Setra's Model 217 is designed for modular "Block" gas sticks and panels. The 217 is ideal for pressure measurement applications that require exceptional insensitivity to environmental extremes, such as temperature transients resulting from the flow of cold gas.
The Model 217, available with a C-Seal or W-seal down-mount pressure port, has a small swept sensor chamber for easy purgeability. All wetted parts are 316L VIM/VAR stainless steel passivated to 5 Ra (7 Ra. max.) finish, which eliminates surface irregularities and provides the proper surface chemistry for corrosion resistance, assuring contaminant-free gas distribution. Every sensor is mass spectrometer helium leak tested to 1 x 10-9 atm.cc/sec.
The top external zero and span adjustments complete this unique design for all UHP down-mount applications. Setra's patented variable capacitance sensor features a 316L stainless steel diaphragm and an insulated electrode plate. A variable capacitor is formed between the sensor body and the electrode plate. An increase in pressure causes a slight rounding of the diaphragm, which decreases the capacitance. The capacitance change is detected and converted to a highly accurate linear DC electric signal by Setra's unique custom integrated circuit, utilizing a patented charge balance principle. Setra’s entire Ultra-High Purity series is based on Setra's proven capacitive sensing technology with highly accurate and stable voltage or current output signals that are virtually EMI/RFI immune.