Pressure Filter Flow Distributor for Uniform Back-Flush Cleaning
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Solution Overview
Problem
Pressure filters used in chemical pulp mills face issues with uneven flow distribution during washing and back-flushing, leading to incomplete cleaning of the filtering surface and potential clogging, which impairs filtrate flow and requires frequent acid washing.
Innovation Solution
A flow distributor is placed inside the tubular filtering elements to evenly distribute the washing liquid across the filtering surface, ensuring uniform cleaning and preventing clogging by directing pressure to both the upper and lower parts of the element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If washing liquid is circulated through the filtering elements from top to bottom during washing, then the filtering elements can be cleaned, but the flow is not distributed evenly and pressure is directed mostly to the lower part, leaving precipitate cake on the upper surface
Solution Approach 1:
The filtering element is divided into multiple flow channels by internal partition walls, which segment the washing liquid flow into several parallel paths. This segmentation ensures that washing liquid is distributed more uniformly across the entire filtering surface, including the upper part, thereby improving cleaning effectiveness without requiring complex external flow distribution systems.
Solution Approach 2:
The invention introduces an internal dimensional structure (partition walls) within the filtering element that transforms the flow distribution from a simple top-to-bottom vertical flow into a multi-directional flow pattern. The partition walls create horizontal flow components that redirect washing liquid to reach the upper filtering surface areas, solving the uneven flow distribution problem by adding spatial complexity to the flow path.
2Reliability
If acid washing is performed frequently to prevent clogging, then the filtering elements remain clean, but process interruptions increase and operational costs rise
Solution Approach 1:
The flow distributor structure performs preliminary flow distribution during normal washing operations, preventing precipitate cake accumulation on the upper filtering surface before it causes clogging. By ensuring uniform washing liquid distribution during routine cleaning, the system prevents the buildup that would otherwise require frequent acid washing interventions, thereby maintaining filter cleanliness while reducing process interruptions.
Solution Approach 2:
The internal partition wall structure enables the filtering element to self-distribute washing liquid uniformly during the washing phase, creating a self-cleaning mechanism that prevents clogging without requiring external intervention or frequent acid washing. The structure serves itself by using the washing liquid flow to maintain its own cleanliness and functionality.
3Reliability
If the filtering surface is not cleaned evenly, then precipitate cake accum on the upper part, but increasing washing water usage or frequency does not resolve the uneven distribution issue
Solution Approach 1:
By segmenting the internal flow path with partition walls, the washing liquid is forced to travel through multiple distributed channels rather than concentrating in a single vertical path. This segmentation ensures that washing liquid reaches all areas of the filtering surface efficiently, achieving uniform cleaning without increasing the total quantity of washing water required.
Solution Approach 2:
The partition walls act as intermediary structures that redirect and distribute the washing liquid flow to areas that would otherwise be poorly reached (the upper filtering surface). These intermediaries enable efficient flow distribution and effective cleaning without requiring additional washing water or increased washing intensity.
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 solution enhances the cleaning efficiency of the filtering surface, reduces operational costs, and allows for longer filter element lifetimes, decreased washing water usage, and reduced frequency of acid washing, thereby minimizing process interruptions.
Implementation Method 1
the flow distributor is configured to create a backpressure in the interior chamber of the filtering element to the wash flow from the filtrate chamber
Implementation Method 2
a porous tubular section, a bottom, an open top and an interior chamber configured to receive filtrate from the container
Data Source
AI summary
A pressure filter for treating liquor suspensions of a cellulose pulp mill, the pressure filter including a container having tubular filtering elements suspended in a horizontal plate, through which elements filtrate flows and the interior of which communicates with a filtrate chamber located above. The filtering elements collect on their outer surface precipitate that is arranged to be periodically removed by making the filtrate in the filtrate chamber travel counter-currently through the filtration surface of the filtering elements. The filtering elements are cleaned by wash liquid passing from the filtrate chamber into the filtering elements and through their filtration surface. The interior of the filtering elements is provided with a flow distributor above the middle of a filtering element for distributing the flow from the filtrate chamber onto the filtration surface of the filtering element.