Flow Switches

Rheotherm flow switches provide reliable switch protection in all Inline flow switchtypes of liquid or gas service. From critical monitoring of extremely low flow process additives to loss of flow protection in large water or air lines, we can handle most flow switch applications. With no moving parts, long term reliability is assured.  Options for hazardous locations (intrinsically safe/explosion-proof) are available.

What Kind of Service?
You name it – all types of liquids and gases, big pipes or small lines, hot or cold. Contact Us about any application you have.

How Are They Installed?
Insertion flow switchOur in-line flow switches for monitoring flows in small lines are typically installed with standard tube fittings, but are optionally available with flanges, NPT, sanitary fittings, etc. Insertion probe flow switches for monitoring large (1” or larger) pipe flows are typically installed with 1” NPT or flange fittings. Can be used in vertical or horizontal lines. For most common applications, the sensor and electronics are an integral unit.

How Do They Work?
Our in-line sensors use a straight-through flow tube with a heated and an unheated RTD attached to the outside of the tube. The insertion probe flow sensors have one tip with a heated RTD and a second tip with an unheated RTD. With either sensor style, the temperature differential between the two RTDs provides the primary flow signal. At high flow rates, flow removes more heat resulting in a lower differential. At low flow rates, flow removes less heat so the differential is higher. Nothing touches the fluid but the metal sensor wall, and there are no mechanical parts to wear, stick or break. Trip points are field adjustable. More on Method of Operation (PDF)

Rheotherm sensor

Inline Sensor

Pipe and duct flow sensing

Insertion Sensor

 

What Models are available?
Model 100CS – Lowest cost industrial option.  Integral sensor/electronics with one SPDT relay.  Can be ordered with in-line or insertion probe sensor.

Model 100FS – Separate sensor and electronics with one SPDT relay.  Option for second relay for high and low set points.  Can be ordered with in-line or insertion probe sensor.

Model 400 – Integral insertion probe sensor and electronics; has nonlinear output signal option.Model 500 flow switch

Model 500 – Flow switch for certain general purpose applications; 24 VDC input power only.

 

How Do I Get One?
Submit your flow switch inquiry today using the form on this page, 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 switch point
  • Maintenance-free
  • Easy installation
  • Choice of wetted materials
  • Long-term reliability

 

  Standard Options
Temperature Process: 0 – 140°F
(-18 – 60°C)
Environment: 0 – 120°F
(-18 – 50°C)
Inline: -20 – 350°F
(-30 – 175°C)
Probe: -20 – 400 °F
(-30 – 200 °C)
Pressure 0 – 1,000 PSI Up to 30,000 PSI
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
  Standard Options
Line Sizes Inline sensor (flow range dependent):
– Capillary;
– 1/16”; 1/8”; 3/16”; 1/4”
– 3/8”; 1/2”; 5/8”; 3/4”; 1”
Probe sensor:
Pipe/Duct from 1.5” – 72”
(round, square, rectangular)
Other sizes via fittings/adapters
Process Connection Inline sensor: Plain tube stubs suitable for compression fittings
Probe sensor:
1″ MNPT
– MNPT;
– Tri-Clover (Sanitary);
– SS Flange (1/2” – 2”);
Most other fittings available
Wetted Material 316 SS – Hastelloy C-276®;
– Monel®;
– Alloy 20;
– Titanium;
– Tantalum;
– Inconel
  Standard Options
Enclosure Sensor:
– Inline – PVC
– Probe – NEMA 4X (junction box)
Electronics:
– Integrated – NEMA 4X Cast Aluminum
– Remote – NEMA 4
Inline sensor: Stainless steel
Remote electronics
:
– Stainless steel
– NEMA 7 Explosion-proof
Hazardous Environment Remote electronics with 100FS only
FM Approved for:
– Class I, Div. 1, Groups A,B,C,D
– Class I, Zone 1, IIB+H2 (US)
– Class II, Div. 1, Groups E, F, G
– Class III, Div. 1
Outputs Single SPDT Form C relay
(10A, 125 VAC)
Remote electronics with 100FS only
– Second independent SPDT relay
– DPDT relay
– Time delay on switch
Input Power 110/230 VAC ±10V 24 VDC ±4V (200 mA)

Inline Sensor Flow Capacities for Liquids

TUBE SIZE
FLOW RATE LIMITS C 1/16 1/8 3/16 1/4 3/8 1/2 5/8* 3/4* 1*
Extended Maximum 2 60 500 0.4 1 2.5 4.6 8 10 20
Normal Maximum 1 30 250 0.25 0.5 1 2 3.5 4.5 8
Normal Minimum 0.03 0.8 6 0.008 0.01 0.03 0.05 0.2 0.3 0.5
Extended Minimum 0.007 0.05 3 0.002 0.006 0.01 0.02 0.07 0.1 0.2
cc/min GPM

*Limited applications. Consult Factory


Inline Sensor Flow Capacities for Gases

TUBE SIZE
FLOW RATE LIMITS C 1/16 1/8 3/16 1/4 3/8 1/2 5/8 3/4 1
Extended Maximum 0.027 1.25 5 11 20 45 80 125 180 320
Normal Maximum 0.017 0.75 3 7 15 34 70 109 160 280
Normal Minimum 0.0017 0.02 0.1 0.2 0.4 0.9 1.6 2.5 3.6 6.4
Extended Minimum 0.0009 0.0017 0.05 0.1 0.2 0.5 0.8 1.2 2 3.2
SCFM

1
2

Probe-type Sensor Flow Capacities for Gases

NPT/2I
VELOCITY LIMITS (ft/min) Liquid* Gas
Maximum 150 25,000
Minimum 0.5 25

*Liquid Applications limited to Flow Switches only

 

pdf (1)  Product Brochure
word Rheotherm Flow Application Data Sheet
(download document)
pdf (1) Rheotherm Method of Operation
pdf (1) Standard Dimensions Insertion Probe Sensor
pdf (1) Rheotherm Sensor Selection Guide
pdf (1) Standard Dimensions Inline (TU/TUL) Sensor
pdf (1) Rheotherm Model Selection Guide
pdf (1) Model 500 Flow Switch Product Brochure
pdf (1) Rheotherm Model 100CS Product Manual
pdf (1) Rheotherm Model 100FS Product Manual

 

Request a Quote

Required fields are indicated with an ‘*’Name*

Email*

Phone

Company

City, State/Prov.

Fluid*

Flow Range* (incl. units)

Fluid Temp.* (indicate °F/°C)

Max. Pressure* (incl. units)

Continuous or Batch Flow*
 Continuous Batch
Batch/Pulse Time

Switch Setpoint*

Pipe/Duct/Size*

Process Fittings

Flange Size/Rating

Input Power*

Desired Output* (ctrl-click for multiple)
Additional Requirements
(Hazardous environment, certificates, etc.)