01
No paddle to stick
A sealed thermal probe has no moving vane or paddle, reducing wear and avoiding the mechanical jamming modes common in contaminated or scaling service.
FGP70 / Thermal electronic flow switch
Low-flow protection without moving parts.
A compact thermal-dispersion flow switch for adjustable flow monitoring in water, hydraulic oil, cutting fluid, compressed air, and compatible gas lines.
- Water velocity
- 1–150 cm/s
- Oil velocity
- 3–300 cm/s
- Outputs
- Relay / PNP / NPN
- Protection
- IP67
Flow state, clearly indicated
Protect pumps and cooling circuits before flow is lost.
The FGP70 uses calorimetric thermal dispersion to monitor flow velocity and switch a control output when the adjustable threshold is crossed.
02
Adjustable set point
The switching threshold is continuously adjustable across the selected medium range, helping one platform fit different operating conditions.
03
Visible operating state
The LED status bar shows low flow, approach to set point, and stable flow above the threshold at the sensor.
04
Machine-control outputs
Relay, PNP, and NPN output choices integrate into pump protection, permissive, alarm, and interlock logic.
Technical specification
Select the right configuration.
Published values represent the available FGP70 platform. Final probe, material, pressure, temperature, output, hazardous-area, and media selections should be confirmed for the application.
- Measuring principle
- Calorimetric thermal dispersion
- Water range
- 1–150 cm/s
- Oil range
- 3–300 cm/s
- Air / gas range
- 20–2,000 cm/s
- Set point
- Continuously adjustable across the applicable range
- Repeatability
- ±3% of set point
- Response time
- 1–10 seconds, media-dependent
- Power supply
- 24 VDC ±10%; 19–36 VDC option
- Switch outputs
- SPDT relay, PNP, or NPN
- Medium temperature
- −20 °C to +85 °C standard; −40 °C to +150 °C optional
- Pressure rating
- Up to 2.5 MPa standard; higher-pressure configuration by review
- Process connections
- G1/2, G3/4, 1/2 NPT, sanitary tri-clamp, or flange
- Probe and wetted material
- SS316L standard; 60 mm, 150 mm, or custom insertion length
- Electrical connection
- M12 connector or cable gland
- Ingress protection
- IP67
Configuration paths
Built around the machine, not a shelf number.
Medium and velocity
Start with water, oil, or gas service and the normal, warning, and low-flow velocity conditions.
Probe geometry
Choose a short, extended, or custom probe around line size, wall thickness, and insertion depth.
Switch signal
Match relay, PNP, or NPN logic to the PLC input and machine fail-safe strategy.
Environment
Review process pressure, temperature, corrosion, washdown, sanitary, and hazardous-area requirements before selection.
Application fit
Flow-loss interlocks where equipment depends on circulation.
Use the switch as a permissive or alarm when pumps, bearings, tooling, heat exchangers, or hydraulic equipment depend on minimum liquid or gas movement.
01Hydraulic power-unit return and cooling loops
02Pump dry-run and low-flow protection
03Lubrication headers
04Machine-tool cooling circuits
05Chillers and heat exchangers
06Compressed-air and purge lines
Start with the operating conditions
Define the flow condition that protects the equipment.
Share the medium, line size, pressure, temperature, normal flow condition, desired trip point, process connection, and control input. Firelands will help configure the FGP70 around the circuit.