Magna-Site Magnetic Level Gauge

Magna-Site Magnetic Level Gauge

Magna-Site Magnetic Level Gauge

Magna-Site™ Magnetic Level Gauge

The KENCO Magna-Site™ is a magnetic liquid level indicator used to determine the volume of liquid contained within a vessel. Because the Magna-Site™ eliminates the need for glass, high pressure applications and hazardous locations are protected from the danger of a chemical spill due to potential glass failure.

The KENCO Magna-Site™ utilizes three major components: the gauge housing chamber, the magnetic float and the magnetic flag assembly.  The gauge housing chamber is mounted adjacent to the side of the vessel.  It is constructed to withstand the same temperatures and pressures as the tank itself.  It is equipped with the appropriate tank mounting connections for easy installation and to allow equalization of liquid level in tank and gauge.

Inside the gauge housing chamber is the magnetic float, which contains radially-positioned magnets to provide a 360° magnetic-flux field. Each float is internally weighted based on specific gravity so that the liquid level in the gauge coincides with the location of the magnets inside the float. Attached to the gauge housing chamber is the magnetic flag assembly. This is the visual means of liquid level indication for the KENCO Magna-Site™. The assembly is made up a of a series of bi-colored fluorescent flags. As the magnetic float rises and falls with the liquid level in the gauge housing chamber, a magnet embedded in each flag reacts to the 360° magnetic flux of the float. This magnetic interaction causes each flag to rotate 180°. The flags below the magnetic flux of the float will flip to fluorescent green, while those flags above the float level remain steel gray.


  • Maximum safety – No glass is used in the construction.
  • Optimum visibility – Fluorescent flags are visible from great distances
  • Float with 360° magnetic flux – Maintains a strong magnetic field in all directions; turbulent liquids will not cause flag assembly to give an inaccurate level indication
  • Double flag protection – Flags are hermetically sealed inside a PTFE encapsulated assembly which is shrouded by a 300 series stainless steel enclosure on three sides with a UV stabilized high-impact clear polycarbonate shield
  • Adjustable viewing angles – Flag assembly can be rotated to any angle to provide maximum visibility
  • Multiple mounting options – Engineered construction allows for a variety of mounting configurations
  • Compatibility – A broad range of materials can be used to withstand harsh chemicals
  • Remote level indication – Explosion-proof magnetostrictive level sensor/transmitter provides a 4-20mA signal output
  • Height scale – 304 stainless steel with no. 3 finish and large etched characters/lines for easy reading
  • High/Low level switches – Explosion proof switches can signal an alarm, operate a pump/valve or act as an emergency shut down
  • Convenience – Easy installation and very low maintenance
  • Warranty – Three year guarantee against defects
  • Reliability – KENCO has been building magnetic liquid level indicators since 1986

Industries Served

  • Chemical and Petrochemical Refineries
  • Water and Waste Treatment
  • Pulp and Paper Processing
  • Power Plants
  • Pharmaceutical Processing
  • Food and Beverage Processing

Common Applications

  • Fuels and Solvents
  • Oil Production and Refining
  • Lubrication Oils
  • Detergents and Soaps
  • Boiler Feedwater Tanks
  • Fertilizers and Pesticides
  • Ammonia Tanks
  • Scrubber Tanks
  • Storage Tanks
  • Acid Tanks


Magna-Site Magnetic Level Gauge Magna-Site Magnetic Level Gauge


KENCO Magnetostrictive Transmitter

KENCO loop powered transmitters electronically monitor the location of the magnetic float within the Magna-Site gauge housing, providing an output in a unit of measure, as a percent of span or a 4-20mA output. The transmitter is available up to a length of 300 inches. Zero and span may be adjusted by using the HART® communications protocol or it may be manually calibrated using the keypad display inside of the explosion proof housing. These transmitters operate within a process temperature range of -40°F to 300°F (-40°C to 148.8°C ). Field replaceable electronics are potted and encapsulated. KENCO transmitters are available as standard with NEMA 4X/7 explosion-proof housings. These housings feature an industrial epoxy coating for corrosion resistance. All KENCO level transmitters use non-contacting, magnetostrictive technology. This simple design ensures no scheduled maintenance or re-calibration — ever. Accurate, non-contact float location sensing is achieved with absolutely no wear to any of the sensing elements.

Principle of Magnetostriction

The level transmitter is composed of two concentric members. The outermost member is a protective stainless steel chamber that withstands aggressive or harsh process industry environments. The heart of the transmitter design is the innermost member, the waveguide, a formed element constructed of a proprietary magnetostrictive material.

A pulse is induced in the waveguide by the momentary interaction of two magnetic fields, one from an electric current pulse launched along the waveguide and the other from the magnet inside the float. This interaction produces a strain pulse that travels along the waveguide. The location of the magnet inside the float is determined by measuring the elapsed time between the launching of the electronic pulse and the detection of the strain pulse by the sensor head. The time period measurement is used to produce a 4-20mA output.

Float Characteristics

  • 360° magnetic-flux field provides constant interaction with flag assembly in turbulent liquids
  • Internally weighted based on specific gravity so that location of magnets
  • Inside float coincide with liquid level in gauge
  • Cylindrical geometric shape ensures more accuracy in interface specific gravity applications
  • Rare earth magnet assembly has an unusually high energy output volume and is highly resistant to demagnetization; they will not demagnetize at high temperatures like ceramic magnets
  • Standard float material is 316 stainless steel. Other float materials available, including: Titanium, Hastelloy™, Inconel™, Alloy 20, Aluminum, PVC and CPVC
  • Standard float good to a minimum specific gravity of 0.50. Custom floats for lower specific gravities available.
  • 360° magnetic-flux field is ideal for interaction with KENCO magnetostrictive transmitter
  • Float is non-vented, so vapors can not condense inside float
  • Compact length minimizes ground clearance requirements

Flag Assembly

  • Fluorescent flags for maximum visibility
  • No glass in flag assembly
  • Shield is UV stabilized high-impact clear polycarbonate
  • Chamber is hermetically sealed and nitrogen filled to prevent internal condensation and ensure 100% flag rotation every time
  • Totally enclosed with clear F.E.P. PTFE tubing for maximum chemical resistance
  • 300 series stainless steel enclosure provides maximum protection from puncture of F.E.P. PTFE tubing
  • 300 series stainless steel is more compatible to corrosive environments than aluminum
  • Double O-ring seal assures that the flag assembly will not lose its nitrogen-filled atmosphere
  • Each flag contains an Alnico 8 magnet, making each flag highly resistant to demagnetization
  • Flags are UV stabilized, high-temperature thermoplastic and molded in color to prevent fading
  • No ceramic magnets are used
  • Maximum constant temperature of 350°F (176.6°C)
  • About the sealing process: The end block on one end of the flag rail is equipped with a positive stop charge valve to allow the flag assembly to be hermetically sealed. The flag assembly is attached to a vacuum pump through a manifold which is connected to a cylinder of ultra high-purity nitrogen gas. We evacuate the flag assembly with a vacuum pump to 28″ Hg and then internally pressurize it with ultra high-purity nitrogen gas to a maximum of 5 psig (-15°C).

High-Temperature Flag Assembly Features

  • Maximum constant temperature of 800°F (426.6°C)
  • Flags are 316 stainless steel
  • Flag color is heat cured at 400°F (204.4°C) with heat resistant paint
  • All 300 series stainless steel flag assemblies are ideal for severe environment
  • Alnico 8 magnets are nickel plated to withstand severe environments

Transmitter Features

Level Output

  • Measured Variable = Product Level
  • Full-Range = 0.5 to 25 ft. (152 mm to 7.6 m)
  • Non-linearity Fullspan = 0.020 % F.S. (Independent BSL) or 1/32 in. (0.794mm), whichever is greater.
  • Repeatability 0.01 % F.S. or 0.015 in. (0.381 mm), whichever is greater.
  • Sensor Operating Temperature = Operating temperature is -40°F to 300°F (-40°C to 148.8°C ). Contact Kenco for higher temperature requirements.

Transmitter Loop

  • Input Voltage Range = 10.5 to 36.1 Vdc
  • Reverse Polarity Protection = Series diodes
  • Safety Approval = CSA certified explosion-proof – Class I, Division 1, Groups B, C, and D ATEX certified explosion-proof – II 1/2 G resp. II 2 G EEx is IIB T4 resp. EEx ia IIA T4


  • Zero Adjust Range = Anywhere within the active length
  • Span Adjust Range = FS > 0.5 ft. (152 mm) from zero


  • Sealing = Potted sensor cartridge and electronics
  • Humidity = 0 to 100 % R.H.
  • Operating Temperature = -30 to 160°F (-34 to 71°C)
  • Materials = 304 stainless steel

Field Installation

  • Transmitter Length = Up to 25 ft (7.6 meters)
  • Wiring = Two-wire connection, shielded cable or twisted pair to screw terminals through a 3/4 in. (12.7 mm) NPT conduit opening


  • Measured Variables = Liquid Level
  • Update Rate = 3 seconds
  • Size = 0.5″
  • Number of Digits = 16
  • Measurement = % of span, a 4-20mA output or any unit of measure
    • Digital Display for zero and span setting and readout
    • Immune from electrical and mechanical noise
    • HART® Communications standard
    • No maintenance required

Explosion-Proof High-or-Low Level Switches

  • Can activate alarms, pumps or valves when the liquid reaches high or low levels
  • Does not come in contact with process liquid

Model 9958: Latching Switch

  • C-UL-US approved for Class I, Div. 1, Div. 2, Groups C & D, Class II, Div. 1, Div. 2, Groups E, F, & G
  • Housing Material: Aluminum (Other Materials Available)
  • Switch: SPDT, latching reed normally open or normally closed form C contacts
  • Maximum temperature: 221°F (105°C). Consult factory for higher temperatures.
  • Maximum switching volts: 100VDC, 140 VAC
  • Maximum switch current: 0.20 Amps DC, 0.14 Amps AC
  • Maximum power: 4 watts
  • Conduit Connection: 1/2″ female NPT

Model 9959: Non-Latching Switch

  • C-UL-US approved for Class I, Div. 1, Div. 2, Groups C & D, Class II, Div. 1, Div. 2, Groups E, F, & G
  • Housing Material: Aluminum (Other Materials Available)
  • Switch: SPST, non-latching reed normally open form A contacts
  • Maximum temperature: 221°F (105°C). Consult factory for higher temperatures.
  • Maximum switching volts: 100VDC, 140 VAC
  • Maximum switch current: 0.25 Amps DC, 0.18 Amps AC
  • Maximum power: 7 watts
  • Conduit Connection: 1/2″ female NPT

Height Scales

  • Standard scales are 304 stainless steel with no.3 finish
  • Standard scales show height in feet/inches or meters/centimeters
  • Large numerical characters offer increased visibility
  • Standard scale division marks/characters are etched and paint filled
  • Can be calibrated for any unit of measure

Insulation Blankets

  • Withstands temperatures up to 750°F (398.8°C )
  • Standard shell material is 18 Teflon® cloth
  • Also available in other materials based on application
  • Steam tracing also available