Resonance screens are particularly useful in large and heavy screening installations of high capacity and output. They operate at high intensity and their fields of application range from large size screening to the screening of fines. Simple, rugged construction is a feature of Don Valley Resonance Screens which, combined with the large cross sectional area of the rubber parts, ensures long life. The working characteristics are capable of adjustment to provide the maximum screening efficiency for any given product. Two or more screen frames can be assembled in line to operate as one complete unit.