KROHNE Group – Company History

The Start

In 1921 Ludwig Krohne began to produce variable area flowmeters in Duisburg, Germany. The company moved from rented facilities to company-owned buildings in 1936. These were destroyed during the 2nd World War. As Ludwig Krohne and his son Karl both lost their lives during and in the aftermath of the war, Ludwig's wife Anna run the company during post-war years.

Starting again

In 1949, Anna Krohne asked her 28 year old grandson Kristian Rademacher-Dubbick to join the company.
He soon took over responsibilities and under his leadership KROHNE – with an initial workforce of only 8 people - grew to become a leading and one of the most innovative companies for flow measuring devices.

The Generation Change

In 1979, Kristian Rademacher-Dubbick relinquished his position of Managing Director and became Chairman of the Board of Directors.
He could still be seen regularly in many KROHNE facilities, and he gladly followed the outstanding development of the company in the recent years.
Kristian Rademacher-Dubbick died in 2014 at the age of 92 years in Duisburg.


Managed by Michael Rademacher-Dubbick (Controlling and Human Resources) and Stephan Neuburger (Sales and Marketing), KROHNE has advanced from an instrument manufacturer to a solution provider while still being an independent company owned by the Rademacher-Dubbick family.

The portfolio has been continuously expanded with complete measuring solutions and additional services to be seamlessly integrated in modern process control concepts, giving the customer as much information about the process as possible.

At the same time, new markets and industries could be won as customers to secure growth and independance from developments on single markets.

KROHNE milestones in measuring technology and industry-specific solutions and services

1921 LUDWIG KROHNE & SOHN is founded: Ludwig Krohne starts manufacturing variable area flowmeters in Duisburg, Germany, to measure the flow of air, gases and liquids.
1952 The first electromagnetic flowmeter (EMF) for industrial measurement is launched
1953 Precision forming of cylindrical glass tubes into high accuracy tapered measuring tubes
1954 First inductive transducers for variable area flowmeters that allows for remote transmission of readings
1955 Production of mechanical level meters for measuring liquids in tanks and containers begins
1959 Level indicator with float and magnetic coupling
1960 Introduction of an accurate conversion method for variable area flowmeters, subsequently adopted as VDI Code
1966 Construction of the world's largest calibration rig for volume flow in Sliedrecht/Netherlands
1972 Development of the pulsed DC field for electromagnetic flowmeters
1978 Development of double-beam ultrasonic flowmeters
1979 Construction of a larger and more accurate volume flow calibration rig in Sliedrecht/NL
1980 First delivery of an ultrasonic flowmeter to Shell for crude oil measurements
1981 First EMF with measuring tube made of oxide ceramics and sintered platinum electrodes
1985 Development and production of Coriolis mass flowmeter starts
1989 Presentation of the first FMCW radar level meter for process tanks, pioneering the use of radar level measurement technology in process applications
1994 First straight-tube Coriolis mass flowmeter
1995 First TDR guided radar level meter
1996 First electromagnetic flowmeter for partially filled pipes (TIDALFLUX).
1996 First ultrasonic custody transfer meter for liquids (ALTOSONIC V)
2000 Installation of the world’s most precise volumetric calibration rig for flowmeters up to DN 3000/120" with a certified accuracy of 0.013 %
2000 First 2-wire FMCW radar level meter
2001 First 2-wire electromagnetic flowmeter with full process application compatibility and intelligent power optimization
2002 New generation of Coriolis mass flowmeters with straight tubes (OPTIMASS series)
2003 First 3-beam ultrasonic flowmeter for the chemical industry (UFM 3030)
2004 New generation of OPTIFLUX electromagnetic flowmeters with built-in diagnostics for process, accuracy and meter integrity
2004 New generation of non-contact and guided radar level meters with a unique wizard-driven operating concept (OPTIWAVE and OPTIFLEX series)
2005 First presentation of analysis instruments for the water industry
2006 First 2-wire vortex flowmeter with integrated pressure and temperature compensation (OPTISWIRL 4070 C)
2006 KROHNE acquires swedish temperature company INOR who invented the headmounted transmitter for thermometers in 1974
2008 First 12-chord ultrasonic gas flowmeter for custody transfer applications with compensating and diagnostic functions (ALTOSONIC V12)
2008 Launch of complete analysis portfolio with digital analytical sensors and systems for wastewater treatment plants (OPTISENS and OPTISYS series)
2008 Launch of turbidity measuring system with unique cuvette calibration and ultrasonic cleaning for easy calibration and low maintenance costs
2009 Introduction of the Drop antenna for OPTIWAVE radar level meters: its ellipsoidal shape prevents from product deposits in dusty or humid atmospheres
2010 First EMF with rectangular cross-section to allow for installation without straight inlets and outlets (WATERFLUX)
2010 First temperature transmitter with dual sensor input in 4-wire connection
2010 KROHNE is the first manufacturer to offer a standardised operating and service concept for both flowmeters and analytical instruments
2011 Implementation of SmartSense insulation resistance monitoring to detect cracks in the thermowell integrated in temperature transmitters
2011 First inline spectroscopic analysis system for continuous inline measurement of protein/fat/lactose/total solids, free fatty acids (FFA) and chemical oxygen demand (COD) (OPTIQUAD series)
2012 Analytical sensor range specially suited for food & beverage processes is introduced
2012 Introduction of OPTIBAR P 3050 C compact pressure transmitter
2013 Unique PP/PTFE Wave Horn antennas for the use of OPTIWAVE radar level meters in corrosive environments
2013 First 2-wire digital analysis sensor portfolio with integrated transmitter technology and direct connection to control system (SMARTSENS series)
2014 First ultrasonic flowmeter for biogas applications with direct measurement of methane content (OPTISONIC 7300 C Biogas)
2014 Release of OPTIBAR DP 7060 differential pressure transmitter
2014 First Vortex flowmeter with integrated gross and net heat measurement for hot water (condensate) and steam
2015 Complete OPTIBAR series of pressure transmitters, diaphragm seals, primary elements and accesories is released