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Steam Flow Meters: High-Temperature Vortex Sensors for Boiler Energy Audits

Quick Answer: High-temperature vortex flow meters from Silver Automation Instruments measure saturated and superheated steam during boiler energy audits. These inline meters work for pipe sizes from DN15 to DN300, handle process temperatures up to 350 °C, and provide 4-20 mA HART plus pulse outputs. Send us your pressure in bar, temperature in °C, pipe size DN, and flow range to get a selection and price.

Boiler energy audits often fail because steam flow data is missing or unreliable.

We have seen this on customer sites many times. A plant manager knows total fuel consumption but cannot separate steam used by process, steam lost through traps, and steam returned as condensate. A high-temperature vortex flow meter changes that picture quickly.

Why Vortex Sensors Fit Boiler Steam Measurement

Vortex flow meters have no moving parts. That matters in steam lines where temperature swings and condensate slugs can damage turbine meters or orifice plates.

They are also easy to install inline. No impulse lines, no condensate pots, no differential pressure transmitter drift.

In practice, a vortex sensor works well from saturated steam at 6 bar to superheated steam at 350 °C. The sensor sheds vortices at a frequency proportional to flow velocity. That gives volume flow data. With pressure and temperature compensation, you can convert volume flow to mass flow in kg/h.

Most engineers skip this part, but the compensation needs a pressure transmitter and a PT100 temperature sensor. Silver Automation Instruments can supply all three as a package.

Key Parameters for High-Temperature Steam Flow Meters

We ask customers to share six things before quote stage.

Pipe size or DN. Steam pressure in bar. Steam temperature in °C. Minimum, normal, and maximum flow rate in kg/h or t/h. Pipe material and schedule. Ambient and hazardous area classification.

These details determine the meter size, sensor material, and whether you need ATEX Zone 1 certification.

For saturated steam from 120 to 240 °C, a standard 316L stainless steel vortex meter works. For superheated steam above 250 °C, we specify a high-temperature version with extended electronics and a sensor rated to 350 °C.

Silver Instruments VSF-HT Series at a Glance

The VSF-HT series covers line sizes from DN15 to DN300. Wetted parts are 316L stainless steel. Process connections include wafer, flanged, and sanitary types depending on site piping.

Standard output is 4-20 mA HART. You can also order pulse, RS485 Modbus, or a local LCD display for total flow and instantaneous flow.

Accuracy for steam is plus or minus 1.5 percent of reading after pressure and temperature compensation. Repeatability is plus or minus 0.25 percent.

Temperature range of the standard sensor is -40 to 260 °C. The high-temperature option extends this to 350 °C. Pressure rating is PN16, PN40, Class 150, or Class 300 depending on flange standard.

For hazardous areas, we offer Ex d IIC T6 Gb enclosures and ATEX Zone 1 documentation. Many boiler houses in Southeast Asia require this for biogas or natural gas co-firing setups.

Installation Notes from Field Audits

Straight pipe run matters. For vortex meters, you need 15D upstream and 5D downstream when a control valve or elbow sits nearby. That is 15 times the pipe diameter upstream and 5 times downstream.

Here is the thing about steam lines. Condensate is always present. Install the meter after a steam trap station or on a vertical line with upward flow if possible. Water slugs can damage sensor elements over time.

Mount the electronics away from radiant heat. Use an extension neck on the high-temperature version. This keeps the amplifier below 85 °C.

One more thing, always commission the meter with actual site p