Multi-Leaf Damper with Oblique Slat Edges to Reduce Opening Torque

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Solution Overview

Problem

Existing multi-leaf dampers require high torque to open due to folded lip seals, and they unevenly withstand pressure, making them difficult to open after being closed, especially in fire protection scenarios where timely operation is crucial.

Innovation Solution

The slats are designed with oblique edges between 10° and 60°, preferably 30°, allowing for easier opening and better seal protection, with a central pivot axis and optional beveled stop surfaces, and using a combination of cold and warm seals for enhanced sealing and fire resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If lip seals are provided on longitudinal edges of slats, then sealing performance is improved, but torque required to open the damper increases significantly

Engineering Contradiction:
Improvesealing performanceVSAvoidtorque required to open
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The patent inverts the conventional seal arrangement by placing seals on the frame rather than on the slats. This reversal allows the seals to remain stationary and be compressed uniformly when slats close, eliminating the folding action that previously caused high opening torque. The seals are pressed against the frame's sealing surfaces by spring elements, creating effective sealing without the mechanical disadvantage of folded seals.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The sealing system is segmented into separate components: stationary sealing elements mounted on the frame and separate slats that close against them. This segmentation allows each component to perform its function independently - the frame provides stable sealing surfaces while slats provide the closing action, eliminating the conflict between sealing and easy opening.

Inventive Principle:
Principle #1Segmentation

2Reliability

If lip seals are folded over in closed position, then sealing is achieved, but the damper cannot withstand pressure evenly and becomes difficult to open

Engineering Contradiction:
ImprovetightnessVSAvoidease of opening
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent inverts the conventional seal arrangement by placing seals on the frame rather than on the slats. This reversal allows the seals to remain stationary and be compressed uniformly when slats close, eliminating the folding action that previously caused high opening torque. The seals are pressed against the frame's sealing surfaces by spring elements, creating effective sealing without the mechanical disadvantage of folded seals.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent changes the physical state and positioning parameters of the seals from mobile (attached to moving slats) to stationary (mounted on fixed frame). This parameter change allows seals to maintain constant contact pressure through spring compression, ensuring uniform pressure resistance and consistent sealing performance regardless of which side pressure is applied from.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If rectangular slats with central pivot axis are used, then manufacturing is simplified, but seal protection under pressure is insufficient

Engineering Contradiction:
Improveslat design simplicityVSAvoidseal protection
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent inverts the conventional seal arrangement by placing seals on the frame rather than on the slats. This reversal allows the seals to remain stationary and be compressed uniformly when slats close, eliminating the folding action that previously caused high opening torque. The seals are pressed against the frame's sealing surfaces by spring elements, creating effective sealing without the mechanical disadvantage of folded seals.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent incorporates spring elements that pre-compress the seals against the frame's sealing surfaces before the slats arrive. This beforehand cushioning ensures that seals are already in a protected, compressed state, ready to withstand pressure differential immediately when the damper closes, enhancing seal protection without complicating slat design.

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

Data Source

PatentEP3299740B9Louvre for use in a conduit of an air conditioning system or a mechanical smoke ventilation assembly
Publication Date: 2020.07.22 TROX GMBH
  • EP3299740B9 patent drawingFigure 1
  • EP3299740B9 patent drawingFigure 2a~2c
  • EP3299740B9 patent drawingFigure 3~6

AI summary

The invention relates to a multi-leaf damper for use in a duct of an air conditioning and ventilation system or a mechanical smoke extraction system (MRA) comprising on the one hand a frame (1) which forms a rectangular opening for the flow of a gaseous medium, and on the other hand at least two rectangular openings formed slats (2), wherein each slat (2), preferably parallel to at least one other slat (2), is mounted in the frame (1) so that it can pivot between its closed position and its open position about a respective pivot axis (4), and each slat (2) has, on the one hand, two longitudinal edges (5) aligned parallel to its pivot axis (4) and, on the other hand, two side edges (6) aligned orthogonally to its pivot axis (4), the pivot axes (4), preferably centrally, between the longitudinal edges (5) is arranged, and wherein at least one of the interacting in the closed position longitudinal edges (5) of adjacent slats a seal ng (9, 10). In order to specify a multi-leaf damper that is particularly easier to open with at least the same level of tightness and - if the multi-leaf damper is used as a fire protection component - can still be opened within a certain period of time after a fire, each of the two surfaces of the longitudinal edges ( 5) at least one pair of adjacent lamellae (2), forming a pair of beveled edges opposite the orthogonal O, which is perpendicular to the plane E spanned by the respective lamella (2), at an angle α of between 10° and 60°, preferably between 25° and 40°, preferably 30°, and in the closed position the two surfaces of this pair of adjacent slats (2) facing each other, in particular parallel, so that the height of the slat (2) in relation to the pivot axis (4) across the width of the slat (2) in the direction of pivoting (V) from the closed position g increases in the open position.