Container vacuum capping method

Claim 1

A METHOD OF TREATING A CONTAINER FILLED WITH POWDERY-LIKE MATERIAL TO OBTAIN LOW OXYGEN CONTENT IN THE SAME, SAID METHOD COMPRISING COVERING THE MOUTH OF THE CONTAINER WITH AN INVERTED CUP-SHAPED FILTER MEMBER WHICH DEFINES A BAROMETRIC LEG OF FROM ABOUT 11/2 TO 3 INCHES IN HEIGHT SO AS TO PROVIDE A SUBSTANTIAL AREA ABOVE THE HEAD SPACE IN WHICH THE MATERIAL MAY EXPAND UPWARDLY, EVACUATING THE CONTAINER THROUGH THE FILTER MEMBER WITH THE EVACUATION BEING CARRIED OUT TO AN EXTENT TO ESTABLISH AT LEAST ABOUT 25 INCHES OF MERCURY VACUUM, REDUCING THE VACUUM TO NO LESS THAN 10 INCHES OF MERCURY VACUUM BY INTRODUCING THEREIN AN INERT GAS, AGAIN EVACUATING THE CONTAINER THROUGH THE FILTER TO ABOUT 25 INCHES OF MERCURY VACUUM, AGAIN REDUCING THE VACCUUM TO NO LESS THAN 10 INCHES OF MERCURY VACUUM BY INTRODUCING THEREIN AN INERT GAS, AND HERMETICALLY CAPPING THE CONTAINER.