Process and apparatus for removing water from fibrous web using oscillatory flow-reversing air or gas

A process and an apparatus for removing water from a fibrous web are disclosed. The process comprises providing a fibrous web having a moisture content from about 1% to about 99%; providing an oscillatory flow-reversing impingement gas having a pre-determined frequency; providing a gas-distributing system comprising at least one discharge outlet designed to emit the oscillatory flow-reversing impingement gas onto the web; and impinging the oscillatory flow-reversing gas onto the web through the plurality of discharge outlets, thereby removing moisture from the web.The apparatus comprises a web support designed to receive a fibrous web thereon and to carry it in a machine direction; at least one rotary valve pulse generator designed to produce oscillatory flow-reversing air or gas; and at least one gas-distributing system in fluid communication with the pulse generator for delivering the oscillatory flow-reversing air or gas to the web. The gas-distributing system terminates with at least one discharge outlet juxtaposed with the web support such that the web support and the discharge outlets form an impingement distance therebetween.