Low Water Cutoff Switch Two-Part Base Assembly

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Solution Overview

Problem

Existing low water cutoff switches used in applications below freezing temperatures, such as chiller applications, face issues with condensation build-up due to heat transfer through conduction and convection, leading to operational failures.

Innovation Solution

A flow switch assembly is designed using a combination of metal and non-metal parts, specifically a non-metallic base part made from materials like Delrin and a metallic insert, reducing heat conductivity and condensation, with the lower base part made from brass or stainless steel and the upper part from Delrin or Nylon, coupled together to form a two-part base assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If an integral brass base is used in the low water cutoff switch, then the structural strength and durability are improved, but condensation build-up occurs due to heat transfer through conduction and convection, leading to operational failure

Engineering Contradiction:
Improvestructural strengthVSAvoidoperational reliability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The base is divided into two separate parts: a brass lower base part that provides structural strength and durability, and a non-metallic upper base part that prevents condensation. This segmentation allows each part to fulfill its specific function without the drawbacks of a monolithic design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses a composite base assembly combining metallic (brass) and non-metallic materials. The brass lower base part provides mechanical strength while the non-metallic upper base part provides thermal insulation properties, creating a composite structure that achieves both structural integrity and condensation prevention.

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If a non-metallic base part is used to reduce condensation, then heat transfer is reduced and condensation is minimized, but the structural strength may be compromised

Engineering Contradiction:
ImprovecondensationVSAvoidstructural strength
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The base is segmented into functional zones: the lower base part made of brass provides structural strength and mounting functionality, while the upper base part made of non-metallic material provides thermal insulation. This segmentation allows the system to achieve both strength and condensation resistance simultaneously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different parts of the base have different material properties optimized for their specific functions. The lower portion requires strength for structural support and mounting, so it uses brass. The upper portion requires thermal insulation to prevent condensation, so it uses non-metallic material. This local quality approach optimizes each region for its primary function.

Inventive Principle:
Principle #3Local quality

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

This design significantly reduces condensation, increases operational life, and offers cost savings, reduced material usage, and easier assembly compared to traditional all-metallic designs.

Implementation Method 1

heat transfer through conduction and convection

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

heat transfer through conduction and convection

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3031063B1Low water cutoff switch
Publication Date: 2020.10.07 FLUID HANDLING LLC
  • EP3031063B1 patent drawingFigure 1A~1C
  • EP3031063B1 patent drawingFigure 2A~2B
  • EP3031063B1 patent drawingFigure 3A~3D

AI summary

A low water cut-off switch assembly features a two-part base assembly having a lower base part and an upper base part. The lower base part is made from a metallic material, configured to be adapted on piping having a fluid flow, and also configured with a central orifice to receive a paddle arm that pivots on an axis in response to the fluid flow in the piping. The upper base part is made from a non-metallic material, configured with a corresponding central orifice to receive the paddle arm, and configured with a channel to receive a pivot arm to mount and allow the paddle arm to pivot on the axis in order to actuate an ON/OFF switch in response to the fluid flow. The non-metallic material of the upper base part has a substantially lower coefficient of heat transfer than the metallic material of the lower base part, so as to substantially reduce condensation build-up in the low water cut-off switch, e.g., especially when the low water cut-off switch is used in applications exposed to temperatures below freezing, including chiller applications.