top of page

Jerguson® Top Mount Level Switches

Jerguson products are also available under the MagneSonics® brand as required based on approved vendor specifications.

Jerguson offers a wide array of mechanical switch and transmitter products to provide reliable level measurement for your application. Our caged level switch products feature a unique, tri-magnet mechanism that offers high current, snap-action switching without the use of cams or springs. Products are available with ASME B31.1/B31.3, FM, UL, CSA, ATEX, & PED approvals.

Jerguson® Top Mount Displacer Operated Level Switch


  • Tri-Magnet Switching

  • Vibration Resistant

  • Pump Control

  • Multi-Point Alarm

  • T316 SST Trim


The displacer element is suspended on a stainless steel cable attached to a spring.  The displacer is always heavier than its equivalent volume of the liquid in which it is to operate, and therefore will always extend the tension spring.  Hanging freely in the air, the spring extends to a predetermined length, limited by a mechanical stop to prevent overstressing.  Attached to the spring is the magnet assembly which is free to move up or down as the spring extends or contracts.

As rising liquid submerges the displacer, a buoyant force is created equal to the weight of the displaced liquid volume.  This buoyancy force reduces the apparent displacer weight, contracting the spring, and moves the magnet upwards inside the pressure tube actuating the switch mechanism.  This simple principle also operates a single switch over a very wide differential by simply providing the buoyancy force from two displacers instead of a single displacer.

Two switch models are available for either two alarm applications, two narrow differentials, or for pump control with appropriate wide differentials.  All models are fully field adjustable by simple re-setting the displacers on the cable at the desired switch actuation point.

Jerguson® Top Mount Displacer Operated Level Switch
bottom of page