A pressure diffuser washer comprising: an outer wall, an inner wall adjacent to the outer wall, the inner wall defining annular baffle chambers between the outer wall and the inner wall, wherein each of the annular baffle chambers is configured to connect to a source of a wash liquid, a reciprocating screen assembly adjacent to the inner wall, the reciprocating screen assembly defining a first annular chamber between the inner wall and the reciprocating screen assembly, an area in the inner wall defining a gap associated with each of the annular baffle chambers, wherein the wash liquid from an annular baffle chamber flows through the gap into the first annular chamber, and an annular baffle screen plate covering the gap, wherein the annular baffle screen plate defines openings sized to prevent rocks and other large particulate debris from entering the annular baffle chambers.