V-Cone steam flow meter suits district energy systems

Paul Boughton
Delivering accurate steam flow measurement in a space-saver design, the V-Cone Steam Flow Meter from McCrometer is suitable for Campus District Energy Facilities and eliminates many of the common equipment layout problems associated with steam processes in HVAC and Electric Power Co-Generation systems.        

Providing precision steam flow measurement, the V-Cone Flow Meter is designed for steam process lines connecting boilers with HVAC systems or co-generation energy systems

At the same time, the V-Cone’s self-conditioning flow design eliminates most of the straight-pipe requirements typically needed with many flow meter technologies by controlling swirl and other flow disturbances in the pipe that affect measurement accuracy.

The V-Cone is accurate to +0.5%, with a repeatability of +0.1%, and requires only 0-3 pipe straight diameters upstream and 0-1 diameters downstream from the meter. Nearly all other types of flow meters require as many as 10 pipe straight diameters upstream and 5 pipe diameters downstream from the meter. In today’s crowded campus district energy equipment environments, the V-Cone typically reduces real estate, piping material, associated pipe support structure and installation labor by 50 percent or more.

With the V-Cone, larger line sizes mean larger savings. For example, when the V-Cone is installed in a typical 36-inch steam process line, it requires from 0 to 3 straight pipe diameters (0-108 inches) upstream and 0-1 (0-36 inches) downstream. A conventional flow meter would require a straight run of 360 inches upstream and 180 inches downstream. Add an elbow or U-joint if the pipeline needs to double back and the straight pipe diameter requirements will then double in cost.

The highly efficient, space-saving and precision-accuracy V-Cone Flow Meter is suitable for steam applications such as those found in campus district energy systems

It features built in flow-conditioning and advanced differential pressure (DP) technologies. Operating over a wide flow range, while maintaining its +0.5% accuracy and +0.1% repeatability, the V-Cone supports line sizes from 0.5 to 120 inches.  It can be installed virtually anywhere in a new campus district energy piping system or be easily retrofit into an existing piping layout, 

Because the flow conditioning function is built-into the basic instrument, the V-Cone Flow Meter’s design is inherently more accurate than traditional DP instruments such as orifice plates and venture tubes. The V-Cone conditions fluid flow to provide a stable flow profile that increases accuracy. It features a centrally-located cone inside a tube. The cone interacts with the fluid flow and reshapes the velocity profile to create a lower pressure region immediately downstream. 

The V-Cone features two pressure sensing taps to measure the pressure difference that is exhibited between the static line pressure and the low pressure created downstream of the cone. One tap is placed slightly upstream of the cone and the other is located in the downstream face of the cone itself. The pressure difference can then be incorporated into a derivation of the Bernoulli equation to determine the fluid flow rate.

The velocity of the liquid flow at the point of measurement is optimized by the central position of the cone in the line. It forms very short vortices as the flow passes the cone. These short vortices create a low amplitude, high frequency signal for excellent signal stability. The result is a highly stable flow profile that is repeatable for continuously accurate flow measurement.  All of this is possible with a minimal straight pipe run of 0 to 3 diameters upstream and 0 to 1 diameters downstream from the meter.          

For more information, visit www.mccrometer.com