125 Series Standard Unobtrusive Adjustable Flow Monitor

125 flow switch: wide adjustment range with minimal pressure drop

The 125 flow switch combines high resolution with a compact size. Because technicians can easily adjust the switch point in the field, this monitor offers maximum flexibility for systems with varying process conditions. In addition, the unique design with magnetic repulsion lets the fluid flow pass through the unit virtually unhindered.

Why the 125 series is the right choice

Thanks to the high-grade choice of materials (316 stainless steel, brass or Teflon®), engineers use the 125 flow switch in critical environments. The monitor performs excellently in the following applications:

• Welding systems: For monitoring shielding gas and cooling water.
• Analysers: For constant flow control of sample streams.
• Vacuum systems: For detecting minimal gas movements.
• Biochemical instruments: For reliable operation in laboratory environments.
• Chillers: For protection against flow loss in cooling circuits.

Innovative operation without springs

Unlike traditional sensors, the 125 flow switch uses magnetic repulsion to position the piston:

1. Magnetic levitation: A fixed magnet holds the magnetic piston in place by repulsion when there is no flow.
2. Flow response: As soon as medium flows through the unit, the piston moves against the magnetic force.
3. Switching: This movement activates a hermetically sealed reed switch. Your system immediately receives a signal when the set value is reached.
4. Reset: When the flow decreases, the magnetic repulsion pushes the piston back to the rest position.

Technical specifications 125-Serie

Installation and engineering support

Preferably mount the 125 flow switch vertically with the inlet port facing up for the standard range. We also strongly recommend using a 10 micron filter to keep the internal moving parts free of contamination.

Do you have an application with aggressive chemicals? Then we offer the Teflon® version for maximum chemical resistance. For systems where the flow/setpoint ratio is smaller than 10:1, you can also look at our 125 BP bypass series. Contact our specialists for technical advice or consult the documentation of manufacturer ChemTec.