Rheotherm flow sensors are a practical option for many high purity applications.
Rheotherm TU flow sensors have a unique design where the flow tube is a piece of unpenetrated tubing. This design allows use of electropolished ultra high purity tubing as the flow tube material. As an option, VCR fittings can be orbitally welded to the flow tube, or the sensor may be directly welded into the line. After factory calibration, sensors can be cleaned in a Class 100 clean room.
Gases metered into a process, or tracked for internal billing purposes, such as argon, oxygen, methane, hydrogen and helium have all been measured using this sensor design, at flow rates as low as a fraction of an SCFM. When required, the meters may be ordered with approved intrinsically safe sensors, which are suitable for use in all Class I areas.
Rheotherm advantage: electropolished wetted surface, high purity cleaning, zero internal impurities storage, intrinsic safety option
Some companies use Rheotherm flow meters in nitrogen lines so that different areas of the plant can be monitored for gas usage. These larger distribution lines require insertion probe sensors installed with threaded fittings. Rheotherm flow meters are used because they provide a reliable mass or standard volume flow output without requiring any external pressure or temperature correction.
Rheotherm advantage: easy installation, mass flow output, no external signal corrections
Fluid to Polishing Process
Rheotherm flow meters were chosen by a semiconductor company to measure the low flow rate of fluid to a polishing tool. With a calibrated range of 3-30 ml/min, the flow meters provide accurate measurement of fluid use, as well as a low flow relay to indicate when flow drops too low. To help maintain purity standards, the sensors were ordered with electropolished high purity tubing for the flow tube material.
Rheotherm advantage: low flow rate sensitivity, electropolished tubing, low maintenance