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Gas Low Flow Meters
Gas Low Flow SensorsRheotherm low gas flow meters provide an easy-to-use technology for measuring gas flow in small lines - typically 1” or smaller at flow rates from a few hundred SCFM down to 25 SCCM. (For flow measurement in larger pipes and ducts, click here). These meters give a repeatable reading in mass or standard volume with no external temperature or pressure correction needed. With no mechanical parts, they are reliable and easy to maintain. Options for hazardous locations (intrinsically safe/explosion-proof) are available.
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What Can We Measure?
Continuous flow of most gases, including corrosive and explosive gases. Our flow meters have been used for everything from hydrogen to uranium hexafluoride. Electropolished sensors are available for ultrahigh purity gases. Contact Us about any application you have.
How Are They Installed?
These are in-line flow sensors typically installed with standard tube fittings, but optionally available with flanges, sanitary fittings, etc. Any orientation is acceptable, except vertical with flow going down. With some models the electronics are integral to the sensor, and other models have a separate electronics enclosure to install, up to 200 feet from the sensor. Electronics Options
What Is the Turndown Ratio?Typical calibration ranges are 10:1 (options up to 200:1), with good accuracy over the entire range. The sensors cannot be damaged by overranging.
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How Do They Work?
Our low flow meters use either a straight-through or looped flow tube with a heated and an unheated RTD attached to the outside of the tube. The temperature differential between the two RTDs provides the primary flow signal: at high flow rates the differential is lower as flow removes more heat, and at low flow rates the differential is higher, as flow removes less heat. Nothing touches the fluid except the flow tube wall, and there are no mechanical parts to wear, stick or break. More on Method of Operation (PDF)How Do I Get One?
Submit your inquiry today to send us the application data to review, or visit our contact us page for telephone, fax and email information.
TU and TUL Sensor Specifications:
| Standard | Options | |
|---|---|---|
| Service | Most gases | |
| Wetted Surface | 316 SS | Alloys 276, 200, 400, 600, 800, 20; 316L SS, titanium, tantalum, quartz |
| Turndown Ratio | 10:1 | 100:1 |
| Process Connection | Tube stubs | Flanges, NPT, sanitary, other |
| Max. Temperature | 140ºF (60ºC) | Up to 350ºF (177ºC) |
| Max. Pressure | 500 - 1,000 psi | 5,000-10,000 psi |
| Location | General purpose | Hazardous (CL I, Div. 1, Grp BCD) |
| Sizes | C, 1/16, 1/8, 3/16, 1/4, 1/2, 3/4, 1 | Consult factory |
| Accuracy (with electronics) | +/- 1% of reading | |
| Repeatability | +/- 0.5% |
TU and TUL Sensor Flow Rates (Typical calibration is for 10:1, up to 200:1, range within these limits):
| Flow Rate | Tube Size | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| C | 1/16 | 1/8 | 3/16 | 1/4 | 3/8 | 1/2 | 5/8 | 3/4 | 1 | |
| Maximum-SCFM (SLPM) | .027 (.7646) | 1.25 (35.4) | 5.0 (142) | 11 (311.5) | 20 (566.3) | 45 (1274) | 80 (2265) | 125 (3540) | 180 (5097) | 320 (9061) |
| Minimum-SCFM (SLPM) | .0009 (.0255) | .0017 (.0481) | .05 (1.416) | .1 (2.832) | .2 (5.664) | .5 (14.2) | .8 (22.7) | 1.25 (35.4) | 2 (56.6) | 3.2 (90.6) |
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