Door Actuator Thermal Oil Release for Fire-Safe Venting

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Solution Overview

Problem

Existing door operators, including closers and drives, pose a safety risk in fire situations due to the use of combustible fluids like hydraulic oil, which can contribute to the spread of fire and fail at high temperatures.

Innovation Solution

A temperature safety concept is implemented in the door actuator, where a thermally activated valve opens at approximately 115°C, allowing the fluid to exit the housing and drip away from the hot assembly surface, and a collecting device directs the fluid to the ground, preventing it from igniting on the door leaf.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hydraulic oil is used in the door actuator for force transmission and damping, then the door actuator can effectively perform opening/closing movements and dampen door movement, but the hydraulic oil poses a fire safety risk as it is flammable at high temperatures

Engineering Contradiction:
Improvedoor actuator performanceVSAvoidfire safety
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A thermal release element is pre-installed in the fluid housing that automatically releases hydraulic oil when a specific temperature is reached during a fire, preventing the fluid from contributing to fire spread. This preliminary safety mechanism ensures that the fire hazard is mitigated before it can cause significant damage.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The hydraulic oil is extracted from the confined space of the fluid housing and directed outward through a release mechanism when thermal conditions warrant, removing the harmful substance from its potentially dangerous position near the mounting surface and preventing ignition.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If the fluid housing is sealed to prevent fluid leakage during normal operation, then the door actuator maintains proper hydraulic pressure for reliable operation, but the fluid cannot escape in case of overheating, leading to component failure

Engineering Contradiction:
Improvehydraulic pressure maintenanceVSAvoidthermal overload resistance
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The fluid housing transitions from a static sealed state during normal operation to a dynamic release state when thermal conditions change. The thermal release element activates automatically at a predetermined temperature, transforming the housing from pressure-retaining to pressure-relieving mode to prevent component failure.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The sealing state of the fluid housing changes based on temperature parameters. Below a critical temperature, the housing remains sealed to maintain hydraulic pressure. Above the critical temperature, the thermal release element activates, changing the sealing parameter from closed to open, allowing fluid escape and preventing thermal damage.

Inventive Principle:
Principle #35Parameter changes

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

Ensures safe operation of the door operator during a fire by preventing fluid from contributing to the fire spread and ensuring controlled fluid discharge, reducing the risk of ignition on the door leaf.

Implementation Method 1

a valve (21) which closes the fluid housing opening (20) and is designed to be activated by thermal influence

Methodology Applied
Scientific EffectThermal activation: Thermal Expansion

Implementation Method 2

the fluid of the door actuator is designed to escape from the interior of the actuator's fluid housing in a controlled manner... and drips onto the ground as far away from the hot surface as possible

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP3916183B1Door actuator for opening and/or closing a door
Publication Date: 2023.01.25 DORMAKABA DEUT GMBH
  • EP3916183B1 patent drawingFigure 1
  • EP3916183B1 patent drawingFigure 2
  • EP3916183B1 patent drawingFigure 3

AI summary

The invention relates to a door actuator (1) for opening and/or closing a door, comprising a fluid housing (3) with an interior (8) filled with a fluid, in particular hydraulic oil, a fluid housing opening (20) in the fluid housing (3) for venting the fluid in case of thermal overload, a valve (21) closing the fluid housing opening (20) and thermally activatable for opening, and a collection device (30) arranged outside the fluid housing (3), opposite the fluid housing opening (20), which forms a collection chamber (36) for the fluid open towards the fluid housing opening (20) and has at least one discharge opening (40) for venting the fluid from the collection chamber (36).