Expert’s answer

Before we get in-depth about the OPTIFLUX 4000 lets first look at the general situation, when it comes to buying yourself a new magmeter.

When you start shopping for a new electromagnetic flow meter, you must pay attention to certain factors. Otherwise, your meter won’t work as well or last as long.

First, your product must have a minimum electrical conductivity. This value will depend on the model and brand, but usually, you’ll find it around five micro-Siemens per centimeter (μS/cm).

In the manual, it says for water you need an electrical conductivity of ≥ 20 μS/cm, with a standard of ≥ 1 μS/cm. I’ve had customers complain about the quality of their flow meters, and a quick check found the electrical conductivity too low. So make sure your equipment can handle your product, people!

OPTIFLUX 4000 liner
Courtesy of KROHNE


Liners protect the measuring tube, so you definitely want one of those.  Depending on the model, you can have a bunch of different materials to choose from. Of course, the chemical compatibility should match the product to avoid degradation that may shorten the life of your meter.

You should also check the minimum and maximum temperature supported by the liner. For instance, Teflon PTFE works better than PFA in nearly all applications, but PTFE supports a lower temperature. If your temp range doesn’t match, you need to jump to the more expensive PFA.

Here we have the list of liners available for the OPTIFLUX 4000 from KROHNE. If you want a different material, then you’ll need to contact your rep and ask.


  • DN2.5 to 15 > PFA
  • DN20 > PTFE
  • DN25 to 150 > PFA
  • DN200 to 1800 > ETFE


  • DN25 to 600 > PTFE
  • DN200 to 1800 > PU
  • DN200 to 3000 > hard rubber (Ex only)
  • Other materials > on request
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