COT Surface Thermocouple: Segmented Sleeve Design for Ethylene Furnace
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Solution Overview
Problem
Existing COT surface thermocouples for ethylene cracking furnaces face difficulties in accurate temperature measurement due to deformation during installation, leading to uneven temperature control, increased coking, reduced equipment lifespan, and high maintenance costs.
Innovation Solution
A COT surface thermocouple design featuring a contact-type temperature measuring component with a curved surface, a concentric non-bending connection to the sleeve, and a clamping sleeve component, allowing for direct and secure welding to the furnace tube, reducing installation complexity and improving thermal response time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the sleeve is bent to form an included angle with the furnace tube for installation space requirements, then the installation space requirement is met, but the thermocouple wire is deformed and difficult to install and replace
Solution Approach 1:
The thermocouple assembly is segmented into distinct functional components: the temperature measuring component with contact welding surface, the sleeve, the clamping component, and the heat preservation layer. This segmentation allows each component to be optimized independently - the contact welding surface provides direct thermal contact while the sleeve remains straight for easy installation and replacement.
2Volume of moving object
If the thermocouple wire passes through a bent part of the sleeve, then the installation space requirement is met, but the measuring point is obliquely deformed and cannot immediately reflect the surface temperature
Solution Approach 1:
The temperature measuring component is extracted from the bent sleeve structure and positioned to make direct contact welding with the furnace tube surface. This extraction eliminates the interference of the bent sleeve on the measuring point's ability to accurately reflect surface temperature, while the sleeve serves only as a protective and positioning structure.
Solution Approach 2:
The contact welding surface is preliminarily formed on the temperature measuring component before installation, ensuring that when installed, the measuring point is already in optimal position for direct thermal contact with the furnace tube surface, immediately reflecting temperature changes without deformation interference.
3Volume of moving object
If the sleeve is bent for installation, then the installation space requirement is met, but the thermocouple is difficult to install and requires removal of heat preservation layer for replacement
Solution Approach 1:
The assembly is segmented into removable components where the temperature measuring component can be independently extracted from the sleeve. The clamping component provides a standardized interface for secure yet reversible attachment, allowing replacement of the measuring component without disturbing the heat preservation layer or sleeve structure.
Solution Approach 2:
The clamping component is preliminarily designed to provide easy clamping and release mechanisms, and the temperature measuring component is preliminarily configured with the contact welding surface already formed. This preliminary preparation enables quick replacement during maintenance without requiring heat preservation layer removal or complex disassembly.
4Measurement precision
If the contact type temperature measuring component is directly welded to the furnace tube surface, then the temperature measurement accuracy is improved, but the installation complexity increases
Solution Approach 1:
The temperature measuring component and the contact welding surface are merged into a single integrated unit. This combination eliminates the need for separate welding operations during installation - the contact welding surface is already formed on the measuring component, reducing installation complexity while maintaining direct thermal contact for high measurement accuracy.
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 design enhances installation ease, maintains accuracy, and extends service life by ensuring a direct and secure contact with the furnace tube, reducing thermal response time and maintenance costs while preventing sleeve bending.
Implementation Method 1
the contact type temperature measuring component is completely in contact welding with the surface of the furnace tube... the outer side of the sleeve is used for conducting temperature
Data Source
AI summary
A COT surface thermocouple including a contact type temperature measuring component, a sleeve, a connecting sealing assembly, a clamping sleeve assembly, a temperature measuring component and a junction box is provided. The COT surface thermocouple is arranged on the surface of a furnace tube of an ethylene cracking furnace. The contact type temperature measuring component is completely in contact welding with the surface of the furnace tube. The whole body is in an inclined angle. The contact type temperature measuring component is connected with the sleeve in a way of concentrically welding a counter bore or connecting an internal thread. The sleeve and the contact type temperature measuring component are concentrically connected without bending. The sleeve is formed by splicing two sections and is connected through the connecting sealing assembly to form a sealing cavity.