Low-Contact Pipe Clamp for Accurate Non-Invasive Temperature Sensing

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Solution Overview

Problem

Existing non-invasive process fluid temperature estimation techniques face inaccuracies due to clamps acting as heat sinks and inadequate insulation, particularly when measuring high-temperature or corrosive fluids, and are limited by the need for precise thermal impedance calculations.

Innovation Solution

A heat flow measurement system with a pipe clamp that minimizes surface contact and uses standoffs for insulation, incorporating a heat flow sensor capsule with temperature-sensitive elements and a microprocessor for accurate temperature estimation, allowing for reduced thermal interference and extended application in harsh environments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a clamp is used to attach the temperature sensor to the conduit, then the sensor can be positioned externally without invasive apertures, but the clamp acts as a heat sink and reduces measurement accuracy

Engineering Contradiction:
Improvenon-invasive installationVSAvoidtemperature measurement accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

A low thermal conductivity standoff is introduced as an intermediary component between the clamp and the conduit surface. This standoff acts as a thermal barrier that prevents the clamp from acting as a heat sink, while still providing mechanical attachment. The standoff's low thermal conductivity ensures minimal heat transfer from the conduit to the clamp, thereby maintaining measurement accuracy while enabling non-invasive installation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If the clamp has large surface contact with the conduit, then secure attachment is achieved, but thermal stray effects increase and measurement accuracy decreases

Engineering Contradiction:
Improveattachment securityVSAvoidtemperature measurement accuracy
Core Design Contradiction:
StrengthVSMeasurement precision

Solution Approach 1:

The clamp is designed with non-uniform thermal conductivity distribution. The portion of the clamp in contact with the conduit has reduced thermal conductivity compared to the main body, creating a localized thermal barrier at the critical interface. This local quality change prevents heat from traveling along the clamp while maintaining structural integrity and attachment security.

Inventive Principle:
Principle #3Local quality

3Device complexity

If traditional clamps are used for temperature sensing, then simple construction is achieved, but inadequate insulation allows thermal stray effects to contaminate measurements

Engineering Contradiction:
Improveclamp construction simplicityVSAvoidtemperature measurement accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The clamp is constructed from composite materials with different thermal conductivities. The main body uses a material with moderate thermal conductivity for structural strength, while the contact portion incorporates low thermal conductivity material to prevent heat transfer. This composite construction provides both mechanical strength and thermal insulation without significantly increasing device complexity.

Inventive Principle:
Principle #40Composite materials

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 system provides improved accuracy and expanded applicability for measuring process fluid temperatures in high-temperature and corrosive environments by reducing thermal stray effects and optimizing insulation, enabling precise temperature calculations without invasive apertures.

Implementation Method 1

the clamp is spaced from the external surface of the process pipe by a standoff (404) to minimize heat sink effects

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

measuring an external temperature of a process fluid conduit... a first temperature sensor disposed to measure an external temperature of a process fluid conduit

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3857191B1Low contact clamp for non-invasive process fluid temperature indication
Publication Date: 2023.09.13 ROSEMOUNT INC
  • EP3857191B1 patent drawingFigure 1A~1B
  • EP3857191B1 patent drawingFigure 2
  • EP3857191B1 patent drawingFigure 3

AI summary

A process fluid temperature estimation system (200) includes a sensor capsule (206) having a temperature sensitive element (254) disposed therein configured to sense an external surface (116) of a process pipe (100). The process fluid temperature estimation system (200) includes measurement circuitry (228) coupled to the sensor capsule (206) and configured to detect a characteristic of the at least one temperature sensitive element (254) that varies with temperature and provide sensor capsule temperature information. A controller (222) is coupled to the measurement circuitry (228) and is configured to obtain a reference temperature and employ a heat transfer calculation with the reference temperature and the sensor capsule temperature information to generate an estimated process temperature output. The process fluid temperature estimation system (200) includes a mounting assembly (302) configured to mount the process fluid temperature estimation system (200) to the external surface of the process pipe (100), wherein a portion of the mounting assembly (302) is offset from the external surface (116) of the process pipe (100).