Tail Seal Composition Using Blown Oils for High Mineral Loading
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Solution Overview
Problem
Existing tail seal compositions for tunneling machines face limitations in achieving high mineral charge concentration without using talc and maintaining environmental compatibility, while ensuring resistance to water wash-out, mechanical wear, and pressure extrusion, while also being non-toxic and hydrocarbon-free.
Innovation Solution
A tail seal composition comprising 30-70% by weight of blown oils as the hydrophobic portion, 30-70% by weight of a non-talc mineral charge, and 2-10% by weight of fibrous material, where blown oils are produced by polymerizing unsaturated oils at elevated temperatures, and the mineral charge is in the form of non-fibrous powders like calcium carbonate, allowing for high viscosity without pour point depressants or emulsifying agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high mineral charge concentration is used in tail seal composition, then the viscosity and consistency of the composition increases, but the pumping efficiency decreases and the composition becomes difficult to handle
Solution Approach 1:
The patent changes the chemical composition parameters by using blown oils instead of conventional hydrophobic portions, which allows achieving high mineral charge concentration (up to 70% by weight) while maintaining acceptable viscosity and pumping efficiency. The blown oil base provides different rheological properties that facilitate high filler loading without excessive thickening.
2Strength
If conventional hydrophobic portions are used in tail seal composition, then adhesion to metallic surface is achieved, but environmental compatibility is compromised due to hydrocarbon content
Solution Approach 1:
The patent changes the chemical composition by replacing conventional hydrocarbon-based hydrophobic portions with blown oils that have different chemical structure. The blown oils provide the necessary adhesion properties while being environmentally compatible and free from harmful hydrocarbons, thus resolving the contradiction between adhesion performance and environmental compatibility.
3Ease of operation
If talc is used as mineral charge in tail seal composition, then lubricant properties are achieved, but environmental compatibility is reduced and alternative materials are limited
Solution Approach 1:
The patent replaces talc with alternative mineral charges such as calcium carbonate, barium sulfate, or silica that can be obtained in clean, environmentally compatible forms. These alternative materials provide similar or superior lubricant properties while being more environmentally friendly, thus resolving the contradiction between lubricant performance and environmental compatibility.
4Temperature
If emulsifying agents and pour point depressants are added to tail seal composition, then low temperature flowability is improved, but the composition complexity increases and more additives are required
Solution Approach 1:
The patent extracts and eliminates the need for emulsifying agents and pour point depressants by using blown oils as the base material. The blown oils inherently provide the necessary rheological properties and low-temperature flowability without requiring these additional additives, thus simplifying the composition while maintaining performance.
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 an eco-compatible tail seal with enhanced resistance to water wash-out and mechanical wear, maintaining stability and adhesion, and meeting environmental compatibility standards, with improved pumping efficiency and performance across a range of operating temperatures.
Implementation Method 1
the oils polymerize by crosslinking through formation of peroxide bridges and C-C linkages
Implementation Method 2
Blown oils are produced at elevated temperatures (60-250°C), by blowing air through unsaturated oils
Data Source
Figure 1~2
AI summary
Tail seal compound (tail seal) for tunnelling machine comprising blown oils, more than 30% by weight of a mineral charge and fibrous material.