Flash Decompression Cleaning of Polymer Filter Components
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Solution Overview
Problem
Filter components used in the polymer industry, particularly those filtering molten polymers, face challenges in removing residual polymer deposits that adhere strongly to their microporous structures, leading to performance impairment and potential scrap due to the inefficacy of conventional cleaning methods.
Innovation Solution
The method involves subjecting the filter components to an atmosphere of superheated steam at elevated pressure, followed by rapid decompression, known as flash decompression, to effectively remove residual polymer deposits by penetrating the interstices and causing instantaneous boiling, which shatters and strips the residues from the filter components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional cleaning methods (solvent heating, steam injection, pyrolysis, oxidation, ultrasonic cleaning, base/acid treatment) are used to remove polymer residues, then some polymer material can be removed, but residual material (0.5-1%) remains strongly adherent to inaccessible parts of the filter
Solution Approach 1:
The invention utilizes phase transition of water from liquid to vapor through flash vaporization. The filter element is heated to generate water vapor in the interstices, then rapidly cooled causing the vapor to condense and create cavitation bubbles that mechanically detach adherent polymer residues. This phase transition mechanism enables complete removal of residual material (reducing from 0.5-1% to negligible levels) that conventional methods cannot remove.
Solution Approach 2:
The cleaning process employs periodic action through cyclic heating and cooling. The filter element is heated to generate vapor, then rapidly cooled to condense vapor and create cavitation. This periodic heating-cooling cycle is repeated multiple times, with each cycle progressively removing more adherent polymer material. The periodic cavitation action accumulates mechanical stress on the polymer residues, enabling complete removal that single-step conventional methods cannot achieve.
2Quantity of substance
If the filter element is heated to melting point of polymer to drain excess polymer, then much of the excess polymer can be drained away, but liquid or gas cannot be fed into the element effectively for cleaning
Solution Approach 1:
The invention uses phase transition of water between liquid and vapor states to solve the accessibility problem. Water is introduced in liquid form, heated to vaporize within the filter element's interstices, then rapidly cooled to condense. This phase transition creates pressure changes and cavitation that open up blocked passages, enabling effective feeding of cleaning agents into the element interior without requiring the polymer to be in a specific state.
3Quantity of substance
If high pressure water is sprayed to remove contaminant polymer after solvent heating, then bulk contaminant polymer can be removed, but residual material remains strongly adherent
Solution Approach 1:
The invention generates mechanical vibration through cavitation bubbles formed during flash vaporization and condensation of water. These vibrating bubbles create shock waves and micro-jets that mechanically impact and detach adherent polymer residues from the filter surface. This mechanical vibration action complements the bulk removal by high-pressure water spray, enabling complete removal of both bulk and adherent polymer material.
Solution Approach 2:
The flash vaporization and condensation of water creates rapid pressure changes and cavitation bubbles that generate mechanical stress on adherent polymer residues. This phase transition mechanism provides the additional mechanical force needed to remove residual material (reducing from 0.5-1% to negligible levels) that high-pressure water spray alone cannot remove.
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 method is highly effective in removing residual polymer deposits that are difficult or impossible to remove by conventional techniques, extending the life of filter components and preventing them from being scrapped, with significant improvements in cleaning efficiency demonstrated in various examples.
Implementation Method 1
subjecting the component to an atmosphere of superheated steam at a pressure of at least 0.5 bar in a vessel and subsequently decompressing the vessel to achieve a pressure reduction of at least 0.5 bar in at most 5 seconds
Implementation Method 2
causing instantaneous boiling, which shatters and strips the residues from the filter components
Implementation Method 3
This technique is used particularly for cleaning of filter elements contaminated with polyesters since low molecular weight oligomers and ultimately the parent acid and alcohol are produced by hydrolysis of the polymer
Implementation Method 4
Oxidation may be used, in effect, to burn off any residual carbon. The technique usually involves heating the filter element in air to a temperature of approximately 360° to 440° C.
Implementation Method 5
The combustion of any adsorbed carbon will at best result in the discoloration and at worst the destruction of part of the element
Implementation Method 6
Ultrasonic Cleaning is often used to remove small intractable pieces of polymer or degraded polymer as well as trapped fillers and other process contaminants and debris
Implementation Method 7
The filter may be subjected to a base (usually caustic soda) treatment to complete the cleaning process, and then an acid treatment to passivate the base and to restore a bright surface to the metal
Data Source
AI summary
A method of cleaning a filter component comprises subjecting the component to an atmosphere of superheated steam at a pressure of a least 0.5 bar in a vessel and subsequently decompressing the vessel to achieve a pressure reduction of at least 0.5 bar in at most 5 seconds. The method is particularly useful for the cleaning of filter components that have been used for the filtration of molten polymer (e.g. polyester) and which are at least partially blocked by solidified polymer.