Safety Valve Lifting Bell Geometry for Reliable Opening
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Solution Overview
Problem
Safety valves struggle to reliably open in systems with counterpressure and pressure losses, especially in gas and steam systems, due to the design limitations that hinder efficient pressure reduction.
Innovation Solution
The safety valve features a lifting bell with a collar inclined at an angle of 60° to 80° to the valve longitudinal axis, which supports the opening movement by creating dynamic pressure and reducing counteracting forces, along with a dynamic pressure edge for efficient flow guidance and pressure buildup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional lifting bell design is used, then the valve structure is simple, but the valve fails to open reliably under back pressure and pressure losses
Solution Approach 1:
The collar is inclined at an angle of 60° to 80° to the longitudinal valve axis, creating an inclined flow path that generates dynamic pressure to support opening movement. This parameter change in the collar angle transforms the lifting bell's interaction with the fluid flow, enabling reliable opening under back pressure conditions.
Solution Approach 2:
The back pressure edge extends from the collar further away from the valve disk in the direction of the longitudinal valve axis, creating a three-dimensional flow path that calms the flow beneath the collar and within the back pressure edge. This dimensional extension allows sufficient space for back pressure to build up and act on the collar.
2Force
If the collar extends perpendicular to the longitudinal valve axis, then the lifting bell structure is simple, but the force on the back of the lifting bell counteracts the opening movement
Solution Approach 1:
The collar is inclined at an angle of 60° to 80° to the longitudinal valve axis (or 10° to 30° to the radius outwards), which reduces the force acting on the back of the lifting bell that would otherwise counteract the opening movement. This angular parameter change optimizes the force balance to support opening.
Solution Approach 2:
The back pressure that would normally oppose valve opening is converted into a beneficial force by the inclined collar design. The inclined flow path created by the collar angles the back pressure to support the opening movement of the valve plate, transforming a harmful force into a helpful one.
3Productivity
If the valve opens rapidly, then pressure reduction is efficient, but the flow becomes turbulent and prevents back pressure buildup
Solution Approach 1:
The inclined collar creates a smooth, curved flow path that calms the flow beneath the collar and within the back pressure edge. This curved geometry guides the flow smoothly, reducing turbulence and allowing back pressure to build up even during rapid opening and pressure reduction.
Solution Approach 2:
The back pressure edge extends from the collar at a specific geometry to create sufficient space for back pressure buildup. This geometric parameter change allows the system to maintain both rapid pressure reduction and sufficient back pressure development by controlling the flow path and pressure 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
This design ensures reliable opening and maintains the valve open to effectively reduce pressure, even under counterpressure conditions, enhancing the safety valve's performance in gas and steam systems by facilitating the opening movement and maintaining the valve open until pressure is reduced.
Implementation Method 1
The selected angle of between 60° and 80°, in conjunction with the back pressure edge, has proven particularly advantageous in that when the valve opens, sufficient back pressure develops beneath the lifting bell to support the opening movement of the valve plate.
Implementation Method 2
The inclined design of the collar calms the flow beneath the collar and within the back pressure edge, allowing the desired back pressure to develop there.
Implementation Method 3
The preload force acting on the valve disk is preferably generated by a spring.
Implementation Method 4
The valve disk is arranged to be movable so that it can lift itself from the valve seat against the preload force, i.e. by overcoming the preload force, and can open the valve.
Data Source
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AI summary
The invention relates to a safety valve with an annular valve seat (2) and a valve disc (4) held in contact with the valve seat (2) by a preload force (S) and movable along a valve longitudinal axis (x), which has a lifting bell (6) surrounding the valve seat (82) on its outer circumference, wherein the lifting bell (6) has a collar (12) surrounding the valve seat (2) which extends outwards to the valve longitudinal axis (x) at an angle (a) between 60° and 80°, and wherein the collar (12) has an annular back pressure edge (14) extending transversely to the collar (12) on its outer circumference.