Hydraulic Flushing Device with Viscosity-Dependent Throttle

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Solution Overview

Problem

Existing hydraulic systems with closed circuits face inefficiencies in fluid flushing, leading to overheating due to constant and abrupt discharge of fluid, which can cause pressure drops and energy wastage.

Innovation Solution

A hydraulic system with a flushing device that utilizes a viscosity-dependent throttle to adjust discharge fluid flow based on the temperature of the hydraulic fluid, ensuring efficient fluid flushing and preventing abrupt pressure drops by increasing flow when the fluid is hot and reducing it when cold, thereby maintaining optimal system operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a constant flushing valve is used to discharge hydraulic fluid, then the hydraulic fluid temperature is reduced, but the discharge fluid flow changes abruptly causing pressure drops

Engineering Contradiction:
Improvehydraulic fluid temperatureVSAvoidpressure stability
Core Design Contradiction:
TemperatureVSStability of the object's composition

Solution Approach 1:

The patent applies the dynamics principle by replacing the constant flushing valve with a variable discharge flow system that adapts to changing operating conditions. The discharge fluid flow is made variable through viscosity-dependent throttles and control mechanisms that respond to temperature and pressure changes, allowing the system to dynamically adjust the flushing rate rather than maintaining a fixed constant flow.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements feedback control through sensors that monitor hydraulic fluid temperature and pressure conditions, with the control unit adjusting the discharge fluid flow accordingly. The control mechanism uses feedback from the system state (temperature, pressure differential) to modulate the flushing valve opening, ensuring stable pressure while achieving effective cooling when needed.

Inventive Principle:
Principle #23Feedback

2Temperature

If the discharge fluid flow is increased to prevent overheating, then the temperature control improves, but energy is wasted and pressure drops occur

Engineering Contradiction:
Improvehydraulic fluid temperature controlVSAvoidenergy wastage
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The system dynamically adjusts the discharge fluid flow rate based on actual temperature conditions and pressure differential, increasing flow only when cooling is needed and reducing it when conditions stabilize. This dynamic adjustment prevents continuous high-rate discharge that would waste energy, while still achieving effective temperature control when the hydraulic fluid overheats.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the discharge flow parameter dynamically based on operating conditions. The control system monitors temperature and pressure differential, then adjusts the discharge fluid flow parameter accordingly - maintaining high flow when temperature is high and pressure differential is sufficient, and reducing flow when conditions improve, thereby optimizing energy efficiency while maintaining temperature control.

Inventive Principle:
Principle #35Parameter changes

3Temperature

If a flushing device is added to remove hydraulic fluid, then temperature regulation is improved, but the device complexity increases

Engineering Contradiction:
Improvetemperature regulationVSAvoidflushing device complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The control unit serves multiple functions: it monitors temperature, measures pressure differential, controls the discharge fluid flow, and manages the overall flushing operation. By consolidating these control functions into a single multi-functional control unit rather than separate dedicated components for each function, the patent achieves effective temperature regulation while minimizing the increase in device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent introduces a control unit as an intermediary that mediates between the hydraulic system and the flushing valve. This intermediary component coordinates the discharge fluid flow based on sensor inputs, providing intelligent control without requiring complex mechanical linkages or multiple separate control devices, thus achieving temperature regulation with moderate complexity increase.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 allows for efficient temperature regulation within the hydraulic system, reducing the risk of overheating and energy wastage by adjusting fluid discharge according to temperature, ensuring a stable and efficient operation of the hydraulic system.

Implementation Method 1

The present invention utilizes the physical fact that the viscosity of the hydraulic fluid decreases with increasing temperature. Thus, the flow rate through the viscosity-dependent throttle increases with rising temperature of the hydraulic fluid.

Methodology Applied
Scientific EffectViscosity-temperature relationship:

Data Source

PatentEP2613058B1Système hydraulique
Publication Date: 2020.03.11 LIEBHERR MACHINES BULLE
  • EP2613058B1 patent drawingFigure 1
  • EP2613058B1 patent drawingFigure 2a
  • EP2613058B1 patent drawingFigure 2b

AI summary

The present invention relates to a hydraulic system with a closed hydraulic circuit consisting of a hydraulic pump and a hydraulic motor, with a feed pump for compensating for volume losses in the closed circuit and with a flushing device (7, 54) for draining a portion of the hydraulic fluid from the closed circuit, wherein the flushing device is designed such that the draining fluid flow depends on the temperature of the hydraulic fluid.