Backwashable Filter Candle for Plastic Melt Contaminant Removal
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Solution Overview
Problem
Existing filter candles for plastic melts require complex and costly cleaning processes due to obstruction by contaminants, leading to frequent replacements and potential damage to the filter medium, which shortens their service life and increases production costs.
Innovation Solution
A filter candle design featuring internal and external supporting bodies with abutment parts and a clamping ring system allows for backwashing without disassembly, using radially directed melt flow during filtration and counter-flow during cleaning to remove contaminants and prevent filter element deformation, thereby extending the filter candle's service life and simplifying maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the filter element is cleaned using chemical solvents or thermal methods, then contaminants are removed from the filter element, but the cleaning process becomes complex and costly, and the filter medium may be damaged
Solution Approach 1:
The patent implements backwashing by reversing the flow direction of the plastic melt through the filter element. Instead of cleaning the filter from the outside in, the melt flows from the filtered side back through the filter medium to the unfiltered side, utilizing the existing filtration structure for cleaning purposes and avoiding external chemical or thermal cleaning methods
Solution Approach 2:
The filter system performs its own cleaning using the plastic melt that it already processes. The backwashing function utilizes the melt flow itself as the cleaning medium, eliminating the need for separate cleaning systems with chemicals or thermal equipment, and reducing complexity while maintaining filter medium integrity
2Ease of operation
If the filter candle is disassembled for cleaning, then the filter element can be cleaned thoroughly, but the cleaning process time increases and production costs rise
Solution Approach 1:
The filter candle performs self-cleaning through backwashing without requiring disassembly. The reversible flow mechanism allows the filter element to be cleaned in situ while remaining assembled in the filter housing, eliminating the time-consuming disassembly and reassembly operations
Solution Approach 2:
The backwashing process can be integrated into the normal operation cycle, allowing the filter to be cleaned during or between filtration cycles without interrupting production. The continuous availability of plastic melt enables cleaning to occur without stopping the molding process
3Duration of action of stationary object
If the filter element is cleaned multiple times, then the service life of the filter candle is extended, but the production costs increase due to elaborate testing and cleaning procedures
Solution Approach 1:
The backwashing mechanism enables the filter element to clean itself repeatedly without external intervention. Each backwash cycle restores the filter medium using the plastic melt flow, allowing multiple cleaning cycles without the need for expensive external cleaning equipment or chemical solvents
Solution Approach 2:
The patent employs a disposable filter element that can be replaced without costly cleaning procedures. While the filter element is designed for limited reuse through backwashing, the simplicity of replacement compared to the cost of elaborate cleaning and testing makes this economically viable, especially when contamination severely degrades filter 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 backwashable filter candle significantly increases the time between cleaning processes, extends its service life, and allows for efficient and damage-free cleaning, reducing production costs by enabling the filter medium to be reused multiple times without elaborate testing.
Implementation Method 1
The filter element is set up to retain contaminants contained in the melt flow so that these no longer have an influence in the further processing of the plastic melt
Implementation Method 2
Forces that result from the pressure difference in the flow direction of the melt before and after the filter element, act on the filter area of the filter element, and would result in a deformation of the filter element without the supporting body, are absorbed by said supporting body
Implementation Method 3
In order to fix the filter element relative to the supporting body, the edge regions of the filter element are welded to the supporting body, for example
Implementation Method 4
a removal of the contaminants from the filter element, for example by means of ultrasonic cleaning
Data Source
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AI summary
A filter candle (1, 1', 1", 1''') to separate contaminants from a plastic melt, having at least one filter element (6, 6', 6") through which a melt flow can be directed and which is set up to retain contaminants contained in the melt flow and a supporting body (2, 2', 2") to support the filter element (6, 6', 6"), in the form of a hollow body which has a wall region having multiple passages for the melt flow. At least one additional supporting body (4, 4', 4") is associated with the filter element (6, 6', 6") on the side of said filter element that faces away from the supporting body (2, 2', 2"), which supporting body (4, 4', 4") is set up to act on surface regions of the filter element (6, 6', 6") and/or to accommodate them such that the filter element (6, 6', 6") can be backwashed.