Combine Harvester Rotary Screen Seal for Debris-Resistant Cooling
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Solution Overview
Problem
Existing rotary screens in combine harvesters suffer from debris ingress due to imperfect seals between the rotating and stationary parts, leading to reduced cooling efficiency and wear of the brush seals.
Innovation Solution
A rotary screen design featuring a brush seal with a radially outwardly extending annular brush and a tapered seal region that overlaps the brush, protecting it from large debris and allowing it to maintain sealing functionality despite wear, with a filtering seal that deforms to adapt to brush wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a brush seal is used between the rotating screen and stationary plate, then sealing performance is improved, but the brush is damaged by large debris and suffers wear over time
Solution Approach 1:
The brush seal is nested inside the rotary screen member, which acts as a protective outer shell. This nested configuration allows the rotary screen to shield the brush from direct contact with large debris while still maintaining the sealing function through the brush's contact with the tapered inner surface of the screen.
Solution Approach 2:
The rotary screen member is positioned in advance to provide protective coverage over the brush seal before debris can reach it. The screen's radial extension creates a preliminary barrier that intercepts large particles, preventing them from damaging the brush while allowing the brush to maintain its sealing contact.
2Reliability
If the brush is positioned to contact the stationary plate for sealing, then sealing is achieved, but the brush is exposed to large debris and prone to damage
Solution Approach 1:
The brush is nested within the rotary screen member's protective envelope, allowing it to perform sealing contact with the tapered inner surface while being shielded from external debris by the screen's radial extension.
Solution Approach 2:
The rotary screen member acts as an intermediary protective element between the harmful debris and the vulnerable brush seal. It provides a radial barrier that filters out large particles while allowing the brush to maintain its sealing function through contact with the screen's tapered inner surface.
3Reliability
If the seal region is made tight to prevent debris ingress, then cleaning efficiency is improved, but the brush wears faster due to increased contact pressure
Solution Approach 1:
The tapered seal region creates a dynamic sealing interface where the contact pressure is distributed along the slope rather than concentrated at a single point. This dynamic geometry allows the brush to maintain sealing contact while reducing localized wear, extending service life.
Solution Approach 2:
The tapered geometry of the seal region changes the contact parameters by distributing pressure along the slope. This parameter modification allows effective debris prevention through maintained contact while reducing peak stresses that would otherwise accelerate brush wear and extend component life.
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 design effectively prevents debris ingress while maintaining sealing performance over the life of the brush, enhancing cooling efficiency and reducing maintenance needs.
Implementation Method 1
a radially outer surface of the brush contacts an inner surface of the seal region to form a seal
Implementation Method 2
a rotating filter mesh through which an air flow is drawn and delivered downstream
Data Source
Figure 1~2
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AI summary
A rotary screen (112) is provided for cleaning an air flow for use by a combine harvester, for example for use by a cooling system. An annular brush (124) is used to provide a seal between a rotating screen member (112) and a static plate (114). The brush (124) extends generally radially outwardly from a support (122) towards the rotary screen member (112), which is fitted around the brush (124) so that a radially outer surface of the brush (124) contacts an inner surface of a seal region (130) of the rotary screen member (112). The seal region (130) tapers radially outwardly towards its axial end and also overlaps the brush (124). In this way, the brush (124) is protected from damage and also has a long lifetime because it still performs its sealing function even after experiencing wear.