Rotatable Manhole Cover Plug for Gas Leak Prevention

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Solution Overview

Problem

Existing manhole cover designs do not adequately address the safety concern of explosive or toxic gases accumulating behind the cover, which can pose a risk when the cover is removed for maintenance.

Innovation Solution

A plug system is introduced that can selectively close an inspection hole in a manhole cover, featuring a rotatable and liftable plug body with a seal and spring mechanism to ensure safe access for inspection probes while preventing gas leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the manhole cover is removed for maintenance, then access to the manhole is improved, but explosive or toxic gases may be released causing safety hazards

Engineering Contradiction:
Improveaccess to manholeVSAvoidgas release hazard
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The plug system allows preliminary inspection of gases through the inspection probe passage before the manhole cover is removed. The plug can be opened to insert detection equipment through the inspection hole, enabling gas composition analysis and concentration measurement in advance, so that maintenance personnel can take protective measures before actual gas release occurs

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The plug acts as an intermediary device between the sealed manhole and the external environment. It provides a controlled interface through the inspection hole, allowing gas sampling and detection without requiring full removal of the manhole cover, thus mediating between the need for access and the need to prevent harmful gas release

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the plug body is made rotatable and liftable, then inspection probe access is improved, but the device complexity increases

Engineering Contradiction:
Improveinspection probe accessVSAvoidplug mechanism
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The plug body is designed with dynamic characteristics, being able to rotate around its axis and lift vertically. The rotation allows alignment of the inspection probe passage with the inspection hole, while the lifting motion exposes the passage for probe insertion. These simple dynamic movements provide flexible access without requiring complex mechanical structures

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The plug mechanism is segmented into independent functional elements: the rotatable plug body, the liftable inspection passage, and the spring-loaded sealing components. This segmentation allows each element to perform its specific function independently, simplifying the overall design while maintaining operational flexibility

Inventive Principle:
Principle #1Segmentation

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 plug system enhances safety by allowing controlled access for inspection probes, reducing the risk of gas release during manhole cover removal and improving overall maintenance safety.

Implementation Method 1

at least one spring configured to urge the plug body to an inspection probe passage closing position

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 2

the seal comprises a membrane with at least one slit to accommodate an inspection probe to extend through the membrane

Methodology Applied
Scientific EffectSealing: Semipermeable Membrane

Data Source

PatentEP4538465A1Plug and manhole cover with plug
Publication Date: 2025.04.16 D & B INGS
  • EP4538465A1 patent drawingFigure 1
  • EP4538465A1 patent drawingFigure 2~11
  • EP4538465A1 patent drawingFigure 4~5

AI summary

The present disclosure relates to a manhole cover and plug therefore. At least the plug 1 is configured to selectively close an inspection hole in the manhole cover 2. To this end the plug 1 comprises a plug body 3 to be inserted in or arranged over a through hole 14 of manhole cover 2. The plug body 3 has an inspection probe passage 4 extending through or along the plug body 3. Further, the plug body 3 is moveable in a face of the manhole cover to selectively open the inspection probe passage 4.