| 摘要 |
An isolator for use in pressure transmitters for isolating the process fluid being sensed from a sensor, comprises an isolating diaphragm that is thin, and made of a suitable corrosion resistant metal, such as tantalum, and which must be anchored to an isolator housing made of a substantially different metal such as stainless steel. Tantalum is very resistant to corrosion, and is a high melting point metal, which is substantially higher than the material comprising the sensor housing so direct welding is virtually impossible. The present invention relates to securing a support ring of the same metal as the diaphragm surrounding the cavity formed for the isolator fluid, preforming a thin metal diaphragm made of the selected material, and then welding the diaphragm and a ring overlying the diaphragm directly to the support ring. Using a support ring that is separately secured in place on the isolator body permits the welding temperature to be raised sufficiently for fastening the high melting point components (tantalum) together without damaging the sensor housing.
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