Precoat Filter Porosity Control Using Cellulose Viscose Fibers
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Solution Overview
Problem
Conventional filter aids like kieselguhr are hazardous, expensive, and lead to uncontrollable filtration results due to compressibility issues, while alternative filter aids such as cellulose fibers fail to achieve desired turbidity and often cause filter cake blockage.
Innovation Solution
A method controlling the porosity of the filter cake by adjusting the volume flow of unfiltrate based on turbidity measurements, using a control unit to regulate pressure differences across the precoat filter, allowing for effective use of compressible filter aids like viscose and cellulose fibers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If diatomaceous earth is used as filter aid, then filtration capability is improved, but health safety deteriorates due to cristobalite inhalation risks
Solution Approach 1:
The patent replaces hazardous diatomaceous earth with cellulose fibers that are safe for health. The cellulose filter aid achieves comparable filtration capability without the cristobalite inhalation risks, effectively substituting a harmful material with a safe alternative that fulfills the same filtration function.
Solution Approach 2:
The patent converts the compressibility of cellulose fibers, which was previously seen as a disadvantage leading to uncontrollable porosity, into a beneficial feature. By controlling the pressure difference during filtration, the compressible filter cake maintains optimal porosity and extends filter service life, transforming a potential harm into an advantage.
2Object-affected harmful factors
If natural cellulose fibers are used as filter aid, then health safety is improved, but filtration efficiency deteriorates due to insufficient turbidity reduction
Solution Approach 1:
The patent modifies the physical parameters of cellulose fibers by controlling their orientation and arrangement in the filter cake. By optimizing fiber orientation through controlled pressure application during filtration, the filter cake achieves both high filtration efficiency for turbidity reduction and maintained health safety benefits of cellulose.
Solution Approach 2:
The patent creates a composite structure within the filter cake by combining cellulose fibers with controlled orientation and arrangement. This composite-like structure of oriented cellulose fibers enhances filtration efficiency while maintaining the inherent safety benefits of natural cellulose, overcoming the limitation of random fiber arrangements.
3Object-affected harmful factors
If natural cellulose fibers are used as filter aid, then health safety is improved, but filter cake stability deteriorates due to rapid clogging
Solution Approach 1:
The patent converts the compressibility of cellulose fibers, which initially seemed to cause rapid clogging and reduced service life, into a beneficial feature. By applying controlled pressure differences during filtration, the filter cake compresses to optimize porosity, preventing rapid clogging and extending filter service life while maintaining health safety.
Solution Approach 2:
The patent introduces dynamic pressure control during the filtration process to adapt the filter cake porosity in real-time. By adjusting the pressure difference based on filtration progress, the system maintains optimal porosity throughout the filtration cycle, preventing rapid clogging and extending the operational life of the filter while using safe cellulose fibers.
4Object-affected harmful factors
If compressible filter aids are used, then health safety is improved, but porosity control deteriorates due to uncontrollable compression
Solution Approach 1:
The patent converts the uncontrollable compression of compressible cellulose fibers into a beneficial feature. By intentionally applying controlled pressure differences during filtration, the system optimizes the porosity of the filter cake, transforming the potential harm of uncontrolled compression into precise porosity control that extends filter service life.
Solution Approach 2:
The patent implements feedback control by monitoring filtration progress and adjusting the pressure difference accordingly. This feedback mechanism allows real-time optimization of filter cake porosity, ensuring that the compressible cellulose fibers are compressed to the optimal degree rather than becoming overly compacted, thereby maintaining precise porosity control throughout the filtration process.
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 approach ensures consistent filtrate quality over extended filtration cycles, extends filter service life, and enables the effective use of compressible filter aids by maintaining optimal porosity and preventing blockages.
Implementation Method 1
The flow of the filtrate creates a suction effect on the unfiltrate side of the filter element, causing the filter aid to be fixed to the element's surface at the point of highest flow
Implementation Method 2
the cloudy beer, i.e., the unfiltered beer, is separated by a filter device into a clear filtrate and a remaining filter residue (filter layer)
Data Source
Figure 1
Figure 2
Figure 3a~3
AI summary
The present invention provides a method for controlling the porosity of a filter cake of a precoat filter which has at least one inlet for raw fluid and at least one outlet for filtrate, comprising the following steps: supplying, via the inlet of the precoat filter, a flow of raw fluid to which is added filtering aid; and drawing off a flow of filtrate from the outlet of the precoat filter; wherein a turbidity of the drawn-off filtrate is measured and is compared by means of the control unit with at least one limit value for the turbidity; and wherein a pressure difference between the raw fluid side and the filtrate side of the precoat filter is controlled by using the control unit to adjust a volume flow rate of the supplied flow in dependence on a result of the comparison of the measured turbidity with the at least one limit value. The invention also relates to a filtering aid for a precoat filter for the filtration of liquid foodstuffs, in particular beer, or the raw materials and intermediate products thereof, which comprises both cellulose fibers and viscose fibers; and to a method for filtering or stabilizing beer with the aid of such a filtering aid.