Pressure Filter Cylindrical Feed Conduit Pre-Settling
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Solution Overview
Problem
In pressure filters used for chemical pulp processing, solid matter often accumulates between filtering elements, disrupting the filtering operation and making it difficult to remove the solids cake efficiently, leading to inefficient use of the filtering container.
Innovation Solution
A cylindrical feed conduit is introduced below the filtering elements, allowing the suspension to settle before filtering, with a tangential inlet creating a swirling motion and deflector plates to guide the flow, and a conical pre-filtering extension to separate coarser solids, reducing clogging and improving solid separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If suspension is fed directly into the upper part near filtering elements, then filtering operation starts immediately, but solid matter accumulates between filtering elements disrupting operation
Solution Approach 1:
The feed conduit with funnel-shaped extension delivers suspension to the upper part where solid matter settles and forms a precoat layer on the filtering elements before actual filtering begins. This preliminary settling action prevents solid accumulation between elements during operation, maintaining both productivity and reliability
2Ease of operation
If feed conduit extends to center of container, then suspension distribution is improved, but solid matter still accumulates between closely located filtering elements
Solution Approach 1:
The feed conduit is positioned to deliver suspension specifically to the upper part near the filtering elements, creating a localized settling zone. The funnel-shaped extension concentrates flow to ensure proper distribution while the upper location allows solids to settle before reaching the filtering surface, preventing harmful accumulation between elements
3Productivity
If filtering elements are closely located to maximize filter capacity, then filter productivity increases, but solid matter accumulates between elements making removal difficult
Solution Approach 1:
By delivering suspension to the upper part where solids settle first, a precoat layer forms on the filtering elements before operation. This preliminary settling prevents solids from penetrating between closely located elements, maintaining high filter capacity while enabling easy solids removal during backflushing cycles
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 enhances filtering efficiency by pre-settling solids, reducing clogging, increasing filter capacity, extending filtration cycles, and decreasing maintenance costs, while minimizing alkali losses at chemical pulp mills.
Implementation Method 1
a tangential inlet creating a swirling motion and deflector plates to guide the flow, and a conical pre-filtering extension to separate coarser solids
Implementation Method 2
A cylindrical feed conduit is introduced below the filtering elements, allowing the suspension to settle before filtering
Data Source
Figure 1
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AI summary
The present invention relates to a pressure filter for thickening treating a solids suspension comprising a container having a feed conduit provided with a feed pump for introducing a suspension to be filtered under pressure and an outlet conduit for discharging the thickened suspension from the bottom of the container and a plurality of tubular filtering elements suspended from a horizontal support plate, through which elements filtrate flows and the interior of which elements communicates with a filtrate chamber located on the opposite side of the support plate, and the filtrate is arranged to be discharged during a filtering stage via a filtrate outlet conduit exiting from the filtrate chamber, and the filtering elements collect on their outer surface solid matter that is arranged to be periodically released by making the filtrate in the filtrate chamber pass counter-currently through the filtering elements and to settle onto the bottom of the container. A cylindrical piece is arranged in the container below the filtering elements and the feed conduit is connected to the cylinder for leading the suspension into the interior of the cylinder. The pressure filter is applicable for use at the causticizing plant of a chemical pulp mill.