Intermediate Tank Hydraulic Circuit for Die Casting Cavitation

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Solution Overview

Problem

Existing hydraulic circuit arrangements for die-casting machines suffer from cavitation-related damage due to high acceleration pressures, leading to costly multipliers and frequent maintenance, as well as Joukowsky shocks from collapsing cavitation bubbles, which cause damage and increase operational costs.

Innovation Solution

Incorporating an intermediate tank in the line connection between the working cylinder rod space and the tank to decelerate the hydraulic fluid, eliminating the need for expensive pressure multipliers and reducing maintenance, with a short connecting line and adequate tank volume to minimize pressure surges and fluid sloshing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a multiplier (pressure intensifier) is used to handle high acceleration pressures, then cavitation effects are prevented, but the device becomes expensive and requires regular maintenance

Engineering Contradiction:
Improveprevention of cavitation damageVSAvoidcost and maintenance of pressure intensifier
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

An intermediate tank is introduced as a mediator between the working cylinder rod chamber and the main tank. This intermediate tank absorbs the hydraulic fluid during high acceleration phases, preventing cavitation in the connecting line without requiring a complex pressure intensifier with moving parts

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The harmful function of the pressure intensifier (handling high acceleration pressures) is extracted from the main hydraulic circuit by isolating it in a separate intermediate tank. This allows the main system to operate without the complexity and maintenance requirements of a pressure intensifier

Inventive Principle:
Principle #2Taking out (Extraction)

2Device complexity

If hydraulic fluid is discharged directly to the tank, then the system is simple, but cavitation bubbles form and collapse causing Joukowsky shocks and damage

Engineering Contradiction:
Improvesimplicity of hydraulic circuitVSAvoidJoukowsky shock and cavitation damage
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The intermediate tank serves as a cushioning element that is positioned in advance in the hydraulic circuit. During high acceleration phases, it absorbs the hydraulic fluid and prevents the formation and collapse of cavitation bubbles that would otherwise cause Joukowsky shocks and damage to the system

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

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 solution effectively prevents cavitation-related damage by braking the hydraulic fluid in the intermediate tank, reducing Joukowsky shocks and lowering manufacturing and maintenance costs, while maintaining high pressures of at least 150 bar.

Implementation Method 1

Without such a multiplier, a cavitation bubble would form in the pipe leading from the working cylinder rod chamber during the second phase. When the cavitation bubble subsequently collapses, the resulting high temperatures cannot be dissipated from the pipe, so damage can occur

Methodology Applied
Scientific EffectCavitation: Cavitation

Implementation Method 2

Furthermore, the backflow of the fluid during the collapse of the cavitation bubble causes a pressure surge known as a Joukowsky shock, which can also lead to damage

Methodology Applied
Scientific EffectJoukowsky shock: Shock Wave

Data Source

PatentEP3495075B1Hydraulic circuit assembly for a cold or hot chamber die casting machine
Publication Date: 2020.04.08 PARKER HANNIFIN EMEA SARL
  • EP3495075B1 patent drawingFigure 1
  • EP3495075B1 patent drawingFigure 2

AI summary

The present invention relates to a hydraulic circuit arrangement for a cold or hot chamber die casting machine for the production of metal components, - with a battery (10) for providing a hydraulic fluid, - with a working cylinder (20) having a working cylinder piston chamber (21) and a working cylinder rod chamber (22), - with a pressure intensifier (30) for increasing the pressure in the working cylinder piston chamber (21), and - with a working cylinder rod chamber line connection (15) leading from the working cylinder rod chamber (22) to a tank (80), characterized in that an intermediate tank (90) is arranged in the working cylinder rod chamber line connection (15) between the working cylinder rod chamber (22) and the tank (80).