Vacuum Belt Filter Capillary Element Underpressure Maintenance
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Solution Overview
Problem
Existing vacuum belt filters require continuous vacuum feed to maintain underpressure, leading to high energy consumption and short service intervals, and they often suffer from air leakage and inefficient cake drying due to the need for extensive rubber belts and complex maintenance.
Innovation Solution
A vacuum belt filter design featuring capillary filters and a vacuum box that can maintain underpressure without a continuous vacuum source, utilizing a rotating suction arrangement with check valves to create and sustain underpressure along the belt, allowing for efficient liquid-solid separation with reduced energy consumption and extended service intervals, and enabling easy replacement of individual components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous vacuum feed is used to maintain underpressure, then underpressure is maintained, but energy consumption increases
Solution Approach 1:
The vacuum box creates underpressure in advance during the suction phase, and the check valve preserves this underpressure during subsequent phases without requiring continuous vacuum application. This preliminary creation of vacuum condition allows the system to maintain underpressure intermittently rather than continuously.
Solution Approach 2:
The check valve enables the vacuum box to maintain its own underpressure condition autonomously without external vacuum source intervention. Once underpressure is created, the check valve prevents backflow and maintains the vacuum state self-sufficiently during belt movement and cake drying phases.
2Area of stationary object
If rubber belts are used for extensive coverage, then filtration area increases, but air leakage occurs and maintenance complexity increases
Solution Approach 1:
The continuous rubber belt is divided into discrete vacuum boxes that can be independently sealed and pressurized. Each vacuum box acts as an independent filtration chamber with its own check valve, eliminating air leakage pathways between sections that plague continuous belt systems.
Solution Approach 2:
Different sections of the belt (individual vacuum boxes) can have different pressure states - some under vacuum for filtration, others at atmospheric pressure for discharge or washing. This localized pressure control prevents air leakage between zones while maintaining large total filtration area.
3Productivity
If continuous vacuum feed is used, then dewatering is maintained, but service interval decreases
Solution Approach 1:
The vacuum application is periodic rather than continuous - vacuum boxes are pressurized during suction phases, then isolated by check valves during transport and drying phases. This periodic operation maintains dewatering effectiveness while extending service intervals between maintenance cycles.
Solution Approach 2:
While individual vacuum boxes are isolated, the belt continues moving and processing material continuously. Multiple vacuum boxes operate in sequence, ensuring continuous productivity while each box can be maintained independently, extending overall service intervals.
4Ease of repair
If individual vacuum boxes are used, then maintenance ease increases, but device complexity increases
Solution Approach 1:
The system is segmented into modular vacuum boxes that can be independently removed and replaced. Each module contains its own filter element and check valve, allowing targeted maintenance without shutting down the entire belt system.
Solution Approach 2:
Each vacuum box serves multiple functions - filtration, vacuum maintenance, and independent isolation - reducing the need for separate systems. The check valve provides universal protection across all vacuum boxes, simplifying overall system design despite increased modularity.
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 solution achieves low energy costs, long service intervals, and efficient cake drying by maintaining underpressure without continuous vacuum feed, reducing air leakage, and allowing for flexible belt lengths and easy maintenance, thereby enhancing the overall efficiency and cost-effectiveness of the filtration process.
Implementation Method 1
A capillary filter refers to a filter the structure and/or the material of which enables a certain amount of liquid, such as water, to be retained in the filter by a capillary action despite a differential pressure formed by a gas surrounding the filter.
Implementation Method 2
the vacuum box being provided with an outlet (8) having a check valve (9) enabling a fluid flow from the inside space (3) of the vacuum box (2) to the outside of the vacuum box (2) for creating an underpressure in the vacuum box (2)
Data Source
Figure 1
Figure 2~3
Figure 4~8
AI summary
The present invention relates to vacuum belt filter comprising a belt (1) with a plurality of vacuum boxes (2), filter means being arranged to the vacuum boxes, drive means (4) for moving the belt (1), and a suction station (5) for creating an underpressure to the vacuum boxes (2) at the suction station (5). In order to enable liquid-solid separation at low energy costs and long service interval of the vacuum belt filter, the filter means is in the form of a capillary filter, each vacuum box (2) being provided with such a filter and each vacuum box being provided with an outlet (8) having a check valve enabling a fluid flow from the inside space of the vacuum box to the outside of the vacuum box for creating an underpressure in the vacuum box when the suction station (5) is connected to the vacuum box, said check valve preventing a fluid flow through the check valve to the inside space of the vacuum box when the vacuum box leaves the suction station (5). The invention relates also to a filter element, a vacuum box (2) and methods for servicing a vacuum belt filter and a method for liquid-solid separation by means of a belt filter.