ISA–The Instrumentation, Systems, and Automation Society Omega Tube Design Extends the Usability of Coriolis Technology in Mass Flowmetering Applications

ISA–The Instrumentation, Systems, and Automation Society

Omega Tube Design Extends the Usability of Coriolis Technology in Mass Flowmetering Applications

Presented by

John Daly

NA Sales Manager

Rheonik USA


Introduction

Topics Covered: Coriolis technology in general Working principles and design goals Engineering elements of the Omega Tube Design Features of the Omega Design Examples and solutions of challenging applications

The objective of this session is to introduce Omega Tube Coriolis technology, comparing it to conventional Coriolis technologies currently available and describe why challenging and extreme flow applications can be solved using it


Overview

Coriolis Mass Flowmeters have been available commercially for about 20 years

Over the past decade, they have been one of the fastest growing flow measurement technologies. Growth has been driven by a unique ability to directly measure mass as well as many other general advantages


Why is Mass so Good?

For most critical measurements, mass or normalized volume is of interest – volume alone is insufficient for many applications

In the Mountains On the Beach Out in Space

1 kg == 1 kg 1 kg


Advantages of Coriolis Meters

No moving parts – essentially no wear

No flow profile issues like those seen with turbine, ultrasonic and other “velocity” measuring meters

No effect from changing viscosity

No effect from density

Easy to install


Different Coriolis DesignsCoriolis meter technology is offered by around a dozen suppliers, each having their own design. Here is a sample of some of the different types:

All work using the same Coriolis Principle but different designs are more suited to specific applications; i.e. straight-through designs may be more suitable for hygienic applications

Cantilevered Triangles

Parallel Straight Tube

S-Shaped Tubes

Torsional Loops


Coriolis Meter Operating Principle

M = Mass of moving element (liquid or gas) in pipeF = Coriolis forcev = velocity of mass movingw = rotation speed / angular velocity

F = 2 * M * v * w

M v

F

w


Operating Principle - continued

Measured time difference / phase shift (t) is proportional to flow


Meter Design GoalsNo ideal design possible – simplified considerations: Preferred Design Features

Long easily bendable pipe system Large distance between oscillation and excitation point Thin wall tube to keep spring constant small High energy excitation to create large oscillation amplitudes

Conflicting Factors Long pipes may create unacceptable pressure drop High pressure, abrasive and/or corrosive media requires thick wall

tubing High energy input may be conflict with hazardous area requirements Excessive excitation may lead to fatigue failure in tubing


2

1

3

flow

Omega Tube Design Offers Some Solutions

1. Semi-circular Measurement Tube

2. Carefully balanced oscillation system consisting of rods and cross bar counter weight

3. Flow Supply Section


flow cross bar

measuring tube

De-coupled Measurement Section

No deformation at increasing pressures

De-coupled from the Process Flow Supply Section


torsion rod

cross bar

Independent Tunable Oscillation System

Stable and highly energized oscillation

Large amplitude / great signal to noise ratio

Adaptable to different tube sizes, thicknesses and materials


Bitumen – High Pressure and Temperature

Thick wall tubing required to meet pressure rating. Without Omega Tube torsion rod/cross bar system, it would not be possible to provide sufficient oscillation for reliable meter operation

Process Conditions 3” Line Size 1350psi / 93 bar 680°F / 360°C Hazardous Area

Hot, viscous liquid


Large Volume Fuel Oil Custody Transfer Flow

Turbine and PD meters not ideal due to abrasive nature of fuel oil

Ultrasonic meters not accurate enough due to flow profile issues

Process Conditions

12” Line Size Heated to

improve flow

Extremely viscous liquid


Gas Flow at Extremely High Pressure Process Conditions

900 bar / 13,000psi Turndown of 100:1 required

H2 dispensing for alternative automobile fuelling requires very accurate metering over a wide range of flowrates

Omega Tube Design can accommodate thick wall tube to meet pressure requirements while providing high accuracy across a range of 0.25 kg/min to 50 kg/min


Flow Measurement of Highly Corrosive Materials Process Conditions

3” Line Size

HCl Flow Highly corrosive to

Stainless Steel and other Alloys

The Omega Tube Design lends itself to variations in material of tube construction. Because of the torsion rod/mass weight design, tubes manufactured from exotic materials such as Tantalum can be accomodated without requiring meter redesign


Cryogenic Gas Flow Measurement

Process Conditions -425°F / -253°C H2 Gas

Omega Tube Design Mass Flowmeters are resilient to extremes of temperature due to remote electronic mounting


Summary The Omega Tube Coriolis Mass Flowmeter design differentiates

from others by its unique construction with torsion rods and cross bar.

With these design elements, the meters operate with large oscillation movements (providing measurement performance) without putting undesirable bending stress on the tubing.

The design allows for the accommodation of exotic materials and thick wall tube without compromising performance.

Extreme applications with temperatures from -250°C up to 400°C and pressures up to 900 bar can be solved, as well as high volume/throughput requirements up to 1500 t/hr.


the Mass Flowmetering Experts

For more information on Omega Tube Coriolis Mass Flowmeters, please come to the South Fork

Instruments Table

www.rheonik.com

Thank you for your attention……..

Documents

ISA–The Instrumentation, Systems, and Automation Society Omega Tube Design Extends the Usability of Coriolis Technology in Mass Flowmetering Applications