Laminated HEPA Filter Medium for Pulse-Cleanable Filtration
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Solution Overview
Problem
Existing HEPA-filters face issues with sudden clogging and unpredictable replacement intervals due to their structure, leading to high energy consumption and maintenance costs, especially in industrial applications like gas turbines and HVAC systems, and there is a need for a pulse-cleanable filter medium that maintains filtering capability over a longer period.
Innovation Solution
A pulse-cleanable HEPA-filter medium composed of two separately manufactured substrates, a pre-filter and a fine-filter, laminated together, utilizing bicomponent fibers and binders to enhance mechanical strength and cleanliness, allowing for predictable and efficient filtration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flow-through filters are used to remove particles from air, then particle removal efficiency is improved, but energy consumption increases over time due to growing air flow resistance
Solution Approach 1:
The filter medium enables recovery of filtering capability through pulse-cleaning that removes accumulated particles from pores, allowing the filter to be reused multiple times instead of being discarded after single-use clogging, thereby reducing long-term energy consumption
2Use of energy by stationary object
If filter replacement interval is reduced to control energy consumption, then air flow resistance is kept low, but service and replacement expenses increase
Solution Approach 1:
Instead of continuous replacement, the filter employs periodic pulse-cleaning actions to restore its performance, creating a cycle of use-clean-reuse that extends the operational interval between replacements while maintaining low air flow resistance
Solution Approach 2:
The filter medium recovers its filtering capability through pulse-cleaning that removes accumulated particles, allowing extended reuse and reducing the frequency of replacement operations, thereby lowering service expenses
3Duration of action of stationary object
If pulse-cleaning is applied to extend filter lifetime, then replacement interval is increased, but mechanical stress on the filter increases
Solution Approach 1:
The filter medium uses a composite structure combining inorganic fibers (micro-glass) for filtering capability with organic binder fibers for mechanical strength, creating a material that can withstand the mechanical stress of pulse-cleaning while maintaining pore structure for extended lifetime
4Ease of operation
If membrane filters or nanofiber filters are used for pulse-cleaning applications, then pulse-cleanability is achieved, but filtering capability is lost suddenly and unpredictably
Solution Approach 1:
The combination of inorganic micro-glass fibers with organic binder fibers creates a composite structure where the binder holds the inorganic fibers in place, preventing sudden collapse of the pore structure and ensuring stable filtering capability over extended periods
5Reliability
If micro-glass fibers are used for depth filtration, then particle trapping capability is improved, but filter fragility increases and cleaning capability is lost
Solution Approach 1:
The filter medium combines inorganic micro-glass fibers (providing particle trapping capability) with organic binder fibers (providing mechanical strength and flexibility), creating a composite that maintains depth filtration performance while enabling pulse-cleaning and reducing fragility
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 filter medium maintains its filtering capability over a longer time, reduces maintenance and replacement costs, and ensures predictable replacement intervals while being cost-effective and resistant to humidity, suitable for both pulse-cleanable and non-pulse-cleanable applications.
Implementation Method 1
In depth filtration the filter medium has pores into which solid particles get trapped
Implementation Method 2
Surface filtration refers to a process where the surface of the filter medium is so dense that the solids separated from the fluid remain on the surface of the filter
Implementation Method 3
the filter device is provided with means for periodically blowing compressed fluid through the filter in the direction opposite the normal filtering direction, whereby the fluid pulses flush most of the solids trapped in the pores of the filter away from the filter
Data Source
AI summary
The present invention relates to a filter medium being at least formed of a pre-filter substrate laminated with a fine-filter substrate by means of a third binder, wherein the pre-filter substrate comprises synthetic fibers and a first binder, the pre-filter substrate working as a combined surface and depth filter, and the fine-filter substrate comprises at least a second binder and one of synthetic fibers and inorganic fibers.