Company Profile

Airflow Meter Hardware: Heavy-Duty Industrial Ventilation and Duct Performance Testing

Quick Answer: Silver Instruments manufactures thermal mass airflow meter hardware for heavy duty industrial ventilation, duct balancing, filter performance checks, and exhaust stack monitoring. Standard inline meters cover DN50 to DN300. Insertion probes handle circular or rectangular ducts from DN100 to DN1200. Outputs include 4-20 mA HART, RS485 Modbus RTU, pulse, and relay alarms.

These meters read mass flow, standard volumetric flow, gas temperature, and totalized flow. Most standard ranges ship in 5 to 7 working days. Send your duct size, gas type, temperature, pressure, and flow range to get a quote within 24 hours.

Why Duct Performance Testing Needs Better Hardware

Most process ventilation systems still use differential pressure devices. Pitot tubes and orifice plates are cheap but they drift in dirty air. In practice, dust, grease, and moisture change the readings slowly. Operators then adjust dampers based on wrong data.

Thermal mass airflow meter hardware solves this with no moving parts. The sensor measures heat transfer from a heated RTD to the gas flow. It works well in air, nitrogen, flue gas, biogas, and compressed air. We have seen this on customer sites many times where a simple insertion probe replaced a fragile averaging pitot tube.

Industrial Ventilation and Duct Performance Applications

Think of a cement plant in Vietnam checking baghouse exhaust after a clinker cooler. A paint booth in Mexico must prove airflow for worker safety. Wastewater treatment plants in Saudi Arabia use airflow meters for aeration blower output. In Western Australia, underground mine ventilation shafts need stable air velocity data. Food drying lines in Indonesia verify exhaust humidity removal.

The common point is that airflow data must be stable, repeatable, and easy to send to a PLC or a building management system. Silver Instruments offers insertion probes for circular or rectangular ducts. For large rectangular ducts, you can install multiple probes and average the signals in the transmitter.

Key Hardware Specifications for Duct Airflow Meters

Standard Silver Instruments thermal mass flow meters include a 316L stainless steel probe, a local display, and a transmitter with 4-20 mA HART output. Power supply is 24 VDC standard. Optional 220 VAC panel power is available.

Measurement range starts from 0.3 m/s and goes up to 120 m/s for air. Accuracy is 1 percent of reading plus 0.5 percent of full scale. Repeatability is 0.2 percent of full scale. Response time is 1 second. Process temperature range is -40 to 200 °C standard and up to 350 °C with a high temperature probe. Process pressure rating is 16 bar standard and 40 bar on request.

For hazardous areas, ATEX Zone 1 and Zone 2 approvals are available. The electronics housing meets IP67. The probe has a stainless steel compression fitting from DN15 to DN50. Insertion length can be 300 mm, 500 mm, 700 mm, or custom up to 1500 mm.

Inline vs Insertion Airflow Meter Hardware

For duct sizes below DN80, an inline flow body works better. The meter body can be wafer type or flanged. For duct sizes from DN100 to DN1200, insertion probes are simpler and cheaper. Most engineers skip flow straighteners when using insertion probes because existing ducts rarely have a perfect flow profile.

But avoid mounting a probe immediately after a bend or damper. The reading may be biased. We usually ask for straight run data before quoting. If the duct is very short, we can supply a flow conditioner to improve the velocity profile.

Customer Case in Southeast Asia

Last year a paint manufacturer in Vietnam asked us to replace a failing averaging pitot tube on a 600 mm exhaust duct. The gas was solvent laden air at 70 °C. Flow range w