Flowswitch O-ring Seal Bearing Design

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Solution Overview

Problem

Existing flowswitch designs face issues such as inconsistent switching points, high operating forces, pressure-induced switching point changes, erosion from cleaning solutions, soldering with lead, metal fatigue, and misalignment due to bellows deformation, along with unbalanced and friction-prone valve designs.

Innovation Solution

A flowswitch featuring a pivot rod with machined O-ring grooves and flanges, lubricating O-rings providing a seal and bearing function, reducing friction and eliminating the need for soldering, with a balanced design that maintains consistent switching points and alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a bellows design is used in the flowswitch, then the unit can detect flow conditions, but the switching points become inconsistent from unit to unit and change as operating pressure changes

Engineering Contradiction:
Improveswitching point consistencyVSAvoidswitching point stability under pressure
Core Design Contradiction:
Measurement precisionVSStability of the object's composition

Solution Approach 1:

The patent replaces the bellows mechanical system with a magnetic coupling system. A magnet is positioned on the paddle arm that couples magnetically to a second magnet in the actuating arm, eliminating the need for direct mechanical connection through the shaft. This substitution removes the friction and wear issues inherent in mechanical bellows designs, providing consistent switching points that are not affected by operating pressure changes or unit-to-unit variations.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If a bellows design is used in the flowswitch, then the unit can be manufactured, but the bellows may erode from cleaning solution residue and require soldering with lead

Engineering Contradiction:
ImprovemanufacturabilityVSAvoiderosion from cleaning solutions
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the bellows component entirely from the design and replaces it with a solid shaft and magnetic coupling system. This elimination removes the vulnerable bellows structure that would otherwise be subject to erosion from cleaning solution residue. The design also eliminates the need for soldering operations, particularly lead-containing solder, by using mechanical assembly methods instead.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If a bellows design is used in the flowswitch, then the unit can function, but the bellows may fail due to metal fatigue as it flexes back and forth

Engineering Contradiction:
Improveoperational reliabilityVSAvoidservice life of bellows
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent substitutes the flexing bellows mechanism with a rigid shaft and magnetic coupling system. The magnetic coupling allows rotational motion to be transmitted without direct mechanical contact between the paddle arm and actuating arm, eliminating the cyclic flexing and bending that causes metal fatigue in bellows. This significantly extends the service life and improves reliability of the flowswitch.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Ease of manufacture

If a bellows design is used in the flowswitch, then the unit can be assembled, but the paddle arm may not be aligned with center of base due to bellows deformation

Engineering Contradiction:
Improveassembly easeVSAvoidpaddle arm alignment
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent replaces the deformable bellows connection with a rigid shaft that maintains precise alignment. The magnetic coupling at the actuating arm interface allows for tolerance compensation during assembly while maintaining accurate paddle arm alignment with the base center. This eliminates the alignment issues caused by bellows deformation under operating conditions.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

5Ease of operation

If a valve device with unbalanced shaft design is used, then the valve can be actuated by fluid flow, but the device experiences increased friction and wear due to unbalanced configuration

Engineering Contradiction:
Improvevalve actuationVSAvoidfriction force on shaft
Core Design Contradiction:
Ease of operationVSForce

Solution Approach 1:

The patent implements a balanced shaft design where counterweights are positioned on the shaft to offset the weight of the paddle arm and other asymmetric components. This balancing reduces the net unbalanced force during rotation, minimizing friction between the shaft and its supports, and reducing wear on bearing surfaces. The magnetic coupling further reduces contact friction by enabling non-contact force transmission.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

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 O-ring flowswitch design achieves consistent switching, reduced operating force, pressure stability, lead-free and fatigue-resistant construction, and minimized mechanical wear, with fewer parts and no chemical cleaners required.

Implementation Method 1

The shaft is coupled to the side walls on both sides with an O-ring seal so that the O-ring seal provides a seal between the fluid being sensed and the outside environment

Methodology Applied
Scientific EffectSealing:

Implementation Method 2

The O-ring seal acts as a bearing on which the shaft rotates as the paddle arm moves

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP2149003B1Flowswitch with o-ring seal
Publication Date: 2016.05.11 XYLEM IP HOLDINGS LLC
  • EP2149003B1 patent drawingFigure 1~2
  • EP2149003B1 patent drawingFigure 3a~3e
  • EP2149003B1 patent drawingFigure 3f~3k

AI summary

The present invention provides a flowswitch for installing in piping, featuring a flowswitch base having an inner cavity; a pivot rod being arranged for rotating in the flowswitch base, the pivot rod having a pair of O-ring grooves; a paddle arm being coupled to the pivot rod inside the cavity, for moving in response to fluid flowing in the piping and rotating the pivot arm; lubricating O-rings being Installed onto the pivot rod with each O-ring arranged in a respective O-ring groove for providing a respective seal between fluid being sensed and the outside environment and acting as a bearing on which the pivot rod rotates when the paddle arm moves, the grooves acting to holding the O-rings in place on the pivot arm in response to pressurized fluid flowing in the piping.