Pressure-Resistant Glass Sphere with Thickened Equatorial Joint

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Solution Overview

Problem

Existing pressure-resistant glass spheres for deep-sea exploration face challenges in weight reduction, increased floating force, and repeated use due to issues with material cost, seal reliability, and structural integrity, particularly at the ground joint surfaces where cracking and peeling occur under pressure.

Innovation Solution

A pressure-resistant glass sphere design where the thickness of the spherical shell is increased only at the equatorial plane portion near the ground joint surfaces, with a predetermined width, to enhance strength and floating force while maintaining thinness elsewhere, using borosilicate glass for improved durability and thermal resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the thickness of the spherical shell is increased to enhance pressure resistance, then the strength and pressure resistance are improved, but the weight increases and floating force decreases

Engineering Contradiction:
Improvepressure resistanceVSAvoidweight of glass sphere
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The spherical shell has non-uniform thickness distribution, with the equatorial plane portion having greater thickness than other portions. This local thickening at the equatorial plane (where ground joint surfaces are located) provides enhanced pressure resistance at the most critical stress area while keeping the overall weight lower than a uniformly thick shell would require.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If adhesive bonding layer is used to join hemispherical bodies, then ease of manufacture is improved, but seal reliability deteriorates due to cracking and peeling under pressure

Engineering Contradiction:
Improveease of joiningVSAvoidseal reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The ground joint surfaces are polished to high precision (flatness of 20 μm or less, average surface roughness of 0.5 μm or less) before joining. This preliminary preparation ensures that when the hemispherical bodies are joined, the contact surfaces are already optimized for stress distribution, preventing cracking and peeling during pressurization.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the surface finish parameters of the ground joint surfaces through precision polishing, achieving a flatness of 20 μm or less and average surface roughness of 0.5 μm or less. These parameter changes enable the adhesive bonding layer to function effectively under deep sea pressure without cracking or peeling.

Inventive Principle:
Principle #35Parameter changes

3Weight of moving object

If the spherical shell is made thin to reduce weight, then floating force is improved, but pressure resistance deteriorates

Engineering Contradiction:
Improveweight of glass sphereVSAvoidpressure resistance
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The spherical shell employs non-uniform thickness distribution, being thinner at poles and thicker at the equatorial plane portion. This allows the shell to maintain adequate pressure resistance at critical areas while minimizing overall weight, achieving better floating force compared to a uniformly thin shell.

Inventive Principle:
Principle #3Local quality

4Reliability

If ground joint surfaces are polished precisely to improve seal reliability, then manufacturing complexity increases

Engineering Contradiction:
Improveseal reliabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention specifies precise surface finish parameters (flatness of 20 μm or less, average surface roughness of 0.5 μm or less) for the ground joint surfaces. While these parameters require careful polishing, they provide a clear manufacturing target that ensures reliable sealing and prevents cracking under pressure, balancing precision requirements with manufacturing feasibility.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3460413B1Pressure-resistant glass sphere
Publication Date: 2020.04.01 OKAMOTO GLASS CO LTD
  • EP3460413B1 patent drawingFigure 1A~1E
  • EP3460413B1 patent drawingFigure 2
  • EP3460413B1 patent drawingFigure 3

AI summary

In a pressure-resistant glass sphere used for exploration of deep sea, ocean floor or the like, it is an important issue to reduce weight and increase a floating force whi le keeping pressure resistance capable of withstanding high water pressure of deep sea or the like and being used repeatedly. Apressure-resistant glass sphere of the present invention is composed of a pair of glass-made hollow hemispherical bodies, wherein the glass-made hollow hemispherical bodies are joined with each other at ground joint surfaces located on an equatorial plane of the pressure-resistant glass sphere so that the ground j oint surfaces serve as a joining surface, and characterized in that a thickness of a spherical shell ofthe glass-made hollow hemispherical bodies is thicker at an equatorial plane portion than the portion other than the equatorial plane portion having a predetermined width from the ground joint surfaces.