 inch diameter) are both small enough to fit in the compact valve but stable enough when working in combination.
Solution Approach 2:
The patent uses stainless steel material for both the inner and outer springs, which provides excellent corrosion resistance and stability for medical gas applications. The nested configuration of these stable stainless steel springs creates a composite spring system that maintains reliability over repeated compression cycles while using smaller individual spring dimensions.
4Productivity
If the residual pressure is set too low (below 0.5 bar), then the refilling speed increases, but contamination risk increases
Solution Approach 1:
The nested spring system provides a mechanical feedback mechanism that automatically maintains residual pressure within the safe 0.5-5.0 psig range. When pressure drops below this range, the springs exert sufficient biasing force on the diaphragm to close the valve and prevent further gas flow, thereby preventing tank emptying and contamination while allowing efficient refilling when pressure is above the threshold.
5Object-affected harmful factors
If the residual pressure is set too high (above 5 bar), then contamination is prevented, but the refilling efficiency decreases
Solution Approach 1:
The nested spring configuration is designed to exert biasing force that closes the valve when pressure exceeds the 0.5-5.0 psig range, preventing over-pressurization. This feedback mechanism ensures contamination prevention by maintaining minimum residual pressure while improving refilling efficiency by allowing the tank to be refilled to optimal pressure levels without excessive pressure buildup.
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 dual spring system achieves a desired residual pressure range of 0.5 bar to 5 bar, enhancing tank refilling efficiency, preventing contamination, and allowing for the use of stainless steel materials suitable for medical gases.
Implementation Method 1
The nested biasing mechanism includes a dual spring system. The dual spring system includes two different sized springs. One spring has a smaller diameter than the other spring. The smaller diameter spring is nested in the larger diameter spring.
Implementation Method 2
The use of two springs creates the effect of a much stiffer spring in less than half the space it would take for a single spring that provide the same amount of biasing force.
Data Source
AI summary
A medical pin index valve includes a pair of pin holes, the positions of which are selected based on the particular gas to be used with the pin index valve. The pin index valve includes a residual pressure device therein. In one embodiment, the residual pressure device is designed so that it closes the valve when the pressure in the tank is between 0.5 bar to 5 bar.