Window and Door Drive Rolling Diaphragm for Thermal Pressure Relief
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Solution Overview
Problem
Existing window or door drive mechanisms using hydraulic fluid face issues with pressure increases due to thermal expansion, leading to seal failure, leakage, and disruptive air accumulation, which affect hydraulic functions and cause noise.
Innovation Solution
A drive mechanism with a volume compensation element containing a rolling diaphragm and a gas-filled compensation housing, where the diaphragm separates hydraulic fluid from gas, allowing pressure equalization through controlled flow, and a flow-dependent check valve to manage sudden pressure changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the actuator is not completely filled with hydraulic fluid to prevent pressure increase, then pressure compensation is achieved, but air accumulation occurs which disrupts hydraulic functions and causes noise
Solution Approach 1:
The actuator is divided into two separate compartments: a main actuator chamber filled with hydraulic fluid and a compensation chamber containing compressible gas. The rolling diaphragm acts as a separator between these compartments. This segmentation allows the hydraulic fluid to remain fully filled in the actuator for reliable hydraulic function while the gas compartment handles pressure compensation independently, preventing air accumulation in the hydraulic circuit.
Solution Approach 2:
The rolling diaphragm serves as an intermediary element that hermetically separates the hydraulic fluid from the compressible gas. It allows controlled interaction between the two substances - the diaphragm deforms in response to pressure differences, enabling the gas to compensate for thermal expansion of the hydraulic fluid without direct mixing. This mediator prevents air from entering the hydraulic circuit while still achieving pressure compensation.
2Temperature
If air is left in the actuator for pressure compensation, then thermal expansion is accommodated, but air position becomes undefined causing noise and hydraulic disruption
Solution Approach 1:
By segmenting the actuator into separate hydraulic and gas compartments with the rolling diaphragm as a barrier, the invention confines the compressible gas to a specific location in the compensation chamber. This prevents air from moving freely within the hydraulic circuit and accumulating at disruptive positions, thereby eliminating noise and hydraulic function disruption while maintaining thermal expansion compensation.
Solution Approach 2:
The rolling diaphragm acts as an intermediary that controls the interaction between hydraulic fluid and gas. It allows the gas to expand and contract in response to temperature changes, accommodating thermal expansion of the hydraulic fluid, while simultaneously preventing the gas from entering the hydraulic circuit and causing noise or functional disruption.
3Reliability
If a rolling diaphragm is used to separate gas from hydraulic fluid, then hermetic separation is achieved, but the diaphragm is subjected to high pressure changes and flow velocities
Solution Approach 1:
The rolling diaphragm serves as an intermediary element positioned in the compensation chamber where it is exposed to pressure changes. By placing the diaphragm in this location rather than directly in the high-velocity hydraulic flow path, the invention reduces the mechanical stress and wear on the diaphragm material while maintaining hermetic separation between the gas and hydraulic fluid compartments.
Solution Approach 2:
The invention uses the compressible gas in the compensation chamber as a pneumatic buffer to absorb pressure changes and thermal expansion effects. This pneumatic mechanism reduces the transmission of high pressure changes and flow velocities to the rolling diaphragm, thereby minimizing material stress and extending the diaphragm's service life while maintaining effective hermetic separation.
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 maintains stable pressure over a wide temperature range, preventing seal failure and noise, ensuring reliable hydraulic function and extended service life by minimizing material stress on the diaphragm.
Implementation Method 1
When the hydraulic fluid heats up, for example due to climatic conditions or a fire, it expands. Since hydraulic fluid is incompressible, this heating leads to a pressure increase within the actuator.
Implementation Method 2
The rolling diaphragm is provided inside the compensation housing which keeps the gas enclosed in the compensation housing and hermetically separates it from the hydraulic fluid and which, when the hydraulic fluid flows through the outlet opening, performs a stroke movement caused by the flowing hydraulic fluid, in which a head of the rolling diaphragm is linearly displaced.
Implementation Method 3
a rolling diaphragm is provided inside the compensation housing which keeps the gas enclosed in the compensation housing and hermetically separates it from the hydraulic fluid
Implementation Method 4
The compensating housing includes a closure element with a flow-dependent check valve that closes the outlet when the back pressure of the hydraulic fluid outside the compensating element exceeds a predetermined value, thus preventing hydraulic fluid from flowing into the compensating element.
Data Source
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AI summary
The invention relates to a drive for a sash of a window or door, in particular a door closer, comprising a drive mechanism for moving the sash, a drive housing in which the drive mechanism is at least partially arranged, a hydraulic fluid, in particular oil, which is contained in the drive housing, and a volume compensation element which is arranged within the drive housing, wherein the volume compensation element comprises a compensation housing which is at least partially filled with a gas, in particular air, wherein the compensation housing has an outlet opening through which the hydraulic fluid flows into the volume compensation element under compression of the gas when the fluid temperature increases and flows out of the volume compensation element under expansion of the gas when the fluid temperature decreases, wherein a rolling diaphragm is provided within the compensation housing.which keeps the gas enclosed in the compensation housing and hermetically separates it from the hydraulic fluid, and which, when the hydraulic fluid flows through the outlet opening, performs a stroke movement caused by the flowing hydraulic fluid, in which a head of the rolling diaphragm is linearly displaced.