Rotating Scraper Filter for Continuous Wood Gas Cleaning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional filter devices for wood gasification struggle with maintaining continuous operation due to increasing flow resistance from filter cake buildup, requiring disruptive cleaning methods that interrupt gas flow and are space-intensive.
Innovation Solution
A scraper mechanism is integrated with the filter element, allowing for partial removal of the filter cake during operation without interrupting gas flow, utilizing a rotatable support cage and adjustable contact pressure for efficient cake removal, and automated operation based on pressure drop monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a filter cake builds up on the filter jacket to improve cleaning performance, then the cleaning effectiveness is improved, but the flow resistance increases and limits maintenance-free operation
Solution Approach 1:
The patent implements periodic removal of filter cake through a scraper system that operates at defined intervals or when pressure differential thresholds are reached. The control unit monitors the pressure differential across the filter element and activates the scraper mechanism periodically to remove accumulated cake, thereby maintaining optimal flow characteristics while preserving cleaning effectiveness during operational periods.
2Reliability
If a pulsed blow-off from the inside of the support basket is used to free the filter element, then the filter cake is removed, but the continuous flow of product gas is interrupted
Solution Approach 1:
The patent introduces an external scraper mechanism as an intermediary device that removes filter cake from the outer surface of the filter jacket without requiring internal blow-off operations. This external scraping system allows cake removal while the filter element remains in place and continues to filter gas, thus eliminating flow interruptions while achieving the cleaning objective.
3Reliability
If a cleaning brush is rotated around the filter element using a rotary arm with gear mechanisms, then the filter element can be cleaned, but the device complexity and space requirement increase considerably
Solution Approach 1:
The patent extracts the cleaning function from a complex rotary arm and gear system and implements it through a simplified scraper mechanism that rotates with the filter element itself. The scraper is directly coupled to the support basket rotation, eliminating the need for external rotary arms, gears, and complex drive mechanisms, thereby significantly reducing device complexity while maintaining cleaning effectiveness.
Solution Approach 2:
The patent merges the cleaning function with the existing rotation mechanism of the support basket. The scraper is positioned to contact the filter jacket and is driven by the same rotation that positions the filter element for operation. This integration combines two functions (filtering and cleaning) into a unified system, eliminating separate cleaning mechanisms and reducing overall complexity.
4Device complexity
If the support basket is made rotatable to enable scraper contact along a generating element, then the design is simplified and space is saved, but the mechanism for ensuring adjustable contact pressure must be structurally simple
Solution Approach 1:
The patent implements a dynamic contact pressure adjustment mechanism that allows the scraper pressure against the filter jacket to be varied during operation. The support basket rotation enables the scraper to maintain consistent contact along the generating element, while spring-loaded or adjustable mounting mechanisms provide the necessary pressure variation capability, balancing structural simplicity with operational flexibility.
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
Enables continuous operation of the filter device by maintaining optimal pressure drop and energy efficiency through automated filter cake removal, ensuring prolonged maintenance-free use with a compact and simplified design.
Implementation Method 1
the entrained solid particles are retained by the filter jacket and form a filter cake
Implementation Method 2
a scraper is provided in the product gas section, resting on the filter jacket along a generating element, and the scraper and support basket are rotatable relative to each other
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A device for cleaning product gas from a wood gasifier is described, comprising a housing (1) having a gas inlet (2) and a gas outlet (3), and at least one filter element (8) arranged between a product gas section (16) connected to the gas inlet (2) and a clean gas section (17) connected to the gas outlet (3). The filter element (8) includes a support basket (9) in the form of a hollow body of revolution formed by straight generating elements and a filter jacket (10) made of a nonwoven fabric, which rests against the outside of the support basket (9) and can be exposed to the product gas from the outside. To ensure advantageous cleaning conditions, it is proposed that a scraper (29) be provided in the product gas section (16), resting along a generating element on the filter jacket (10), and rotatable about the axis of rotation (28) of the support basket (9).