Bidirectional filter drier
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Solution Overview
Problem
Conventional bidirectional filter driers for HVACR systems are complex and costly, with designs that often reintroduce contaminants when refrigerant flow is reversed due to their cylindrical shape and check valve mechanisms.
Innovation Solution
A simplified, spherical bidirectional filter drier design featuring flexible filter elements on either side of a desiccant core, held in compression by supports within an outer shell, which deflects to create a compliant seal and ensure contaminants are captured on the core side during both flow directions, preventing re-introduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional cylindrical bidirectional filter drier with check valves is used, then bidirectional flow control is achieved, but the design complexity and cost increase
Solution Approach 1:
The patent removes the check valve mechanism from the filter drier design entirely. Instead of using mechanical check valves to control bidirectional flow, the invention uses the natural deflection of flexible filter elements against the outer shell to create flow directionality, thereby eliminating the complex valve mechanism while maintaining bidirectional functionality
Solution Approach 2:
Instead of using rigid check valves that mechanically open/close based on flow direction, the invention inverts the approach by using flexible filter elements that naturally deflect in response to flow pressure. The filter elements themselves become the flow control mechanism, reversing the traditional role of separate valve components
2Adaptability or versatility
If check valves with peripheral holes are used to direct flow, then bidirectional filtration is achieved, but the risk of contaminant re-introduction increases
Solution Approach 1:
The patent employs flexible filter elements that can deflect and seal against the outer shell. This flexibility allows the filter elements to dynamically respond to flow direction, creating a compliant seal that prevents contaminants from bypassing the filtration media and being re-introduced into the system during reverse flow
Solution Approach 2:
The filter elements serve dual functions: they filter contaminants during normal operation and simultaneously act as flow direction control mechanisms during reverse flow. The same flexible elements that perform filtration also deflect to block the circumferential pathway, eliminating the need for separate valve components and ensuring contaminants are never re-introduced
3Device complexity
If a simplified spherical design with flexible filter elements is used, then device complexity is reduced, but flow path control must be maintained
Solution Approach 1:
The patent uses dynamically responsive flexible filter elements that automatically adjust their position based on flow direction and pressure. During forward flow, the elements remain in their natural position allowing filtration; during reverse flow, they deflect against the outer shell to block the circumferential pathway, providing automatic flow path control without complex mechanical mechanisms
Solution Approach 2:
The flexible filter elements change their physical state and position in response to changes in flow pressure and direction parameters. This parameter-driven behavior allows the simplified spherical design to maintain effective flow path control, as the elements naturally deflect to the appropriate position based on the operational conditions
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 spherical design effectively filters contaminants in both flow directions without re-introducing them, reducing system complexity and costs while maintaining effective contaminant removal, ensuring the HVACR system's longevity and performance.
Implementation Method 1
The flexible filter elements and core assembly are held in compression by supports located on either side of the core and filter elements. The supports, filter elements and core are held in compression by the outer shell such that there is a space forming a circumferential pathway between the core and the outer shell. When fluid flows through the filter drier from the first opening to a second opening, an edge portion of the first filter element is deflected to open a pathway between the filter element and the outer shell. An edge portion of the second filter element is deflected against the outer shell to form a compliant seal that obstructs the pathway
Implementation Method 2
The function of a filter drier in a HVACR system is to remove harmful contaminants, such as moisture, acid, copper oxides, particulates, metal chips, wax-like compounds and the like from refrigerant in the system
Data Source
Figure 1
Figure 2~3
AI summary
A bidirectional filter drier has a generally spherical outer shell having a first opening and a second opening. The shell contains a desiccant core and first and second filter elements. The first filter element is on a first side of the core, adjacent the first opening, and the filter flexible element on a second side of the core adjacent the second opening. The first filter element and the second filter element control flow around and through the core depending on the direction of fluid flow through the filter drier.