BW 25

Displacer level transmitter for heavy-duty level and interface applications

  • Continuous measurement of level, liquid-liquid interface or density at extreme process conditions
  • Measuring range: 0.3…5.5 / 1…18 ft
  • Density: ≥0.45 kg/l /≥28.1 lb/ft3
  • -40…+400°C / +752°F; -1…400 barg / -14.5…10000 psig

BW 25 – Version with aluminium housing

BW 25 Displacer level transmitter – Version with aluminium housing

The BW 25 is a loop-powered displacer level transmitter for measuring and/or detecting liquid level or liquid-liquid interface under extreme process conditions. It can deal with corrosive media, high temperatures (up to +400°C / +752°F) and high pressures (up to 400 barg / 5800 psig).

The BW 25 can be used as level indicator without the need of auxiliary power supply. Equipped with a switch module the unit can be used as level switch. With a transmitter module, the unit will function as level transmitter. The three function modes can be combined. Retrofitting the device for receiving add-on functionality is possible without interrupting the process. The BW 25 can also be installed in a bypass chamber, e.g. for applications with agitators.

Product highlights

  • Transmitter, level switch and indicator in one device
  • Easy adjustable level switch with max. 2 set points
  • Can be used as mechanical indicator without auxiliary power supply
  • Modular design for retrofitting under process conditions
  • Welded process seal with external mount housing

Typical applications

  • Tanks with hydrocarbons, solvents, bases at extreme process conditions
  • Interface measurement with large emulsion layers
  • Bypass chamber for applications with agitators
  • Applications in non-hazardous and hazardous areas

Case studies

Product details

Product categoryDisplacer level transmitter
Alternative product categoriesBuoyancy transmitter, Spring range displacer

Technical data

Product typeLevel transmitter
Measurement principlesDisplacer
Level measurement typeContinuous measurement
Measured mediaLiquid/liquid interface, Liquids
Contact to measured mediumYes
Interface measurementYes
Displacement rod length0.3…6 m/
1…20 ft
Measuring range (liquids)0.3…5.5 m/
1…18 ft
Process pressure (relative)-1…400 barg/
-14.5…5800 psig
Wetted partsAustenitic stainless steel (1.4404/316L)
Process sealsEPDM, FKM/FPM, Kalrez® 6375
Accuracy (full scale)+1.5%


Certificates/Approvals ExATEX, EAC
Certificates/Approvals OthersNACE
Ingress protectionIP67, NEMA4X


Digital outputsHART®
Binary outputsLimit switches
Analogue outputs4…20 mA

Process connections

Flange connectionsEN (1092-1): DN50…100
ASME (B 16.5): 2…4"

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