Method of removing an article from a chamber having a reduced pressure therein

Claim 1

In a method of producing a low density foamed thermoplastic resin article by extruding a foamable thermoplastic resin into a chamber at subatmospheric pressure and withdrawing the foamed thermoplastic resin extrudate from said chamber into the atmosphere, the improvement comprising, providing a vacuum chamber with means to evacuate it, a barometric leg connected to said vacuum chamber and terminating in a pool of liquid open to the atmosphere, the density of the liquid being greater than the density of said foamed thermoplastic resin extrudate and the barometric leg having a conveyor therein extending from the vacuum chamber into said pool of liquid, conveying said extrudate from said chamber without substantial tension sufficient to deform said extrudate into said pool of liquid whereby said workpiece floats up into engagement with said conveyor and moving said extrudate with said conveyor into said pool of liquid and through said liquid out into said atmosphere, said conveyor having a relatively flat underside inclined at an acute angle to the horizontal such that friction between the workpiece and the conveyor is sufficient to cause said extrudate to move along with the conveyor through said pool of liquid.