Pressure Exchanger Piston Braking for Wear and Pressure Peaks

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Solution Overview

Problem

Pressure exchangers experience wear and inefficiency due to piston collisions with valve plates and abrupt energy loss, leading to maintenance issues and low energy efficiency.

Innovation Solution

Incorporation of a piston braking system with a pressure relief arrangement, featuring thrust pads and conical parts for soft impact and pressure management, along with a floating piston design and lubrication system to reduce wear and maintain energy efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the piston velocity is increased to improve productivity, then the pressure peak increases causing potential damage to the piston or cylinder barrel

Engineering Contradiction:
Improvepiston velocityVSAvoidstructural integrity
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The pressure relief arrangement is pre-configured in the piston to activate when pressure peaks occur during high-velocity operation. This beforehand preparation allows the system to handle sudden pressure increases without structural damage, enabling higher productivity while maintaining safety margins.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The pressure relief arrangement dynamically changes the pressure parameter within the piston by providing fluid communication between opposite sides when pressure exceeds a threshold. This parameter change prevents destructive pressure peaks while allowing high-velocity operation for improved productivity.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the piston braking system is used to reduce piston velocity and prevent collisions, then wear is reduced, but pressure peaks occur that may damage the piston or cylinder barrel

Engineering Contradiction:
Improvewear resistanceVSAvoidstructural integrity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The pressure relief arrangement is merged with the piston structure itself, combining the braking function with pressure management in a single integrated component. This allows the piston to slow down and prevent collisions while simultaneously relieving pressure peaks through internal fluid communication channels.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The pressure relief arrangement acts as an intermediary mechanism between the piston's kinetic energy and the structural components. By providing fluid communication paths, it mediates the energy transfer and prevents both mechanical impact damage and pressure-induced structural failure.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If the piston stops abruptly to complete the fluid displacement cycle, then the fluid transfer is completed, but kinetic energy is lost and energy efficiency decreases

Engineering Contradiction:
Improvefluid transfer completionVSAvoidkinetic energy loss
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The pressure relief arrangement dynamically activates only when needed (during pressure peaks from braking), rather than continuously. This dynamic operation allows the piston to maintain kinetic energy during normal operation for efficient fluid displacement, while providing relief only when pressure becomes excessive, thus balancing productivity with energy efficiency.

Inventive Principle:
Principle #15Dynamics

4Reliability

If the piston velocity is reduced to prevent collisions with valve plates, then wear and maintenance needs are reduced, but energy efficiency decreases due to loss of kinetic energy

Engineering Contradiction:
Improvemaintenance frequencyVSAvoidenergy efficiency
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The pressure relief arrangement is a self-activating feature within the piston that automatically responds to pressure conditions without external control. It serves itself by using the pressure differential to open fluid communication paths, providing wear protection while maintaining energy efficiency through automatic, condition-based operation.

Inventive Principle:
Principle #25Self-service

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 solution effectively reduces wear and maintenance, enhances energy efficiency by managing pressure peaks, and minimizes fluid mixing, resulting in a more reliable and efficient pressure exchange process.

Implementation Method 1

The pressure relief arrangement allows at least temporarily a fluid connection between both sides of the piston (8). Excess pressure can be discharged from a high pressure side to a low pressure side of the piston (8).

Methodology Applied
Scientific EffectPressure equalization: Pascal's Law

Implementation Method 2

a piston braking system and the piston comprises a pressure relief arrangement. The piston braking system allows to decrease the pistons velocity close to one of the end positions

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4130492A1Pressure exchanger
Publication Date: 2023.02.08 DANFOSS AS
  • EP4130492A1 patent drawingFigure 1~5
  • EP4130492A1 patent drawingFigure 6~7
  • EP4130492A1 patent drawing

AI summary

A pressure exchanger comprises a cylinder barrel (1), two valve plates (2) and two port plates (3, 4), wherein the cylinder barrel (1) comprises at least one cylinder (7) which accommodates a piston (8). The pressure exchanger further comprises a piston braking system (16,17), wherein the piston (8) comprises a pressure relief arrangement (9).