Split-Piston Pressure Relief Valve for Bidirectional Flow
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Solution Overview
Problem
Pressure relief valves often fail to operate bidirectionally and are affected by flow forces, leading to reduced performance and potential equipment damage due to misalignment and leakage issues in conventional designs.
Innovation Solution
A bidirectional pressure relief valve design featuring a split piston configuration with an outer and inner piston, a seat element, and a setting spring, allowing fluid flow in both directions and reducing flow forces through geometric features that minimize Bernoulli effects, and eliminating the need for costly threaded engagements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional pressure relief valve is used, then it can relieve pressure in one direction, but it cannot operate bidirectionally and suffers from misalignment and leakage issues
Solution Approach 1:
The valve is segmented into two separate piston elements: an outer piston for controlling flow from the first port and an inner piston for controlling flow from the second port. Each piston independently manages one direction of flow, eliminating the misalignment and leakage problems associated with conventional single-valve bidirectional designs.
2Power
If fluid flows around a conventional poppet, then pressure relief occurs, but Bernoulli flow forces oppose the actuation force and prevent expected operation
Solution Approach 1:
The segmented piston design separates the flow paths for each direction, allowing independent optimization of each piston's geometry to minimize Bernoulli effects specific to its flow direction, rather than having a single poppet handle both directions with conflicting force requirements.
Solution Approach 2:
Each piston is designed with specific local geometric features optimized for its particular flow direction, creating localized flow characteristics that reduce adverse Bernoulli forces on each piston individually while maintaining overall pressure relief effectiveness.
3Ease of manufacture
If threaded engagements are used in valve construction, then components can be assembled, but costly machining and threaded components are required
Solution Approach 1:
The design extracts and eliminates the need for threaded engagements and complex machining operations by using a simpler piston-and-seat geometry that can be manufactured with basic machining processes, reducing both cost and complexity while maintaining assembly capability.
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 valve effectively relieves pressure in both directions, reduces flow forces, and minimizes leakage and misalignment issues, ensuring reliable operation and cost-effectiveness by eliminating the need for expensive machining and threaded components.
Implementation Method 1
a setting spring applying a biasing force on the inner piston in a distal direction
Implementation Method 2
fluid received at the first port applies a net fluid force on the outer piston and the inner piston that overcomes the biasing force
Implementation Method 3
fluid received at the second port pushes the outer piston in the distal direction against the seat element while applying a respective net fluid force on the inner piston
Implementation Method 4
reduces flow forces through geometric features that minimize Bernoulli effects
Data Source
AI summary
An example valve includes a seat element; an outer piston configured to be seated against the seat element at when the valve is in a closed position to block fluid flow from a first port of the valve to a second port of the valve; an inner piston disposed partially within the outer piston and configured to be seated against the outer piston when the valve is in the closed position to block fluid flow from the second port to the first port; and a setting spring applying a biasing force on the inner piston in a distal direction. The valve can operate in: (i) a first mode of operation wherein fluid is received at the first port and relieved to the second port, and (ii) a second mode of operation, wherein fluid is received at the second port and relieved to the first port.