Partially preloaded pump diaphragms

摘要

A partially preloaded diaphragm (10) having an outer attachment portion (12) defining a first plane (P) and disposed about an axis (21) substantially perpendicular to the first plane. An inner attachment portion (16) is disposed substantially perpendicular to the axis of the outer attachment portion and defines a second plane (C). The inner attachment portion is movable away from the outer attachment portion into a fully extended pumping position defining a third plane (F). The first plane and the second plane are spaced at a distance to define a preload distance (PC) when the diaphragm is at rest, and the first and third plane are spaced to define a pump stroke distance (PF) when the diaphragm is fully extended. The preload distance is from about 25 percent to about 85 percent of the pump stroke distance. <IMAGE>