Refractory Envelope Heating Elements for Screw Protection
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Solution Overview
Problem
Heat treatment devices face challenges in maintaining high temperatures due to the risk of screw damage and accumulation of unprocessed product, particularly when dealing with products that soften or melt, leading to screw blocking.
Innovation Solution
Incorporating a refractory envelope with heating elements arranged within the walls to supplement the heat treatment, allowing continued processing even when the screw is not powered, and using a separate power supply for the heating elements to maintain envelope temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the screw is used as the primary heating means, then the heat treatment can be effective, but the screw risks being damaged at excessive temperatures
Solution Approach 1:
The refractory envelope acts as an intermediary heating medium between the screw and the product. The screw heats the refractory envelope, which then radiates heat to the product, reducing the screw's thermal load and preventing damage while maintaining effective heat treatment.
Solution Approach 2:
The heating function is segmented between two components: the screw (which provides initial heating) and the refractory envelope (which stores and radiates heat). This segmentation allows the screw to operate at lower temperatures while the envelope maintains the high temperature environment needed for product treatment.
2Reliability
If the power supply to the screw is cut off to protect it from overheating, then the screw temperature is controlled, but the heat treatment cannot continue effectively
Solution Approach 1:
The refractory envelope is preheated by the screw before the power supply is cut off. This preliminary heating stores thermal energy in the envelope, allowing it to continue providing heat to the product even after the screw is deactivated, ensuring uninterrupted heat treatment.
Solution Approach 2:
The refractory envelope maintains continuous heat treatment action even when the screw is not powered. The envelope's thermal mass ensures that heating continues without interruption, preventing product accumulation and maintaining productivity while protecting the screw.
3Reliability
If the screw cools down during power interruption, then the screw is protected from damage, but the product at the inlet cannot be heated sufficiently
Solution Approach 1:
The refractory envelope serves as a thermal mediator that maintains temperature at the inlet zone even when the screw cools down. The envelope radiates heat to the product at the inlet, ensuring sufficient heating continues while the screw temperature is reduced for protection.
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
This solution prevents screw blocking, ensures continuous heat treatment with reduced energy costs, and optimizes heating efficiency by using the refractory envelope to maintain product temperature.
Implementation Method 1
The device (1) comprises at least one heating element arranged in at least one of the walls of the casing (11)
Implementation Method 2
Due to the temperature of the screw, the product is heated as it progresses
Implementation Method 3
The screw continuously pushes the product towards the outlet of the enclosure
Implementation Method 4
the screw constituting a means of heating the internal walls so that said internal walls themselves constitute means of heating by radiation the divided solids
Data Source
Figure 1~3
AI summary
The invention relates to a device for heat treatment of a product, including: - an enclosure (2) comprising a casing made of refractory material; - a screw (10) mounted to turn in the casing about a geometric axis of rotation in order to move the product between an inlet of the casing and an outlet of the casing, the screw furthermore forming a heating means for heat treatment of the product by supplying electricity to the screw. According to the invention, the device comprises at least one heating element (17a, 17b) for heating the casing in operation, the heating element being arranged inside at least one of the walls of the casing. The invention also relates to a corresponding method.