Rotary Mixer Temperature Sensing With External IR Detection

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Solution Overview

Problem

Existing temperature sensors in rotary mixers are subjected to high centrifugal forces, leading to maintenance issues and measurement inaccuracies due to contamination and thermal insulation by baked-on material, and require complex design adaptations for non-contact sensors within the mixing vessel.

Innovation Solution

A non-contact radiation detector, such as a pyrometer, is mounted outside the mixing container, detecting infrared radiation from the mixture through a focused beam path, with a data processing unit to calculate accurate temperature values and distinguish between mixture and other peaks, and optionally using a germanium disc for sealed vacuum processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If temperature sensors are embedded in the mixer drum or impeller, then temperature measurement is possible, but the sensors are exposed to harsh chemical environments and mechanical stress leading to frequent failures

Engineering Contradiction:
Improvetemperature measurement capabilityVSAvoidsensor durability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent introduces a temperature-sensitive resin as an intermediary medium that transfers thermal information from the mixture to the sensor. The resin is applied to the outer surface of the mixer drum, allowing the sensor to measure temperature indirectly through the resin layer rather than direct contact with the harsh chemical environment, thus protecting the sensor while maintaining measurement capability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces direct mechanical contact between sensors and the mixture with a thermal coupling system using temperature-sensitive resin. Instead of embedding sensors in the drum or impeller that directly contact the mixture, the system uses thermal conduction through the resin to transfer temperature information, eliminating the need for sensors to withstand mechanical stress and chemical corrosion

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

2Measurement precision

If temperature sensors are placed in direct contact with the mixture, then accurate temperature measurement is achieved, but the sensors are exposed to chemical corrosion and mechanical stress

Engineering Contradiction:
Improvetemperature measurement accuracyVSAvoidchemical corrosion and mechanical stress
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The temperature-sensitive resin serves as a protective intermediary layer between the sensor and the harsh chemical environment. The resin is applied to the outer surface of the mixer drum and allows thermal energy to pass through while blocking direct contact between the sensor and corrosive chemicals, thus maintaining measurement accuracy while protecting the sensor from harmful factors

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent uses a thin film of temperature-sensitive resin that covers the outer surface of the mixer drum. This flexible film allows thermal conduction for accurate temperature measurement while providing a protective barrier that isolates the sensor from chemical corrosion and mechanical stress, effectively solving the contradiction between measurement accuracy and sensor protection

Inventive Principle:
Principle #30Flexible shells and thin films

3Reliability

If the mixer drum is made of materials resistant to chemical corrosion, then the drum durability is improved, but the cost of the mixer increases

Engineering Contradiction:
Improvemixer drum durabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The temperature-sensitive resin acts as an intermediary protective layer that allows the use of standard, less expensive mixer drum materials. Instead of requiring the drum itself to be made from costly corrosion-resistant materials, the resin layer provides the necessary chemical resistance and sensor protection, reducing manufacturing costs while maintaining durability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies a thin film of temperature-sensitive resin to the outer surface of the mixer drum, providing chemical resistance and sensor protection without requiring the drum material itself to be expensive corrosion-resistant material. This thin film approach maintains drum durability while significantly reducing manufacturing costs compared to using expensive materials for the entire drum structure

Inventive Principle:
Principle #30Flexible shells and thin films

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

Provides accurate temperature measurement without mechanical stress on sensors, reduces maintenance costs, and prevents contamination, ensuring precise in-process control and quick identification of mixing deviations.

Implementation Method 1

temperature-sensitive resin that transforms into a conductive state when exposed to heat

Methodology Applied
Scientific EffectThermal energy transformation: Seebeck Effect

Data Source

PatentEP4396548B1Device for determining the temperature of a mixture in a rotary mixer
Publication Date: 2026.05.13 HAUSCHILD GMBH & CO KG
  • EP4396548B1 patent drawingFigure 1

AI summary

A device (1) for determining the temperature of a mixture (13) in a rotary mixer (2) is presented, the device comprising: - a stationary housing (3); - a mixing container (10), which can be moved on a circular path (14) into different rotation positions about a main axis of rotation (16) and which has a mixture holder (9) having a bottom (7) and having a side wall (8) and which is in the form of a solid of revolution having an axis of symmetry (11) oblique to the plane (15) of the circular path (14) and orthogonal to the bottom (7); wherein: the mixing container (10) is mounted for rotation about the axis of symmetry (11); in an idle state (R), the device (1) has no mixture (13), and in a working state (A), in which the mixing container (10) is filled with a mixture (13), the device (1) rotates on the circular path (14); a contactlessly measuring radiation detector (4) is fixedly arranged on the housing (3) and is directed at the circular path (14).