Self-Purging Filter for Subatmospheric Pump Inlets
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Solution Overview
Problem
Existing fluid filtration systems require depressurization and shutdown to replace or clean filtering cartridges, which disrupts the flow of filtered fluid when the filtrate outlet is at subatmospheric pressure, making self-cleaning and purging operations inoperable.
Innovation Solution
A fluid filtering apparatus with a pressure vessel containing an annular filter media element, a movable piston with wipers, and remotely operated valves for purging debris without interrupting filtration flow, allowing for self-cleaning and pressure equalization between chambers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the filtration system operates with the filtrate outlet connected to subatmospheric pressure to increase flow through the filter media element, then filtration efficiency and flow rate are improved, but self-cleaning and purging operations become inoperable due to inability to maintain positive pressure
Solution Approach 1:
The system is divided into two separate chambers: a filtration chamber where fluid flows through the filter media element at subatmospheric pressure, and a purge chamber where self-cleaning operations occur at positive pressure. The piston and valves enable independent operation of these chambers, allowing the filtration chamber to maintain continuous flow while the purge chamber performs maintenance without interrupting filtration.
Solution Approach 2:
The piston acts as an intermediary mechanism that transfers debris from the filtration chamber to the purge chamber during the cleaning cycle. By moving the piston, debris is pushed into the purge chamber where it can be removed, while the filtration chamber maintains its subatmospheric pressure and continuous flow operation.
2Ease of operation
If the system maintains positive pressure at both fluid inlet and discharge outlet to enable self-cleaning purging operations, then self-cleaning functionality is achieved, but the outlet cannot be connected to subatmospheric pressure systems or pump inlets
Solution Approach 1:
The system separates the pressure requirements for different functions into different chambers. The filtration chamber operates at subatmospheric pressure for compatibility with pump inlets and process systems, while the purge chamber operates at positive pressure to enable self-cleaning operations. This segmentation allows the system to adapt to both subatmospheric and atmospheric pressure requirements simultaneously.
3Ease of operation
If the piston is moved downwardly to scrape debris from the filter media element, then cleaning effectiveness is improved, but the main valve must close to isolate the purge chamber, interrupting fluid flow
Solution Approach 1:
The system performs preliminary isolation of the purge chamber by closing the main valve before the piston begins its downward cleaning stroke. This ensures that when debris is scraped off the filter media element and pushed into the purge chamber, the purge chamber is already isolated and ready to contain and remove the debris without affecting the filtration chamber's continuous flow operation.
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
Enables continuous filtration flow during cleaning and purging operations by isolating the purging chamber from the filtration chamber, allowing for effective debris removal without depressurizing the system or interrupting fluid flow.
Implementation Method 1
The piston includes wipers for scraping accumulated debris from the upstream or interior side of the filter media element
Implementation Method 2
sequential opening of a drain valve and the purge valve permits pressurized fluid to be applied through the separate purge fluid inlet to the purge chamber and flushes accumulated debris from the purge chamber through the open drain valve
Implementation Method 3
initial movement of the piston opens a bleed valve provided in the main valve to permit pressure equalization between the purge chamber and the filtration chamber
Data Source
AI summary
A self-purging filtering apparatus having a pressure vessel connected for discharging clean filtrate to subatmospheric pressure at a pump inlet. Actuators connected to an outwardly extending rod move a wiper piston to scrub the upstream side of an annular filter media element. The piston moves a main valve member to isolate a purge chamber from the filtering chamber. Remotely operated valves control flushing of the purged chamber. The main valve has a bleed valve to provide pressure equalization for facilitating main valve movement.