Jim Mimlitz, NRI
Extreme Cold and Pressure Sensors
During extremely cold temperatures, it is important to keep in mind that the pressure sensing devices in your system — and the tubing that feeds them — should be prevented from freezing. These devices include pressure transducers, pressure switches, and pressure gauges.
If the water in the sensor or sensing line freezes, the expanding ice is capable of building up a tremendous amount of pressure that is capable of destroying a transducer, gauge, or switch.
For example, if a transducer is installed in a below-grade pit, please make sure that the lid is fully seated and sealing the top. It also may be necessary to cover the lid with additional insulation. If a transducer is installed above-grade and sensing pressure from an oil-filled line, the line should be inspected to make sure that it is still filled with oil. If the oil has leaked out and back-filled with water, then it poses a freeze possibility.
Also, keep in mind that the potential for sensing lines to freeze up is amplified by high winds, as the cold air will tend to force its way into holes and cracks that normally may stay warm.
Powered Freeze Protection for Below Grade Transducer Pits
We recently introduced an active-heat feature that can be added to below-grade transducer pits. To read about this technology, please click HERE.
Ice Caps Within Water Towers
During extended periods of extreme cold, it is possible that an ice cap can form on the top water surface within a water tower. Because ice has less density than water, its presence can cause the telemetry tank level reading to display lower than the true level; and therefore it may be wise to drop the PUMP_OFF level of the control system.
Another good reason to drop the PUMP_OFF level is to keep an ice cap away from any installed cathodic protection eqiupment that is installed at the top-inside of the tank, thereby preventing the ice from damaging the instrumentation.
Increasing the deadband — the difference between the PUMP_OFF and the PUMP_ON setpoints can increase the amount of water turnover inside the tank, and this may also help keep the water temperature warmer and decrease the amount of ice.
Emergency Services – Our Contact Info
Please make sure to include our phone numbers as part of the critical contact list in your emergency preparation plans:
https://www.wireless-telemetry.com/contact/contact.htm
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