Internal-Rail Flat Exhaust Duct for Stable Width and Compact Size

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Solution Overview

Problem

Existing exhaust ducts with a flat riser section suffer from width fluctuations and increased pressure loss due to plate deflections, which can be mitigated by adding ribs, but this enlarges the duct and apparatus size.

Innovation Solution

Incorporating vertically elongated rails inside the riser duct section to connect front-side and back-side plate parts, preventing width fluctuations and maintaining compact dimensions, while optimizing duct coupling and rail placement to reduce pressure loss and noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If ribs are erected on the external surface of plate parts to increase rigidity, then deflection of plate parts is prevented, but the dimensions of the riser duct section increase and the apparatus size enlarges

Engineering Contradiction:

Improverigidity of plate partsVSAvoidsize of exhaust duct

Core Design Contradiction:

Stability of the object's compositionVSVolume of moving object

Solution Approach 1:

The support members are disposed inside the riser duct section, nesting the reinforcement structure within the existing duct volume. This allows the plate parts to be supported and prevented from deflecting without adding external ribs that would increase the overall dimensions of the exhaust duct and apparatus.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

Instead of adding reinforcement in the external direction (increasing duct thickness), the support members are positioned in the internal space of the riser duct section. This dimensional repositioning provides structural support while maintaining the compact external dimensions of the exhaust duct.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Object-affected harmful factors

If the riser duct section is formed into a flat shape to reduce exhaust noises, then exhaust passage width is reduced, but the front-side and back-side plate parts become larger and more prone to deflection

Engineering Contradiction:

Improveexhaust noisesVSAvoidstability of plate parts

Core Design Contradiction:

Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The support members are nested inside the flat riser duct section to provide internal reinforcement. This allows the plate parts to maintain their larger flat shape for noise reduction while being supported from within to prevent deflection, resolving the contradiction between shape stability and noise reduction.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The support members act as intermediary elements between the front-side and back-side plate parts. These members prevent the plate parts from deflecting toward each other while maintaining the narrow flat shape of the exhaust passage, thus mediating between the conflicting requirements of shape stability and compact dimensions.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If the width between front-side and back-side plate parts is reduced to make the exhaust passage narrower, then exhaust noises are reduced, but pressure loss increases due to plate deflection

Engineering Contradiction:

Improveexhaust noisesVSAvoidpressure loss

Core Design Contradiction:

Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The support members are nested within the narrow exhaust passage to provide structural support without increasing the passage width. This prevents plate deflection that would cause pressure loss while maintaining the narrow flat shape necessary for noise reduction.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The support members serve as intermediary structures that maintain the narrow width of the exhaust passage while preventing plate deflection. By supporting the plate parts from within, they ensure consistent passage dimensions for reduced pressure loss while preserving the noise-reducing flat shape.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS10443480B2Exhaust duct

Publication Date: 2019.10.15 RINNAI CORP

AI summary

An exhaust duct has a riser duct section which is connected to an exhaust port having such an inlet port at a lower portion of the riser duct section as is connected to an exhaust port for the combustion gas. The riser duct section extends upward along an external surface of the combustion box. A horizontal direction perpendicular to the front-to-back direction is defined as a lateral direction, then the riser duct section is formed into a flat shape having a smaller dimension in the front-to-back direction than the dimension in the lateral direction. Fluctuations in width between front-side and back-side plate parts of the riser duct section are devised to be restrained, and increase in size can be avoided. The riser duct section has a rail inside the riser duct section, the rail being elongated in the vertical direction and connecting together the front-side and the back-side plate parts.