Plastic Filtration Device With Displacement Piston Backflush

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Solution Overview

Problem

Existing filtration devices for liquefied plastic face challenges in maintaining constant pressure during backflushing, leading to material loss and potential clogging, especially when using valve devices that complicate the process and can result in material decomposition.

Innovation Solution

A device with a housing, supply, discharge, and backflush channels, featuring slideably supported screen carriers with filter elements and displacement pistons that maintain constant process pressure by forcing contaminant-free material through filter elements at higher pressures than the production side, ensuring efficient backflushing without material loss or accumulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a reservoir is connected to both the screen nest and production channel, then backflushing can be performed, but plastic material flows in the wrong direction causing mass loss and pressure loss

Engineering Contradiction:

Improvebackflushing capabilityVSAvoidplastic material loss

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The discharge channel is divided into two separate channels: a first discharge channel for receiving plastic material during normal operation and a second discharge channel for backflushing. This segmentation prevents mixing of normal flow and backflush flow, eliminating material loss and pressure loss while maintaining reliable backflushing capability.

Inventive Principle:

Principle #1Segmentation

2Reliability

If valve devices are used to close backflush channels during production, then backflushing can be controlled, but clogging and decomposition occur

Engineering Contradiction:

Improvebackflush controlVSAvoidclogging and material decomposition

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The harmful valve devices are completely removed from the system. Instead of using valves to control backflushing, the invention uses a displacement piston that mechanically forces plastic material through the screen nest in reverse, achieving backflush control without any valves that could clog or cause decomposition.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The displacement piston automatically performs the backflushing function by forcing plastic material through the screen nest without requiring external valve control. The system self-regulates the backflushing process through the piston's movement, eliminating the need for complex valve mechanisms.

Inventive Principle:

Principle #25Self-service

3Reliability

If check valves are installed in the discharge line, then backflushing can be enabled, but clogging occurs quickly and dead zones form

Engineering Contradiction:

Improvebackflushing functionVSAvoidmaterial accumulation in dead zones

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

Check valves are completely removed from the discharge line. The displacement piston provides positive displacement backflushing that forces material flow without relying on check valves, eliminating clogging issues and dead zones where material could accumulate and disintegrate.

Inventive Principle:

Principle #2Taking out (Extraction)

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 allows for immediate backflushing with constant process pressure, preventing material loss and decomposition, and simplifies the replacement of components, reducing the risk of clogging and maintaining equipment functionality.

Implementation Method 1

a displacement piston (22) opens into this partial channel (20) and feeds the contaminant-free material located in this partial channel (20) with a pressure that is much higher than the pressure that normally prevails on the clean screen side in the production position of the screen carrier (4) to the back of the filter element (6)

Methodology Applied

Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 2

at least one filter element (6) each is arranged in a corresponding screen chamber (8) and can be linked to the supply channel (2) and the disposal channel (3)

Methodology Applied

Scientific EffectPhysical filtration: Filter (physical)

Data Source

PatentUS8153012B2Device and method for filtering a fluid, in particular for plastics processing plants

Publication Date: 2012.04.10 NORDSON HLDG S A R L & CO

AI summary

The invention relates to a device for filtering a fluid, in particular a liquefied plastic, with a housing with backflush channel and screen carrier and filter element whereby, in order to accelerate and improve the backflush effect, one or more displacement cylinders are provided that guide material removed from the production at adjustable high pressure and speed to the screen to be cleaned from the clean screen side to the dirty screen side, whereby an additional pressure generator ensures constant process pressure.