Rotating Pump Piston for Symmetrical Sealing Ring Wear

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Solution Overview

Problem

Fluid dispensing systems with axial displacement pumps experience accelerated wear and asymmetrical wear on sealing rings due to reciprocating motion and debris, leading to imbalance and potential bypass channels.

Innovation Solution

A rotating piston design that induces symmetrical wear on packing rings by rotating circumferentially during reciprocation, distributing wear evenly and preventing imbalance, while also self-tightening with the piston head.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a reciprocating piston is used in an axial displacement pump, then fluid can be pumped from source to downstream, but accelerated wear and asymmetrical wear occur on sealing rings due to reciprocating motion and debris

Engineering Contradiction:
Improvefluid pumping capabilityVSAvoidsealing ring wear resistance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The piston is modified to rotate about its longitudinal axis during reciprocating motion. This dynamic addition transforms the piston from a purely translational component to one with combined translational and rotational movement, causing the sealing rings to wear symmetrically across their circumference rather than asymmetrically at single points, thereby improving reliability while maintaining productivity

Inventive Principle:
Principle #15Dynamics

2Reliability

If sealing rings tightly interface with the piston during reciprocating motion, then vacuum condition is created for fluid pumping, but debris becomes lodged between sealing rings and piston causing accelerated wear

Engineering Contradiction:
Improvevacuum sealing capabilityVSAvoiddebris-induced wear
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The rotating piston design ensures that any debris lodged between the piston and sealing rings is gradually worked around the circumference as the piston rotates. This dynamic action prevents debris from remaining stationary and causing localized accelerated wear, while the tight interface is maintained to preserve vacuum sealing capability

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The rotation of the piston converts the potentially harmful effect of debris lodging into a beneficial self-cleaning action. As the piston rotates, debris is gradually moved along the interface and prevented from causing concentrated wear, transforming a harmful static condition into a beneficial dynamic self-cleaning mechanism

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of operation

If asymmetrical wear occurs on sealing rings, then fluid penetration increases and piston reciprocation becomes imbalanced, but the root cause is reciprocating motion without rotation

Engineering Contradiction:
Improvepiston reciprocation smoothnessVSAvoidsealing ring interface uniformity
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

By adding rotational motion to the reciprocating piston, the design ensures that wear is distributed uniformly around the sealing ring interface. This dynamic rotation prevents the development of asymmetrical wear patterns that would otherwise lead to fluid penetration and reciprocation imbalance, maintaining both operational smoothness and interface uniformity

Inventive Principle:
Principle #15Dynamics

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 rotating piston design minimizes premature failure of sealing components, maintains pump balance, and ensures consistent fluid dispensing by distributing wear symmetrically and preventing bypass channels.

Implementation Method 1

Each flute includes an angled surface oriented to redirect the fluid in a same circumferential direction about the piston rod

Methodology Applied
Scientific EffectFluid flow redirection:

Implementation Method 2

The moment imparted on the piston rod by the fluid encountering the angled surfaces causes the piston to rotate circumferentially about the longitudinal axis

Methodology Applied
Scientific EffectMoment-induced rotation:

Implementation Method 3

rotating piston design induces symmetrical wear on packing rings by rotating circumferentially during reciprocation, distributing wear evenly

Methodology Applied
Scientific EffectSymmetrical wear distribution: Wear

Data Source

PatentEP3187728B1Rotating piston for pumps
Publication Date: 2021.06.16 GRACO MINNESTOA INC
  • EP3187728B1 patent drawingFigure 1A
  • EP3187728B1 patent drawingFigure 1B
  • EP3187728B1 patent drawingFigure 2

AI summary

A piston is the driven component within a pump. The piston is driven along a longitudinal axis to pump a fluid through the pump. The fluid flows through the piston between an upstream end of the pump and a downstream end of the pump. The piston outputs the fluid into the downstream end of the pump at a vector offset from the longitudinal axis, thereby inducing rotation of the piston throughout the pumping process. Rotating the piston encourages even wear on various components within the pump, such as sealing rings surrounding the piston, thereby increasing the lifespan of the components and increasing the efficiency of the pump.