Modular Measuring Insert for Thermocouple Purging
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Solution Overview
Problem
Existing thermocouple and temperature measurement systems in process plants are not replaceable in the field without shutting down the process, limiting their maintenance and efficiency.
Innovation Solution
A modular measuring insert with a core part having bores for electric conductors and a purging gas flow path, integrated with a modular connecting piece that allows for efficient purging and replacement of the insert without process shutdown, using a system of chambers and barriers to ensure gas tightness and prevent contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a traditional thermocouple assembly with protective sheath and terminal block is used, then the measurement system provides stable temperature monitoring, but the sensing elements cannot be replaced in the field without shutting down the process
Solution Approach 1:
The measurement system is divided into separate modular components: a removable measuring insert containing the sensing element and a stationary terminal block assembly. The measuring insert can be extracted and replaced through the protective tube opening without shutting down the process, while the terminal block remains fixed for continuous electrical connections.
Solution Approach 2:
The sensing element is extracted from the traditional fixed assembly and placed in a removable measuring insert that can be taken out through the protective tube. This allows the sensing element to be replaced in the field without removing the entire measurement system or shutting down the process.
2Ease of repair
If the thermocouple wires are directly exposed in the process environment, then replacement is easier, but the sensing elements are susceptible to oxidation and contamination
Solution Approach 1:
The measuring insert is nested within the protective tube, which provides a sealed environment protecting the sensing element from oxidation and contamination. The nested structure allows the insert to be accessed and replaced through the tube opening while maintaining protection during operation.
Solution Approach 2:
The protective tube acts as an intermediary barrier between the sensing element and the harsh process environment. It provides a sealed pathway for the sensing element to extend into the process while protecting it from harmful factors like oxidation and contamination.
3Object-affected harmful factors
If a sealed protective environment is provided for the thermocouple, then protection from contamination is achieved, but purging gas flow paths become complex
Solution Approach 1:
The purging system is segmented into distinct zones: a first chamber for purging gas introduction and a second chamber for exhaust, separated by the measuring insert. This segmentation creates simple, defined flow paths through the protective tube without requiring complex internal structures.
Solution Approach 2:
The purging function is extracted and applied to the protective tube environment rather than the sensing element itself. Purging gas flows through the protective tube to create a protective atmosphere around the sensing element, simplifying the overall system architecture.
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
Enables efficient purging and replacement of the temperature sensing elements, extending their lifespan by preventing oxidation and allowing for maintenance without halting the process, while maintaining gas tightness and preventing process fluid contamination.
Implementation Method 1
enables efficient purging and replacement of the temperature sensing elements, extending their lifespan by preventing oxidation
Implementation Method 2
the purging fluid is able to flow from the bottom of the core part and the outside of the core part to an exit chamber of the measuring insert
Implementation Method 3
maintaining gas tightness and preventing process fluid contamination
Data Source
Figure 1
Figure 2
Figure 3a~3b
AI summary
Measuring insert (3.3), especially for measuring temperature, wherein the measuring insert (3.3) has a core part (3.5), in which core part (3.5) bores (3.7) for receiving electric conductors, e.g. thermoelements of a thermocouple or connection wires of a RTD, are provided, which bores (3.7) extend from the top to the bottom of the core part, wherein at the bottom there is at least one opening allowing for a purging gas to flow through the bores (3.7) and the opening.