Diaphragm Design Manual - Simrit

Glossary of TermsDiaphragm RelatedAs-Molded Position – Refers to the molded shape of a diaphragm. This shape is typicallydetermined by the system assembly requirements and or the diaphragm stroke requirements.Bead & Groove – The bead is a raised rubber ridge around a portion of the diaphragm (usuallyand ID hole or the OD trim) for the purposes of enhancing the seal. The groove is that portion ofthe hardware that accepts the bead and compresses it for the seal.Bias of the Fabric – The direction 45 o to the weave of the fabric.Bleed through – Refers to the movement of fabric – shown in red in Figure 23 below - towardthe pressure side of the diaphragm during the molding operation. This type of fabric movementcan expose the fabric to pressure, potentially causing a leak path from one side of the diaphragmto the other.Bore – See Cylinder Diameter.Figure 23 – Fabric Bleed ThroughConvolution – The portion of the diaphragm that is available to flex or move.Convoluted Diaphragm – Conversely to a Top Hat Diaphragm, a convoluted diaphragm has amolded in convolution and requires no hand shaping of the convolution before installation.Convolution Width – This is the distance between the inside diameter of the bore and theoutside diameter of the piston.Cornering – A fold or gathering of material within the convolution. The fabric weave, hardware,diaphragm shape or slack material can cause this phenomenon. Cornering normally results in© Copyright FNGP 200947