A formed metal diaphragm for use in fluid pressure regulators includes a dome-shaped central portion and a convoluted shaped flexible area. The convoluted shaped flexible area includes a series of radially spaced elliptically shaped impressions in the diaphragm surface. The major elliptic axis of each impression is aligned with a radius emanating from the center of the diaphragm. The minor ellipse axis of the impressions is located on a concentric axis outward from the center of the diaphragm.

A diaphragm pump (1) has a shaped diaphragm (2) of elastic material. The central zone (3) of the diaphragm (2) is thickened in the direction of stroke and is surrounded by a flexible annular zone (5) held on the pump case by an external clamping edge (6). The central zone (3) of the diaphragm (2) is engaged by a connecting rod (11) with which the shaped diaphragm (2) is displaceable from a top to a bottom dead-centre position and vice versa. Radial ribs (19) as well as stabilizing ribs (19) extending in the circumferential direction are arranged on the underside (17) of the annular zone (5). Therefore a shaped diaphragm (2) is obtained which in the annular zone (5) is flexible about a circumferential line, but which nevertheless exhibits comparatively high flexural strength about a diametral line. Deformation of the shaped diaphragm (2) under vacuum is thereby reduced.

In a diaphragm pump apparatus having a first chamber and a second chamber divided from the first by a movable diaphragm, the diaphragm comprises on both sides annular surfaces, whereby the annular surface is rounded out and goes over into a conically tapering thickened area and the other annular surface is provided with a concavely curved rounded-out portion incorporated into the thickened area of the diaphragm. By means of this design it is achieved that even highly viscous media can be pumped with the diaphragm pump apparatus, that the diaphragm has a long lifespan and that trouble-free operation of the diaphragm pump apparatus is ensured.

An undulated diaphragm, which has an approximately circular, flat plate-shaped central portion and a peripheral portion composed of a series of alternate, approximately concentric convex and concave portions, is clamped between two undulated container members each having an approximately bowl-shaped recess. The recesses of the container members are each composed of a series of alternate, approximately concentric concave and convex portions, which are complementally formed to correspond to the approximately concentric convex and concave portions of the diaphragm when extended. When the pressure in one recess is raised, the diaphragm successively moves toward the other recess and finally comes in contact with the second recess completely and snugly fits thereto. When the pressure in the first recess is lowered, the diaphragm successively moves toward the first recess and finally comes in contact with the first recess completely and snugly fits thereto. Deformation of the diaphragm during movement is restricted by virtue of the elasticity and rigidity of the diaphragm and the structure thereof, which includes a series of alternate, approximately concentric convex and concave portions. Thus, the diaphragm regularly extends and contracts without causing local inversion of the direction of bending during the movement.

Fluid cooled diaphragms for diaphragm compressors are provided which utilize a multi-layer diaphragm with an upper or gas contacting later, and a bottom or lower layer, which has cooling grooves through which cooling fluid is circulated to reduce the diaphragm temperature. Additionally the upper surface of the diaphragm may be subjected to high loading to indent the surface and produce grooves for gas escape passageways. The gas contacting and grooved layer can be joined over part of the entire surface, or the grooved layer not connected to the other layer. Two or more layers may be used as required.