Abstract: The present invention relates generally to on board inert gas generating systems, and more particularly, to an on board inert gas generating system having a fast warm up feature. Even more particularly, the present invention relates to a method and apparatus for quickly warming up a permeable membrane air separation system.

Abstract: A method and mechanism for controlling the material feed of a machine for chipping wood or brush. The machine has a pair of coacting feed rolls which feed material to be chipped into a rotating chipper that is driven by an engine of variable speed. Hydraulic motors for driving each of the feed rolls are actuated when the speed of the engine is at least a selected high level appropriate for efficient chipping. If the material is of a size or composition to load the engine below a selected low level adverse to efficient chipping, the hydraulic motors are interrupted to stop feeding of the material to allow the engine to return to an efficient chipping speed. When the engine has recovered to at least the selected high level, the hydraulic motors are reactivated to again feed material into the chipper.

Abstract: The guard unit for the cutter wheel of a stump removing machine has an upper member pivotally mounted on the machine for up and down pivotal movement, within defined limits, to maintain a shield member in a continuous covering clearance with the cutter wheel during a stump removal operation. A bottom member of the guard unit has a central portion and outwardly and upwardly inclined end portions. The central portion is rideable on the top surface of a stump during a cutting movement laterally of the stump and on a reversal of the lateral cutting movement an end portion is engageable with an edge portion of the top surface to position the central portion on the stump top surface.