Door Drive Pressure Compensation Device

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Solution Overview

Problem

Existing door and window drive systems face challenges with complex and potentially leaky sealing of pressure equalization devices, particularly due to aging, which affects the reliability of thermal expansion compensation in hydraulic fluid systems.

Innovation Solution

A pressure compensation device with a compensation housing and a channel designed as a weight, floating in hydraulic fluid, ensures that a gas volume is enclosed and rotates to prevent gas escape, allowing for effective temperature-related volume changes without moving parts or special sealing surfaces, and can be filled with vacuum to maintain a gas-free interior.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an elastic enveloping body is used to enclose the gas volume for pressure equalization, then the pressure compensation function is achieved, but the sealing becomes complex and unreliable due to aging

Engineering Contradiction:
Improvesealing reliabilityVSAvoidsealing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts the gas volume from the hydraulic fluid system by providing a separate compensation chamber that is connected to the hydraulic circuit. This separation eliminates the need for complex sealing of an elastic enveloping body, as the gas is contained in a rigid chamber with simple fixed seals, resolving the contradiction between sealing reliability and device complexity

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention introduces a compensating piston as an intermediary element between the hydraulic fluid and the gas volume. This piston transmits pressure changes from the hydraulic fluid to the gas volume, enabling pressure equalization while maintaining simple, reliable sealing on both sides of the piston without requiring complex elastic enveloping bodies

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a pressure compensation piston is used to seal the air volume in the damping piston cavity, then pressure equalization is achieved, but sealing problems persist due to the moving seal interface

Engineering Contradiction:
Improvepressure equalization reliabilityVSAvoidsealing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts the gas volume from the damping piston cavity and places it in a separate compensation chamber. This eliminates the need for a pressure compensation piston moving within the damping piston cavity, removing the complex moving seal interface while maintaining pressure equalization functionality through the connected hydraulic circuit

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of manufacture

If the drive is filled with hydraulic fluid under normal conditions, then the hydraulic system is simple to fill, but air cushions remain trapped causing operational issues

Engineering Contradiction:
Improvefilling simplicityVSAvoidoperational reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The invention applies preliminary action by evacuating air from the hydraulic circuit before filling with hydraulic fluid. This pre-treatment ensures that no air cushions remain trapped in the system, eliminating operational issues while maintaining simple filling procedures, thus resolving the contradiction between filling simplicity and operational reliability

Inventive Principle:
Principle #10Preliminary action

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 provides a simple, reliable, and position-independent pressure equalization, suitable for various installations and temperatures, ensuring the door or window drive operates effectively without air cushion-related issues, maintaining pressure balance across temperature changes.

Implementation Method 1

The pressure compensation device floats in the hydraulic fluid present in the housing of the drive, with the pressure compensation device, due to its weight, always rotating in such a way that the channel is directed downwards

Methodology Applied
Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Implementation Method 2

Since gases are compressible or expandable, a temperature-related change in the volume of the hydraulic fluid is compensated

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 3

The interior of the differential housing, in which a volume of gas is located, is connected to the interior of the housing of the drive via the channel. The pressure compensation device floats in the hydraulic fluid present in the housing of the drive

Methodology Applied
Scientific EffectHydraulic pressure transmission: Pascal's Law

Data Source

PatentEP2388422B1Drive to operate the leaf of a door or window
Publication Date: 2015.07.08 GEZE GMBH
  • EP2388422B1 patent drawingFigure 1~2
  • EP2388422B1 patent drawingFigure 3~4
  • EP2388422B1 patent drawingFigure 5~6

AI summary

The drive (1) has a piston acting upon a spring and arranged in a housing (2). The piston cooperates with a driven shaft for opening and/or closing a wing of a window and a door. A pressure equalization device (8) is arranged in the housing that is filled with hydraulic fluid (9). The pressure equalization device has a differential housing (11) whose inner space is in contact with an inner space of the housing by a channel (12) that is arranged in weight (15) of the differential housing. The channel is closed by a stopper, so that vacuum filling of the drive is enabled.