Thermostatic Mixing Valve Segmented Plug Design

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Solution Overview

Problem

Existing thermostatic mixing valves with orthogonal hot and cold water inlets face challenges such as limited size options due to pressure forces, complex manufacturing, assembly difficulties, and high risks of malfunction from dirt and detritus, along with increased costs and maintenance complexities.

Innovation Solution

A thermostatic mixing valve design featuring a slidable plug element with circumferential passage openings and an annular closing sealing element that allows for controlled fluid passage, enabling easy assembly and maintenance, reduced risk of malfunction, and adaptable sizing, using a tubular body with slits and an elastic closing portion for precise temperature control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conical plug with solid second part is used to control cold water passage, then the valve can maintain temperature control function, but the pressure forces on the lower part become significant and limit valve size options

Engineering Contradiction:
Improvetemperature controlVSAvoidvalve size options
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The plug is divided into a first part and a second part that are movable with respect to each other, allowing the solid second part to be separated from the main plug body. This segmentation reduces the pressure forces acting on the lower part of the plug, enabling the valve to be produced in larger sizes without constructional or operational problems.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If precision machining is performed in two different and far zones for passage ports, then the valve can control both hot and cold water flows, but the manufacturing complexity and costs increase

Engineering Contradiction:
Improvefluid flow controlVSAvoidmanufacturing complexity
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The first and second passage ports are positioned close to each other in the valve body, allowing both ports to be machined in the same zone. This merging of port locations eliminates the need for precision machining in two different and far zones, reducing manufacturing complexity and costs while maintaining the ability to control both hot and cold water flows.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of operation

If the plug is made of two distinct parts coupled together, then the valve can control fluid passage, but assembly becomes difficult and maintenance inspection is complicated

Engineering Contradiction:
Improvefluid passage controlVSAvoidassembly and maintenance
Core Design Contradiction:
Ease of operationVSEase of repair

Solution Approach 1:

The second part of the plug is extracted as a separate movable component that can be independently removed from the valve body through the second inlet. This design allows easy assembly and disassembly for maintenance and inspection, as the second part can be accessed and removed without dismantling the entire valve, while still maintaining fluid passage control functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

4Ease of operation

If passage ports are positioned far from each other, then the valve can control separate fluid flows, but the structural complexity and manufacturing time increase

Engineering Contradiction:
Improveseparate fluid flow controlVSAvoidvalve structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The first and second passage ports are positioned close to each other in the valve body, creating a compact structure. This merging of port locations reduces the overall valve structure complexity and manufacturing time, while the movable second part of the plug maintains the ability to independently control the cold water flow through the second passage port.

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 allows for improved reaction sensitivity, easier assembly and maintenance, reduced risk of malfunction, and cost-effective production with adaptable sizing options, ensuring effective temperature control and fluid mixing while minimizing the impact of dirt and detritus.

Implementation Method 1

a thermosensitive element (10) that is slidably connected to the plug element (6), characterised in that the plug element (6) comprises a tubular body (12)

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

counteracting elastic means (11) arranged for driving said plug element (6)

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2860603B1Thermostatic mixing valve
Publication Date: 2018.07.11 BOME
  • EP2860603B1 patent drawingFigure 1A~1C
  • EP2860603B1 patent drawingFigure 2
  • EP2860603B1 patent drawingFigure 3

AI summary

A thermostatic mixing valve for a hydraulic circuit comprises a valve body (2) provided with a first connection (3) for the entry of a first flow (F1) of a fluid in a first direction (X1), a second connection (4) connected to a valve body (2) for the entry of a second flow (F2) of fluid in a second direction (X2) arranged transversely to the first direction (X1); a third connection (5) for the exit of a third flow (F3) of mixed fluid, in a third direction (X3) that is transverse to the second direction (X2); a plug element (6) that is slidable inside a housing cavity (7) defined between the valve body (2) and the second connection (4), and on which passage opening means (8) is obtained for the first (F1) and second (F2) flow; a closing portion (9) cooperating with the passage opening means (8) to define a first passage port (P1) for the first flow (F1) and a second passage port (P2) for the second flow (F2) of fluid; thermostatic actuating means (10) and counteracting elastic means (11) arranged for driving the plug element (6) and varying in a controlled manner the first (P1) and second (P2) passage port so as to maintain constant, at a desired value, the temperature of the third flow (F3) of fluid. The plug element (6) comprises a tubular body (12) bounded externally by a cylindrical surface (13) on which the passage opening means (8) is circumferally obtained, and the closing portion is defined by an annular closing sealing element (9) housed in a seat (18) defined between the valve body (2) and the second connection (4) and projecting radially so as to intercept the passage opening means (8) for the fluid.