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Steam Flow Energy Measurement

Dec 21, 2018

From facilities management to district heating applications, accurate steam flow energy measurement is a critical flow measurement needed to incur substantial savings on energy and maintenance costs. However,  steam flow energy measurement is also the most difficult flow measurement to make due to the unknown factors of what type of steam is being produced, various pipe sizes, and difficulty in steam flow meter installation. In most cases, you need to shut down the steam production, which can cost thousands of dollars in lost productivity, to install the steam flow meter.

Glen Coblentz, VP Sales North America for Sierra, has over 30 years experience dealing with the challenges of getting accurate steam flow measurements in facilities. Learn some tricks of the trade in his new Flow Tip Video, “Do You Know Your Steam Flow Measurement?” He tackles 3 important questions for accurate steam flow measurement:

  1. What kind of steam is your facility making? Are they producing saturated or superheated steam?

  2. What type of measurement, mass or volumetric, provides the most accurate steam flow measurements?

  3. What do you do when you absolutely cannot shut down the process, but you find you need to measure steam flow?

Determine if your Steam is Saturated or Superheated Steam

To measure steam flow effectively,  you need to know what type of steam you are producing. Saturated steam and superheated steam are very different and measuring incorrectly for either one will cost you big time.

It may seem like this would be obvious, but let’s say you are creating superheated steam.  If you have to continually add lots of heat (energy) to the steam so that you can create the superheated steam you may have something wrong with your process. When you specify, your steam flow meter make sure you know what type of steam you are measuring as this determines how the steam flow meter is set up from the factory. Incorrect set up results in incorrect steam flow readings. The density of saturated steam varies with either temperature or pressure, while superheated steam varies with temperature and pressure, so multivariable vortex flow meters assure the flow meter’s density calculations are correct, and therefore, mass steam flow measurements are correct maximizing steam productivity. Sierra’s multivariable vortex flow meters provide steam accuracy of +/- 1% of reading, 30:1 turndown plus pressure and temperature compensation.

Use the Right Flow Meter Technology to Ensure the Most Accurate Steam Flow Measurements

While there are a multitude of steam flow measuring technologies out there, an insertion multivariable mass flow vortex meter will be your best option for accurate data to help make informed decisions about your steam flow system.

Unlike differential pressure devices commonly used for steam flow which are inherently volumetric flow measurements, a multivariable mass flow vortex uses mass flow as its basis of measurement. This is important,  because changes in pressure and temperature will change the mass flow rate of steam. Even a “small” change of 10 percent in steam pressure will result in a 10 percent error in non-compensated mass flow. This means that, in a typical differential pressure measurement installation, the volumetric flow rate measured by the device must be compensated by measuring temperature and pressure, and then these three measurements (ΔP, T and P) integrated with a flow computer to calculate mass flow.

Choosing an insertion multivariable vortex meter gives engineers the benefit of using one instruments and one process connection to simultaneously measure mass flow rate, temperature, pressure, volumetric flow rate, and fluid density.

When Shutting Down is Not an Option – Hot tap

In many facilities, a very real challenge is the need to measure steam flow but shutting down your process is not an option. So, what do you do in these situations?

The answer is to use Sierra’s 241i insertion vortex flow meter. Unlike other options out there, the 241i has full packing gland and hot tapping capability allowing engineers to insert the sensor into any size pipe they want, anytime they need to do so to make a steam flow energy measurement without shutting down the process.

    • Insertion probe up to 72 inches (2M); optional hot tap

    • Ideal for saturated or superheated steam, gas, and liquid

    • Low-cost alternative to Coriolis meters for large pipes and ducts

    • Easy single-point installation; hot tap and hot tap retractor available

    • Volumetric flow rate or mass flow

    • Multivariable for five measurements in one device with one process connection:

      • Mass flow rate

      • Volumetric flow rate

      • Temperature

      • Pressure

      • Fluid density

    • Complete suite of digital communications

    • Rugged, long-lasting design for the toughest applications; no leaks with all welded gasket-free flow body

Learn more about Sierra’s vortex volumetric flow and multivariable mass flow meters.

Discover how vortex flow meter works.

Scott Rouse, Product Line Director
Written By:
Scott Rouse, Product Line Director
Sierra Instruments

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