Abstract: A unitary diaphragm assembly for use in conventional flush valves. The diaphragm assembly has a flexible diaphragm which includes a seating portion and a mounting portion at the outer peripheral edge. A flow ring is positioned adjacent to the seating portion of the diaphragm. An elongated barrel member extends from the diaphragm in a longitudinal direction and includes a plurality of radial guides positioned circumferentially around the outer surface of the barrel member along a portion of the length of the barrel member. A second embodiment has a flexible diaphragm connected to a cylinder slide. The cylinder slide includes a longitudinal barrel member with a relief valve positioned in the interior of the lower portion of the barrel member.