Abstract: An isolator diaphragm is formed and connected to a support member so it will withstand periodic high pressure cleaning. Such periodic cleaning includes use of heated, concentrated cleaning solutions flowing under high pressure from a nozzle which moves rapidly over segments of an exposed surface of the isolator diaphragm. The present invention prevents isolator diaphragm failure precipitated by the substantially incompressible isolator fluid driven toward the perimeter of the diaphragm during cleaning operations. Such cleaning operations generate a separating force between the isolator diaphragm and diaphragm support. The isolator diaphragm has a peripheral wall portion bonded to a planar support surface and is formed to have an offset center region. The peripheral wall and center region are joined by a conical, inclined wall bounding the center portion. The support member has a correspondingly shaped recess with an inclined annular wall that supports the conical wall of the diaphragm.