Mixing Valve Inlet Obstruction for Accurate Temperature Sensing

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Solution Overview

Problem

In mixing valves used in heating and cooling systems, the flow from one inlet can interfere with temperature measurements at the other inlet, leading to inaccurate readings due to cross-flow, especially when one inlet has a higher flow rate.

Innovation Solution

A mixing valve design with an obstruction inside the second inlet port, positioned to deflect flow from the first inlet, preventing it from entering in the opposite direction and reducing interference with temperature sensors, allowing precise temperature measurement by directing the flow into the valve chamber.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If temperature sensors are placed in the inlet ports to measure temperature, then temperature control precision is improved, but measurement accuracy deteriorates due to cross-flow interference from higher flow rates

Engineering Contradiction:
Improvetemperature control precisionVSAvoidtemperature measurement accuracy
Core Design Contradiction:
Manufacturing precisionVSMeasurement precision

Solution Approach 1:

A flow separator is introduced as an intermediary component in the inlet port. This separator acts as a mediator between the high-flow stream and the temperature sensor, preventing direct interference while allowing the sensor to accurately measure the temperature of the return flow without being affected by cross-flow from the supply flow

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The inlet port is segmented into distinct flow regions using the flow separator. The separator divides the inlet port such that the return flow and supply flow are separated, with the temperature sensor positioned in the return flow region where it can measure temperature accurately without interference from the supply flow

Inventive Principle:
Principle #1Segmentation

2Productivity

If flow rate through one inlet increases, then mixing efficiency is improved, but temperature measurement accuracy in the other inlet deteriorates due to flow entering in opposite direction

Engineering Contradiction:
Improvemixing efficiencyVSAvoidtemperature measurement accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The flow separator serves as a mediator that allows high flow rates through one inlet to improve mixing efficiency while preventing this high-flow stream from interfering with temperature measurements in the other inlet. The separator maintains flow separation even under imbalanced flow conditions

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

The obstruction effectively prevents cross-flow interference, enabling accurate temperature measurement in both inlets by directing flow away from the temperature sensor, thus improving the precision of temperature adjustments in heating and cooling systems.

Implementation Method 1

the obstruction forms an element reducing or inhibiting a flow into the second inlet port in a direction opposite to the normal flow direction in this second inlet port

Methodology Applied
Scientific EffectFlow deflection:

Data Source

PatentEP4006685B1Mixing valve and heating or cooling system
Publication Date: 2024.07.10 GRUNDFOS HLDG
  • EP4006685B1 patent drawingFigure 1~2
  • EP4006685B1 patent drawingFigure 3~4
  • EP4006685B1 patent drawingFigure 5~6

AI summary

The invention refers to a mixing valve having a first inlet port (4), a second inlet port (6) extending transverse to said first inlet port (4) and an outlet port (8), wherein the inlet ports (4, 6) open out into a valve chamber (10) and the outlet port (8) branches off this valve chamber (10), inside which a movable valve element (12) is arranged, having an obstruction (32) inside the second inlet port (6), which protrudes from an inner circumference (36) of the second port (6) into its interior, and which extends at least along a portion of the inner circumference (36), which portion of the circumference (36) is located on an inner side of the second inlet port (6) being distant from the first inlet port (4), and to a heating or cooling device comprising such a mixing valve.