Features
  • Fast Response for Time Critical Applications
  • Threaded, Flanged, Retractable Probes
  • Explosion Proof Enclosures
  • No Moving Parts
  • Temperatures to +350F
  • Pressures to 2,000 PSIG
  • 316L Stainless Steel Sensor/Nickel Braze
  • Simple and Easy Field Calibration
  • Field Programmable Relay Energization
Operation

The QL series level switch offers the same reliability as our LX series and also offers a faster response time. The QL series level switch offers versatility not seen in other level control devices. One unit can be field calibrated to detect the interface of air/foam, foam/liquid, oil/emulsion, emulsion/water, oil/water, and a solid in a liquid. The instrument can detect agitation in a tank, vessel, or pond. It can also be used as a universal high level switch that will quickly alarm if any type of liquid comes in contact with the probe. In applications where response time is critical the QL series level switch responds three times faster then our standard LX level switch.

The QL sensor head employs two temperature sensors with a constant very low power heating source physically attached to one of the temperature sensors while the second temperature sensor is isolated from the heating source and provides compensation for changing process temperatures. The probe operates by sensing the thermal conductivity (not electrical conductivity) of the product surrounding the probe. Air and gasses have poor thermal conductivity which produces the highest temperature differential between the heated and unheated sensor. Liquids are much more thermally conductive then air or gasses and produce the smallest temperature differential. All liquids that form an interface will have a difference in thermal conductivity that can be detected.

No moving parts exposed to the process provide end users with an extremely reliable and repeatable flow switch even in viscous or corrosive applications.

Single or dual switch point electronics are available. The dual switch point option allows one sensor to detect two different interfaces or one interface and another process variable such as fluid agitation. Temperature monitoring is also available with either a switch output or a linear 4-20 mA output.

Relay outputs are standard and are offered with several different configurations and contact ratings. Remote mounting of the electronics is also available.

Applications
  • Wet/Dry: Point sensor detects high and or low level of practically any liquid.
  • Liquid to Liquid Interface: Detects any liquid to liquid interface
  • Agitation Monitor: Detects the difference between agitated and non-agitated liquids or slurries.
  • Overflow/Drain line Sensor: Capable of detecting liquid in partially filled lines.
  • Emulsion Detector: Emulsions typically can be detected from their base liquids.
  • Solids in Liquids: Detects solids surrounding sensor probe in settling tank applications.
  • Redundant/diversified Level Indicator: Provides primary or secondary high or low level alarms to meet critical applications that require redundant/diversified technologies.
  • Universal Level Switch: Detects liquids in low or high levels applications regardless of fluid dielectric properties.
  • Foam Detector: Differentiates differences between foam and liquids or foam and gases.
  • Flood alarm: Can be mounted in overflow collection basins to alarm when liquid is present. As little as ⅛” of liquid can be detected.
  • Retractable Probe Mounting: Retractable probe mounting is available for an adjustable detection point in top mounted applications