Vacuum accumulator and method for producing a vacuum accumulator

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Solution Overview

Problem

Existing vacuum storage tanks for hot water suffer from high heat transfer from the tank interior to the outside due to components and their openings, necessitating continuous optimization to reduce heat loss while maintaining low manufacturing costs.

Innovation Solution

A vacuum storage device with an inner and outer container, a gap between them filled with insulating material, and a two-part outer container base, using low thermal conductivity materials and a specific manufacturing process to ensure complete enamel coating and insulation, including a connecting flange for components like the heating element and sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If components and their openings are added to the tank for functionality (heating element, sensors, inlet/outlet connections), then the tank can perform its required functions, but heat transfer from the tank interior to the outside increases

Engineering Contradiction:
Improvefunctional capabilityVSAvoidheat loss
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent extracts the problematic heat transfer path by removing the traditional flange connection from the tank interior. Instead, components are connected from the exterior through openings in the outer tank, eliminating the need for interior flanges that create thermal bridges. This separates the functional connection needs from the thermal insulation requirement.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an intermediary thermal insulation structure between the inner tank and outer tank. This intermediate insulating layer acts as a thermal barrier that mediates between the functional requirements (allowing component connections) and the thermal insulation requirements, reducing heat transfer while maintaining functionality.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If traditional flange connections are used in the tank interior for component mounting, then components can be securely mounted, but the enamel coating cannot be completely applied and heat transfer increases

Engineering Contradiction:
Improvecomponent mounting securityVSAvoidheat loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent removes the flange connection from the tank interior where it would interfere with enamel coating application. By relocating the connection to the exterior of the outer tank, the interior surface remains uninterrupted, allowing complete enamel coating application while maintaining secure component mounting through alternative exterior connection methods.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of mounting components from the interior of the tank (traditional approach), the patent inverts the connection approach by mounting components from the exterior of the outer tank. This reversal eliminates the conflict between interior flanges and enamel coating while maintaining secure component attachment.

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

3Ease of manufacture

If the outer tank base is made as a single piece, then manufacturing is simpler, but complete enamel coating of the inner tank base cannot be achieved

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidenamel coating completeness
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent segments the outer tank base into two separate parts: the outer tank base and the flange connection piece. This segmentation allows the inner tank base to be completely coated with enamel before assembly, as there is no single-piece flange structure interfering with the coating process. The segmented design maintains manufacturing feasibility while achieving complete coating coverage.

Inventive Principle:
Principle #1Segmentation

4Ease of operation

If insulation material is not used in the lower section, then component access is maintained, but thermal insulation performance deteriorates

Engineering Contradiction:
Improvecomponent accessVSAvoidheat loss
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The patent extracts the component connections from the interior of the inner tank to the exterior of the outer tank. This extraction allows insulation material to be applied continuously throughout the entire gap between the inner and outer tanks, including the lower section, without interfering with component access or functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses the gap between the inner tank and outer tank as an intermediate insulating space. This intermediate space can be completely filled with insulation material, creating a continuous thermal barrier that mediates between the need for component access and the requirement for thermal insulation performance.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution provides improved thermal insulation, reducing heat loss and maintaining water temperature, while minimizing manufacturing complexity and costs.

Implementation Method 1

The gap between the inner and outer containers can be used as an insulating layer or can accommodate insulating material. The bottom of the outer container is formed in two parts

Methodology Applied
Scientific EffectVacuum insulation: Vacuum

Implementation Method 2

A vacuum tank containing a water reservoir is used for this purpose. The gap between the outer and inner tanks is evacuated and filled with a special insulating powder, typically containing pyrogenic silica

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP4386277B1Vacuum accumulator and method for producing a vacuum accumulator
Publication Date: 2026.03.18 STIEBEL ELTRON GMBH & CO KG
  • EP4386277B1 patent drawingFigure 1
  • EP4386277B1 patent drawingFigure 2
  • EP4386277B1 patent drawingFigure 3

AI summary

Vacuum storage tank (1), for storing hot water, comprising an inner tank (100) made of steel for holding water, an outer tank (200) surrounding the inner tank (100), an insulating unit between the inner tank (100) and the outer tank (200), a connection flange (110) connected to the inner tank (100) for receiving and attaching a closure body, characterized in that the connection flange (110) is formed in one piece from steel and has an annular pipe section (111) with a flange part (112) and the lower bottom (210) of the outer tank (200) is made of stainless steel and is attached to the connection flange (110).