CEMFLOW
For monitoring flow with a Continuous Emissions Monitoring System, Monitoring Solutions offers CEMFlow: an S-Type pitot tube gas flow monitoring system for the ultimate in reliability and availability. Pitot tube gas flow monitoring systems also offer the lowest installation and maintenance costs of any flow system on the market today.
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Principle of Operation…
A simple pitot tube is utilized inside the stack which measures differential pressure as gas flows across a downward facing and upward facing tube. A hi and lo pressure are measured and used to calculate stack velocity (using the Bernoulli equation). This velocity is converted to flow simply by multiplying it by the stack diameter.
This technology is used to accurately measure gas flow from as low as 5 ft./sec. to as high as 900 ft./sec, and can withstand temperatures up to 1800°F (different probe materials can allow for higher temperatures where an application demands it).
CEMFlow sensors utilize a variety of designs and materials (appropriate metallurgy/ceramic, etc.) to accommodate a large number of flow applications.
Several other components are provided and located off-stack allowing for ease of maintenance and control. These include:
· Pressure Signal Conditioning Interface
· Differential Pressure Transducer
· Temperature Measurement System
· Primary Reference and Pressure Auto-Calibration System
Features…
The largest advantages lie in the features of CEMFlow:
- +99.99% uptime: with no moving parts or electronics exposed to the elements up on the stack, CEMFlow offers unparalleled performance and reliability.
- Low Installation and Initial Cost: the pitot sensor requires one sample port at one given level on the stack compared to other systems that require two sample ports at different levels. There are also no utilities necessary at the sample location.
- Ease of Maintenance: there are no blower assemblies or filters at the sample location. The unit may be serviced with nothing more than a test meter and lower level technical support (compare to other flow technologies that require oscilloscopes and/or laptops up on the stack to troubleshoot problems).
- Low Maintenance Costs: pitot tube technology utilizes solenoids, a simple power supply, DP cell, commonly used pressure switches and regulators, manometer, and an easily interchangeable control unit – all relatively inexpensive. The thermocouple used to monitor temperature at the sample point is a common standard type.
Compare this to other technologies, which utilize consumables to maintain a blower motor, and expensive spares to maintain the system due to sensors being exposed to hot corrosive stack gases at the sample location. Potential circuit board failures of these systems can require expensive parts replacement and service visits for installation and recalibration of the system. - No Utilities at the Stack or Duct: only the sensor is mounted on the stack or duct therefore CEMFlow can be operated in hazardous environments.
- Fully Automated Calibration and Constant Purge: this offers complete unattended operation. Plugging is avoided by constant purging. In the event of a purge or calibration failure, an alarm is provided to notify an operator.
- Onboard Primary Reference Manual Calibration Capability: the signal output is easily verified against standard EPA#2 methods via an onboard manometer. There is no need to ever send a system back to the factory for adjustment or re-calibration.
- Robust In-Situ Sensors: sensors are available in a wide range of desired materials designed to allow them to stand up to corrosion, high temperatures and other hostile environments.
- Accurate Determination of Gas Flow above 5 ft./sec.: this allows sources with high levels of static variation to be monitored with a minimum of interference. Very hostile conditions can also be monitored without endangering the instrument package.
- Simple Certification: other flow device technology typically requires preliminary RATA testing in the field and then a curve fit prior to running the actual RATA. The S-Type pitot tube gas flow monitoring system is the standard used to perform RATA testing.
- Cost: All this simplicity and reliability comes together in a lower cost instrument – typically several thousand dollars less than instruments utilizing other technologies.