Expandable Heating Elements in Conveyor Screw Shafts
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Solution Overview
Problem
Existing conveyor screw heating systems face challenges such as temperature gradients, limited maximum temperature, high costs due to pressure-resistant components, fluid leakage, energy inefficiencies, and complex temperature control, especially when using heat transfer fluids or electrical heating elements.
Innovation Solution
A heating device with interconnected heating elements and an expansion mechanism that allows direct contact with the conveyor screw shaft, eliminating the need for conductive media and enabling efficient temperature control through a resilient, expandable design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heat transfer fluid is pumped through the hollow compartment of the shaft, then the conveyor screw can be heated, but the maximum temperature is limited to approximately 290 °C due to thermic oil degradation
Solution Approach 1:
The patent replaces the heat transfer fluid system with an electrical heating system. Electrical heating elements are inserted into the hollow compartment of the shaft and supplied with power via a slip ring, allowing direct electrical heating without the temperature limitations of thermic oil. This substitution enables temperatures above 300 °C while avoiding fluid degradation issues.
Solution Approach 2:
The patent introduces a thermally conductive medium as an intermediary between the electrical heating elements and the shaft. This medium ensures efficient heat transfer from the heating elements to the shaft, enabling effective heating at high temperatures without requiring the heating elements to be in direct contact with the shaft surface.
2Temperature
If heat transfer fluid is circulated through piping and tubing, then the conveyor screw can be heated, but pressure-resistant components are required increasing cost
Solution Approach 1:
The patent replaces the pressurized heat transfer fluid system with an electrical heating system. Electrical heating elements powered through slip rings eliminate the need for pressurized piping, tubing, and associated pressure-resistant components, significantly reducing system cost while maintaining heating capability.
3Temperature
If heat transfer fluid is used for heating, then the conveyor screw can be heated, but leakage occurs at rotatable couplings
Solution Approach 1:
The patent replaces the heat transfer fluid circulation system with an electrical heating system. Electrical heating elements powered through slip rings eliminate the need for pressurized fluid circulation, thereby eliminating leakage issues at rotatable couplings and improving system reliability.
4Temperature
If heating is applied only to the housing, then the housing temperature increases, but a temperature gradient is created in the conveyed material
Solution Approach 1:
The patent segments the heating system into multiple independent heating zones. Electrical heating elements are distributed along the shaft, allowing independent control of temperature at different locations. This segmentation enables uniform heating of the conveyed material by preventing large temperature gradients that would occur with single-point housing heating.
Solution Approach 2:
The patent applies heating locally at multiple positions along the shaft rather than uniformly throughout the housing. Electrical heating elements can be strategically positioned to heat specific zones, ensuring uniform temperature distribution in the conveyed material while allowing differential temperature control in different regions.
5Temperature
If electrical heating elements are inserted in the shaft, then high temperature is achievable, but the heating elements are prone to burning out
Solution Approach 1:
The patent introduces a thermally conductive medium as an intermediary between the electrical heating elements and the shaft. This medium distributes heat evenly, preventing localized overheating and burning out of the heating elements while maintaining high temperature capability. The thermally conductive medium acts as a heat sink that protects the heating elements from thermal stress.
6Temperature
If thermic oil is used for heating, then heat transfer is achieved, but rapid aging and degradation occur at temperatures above 300 °C
Solution Approach 1:
The patent replaces the thermic oil heat transfer system with an electrical heating system. Electrical heating elements powered through slip rings eliminate the need for thermic oil, avoiding degradation issues at temperatures above 300 °C. This substitution maintains heat transfer capability while extending system service life by eliminating fluid degradation.
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 solution provides easy replacement, efficient heat transfer, and precise temperature control without energy loss, suitable for high-temperature applications like pyrolysis, while minimizing installation complexity and reducing material contamination risks.
Implementation Method 1
a plurality of interconnected heating elements, arranged at an outer circumferential surface of the heating device
Implementation Method 2
an expansion mechanism, connected to at least two heating elements of the plurality of interconnected heating and located in between the at least two heating elements
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3C
AI summary
The present invention relates to a heating device for placement in a central shaft of a conveyor screw, wherein the heating device has an at least partly cylindrical shape and comprises a plurality of interconnected heating elements, arranged at an outer circumferential surface of the heating device; and an expansion mechanism, connected to at least two heating elements of the plurality of interconnected heating and located in between the at least two heating elements, and wherein the expansion mechanism is configured to increase a distance between the at least two heating elements. Optionally at least one heating element of the plurality of interconnected heating elements is a ceramic heating element, preferably wherein each heating element is a ceramic heating element.