New V-Cone Steam Flow Meter Gets Process and HVAC Systems Out Of Tight Spots
October 3, 2016
High-Performance, Space-Saver Design for Crowded Plants & Institutional Facilitiest
Process, plant and facility engineers will find the new V-Cone Steam Flow Meter from McCrometer delivers precision steam flow measurement in a space-saver design that eliminates many of the common equipment layout headaches typically associated with a wide variety of processes requiring steam injection or heating, as well as in HVAC systems for plants and institutional facilities.
The new V-Cone Flow Meter for steam provides accurate flow measurement in steam process lines connecting boilers with process equipment or HVAC systems. At the same time, the V-Cone’s self-conditioning flow design eliminates most of the straight-pipe requirements typically needed by many flow meter technologies, by controlling swirl and other flow disturbances in the pipe that affect measurement accuracy.
Accurate to +0.5%, with a repeatability of +0.1%, the V-Cone 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 plant equipment environments, the V-Cone typically reduces real estate, piping material, associated pipe support structure and installation labor by 50 percent or more.
The bigger the line size, the bigger the savings with the V-Cone. 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 V-Cone Flow Meter’s built in flow-conditioning and advanced differential pressure (DP) technologies make it a highly efficient space-saving, precision-accuracy flow meter that is ideal for steam applications. Operating over a wide flow range of 10:1, 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 piping system or be easily retrofit into an existing piping layout.
Unlike traditional DP instruments, such as orifice plates and venturi tubes, the
V-Cone Flow Meter’s design is inherently more accurate because the flow conditioning function is built-into the basic instrument. 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 pressure difference, which is exhibited between the static line pressure and the low pressure created downstream of the cone, can be measured via two pressure sensing taps. 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 cone’s central position in the line optimizes the velocity of the liquid flow at the point of measurement. 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 flow meter.