- Used with large axial or centrifugal fans
- Resistant to moisture, oil and chemical attack in dirty mine air or scrubber applications
The mining sector alone accounts for 22% of Canada's total industrial energy consumption (Jaccard & Willis, 1996). Globally, mining and other industrial sectors are attempting to consume less energy due to increased electrical cost and/or lack of electrical capacity.
As a result, modern large industrial fans are being delivered with high efficiency motors and variable frequency drives (VFD). This allows the mine the ability to adjust the total airflow based on the mine operating requirements (blasting, shift changes, occupancy and operational activity). By doing so, the mine can maintain proper air quality whilst saving valuable operating capital.
Every ventilation system and fan needs to be designed based on the system curve that represents the current (SC1) and future (SC2) ventilation requirements. To assist the mine with changing ventilation requirements and fan power monitoring, it is recommended to measure real time airflow (Q) and static pressure (P).
VFDs and electrical noise
In the past, fan VFD electrical noise and lack of mounting space on the fan evase created technical problems with conventional measurement techniques. "VFDs generate electrical noise that interferes with the power quality of the supporting electrical supply" (Improving Fan System Performance - The United States Department of Energy & Air Movement and Control Association International, Inc.)
New Maestro technology solves legacy issues
Maestro's digital sonic dual sensor technology allows the averaging of the flow velocity across the fan evase thereby eliminating the requirement of long straight runs of piping while still providing accurate and repeatable flow measurement.
The digital output from the sonic sensors are immune to EMI (Electromagnetic Interference) from VFD motors and RFI (Radio Frequency Interference) from mobile radios. This results in stable and accurate measurements unlike analog sensors that are severely affected by this electrical noise.
Simple installation of airflow sensors
- No welding required
- Simple installation
- EZ sensor alignment
- Self sealing design
The universal primary fan mounting bracket is self contained and does not require any welding to the fan evase. Simply cut the evase to the bracket pattern and install. The ultra-thick gasket will provide a tight seal to the evase. The sensor threads into an articulating ball that allows for simple sensor alignment
Condition based monitoring provides early failure warning
Prevent costly mine operation disruptions due to unplanned fan failures.
Primary mine ventilation fans are subjected to many different environmental factors that can lead to premature failure. Proper fan design and system engineering can safe guard against most of these factors. However, the remainders require the assistance of a proper real time condition based monitoring system.
Typical modes of failure:
- Imbalance caused by shotcrete residue, dirt buildup, corrosion or abrasion of fan blades
- Bearing failure due to lubrication failure and wear
- Motor winding insulation failure
- Operating fans at or near the system natural resonant frequencies when using VFD motors
- Fatigue of blades due to cyclical bending stresses caused by mass and volumetric imbalances from unequal distribution of heater mine air into the fan
Real time vibration diagnostic systems can be used to measure and alarm on these conditions. The sensor technology has been greatly influenced by the commercialization of airbag technology in the automotive industry.
MEMS sensor technology
Maestro FanMon and FanVibe systems take advantage of the reliable, accurate and compact MEMS (Microelectromechanical Systems) accelerometers. The microscopic mechanical element moves in response to rapid deceleration, and this motion causes a change in the capacitance which is detected by the electronics on the chip.
The signal is transmitted to a full frequency spectrum monitor for instant evaluation. These sensors are installed to measure the x-y-z axis vibration on the fan.
A configured system can quickly predict several different failure modes before they become catastrophic in nature. This will normally allow the user to safely plan an outage to address or replace the defective components.
Prediction and alarming functions
- Inner raceway bearing vibration
- Outer raceway bearing vibration
- Roller bearing vibration
- Fan imbalance
- Overall system vibration
- Frequency and time domain monitoring
- Peak and weighted acceleration
- Average velocity
- Motor winding temperatures
- Bearing temperatures
Real time vibration data
All data is accessable by an Ethernet connection using the provided PC based software.
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