Liquid Low Flow Meters
Rheotherm flow meters are an excellent, and often times the only choice for reliable liquid flow measurement at low flow rates. For flow rates from 1 gallon/year (10 cc/day) to a few GPM, they provide repeatable liquid flow measurement with little or no maintenance. Options for hazardous locations (intrinsically safe/explosion-proof) are available.
What Can We Measure?
Continuous flow of most homogeneous liquids with low or high viscosity as well as slurries. Our flow meters have been used to measure everything from liquefied gases to thick oils and pastes, corrosive chemicals, light hydrocarbons, water and water-based fluids – Contact us about any flow measurement application you have.
How Are They Installed?
Rheotherm flow meters incorporate 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 downward flow direction. With some models the electronics are integral to the sensor. Other models have a separate electronics enclosure that can be installed 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.
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 heat more readily. At low flow rates the differential is higher because less heat is removed. 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 Rheotherm inquiry today using the form on this page so we can review your application and prepare your quotation. You can also call or visit our Contact Us page for telephone, fax and email information.
- No moving parts
- Exclusive inline TU sensor
- Advanced signal processing electronics
- Field adjustable
- Easy installation
- Choice of wetted materials
- Long-term reliability
|Temperature||Process: 0 – 140°F
(-18 – 60°C)
Environment: 0 – 120°F
(-18 – 50°C)
|-20 – 350°F
(-30 – 175°C)
|Pressure||0 – 1,000 PSI||Up to 30,000 PSI|
|Calibration Ranges||– 10:1 Turndown
– 0.007 cc/min to 20 GPM
|– Up to 200:1 turndown;
– Four calibration channels available (for multiple flow ranges or fluids using the same sensor)
|Calibration Accuracy||± 1% of reading typical|
|Response Time|| 1 sec. ; 3 – 5 sec. typ.
(63% of range)
|Time constant/delay option|
|Repeatability||± 0.5% of reading|
(flow range dependent)
1/16”; 1/8”; 3/16”; 1/4”;
3/8”; 1/2”: 5/8”; 3/4”; 1”
|Other sizes via fittings/adapters|
|Process Connection||Plain tube stubs suitable for compression fittings||– MNPT:
– Tri-Clover (Sanitary);
– SS Flange (1/2″ – 2″);
Most other fittings available
|Wetted Material||316 SS||– Hastelloy C-276®;
– Alloy 20;
|Display||2 X16 backlit LCD with selectable display of:
– Mass/volume flow rate
– total accumulated flow
Integratd Electronics: NEMA 4X Cast Aluminum
Remote Electronics: NEMA 4
|Sensor: Stainless steel
– Stainless steel
– NEMA 7 Explosion-proof
|Hazardous Environment||Integrated electronics
– Class I, Div. 1, Groups B,C,D
– Class I, Zone 1, IIB+H2 (US)
– Class II, Div. 1, Groups E, F, G
– Class III, Div. 1
Same as above except addition of Group A using ISB
|Outputs||4 – 20 mA (flow rate) or Serial Burst with Flow Rate, Totalizer, and Fluid Temperature||– 0 – 10 or 0 – 5 VDC;
– Pulse (5 VDC open collector);
– HART (4-20 mA) ;
– SPDT relay;
– 4 to 20 mA temp
|Input Power||24 VDC ±4V
(200 mA – blind unit; 300 mA w/display option)
|110/230 VAC ±10V|
Inline Sensor Flow Capacities for Liquids
|FLOW RATE LIMITS||C||1/16||1/8||3/16||1/4||3/8||1/2||5/8*||3/4*||1*|
*Limited applications Consult Factory