Setra's Model 223 ultra-high purity pressure transducer is designed for the most demanding specialty gas monitoring and control applications, where construction integrity, purity and performance cannot be sacrificed.
The 223 has a small, streamlined sensor chamber for easy purgeability. The sensor is designed to provide superior mechanical and thermal stability, especially in transient temperature conditions resulting from flowing gases. Isolation of the sensing element from the pressure fitting virtually eliminates any torque effect.
The superior mechanical and thermal stability is achieved through Setra's patented variable capacitance sensor. Its fundamentally simple design features a 316L VIM/VAR stainless steel sensor passivated to 5 Ra (7 Ra. max.) finish, which eliminates surface irregularities and provides the proper surface chemistry for corrosion resistance, and an insulated electrode plate fastened to the center of the sensor diaphragm, forming a variable capacitor. As pressure increase or decreases the capacitance changes. This change in capacitance is detected and converted to a linear analog signal by Setra's unique electronic circuit. Various tube diameters are available with optional face seal fittings. Sturdy construction allows for trouble-free installation and high tolerance of system torsion and welding effects, providing confident installations.
Model 223 transducers are able to endure bakeout to 185°F (85°C), without affecting calibration. Every sensor is mass spectrometer helium leak tested to 1 x 10-9 ATM.CC/sec. This ultra-high purity series is based on Setra's proven capacitive sensing technology and the highly accurate and stable voltage or current output signals are virtually EMI/RFI immune.
After manufacture and assembly, Setra's Ultra- High Purity pressure transducers are flushed with deionized water, purged with high-purity heated nitrogen, baked, double bagged, backfilled with nitrogen and sealed, prior to shipping.