NOVELTY - The method involves providing a feedstock. A flow of the feedstock is formed. The flow of the feedstock is delivered to a gasifier such that the flow of the feedstock provides an airtight seal to the gasifier. The feedstock is delivered to an auger to form the flow of the feedstock. The flow of the feedstock is advanced from the auger to a water-cooled outlet tube (30) for delivery to the gasifier. Water is circulated around the tube in a channel (110) between an inner wall (38) and an outer wall (48) of the tube, where the tube is split into a first tube section and a second tube section.    USE - Method for providing a feedstock material e.g. solid waste material (claimed) such as municipal solid waste (MSW), to gasifier i.e. plasma furnace. Can also be used for providing organic materials, fossil-based carbonaceous materials e.g. coal and petroleum coke, biomass materials and waste-derived feedstocks e.g. wood, plastic, aluminum, refuse-derived fuel (RDF), agricultural and industrial wastes, sewage sludge, switch grass, various crop residues and black liquor, to counter-current fixed bed, co-current fixed bed, fluidized bed, entrained flow bed and free radical bed.    ADVANTAGE - The method enables isolating an area or flow of material. The method enables creating the airtight seal with a flow of a continuous plug of the material to the gasifier. The method allows a plug of material that is airtight, which prevents airflow through the tube. The method allows a blade to be closed for maintenance functions, power shut downs and tube burn back protection in a gasification system to prevent burning of feedstock material back through the screw extrusion system. The method enables providing the feedstock material to the gasifier in an improved manner.    DESCRIPTION OF DRAWING(S) - The drawing shows a side elevational view of a system for extruding a feedstock material.    System for extruding feedstock material (10)    Water-cooled outlet tube (30)    Inner wall of outlet tube (38)    Outer wall of outlet tube (48)    Channel (110)