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SB mechatronic flow meters

Technology overview

The SB mechatronic flow meter works on the principle of a spring supported piston. Flowing liquids lift the piston and the position of the piston is monitored by a magnetic sensor. The spring forces the piston to its original position with decreasing flow and the built-in check valve prevents back flow.

Diagram explaining flow sensor with mechatronic technology for measuring media flowing by the sensor

This design means the meter can be installed without regard to inlet/outlet piping requirements. Because a magnetic sensor is detecting the piston position, response time is ≤ 10 msec. Since flow is typically relatively stable, there is very little flexing of the spring. The meter has been successfully tested to 10 million cycles without any detectable wear.


Machine tool

Coolant is used to keep cutting tools cool and remove chips from the part. It is turned on and off frequently during the cutting cycle. How important is it for your flow switch to respond quickly to the change in coolant flow?

The SB flow meters use a magnetic sensor to detect the position of a piston. Response time is < 10 msec.

Industrial furnaces

Loss of coolant flow in industrial furnaces can damage components. What if your flow switch was unaffected by medium temperature changes?

The SB technology makes it immune to changes in medium temperature and pressure. Installation is easy with no inlet/outlet piping requirements.

Unlock sensor potential with IO-Link

With IO-Link, process sensors have the ability to transmit multiple sensor values.  Via IO-Link, the SB family can provide:

  • Current flow rate
  • Current temperature
  • Switching status


Q. What media curves are available for the SB?

A. Media curves are integrated for oil (below 46 cSt at 40 °C) and water solutions.

Q. How does the SB handle media more viscous than 46 cSt?

A. Generally, the more viscous the media, the higher the piston is pushed. Therefore, the measured flow rate is higher than actual. For an engineering fee and for an annual volume of 150+ pieces, we can provide custom calibration for oils up to 320 cSt. Please contact our service center at 800.441.8246 or email to info.us@ifm.com.


Q. How do solids in the medium affect the sensor?

A. Very small solids (up to 200 µm) such as metal swarf do not affect the sensor. For larger solids, a 200 µm filter should be installed upstream of the sensor. Media such as sand or quartz should be avoided as they can clog the piston.

Q. “Mechatronic”? Aren’t mechanical switches bad?

A. Fully electronic switch has no moving parts to stick or to wear over time like mechanical switches have. For the SB family, the sensing principle is electronic, so it has much better precision when setting a switch point, a smaller hysteresis and a very fast response time. The mechanical part of the sensor, the piston/spring assembly has been tested to > 10 million cycles. Additionally, flow is generally relatively stable, so there is typically very little motion of the spring.

Q. Is a frequency output the same thing as a pulse output for totalizing?

A. No. For totalizing applications, a pulse output is required.  A 24 VDC signal is sent every time a specified volume (e.g., 0.1 gallons, 1 ml, etc.) flows through the meter regardless of the flow rate. A frequency output provides a digital signal directly relatable to the flow rate. This digital signal can be further evaluated with counters, PLCs, etc. Frequency outputs are often used for mechanical flow meters like turbine meters. The rotational motion of the turbine, which turns according to the flow rate, is detected and converted into frequency signal. 

For meters with totalizing function, please refer to the SM and SU families.