Pressure limiter and electric continuous-flow heater comprising the same

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Solution Overview

Problem

Existing safety pressure limiters are mechanically complex, prone to errors, and require significant installation space, leading to unreliable and inefficient triggering, which can result in device damage and assembly issues.

Innovation Solution

A safety pressure limiter design featuring a piston element and snap-action disk that transitions from a metastable to a stable state upon exceeding a predetermined pressure, with a locking element and contact set element for precise electrical switching, and a compression spring for controlled resetting, ensuring quick and reliable shutdown.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional safety pressure limiters are used, then pressure protection function is provided, but device complexity increases and reliability decreases due to mechanical complexity and multiple components

Engineering Contradiction:
ImprovereliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the pressure sensing function, switching element, and actuation mechanism into a single integrated device. The pressure sensor element directly actuates the switching element through a membrane structure, eliminating the need for separate mechanical components like snap discs, arms, and linkages found in conventional limiters. This integration reduces the number of parts and assembly steps while improving reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts and eliminates unnecessary mechanical transmission components from conventional safety pressure limiters. By using a direct actuation mechanism where the pressure sensor element itself serves as the actuating component, the design removes intermediate mechanical elements that contribute to complexity and potential failure points.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If conventional safety pressure limiters are used, then pressure protection is provided, but installation space increases due to larger component size

Engineering Contradiction:
Improvetriggering precisionVSAvoidinstallation space
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent employs a nested structure where the pressure sensor element is integrated within the housing, and the switching element is positioned within the same compact space. The membrane structure allows the sensing and actuation functions to occupy overlapping spatial volumes, maximizing space utilization and minimizing the overall device footprint.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent utilizes a three-dimensional membrane structure that responds to pressure in one dimension while actuating the switching element in a perpendicular dimension. This dimensional transformation allows compact packaging of the actuation mechanism within the pressure sensing volume, reducing the required installation space.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If conventional safety pressure limiters are used, then pressure switching function is provided, but manufacturing cost increases due to multiple components and assembly complexity

Engineering Contradiction:
Improveswitching behavior reliabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines multiple functions into fewer components, reducing the total part count and assembly operations required. The integrated pressure sensor and switching element eliminate the need for separate mechanical linkages and adjustment mechanisms, simplifying manufacturing processes and reducing assembly time and labor costs.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The pressure sensor element serves multiple functions: it acts as the pressure sensing component, the actuating mechanism, and the direct driver of the switching element. This multi-functionality reduces the number of specialized components needed, lowering manufacturing complexity and cost while maintaining reliable switching behavior.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Reliability

If conventional safety pressure limiters are used, then pressure limiting is provided, but assembly errors increase due to multiple components from different suppliers

Engineering Contradiction:
Improvetriggering accuracyVSAvoidassembly error susceptibility
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent integrates the pressure sensing and switching functions into a single device manufactured as one unit or pre-assembled module. This integration eliminates interface issues between components from different suppliers, ensuring consistent triggering accuracy and reducing assembly errors related to component compatibility and alignment.

Inventive Principle:
Principle #5Merging (Combining)

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 a compact, reliable, and precise triggering mechanism that prevents unwanted shutdowns and assembly errors, ensuring immediate and accurate pressure limiting with reduced manufacturing complexity and cost.

Implementation Method 1

a snap disc (17) which is deformable by means of the piston element (14) at least substantially between two states, in particular between a metastable state (15) and a stable state (16)

Methodology Applied
Scientific EffectMetastability: Metastability

Implementation Method 2

The operating element (24) is connected to a free end (26) of the locking element (19) via a compression spring (25)

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

a pressure receiving part (11) which is configured to be connected to a fluid line (12) carrying a fluid... and a piston element (14) arranged to be slidably movable in a longitudinal direction (13)

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Increase

Data Source

PatentEP3702692B1Pressure limiter and electric continuous-flow heater comprising the same
Publication Date: 2021.09.15 GERDES HLDG GMBH & CO KG
  • EP3702692B1 patent drawingFigure 1
  • EP3702692B1 patent drawingFigure 2
  • EP3702692B1 patent drawingFigure 3

AI summary

The invention relates to a safety pressure limiter (10) with a pressure receiving part (11), wherein the pressure receiving part (11) comprises a piston element (14) arranged to be slidably movable in a longitudinal direction (13) and a deformable snap disc (17), further comprising a housing (18) and a locking element (19) arranged to be slidably movable in the longitudinal direction (13), a contact set element (20) which is arranged to be slidably movable by spring bias in a transverse direction (22) for opening at least one electrical contact point (21) and comprises a locking recess (23) into which the locking element (19) engages in a locking position with at least partial positive locking and locks the contact set element (20) in a closed position under spring bias, and the locking element (19) is arranged to release the locking recess (23) in a release position of the locking element (19).so that the contact element (20) under spring preload automatically moves into an open position of the at least one electrical contact point (21) in the transverse direction (22). The invention also relates to an instantaneous water heater comprising such a safety pressure limiter (10).