SMN Displacer Flow Switch

Brand: KOBOLD Instruments, Inc.

The KOBOLD model SMN flow switch is used when extremely low flow switch points are required together with minimum pressure loss at high flow rates.

The flow switch operates on the well-known float principle. An orifice float with its integral circular magnet moves within a cylindrical flow tube in the direction of flow and against a spring.

The magnetic field of the float activates a reed contact which is mounted on the outside of the instrument in a sliding protective casing.

The special construction of the float and flow tube means that only a low flow is required to raise the float and hence activate the reed contact. If the flow rate increases further and the float reaches the top of its travel an additional flow path opens allowing high flow rates without a significant increase in the pressure loss.



  • ± 5 % of Full Scale


  • Cooling Circuits
  • Heating Installations
  • High Pressure Purifiers
  • Infusion Pumps
  • Precision Fluid Control
  • Prevention of Low Water Levels
  • Sanitary Technology
  • Water Cycles

Approvals & Certifications

  • ATEX
  • cCSAus

BSP Connection

  • G 1" Female

Electrical Connectors

  • DIN EN 175301-803

Electrical Contacts

  • 1 Bistable Reed Contact
  • 1 Changeover Contact
  • 1 Normally Open Contact

Electrical Rating

  • Maximum

Enclosure / Body Material

  • 304 Stainless Steel
  • Brass, ms 58

Environmental Protection

  • IP65

Flow Rate

  • 1 to 100 LPM to Water

Materials of Construction

  • 304L Stainless Steel - Float & Pin
  • Brass ms 58 - Float & Pin
  • Ceramic - Magnet

Maximum System Pressure

  • psi: 5,000 (kPa: 35,000, bar: 350)

Mounting Position

  • Horizontal
  • Vertical (Upward Direction)

NPT Connection

  • 1" NPT Female

Spring Material

  • Stainless Steel

Switch Point Range

  • 1 LPM Water

Temperature Range

  • Maximum

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