Rotary Drum Valve for Stepless Water Flow Control

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Solution Overview

Problem

Existing liquid dispensing systems for engine-driven tools, such as handheld cutting machines, lack a smooth and stepless control mechanism for water flow, making them difficult for users to manage effectively, as current valves often require multiple revolutions or are hard to turn due to conical shapes and high pretension.

Innovation Solution

A liquid dispensing system featuring a control valve with a rotatable drum part and seals that allow for a smooth, stepless adjustment of water flow by varying the fluid connection between inlet and outlet openings, enabling easy and precise control of water flow through a rotating mechanism with oval-shaped openings and seals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a conical inner rubber body is turned inside a conical plastic housing to control water flow, then the valve structure is compact, but the valve handle becomes hard to turn due to axial force and high pretension

Engineering Contradiction:
Improvevalve structureVSAvoidvalve handle operation
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

Instead of turning a conical body axially within a conical housing (which generates axial force), the patent inverts the approach by using a cylindrical drum part that rotates within a cylindrical housing. The flow control is achieved by rotating the drum to align circumferential openings with inlet/outlet openings, eliminating axial force on the handle while maintaining compact structure

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

Solution Approach 2:

The patent replaces the conical mechanical throttling mechanism with a rotational valve mechanism where a drum part with circumferential openings rotates within a cylindrical housing. This substitution eliminates the axial force problem inherent in conical designs while achieving smooth stepless flow control through rotational movement

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

2Measurement precision

If a throttling valve requires several revolutions to adjust water flow, then the valve provides precise flow control, but the operation becomes awkward and time-consuming

Engineering Contradiction:
Improveflow control precisionVSAvoidadjustment time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent implements dynamic flow control through a rotatable drum part that can be quickly positioned to any desired angle. The circumferential openings in the drum allow for smooth stepless adjustment of water flow by simply rotating the drum to the appropriate position, eliminating the need for multiple revolutions and reducing adjustment time while maintaining precision

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If a valve provides smooth and stepless water flow control, then the ease of operation is improved, but the device complexity increases

Engineering Contradiction:
Improvewater flow controlVSAvoidvalve mechanism
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent segments the flow control function into discrete circumferential openings in the drum part that can be independently aligned with inlet and outlet openings. This segmentation allows for smooth stepless flow control through simple rotation while keeping the overall valve mechanism relatively simple and compact, avoiding excessive complexity

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2953756B1A liquid dispensing system
Publication Date: 2018.04.25 HUSQVARNA AB
  • EP2953756B1 patent drawingFigure 1
  • EP2953756B1 patent drawingFigure 2
  • EP2953756B1 patent drawingFigure 3

AI summary

The present invention relates to liquid dispensing system for a rotatable work tool (2), comprising a control valve (13), an inlet and outlet liquid guiding device (11, 15). The control valve (13) comprises a housing (18) with a rotatable drum part (19) arranged to rotate. The housing (18) comprises inlet and outlet tubes (21, 22) arranged to be connected to the liquid guiding devices (11, 15). The tubes (21, 11) have corresponding inlet and outlet openings (23) facing the drum part (19). The drum part (19) comprises a first seal (25) and a third seal (27), the seals (25, 27) running around the drum part (19). The third seal (27) has an extension (34) running partially along the first seal (25), such that a first and second volume (28, 29) are formed. Each opening (23, 24) is connected to one of the volumes, or both. At least one volume (29) enables fluid connection between the openings (23, 24) that is variable by means of the third seal (27) moving over one or more of the openings (23). Each such opening has a first maximum extent (30) in a first extension (35) and a second maximum extent (31) in a second extension (36), orthogonal to the first extension (35), the first extent (30) exceeding the second extent (31).