Application advice: Steam flowmeter for energy distribution systems

V-Cone flowmeter from McCrometer fits well in crowded steam distribution and cogeneration systems.

03/16/2010


McCrometer V-Cone

McCrometer V-Cone flow sensor

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

One of the challenges of monitoring consumption in steam distribution systems is finding space to install precise flow sensors within the confines of crowded piping systems. One solution is to use McCrometer's V-Cone steam flowmeter sensor. The design helps save space by providing accurate flow measurement without the need for straight-pipe requirements to stabilize the flow profile and distribution.

McCrometer says the V-Cone flowmeter is designed to provide critical flow measurement for steam process lines connecting boilers with HVAC systems or co-generation energy systems. Its self-conditioning flow design eliminates most of the straight-pipe requirements typically needed with many flowmeter technologies by controlling swirl and other disturbances in the pipe that affect measurement accuracy.

Accurate toter. In the type of environment typical of crowded campus district energy distribution systems, the V-Cone typically reduces real estate, piping material, pipe support structure, and installation labor by 50% or more, depending on the pipe size.

This is particularly important with larger line sizes. For example, when the V-Cone is installed in a typical 36 in. steam line, even three diameters is 9 ft. A conventional flow meter would require a straight run of 30 ft. upstream and 15 ft. downstream. If the pipe has to double back, the amount of pipe added can be twice that.

The V-Cone's differential pressure technology is highly scalable, making the design suitable for pipe sizes from 0.5 to 120 inches. McCrometer contends that its inherent flow conditioning capability makes sensor more accurate than traditional differential pressure instruments such as orifice plates and venturi tubes. The sensor's cone is placed in the center of the tube and interacts with the fluid flow, reshaping the velocity profile to create a lower pressure region immediately downstream.

The V-Cone features two pressure sensing taps that measure the difference between the upstream line pressure and the low pressure zone created downstream of the cone. The low tap is in the face of the cone itself. The transmitter converts the pressure difference into a fluid flow rate using a derivation of the Bernoulli equation.

The cone's central position optimizes the velocity of the liquid flow at the point of measurement, forming very short vortices as the fluid passes the cone. These short vortices create a low-amplitude, high-frequency signal with excellent stability. The result is a highly stable flow profile that is repeatable for continuously accurate flow measurement.

-Edited by Peter Welander, process industries editor, PWelander@cfemedia.com
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