Dryer Air Recirculation Grid Protecting the Heat Exchanger
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Solution Overview
Problem
The complexity of modern rotary-drum laundry dryers' closed-circuit heat-pump systems makes assembly and maintenance cumbersome, as existing designs lack simplification and protection for heat exchangers from debris.
Innovation Solution
Incorporating a rigid, grid-like protective assembly within the air recirculating conduit downstream of the filtering assembly and upstream of the heat exchanger, which is unremovably fixed and designed to minimize airflow obstruction while protecting the heat exchanger from foreign objects, and utilizing a segmented air recirculating conduit housed within a lower supporting base that couples into an upper shell to secure the protective assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a closed-circuit heat-pump type hot-air generator is used to rapidly dry laundry, then drying efficiency is improved, but device complexity and maintenance difficulty increase
Solution Approach 1:
The patent combines the protective function with the existing filtering assembly by positioning it upstream of the heat exchanger within the air recirculating conduit. This integration adds protection without requiring a completely separate system, thereby improving reliability while controlling complexity.
Solution Approach 2:
The filtering assembly acts as an intermediary element between the drum environment and the heat exchanger. It captures fluff and lint particles before they can reach and damage the heat exchanger, thus protecting the critical component while maintaining system functionality.
2Reliability
If a filtering assembly is added to protect the heat exchanger from fluff and lint, then heat exchanger reliability is improved, but device complexity increases
Solution Approach 1:
The filtering assembly serves multiple functions: it filters fluff and lint from the air stream, protects the heat exchanger from debris accumulation, and maintains airflow efficiency. By combining these functions into a single component, the patent improves reliability without proportionally increasing complexity.
3Reliability
If a rigid protective assembly is fixed inside the air recirculating conduit upstream of the heat exchanger, then protection from foreign objects is improved, but airflow obstruction may increase
Solution Approach 1:
The protective assembly is designed with a grid-like structure that provides protection only where needed - upstream of the heat exchanger where debris accumulation is most harmful. The grid geometry allows airflow to pass through while blocking larger particles, thus providing localized protection without significantly obstructing the overall airflow.
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 configuration simplifies assembly and maintenance by preventing damage to heat exchanger fins and ensuring efficient airflow, thereby maintaining the dryer's performance and reducing the risk of heat transfer efficiency reduction.
Implementation Method 1
at least one heat exchanger located along the air recirculating conduit and structured to cool the moist air arriving from the rotatable drum so to cause the condensation of the surplus moisture inside the airflow
Data Source
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AI summary
Rotary-drum laundry dryer (1) comprising a revolving drum (3) structured for housing the laundry to be dried, a hot-air generator (6) structured to circulate a stream of hot air through said revolving drum (3), and a lower supporting base or socle (9) which is structured for resting on the floor and for housing at least part of the hot-air generator (6); the hot-air generator (6) in turn comprising: an air recirculating conduit (12) having its two ends connected to the revolving drum (3); air circulating means (13) which are located along the air recirculating conduit (12) and are structured to produce, inside the air recirculating conduit (12), an airflow (f) which flows through the revolving drum (3) and over the laundry inside the drum (3); and at least one heat exchanger (15) located along the air recirculating conduit (12) and structured to cool the moist air arriving from the rotatable drum (3) so to cause the condensation of the surplus moisture inside the airflow (f); a segment (12c) of the air recirculating conduit (12) extending across the lower supporting base or socle (9), and being structured so as to house said at least one heat exchanger (15) of the hot-air generator (6); the hot-air generator (6) additionally comprising air filtering means (18) located along the air recirculating conduit (12), upstream of said at least one heat exchanger (15), and a rigid, grid-like protective assembly (19) which is firmly fixed inside said segment (12c) of the air recirculating conduit (12), downstream of the filtering assembly (18) and upstream of the at least one heat exchanger (15), so to bar said segment (12c) of the air recirculating conduit (12) for preventing a generic hard foreign body to reach the heat exchanger (15).