Low Head-to-Stem Ratio Poppet Valve Flow Resistance

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Solution Overview

Problem

Current poppet valve designs for compressors face inefficiencies in fluid dynamics, leading to high resistance and operational costs, as well as reliability and maintenance challenges due to design complexities and manufacturing difficulties.

Innovation Solution

The design of a low head-to-stem ratio poppet valve with specific geometrical features such as rounded edges, a concave depression on the valve head, and a tapered socket for the spring, which reduces pressure losses and tensile stresses, enhancing sealing effectiveness and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a conventional poppet valve design is used, then the valve provides basic flow control, but the fluid flow resistance is high (K value around 0.5) leading to increased operational costs

Engineering Contradiction:
Improvefluid flow resistanceVSAvoidoperational efficiency
Core Design Contradiction:
Loss of energyVSProductivity

Solution Approach 1:

The valve body incorporates rounded edges at the inlet and outlet openings, and a concave depression on the valve head surface. These curved geometries eliminate sharp corners that cause flow separation and turbulence, enabling smoother fluid flow paths that reduce the resistance coefficient from 0.5 to 0.03 and minimize energy losses.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention optimizes the geometric parameters of the valve body, specifically the head-to-stem ratio and the curvature radii of rounded edges. By carefully selecting these dimensional parameters, the valve achieves minimal flow resistance while maintaining effective sealing capability.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the valve head size is increased to improve sealing, then sealing effectiveness improves, but the head-to-stem ratio increases causing higher tensile stresses and reduced durability

Engineering Contradiction:
Improvesealing effectivenessVSAvoidtensile stress resistance
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The invention optimizes the head-to-stem ratio parameter to a specific range that balances sealing effectiveness with stress management. This optimized ratio ensures adequate sealing surface area while preventing excessive tensile stresses that would compromise stem durability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The concave depression on the valve head and rounded transitions create smoother stress distribution patterns, eliminating stress concentration points that would otherwise lead to premature fatigue failure under cyclic loading conditions.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Ease of manufacture

If sharp edges are used in valve geometry, then manufacturing is simpler, but flow separation and turbulence increase leading to higher pressure losses

Engineering Contradiction:
Improvegeometric simplicityVSAvoidpressure loss
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The valve incorporates rounded edges at all flow-critical locations including inlet openings, outlet openings, and the valve head periphery. These curved geometries eliminate flow separation and turbulence while remaining manufacturable through standard casting or machining processes.

Inventive Principle:
Principle #14Spheroidality (Curvature)

4Weight of moving object

If the valve stem is made thinner to reduce mass, then the valve becomes lighter, but the structural strength and resistance to tensile stresses decrease

Engineering Contradiction:
Improvevalve massVSAvoidstem strength
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The invention optimizes the stem diameter and head-to-stem ratio parameters to achieve the minimum necessary cross-sectional area for structural integrity. This optimized geometry provides adequate tensile strength while minimizing the moving mass of the valve assembly.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2971903B1Low head to stem ratio poppet valve
Publication Date: 2020.04.29 DRESSER RAND CO
  • EP2971903B1 patent drawingFigure 1
  • EP2971903B1 patent drawingFigure 2~3
  • EP2971903B1 patent drawingFigure 4~5

AI summary

A valve member for a poppet valve is provided. The valve member may include a valve stem, a valve head, a face formed on the valve head, a sealing surface disposed between the face and the perimeter of the valve head, a tapered socket, and a bevel. The valve stem may include an outside surface defining a stem diameter. The valve head may include a maximum diameter greater than the stem diameter. The face may be formed on the valve head opposite the valve stem. The sealing surface may include a transition ring disposed between the perimeter of the face and the maximum diameter of the valve head. The tapered socket may be disposed in an end of the valve stem, defining an opening with a socket perimeter sized to receive a spring therein.