Winter Weather and how it affects Air Flow Measurement - Freezing Flow Measurement Issues
Even though it does not feel like it here in the Eastern US, it is definitely winter in many parts of the world. And something happens every winter at process plants all around the world, namely instruments and instrumentation begin to have issues due to the temperatures, moisture, and the winds of winter. These issues send Instrumentation Techs, Engineers, and Maintenance people scrambling to get them back online and functioning properly.
One of the biggest issues is when an instrument that is crucial to the proper operation of the a plant gives erroneous readings or stops working all together. This is especially the case with flow measurement devices and instruments. Having a transmitter or moisture in the differential pressure lines freeze up will cause the transmitter to stop responding or give incorrect flow measurement readings. These can be handled sometimes (depending on the temperatures) by putting the transmitters inside a building or under a covering, protecting them from the elements, or installing a heater in the enclosure they are installed in. The differential pressure lines or impulse lines can have a heat trace system added to them, helping to prevent moisture from freezing. The one part of this system that normally does not get any attention is the flow element or averaging pitot tube itself. Since they are inside the duct, they may not be accessible, or cannot be removed to be "de-iced" while the process is running. These devices can get winter moisture on them, and when the temperature drops, they freeze right up. They can be coated in ice like the branches on a tree, having their pressure ports covered, blocked, or plugged up with ice. Wouldn't it be great if these probes could have a heat trace system put on them so that they will work in the winter temperatures??
Most of the time the issue never gets resolved or the measurement is temporarily bypassed, and when warm weather returns, it is forgotten about altogether. Then the next winter, it rears its ugly head again......
Well, there is a solution to this yearly issue of freezing pitot tubes, it is the Heated Pitot from Eastern Instruments! The Heated VAP³ Pitot is not just a typical averaging pitot tube with heat trace, but a device with an Integral Heater in the actual probe! This patented design includes an Integral Heater that traverses the length of the probe, heating from within, instead of on the outside surface. This is an important distinction, because the metal of the probes is heated, thus keeping it from freezing AND not impeding or disturbing the flow pattern around the probe. Applying heat trace to the outside would only heat the contacted surface AND would definitely affect the flow pattern, and thus the flow measurement.
The System consists of the Velocity Averaging Pitot with Integral Heater and a Control Enclosure with a Temperature Controller and Temperature Alarm Controller. While heating the pitot material will keep it from freezing, allowing it to become overheated can damage or destroy the probe. So, the Temperature Controller controls the temperature, while the Temperature Alarm will assist in preventing the system from allowing it to get over temperature. This also saves money because the system will only apply power to the Integral Heater when it is needed, keeping the probes ice free when they need it! The system controls itself, give a maintenance free solution to a yearly problem plaguing process plants.
The Heated VAP³ Pitot can be used in any application where there is a chance of freezing temperatures and moisture being present. When ducts are large, as is the case in Inlet Air applications, multiple probes can be used, thus keeping them shorter so that the heating system works optimally, but allows a full traverse of the duct.
For more information on the Heated VAP³ Velocity Averaging Pitot Tube, please visit our website at https://easterninstruments.com, give us a call at 910-392-2490, or email us at sales@easterninstruments.com today!!
One of the biggest issues is when an instrument that is crucial to the proper operation of the a plant gives erroneous readings or stops working all together. This is especially the case with flow measurement devices and instruments. Having a transmitter or moisture in the differential pressure lines freeze up will cause the transmitter to stop responding or give incorrect flow measurement readings. These can be handled sometimes (depending on the temperatures) by putting the transmitters inside a building or under a covering, protecting them from the elements, or installing a heater in the enclosure they are installed in. The differential pressure lines or impulse lines can have a heat trace system added to them, helping to prevent moisture from freezing. The one part of this system that normally does not get any attention is the flow element or averaging pitot tube itself. Since they are inside the duct, they may not be accessible, or cannot be removed to be "de-iced" while the process is running. These devices can get winter moisture on them, and when the temperature drops, they freeze right up. They can be coated in ice like the branches on a tree, having their pressure ports covered, blocked, or plugged up with ice. Wouldn't it be great if these probes could have a heat trace system put on them so that they will work in the winter temperatures??
Most of the time the issue never gets resolved or the measurement is temporarily bypassed, and when warm weather returns, it is forgotten about altogether. Then the next winter, it rears its ugly head again......
HEATED VAP³ PITOT SYSTEM from EASTERN INSTRUMENTS
 |
| HEATED PITOT SYSTEM |
Well, there is a solution to this yearly issue of freezing pitot tubes, it is the Heated Pitot from Eastern Instruments! The Heated VAP³ Pitot is not just a typical averaging pitot tube with heat trace, but a device with an Integral Heater in the actual probe! This patented design includes an Integral Heater that traverses the length of the probe, heating from within, instead of on the outside surface. This is an important distinction, because the metal of the probes is heated, thus keeping it from freezing AND not impeding or disturbing the flow pattern around the probe. Applying heat trace to the outside would only heat the contacted surface AND would definitely affect the flow pattern, and thus the flow measurement.
The System consists of the Velocity Averaging Pitot with Integral Heater and a Control Enclosure with a Temperature Controller and Temperature Alarm Controller. While heating the pitot material will keep it from freezing, allowing it to become overheated can damage or destroy the probe. So, the Temperature Controller controls the temperature, while the Temperature Alarm will assist in preventing the system from allowing it to get over temperature. This also saves money because the system will only apply power to the Integral Heater when it is needed, keeping the probes ice free when they need it! The system controls itself, give a maintenance free solution to a yearly problem plaguing process plants.
The Heated VAP³ Pitot can be used in any application where there is a chance of freezing temperatures and moisture being present. When ducts are large, as is the case in Inlet Air applications, multiple probes can be used, thus keeping them shorter so that the heating system works optimally, but allows a full traverse of the duct.
For more information on the Heated VAP³ Velocity Averaging Pitot Tube, please visit our website at https://easterninstruments.com, give us a call at 910-392-2490, or email us at sales@easterninstruments.com today!!
