| 摘要 |
<p>1481179 Making diaphragms stretching ITT INDUSTRIES Inc 1 Oct 1974 [1 Oct 1973] 42562/74 Headings B3A and B3E 42562/74 [Also in Division G1] A method of making a metal diaphragm 123 includes holding an annular edge portion 124 and applying a force to the centre portion 126 of the diaphragm approximately normal to it so as to stretch the diaphragm beyond its yield point. The diaphragm 123 is formed in a press, which embosses one face of it, and is preferably precipitation hardenable stainless steel or cobalt alloys and it may be plastics coated, the precipitation hardening being performed by any conventional manner. Prior to stretching the portion 124 is seam welded to a plate (109), Fig. 11 (not shown) of a differential pressure unit. The plate and diaphragm are held in a vice or jig and the force is applied by a mandrel 301, which has the same diameter as the centre portion 126, on the opposite face to the diaphragm's embossed face. The effect of stretching the diaphragm is to reduce its spring rate and to improve the linearity between pressure loading and deflection.</p> |
