Mercury Displacement Industries Incorporated, better known in the industry we serve as MDI, was incorporated in Michigan in 1975. The primary product line is switch gear components including mercury type contactors, tilt switches and liquid level float controls.

Contactors are rated from 30 to 100 Amperes and are commonly used in various heating, lighting, and many other industrial applications including high voltage ultraviolet type loads. The contacts are encased in hermetically sealed stainless steel tubes to provide reliable switching for millions of operations. All basic units are UL, CSA, and CE approved.

The liquid level control floats are manufactured with mechanical or mercury switches. The float material is High Impact Polystyrene for normal alarm, sump pump or water applications, For sewage, 1 or 2 H.P. or high temperature, 86°C (186°F) requirements Acrylonitrile Butadiene Styrene, (ABS) float material is provided.

Mechanical Floats

These high quality float switches are designed for pilot duty or control panels. The float switch is as normally open or pump down (circuit is complete when the float is elevated.

The float cord is intended to be attached to a vertical pipe a band clamp, cable tie or tether clamp. As an option the float can be installed with a cable weight as the pivot point.

This float has skived ends, where the insulated wire leads inside the cable are intended to be wired into other system components inside a junction box

Mercury Hg Floats

Float switch is used to accurately monitor high (normally open) or low (normally closed) liquid levels to activate pump control panels and alarms in non-potable water and sewage applications.

Normally Open Models (high level): The control switch turns on (closes) when the float tips slightly above horizontal signaling a high level and turns off (opens) when the float drops slightly below horizontal.

Normally Closed Models (low levels): The control switch turns on (closes) when the float tips slightly below horizontal signaling a low level and turns off (opens) when the float tips slightly above horizontal.

This switch is not sensitive to rotation and is suitable for use with intrinsically safe circuits. 

  • Operation:
    • Normally Open (Pump Down)
  • Cord:
    • 20′ Flexible 16 Gauge 2 Conductor SJOOW (UL & CSA) CPE (Chlorinated Polyethylene) Jacketed
  • Float Material:
    • Polypropylene
  • Float Filling:
    • Polyurethane Foam
  • Pump Range:
    • 7″ to 28″ adjustable based upon length of cable beyond clamp / tether

Stainless Steel Floats

CONTEGRA’s FS 90 is a rugged, reliable raw sewage or sludge wet well point-level sensing device. It is also applicable as a process sump or water reservoir sensor where its simplicity of operation, quality, and ruggedness provide years of reliable service.
Two simple mounting methods are available: cable or pipe. Cable suspension provides
simplicity of installation and adjustment of the pump on/off and alarm setpoints as shown in the figure at the right. Alternatively, the floats can be mounted on a pipe within the sump. The switch has a 8” differential. The switch activates when the process level rises 4” above the fixed mounting position and deactivates when the level decreases to 4” below the fixed mounting position.