Patent ID: 7338357
Filing Date: 2008-03-04
Classification: B60H

Abstract:
1. A fixed air circulation system for an off-highway vehicle having a cab body, a generally dust-tight operator's enclosure and work station within said cab body, and a cab door pivotally mounted on said cab body and adapted to open and close said operator's enclosure permit ingress thereto and egress therefrom, said circulation system comprising: a distribution plenum for distributing a combination of fresh air and recirculated air into said operator's enclosure; a heating and air conditioning core housing; a fresh air inlet port through said cab body; a fresh air filter arranged such that air passing through said inlet port also passes through said filter; a blower in air flow communication with said plenum and said core housing, said blower, core housing, fresh air inlet port and air filter arranged such that said blower causes fresh air to flow through said fresh air inlet port and air filter along a first air flow path through said core housing into said plenum and thence into said operator's enclosure; a second air flow path extending directly from said fresh air inlet port, through said air filter, into said cab enclosure; a bypass valve between said fresh air inlet port and said operator's enclosure, said fresh air bypass valve having a closed position allowing air to flow along said first air flow path and not along said second air flow path, and an opened position allowing air to flow along both said first and second air flow paths; and a purge control connected to said fresh air bypass valve and said cab door such that said fresh air bypass valve is activated to said opened position when said cab door is opened, and activated to said closed position when said cab door is closed.