Bare-Wire Heater Cartridge Flow Deflection Against Dead Zones

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Solution Overview

Problem

Bare wire instantaneous water heaters suffer from 'dead zones' and air bubble formation due to changing water flow directions, leading to reduced water flow, potential thermal overload, and risk of coil damage.

Innovation Solution

Incorporating water deflection elements at the inlet and outlet areas of the heating cartridge to maintain a consistent flow direction, combined with modular and compact design features such as flow guiding elements to prevent passive zones and ensure safe operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If water inlet and outlet are arranged on the shell side of the heating cartridge, then the structural compactness is improved, but passive zones and air bubble formation occur due to flow direction changes

Engineering Contradiction:

Improvestructural compactnessVSAvoidheating reliability

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The heating cartridge is divided into multiple heating zones with independent water inlet and outlet arrangements. Each heating zone has its own water flow path, preventing the formation of large passive zones and ensuring continuous water flow through all heating sections, thereby maintaining heating reliability while achieving compact structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent transitions from a single linear water flow path to a multi-dimensional flow distribution system. Water is distributed through multiple inlet/outlet positions arranged in different spatial locations, creating parallel flow paths that eliminate dead zones and improve flow uniformity throughout the heating cartridge.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Ease of operation

If water flow direction changes multiple times in the cartridge interior, then the water can enter and exit through shell side connections, but passive zones form and air bubbles accumulate

Engineering Contradiction:

Improvewater connection convenienceVSAvoidair bubble formation

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

Different sections of the heating cartridge are designed with locally optimized water flow characteristics. The inlet and outlet positions are strategically arranged to create smooth flow transitions in each local region, preventing flow separation and air bubble formation while maintaining ease of water connection.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent converts the potential harm of flow direction changes by designing gradual transition sections and flow guidance structures. These features transform abrupt flow direction changes into smooth transitions, preventing passive zone formation while maintaining the beneficial shell-side connection arrangement.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Volume of moving object

If the heating cartridge operates with air bubbles in passive zones, then thermal overload of the bare wire heating coil occurs, but the structural design allows for compact dimensions

Engineering Contradiction:

Improveheating cartridge sizeVSAvoidheating coil safety

Core Design Contradiction:

Volume of moving objectVSStrength

Solution Approach 1:

The heating cartridge design incorporates preliminary flow guidance features and water distribution structures that prevent air bubble formation before it can cause thermal overload. The water flow path is pre-configured to maintain continuous contact between water and heating coil, eliminating the need for oversized safety margins.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces flow distribution intermediaries and water guidance structures that mediate between the compact structural design and the safety requirements. These intermediaries ensure uniform water distribution and prevent air bubble accumulation, protecting the heating coil while maintaining compact dimensions.

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

Prevents the formation of passive zones, ensures consistent water flow, and reduces the risk of air bubble accumulation, thereby enhancing the reliability and safety of the heating cartridge operation.

Implementation Method 1

a bare wire heating coil (16) for heating the water to be heated

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

heat the water while it flows through the continuous-flow heater or the heating cartridge

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2597394B1Bare wire continuous-flow heater

Publication Date: 2015.04.01 GERDES

Figure 1
Figure 2
Figure 3~4

AI summary

The heater has a heater cartridge (4) comprising a cartridge inner space (8) through which water flows. A water inlet (10) and a water outlet (12) are arranged on a casing side of the cartridge. A module-like functional element (14) comprises a bare wire heating coil (16) and receiving areas (18) at front ends (34). The receiving areas hold ends of the coil. A water deflecting element (22) is arranged in an inflow region (38) of the cartridge inner space upstream of the coil in a water flow direction (S) and/or in an outflow region (40) of the cartridge inner space downstream of the coil. The water deflecting element is concave, arc-shaped or wedge-shaped.