THE ROLLING Rubber diaphragm CONCEPT CONQUERING FRICTION
The Rolling Rubber diaphragm is a tough, flexible seal with a unique configuration that permits relatively long piston strokes while completely eliminating sliding friction. Formed in the shape of a truncated cone, or top hat, the diaphragm is turned in on itself when installed so that, during the stroke, it rolls and unrolls alternately on piston skirt and cylinder wall. The rolling action is smooth and effortless, completely eliminating sliding contact and breakaway friction. With the outer flange clamped to the cylinder and the center fastened to the piston head, the forms a perfect barrier, preventing blow-by leakage and pressure loss.
Depending on the materials and geometry selected, can function effectively with applied pressures of 3000 pounds. Operating temperatures may range from –120oF to +600oF.highly resistant to oil, ozone, acids, alkalis, steam and other corrosive fluids. Rubber diaphragm material is essentially a layer of specially woven fabric, impregnated with a thin layer of elastomer. Total thickness is usually 0.015 to 0.045 inches. The fabric, which lends high tensile strength to the diaphragm, is designed to permit free circumferential elongation (allowing free rolling action) while preventing axial distortion. This eliminates stretching or ballooning during the stroke.
The flex life of the rolling Rubber diaphragm depends on operating pressures, amount of axial and cir- conferential stress applied during the stroke, and the materials which form it. In general, a properly installed will provide a life of millions of cycles. Because of its unique properties, the is widely used in controls and actuators requiring high sensitivity to small pressure changes and excellent accuracy and reproducibility.
They are also used where no leakage can be tolerated, and where more liberal machining tolerances can significantly reduce hardware costs. Typical products using the include: pressure regulators, linear actuators, demand valves, dashpots, measuring instruments, gauge protectors, air relays, etc. The applications for are found in every industry–automotive, agricultural, aerospace, medical, etc. For proper Rolling Rubber diaphragm selection the Design Parameter Sheet is an indispensable tool. The design format provides all the necessary data for correct diaphragm design.
