Fusible Plug Safety Valve Creep Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The fusible piece in existing pressure relief valves is prone to creep deformation due to low compressive strength, causing the valve element to remain open even when the temperature is below the melting point, leading to increased manufacturing costs due to the need for larger diameters and more fusible metal, which is often expensive and contains rare metals.
Innovation Solution
A fusible plug type pressure relief valve design featuring a supporting body with an inclined contact surface that disperses the applied force, reducing surface pressure and preventing creep deformation, while maintaining a compact size by using a porous member or specific geometric shapes like truncated cones or partially spherical surfaces to distribute the force effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the outer diameter of the supporting body is increased to reduce surface pressure and suppress creep deformation, then the creep deformation amount is reduced, but the outer diameter of the entire pressure relief valve device increases and the manufacturing cost increases
Solution Approach 1:
The supporting body is designed with a curved surface (spheroidal or rounded geometry) instead of a flat surface. This curvature increases the contact area between the supporting body and the valve element, thereby distributing the pressing force more evenly and reducing surface pressure. This allows the supporting body to maintain its shape and suppress creep deformation without requiring an increase in outer diameter, thus resolving the contradiction between stability and device size.
2Stability of the object's composition
If the outer diameter of the supporting body is increased to reduce surface pressure and suppress creep deformation, then the creep deformation amount is reduced, but the volume of the supporting body increases and the amount of fusible metal used increases, leading to higher manufacturing cost
Solution Approach 1:
The curved surface design of the supporting body increases the effective contact area without requiring an increase in outer diameter. This allows the same pressing force to be distributed over a larger area, reducing surface pressure and suppressing creep deformation. Since the outer diameter is not increased, the volume of fusible metal required remains the same, thus resolving the contradiction between stability and material quantity.
3Reliability
If a fusible metal is used for the supporting body, then the valve element can be maintained at the closed position, but the compressive strength is low and creep deformation occurs easily under high primary pressure
Solution Approach 1:
The curved surface of the supporting body distributes the primary pressure more evenly across the contact area, reducing peak surface pressure. This reduces the stress concentration on the fusible metal, thereby suppressing creep deformation even under high primary pressure conditions. The fusible metal maintains its reliability in holding the valve element at the closed position while the curved geometry compensates for its low compressive strength by improving stress distribution.
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 effectively suppresses creep deformation and maintains the valve element in a closed position until the predetermined temperature is reached, reducing the outer diameter and the amount of fusible metal required, thus lowering production costs without compromising the valve's functionality.
Implementation Method 1
a fusible piece melts at a predetermined melting temperature to be discharged to the atmosphere
Implementation Method 2
The valve element is biased by a spring member toward an open position
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A fusible plug type pressure relief valve 1 includes a housing 11, a valve element 12, a spring member 13, and a fusible piece 14. A valve passage 21 is formed in the housing 11. A valve element 12 is arranged at a closed position in the housing 11, the closed position being a position at which the valve element 12 closes the valve passage 21. The valve element 12 is movable to an open position at which the valve element 12 opens the valve passage 21. The spring member 13 presses the valve element 12 in an open direction. The fusible piece 14 supports the valve element 12 against pressing force of the spring member 13. The fusible piece 14 melts at not less than a predetermined melting temperature. An inner surface of a concave portion 51 of the fusible piece 14 contacts the valve element 12. The concave portion 51 includes a tapered portion 55 inclined relative to an axis line of the valve element 12.