Coriolis Flow Transmitter, 1 Fundamentals of the … flow transmitter of the ... basics required to...

© Festo Didactic 85995-00 1

Learn the working principle of Coriolis flowmeters, familiarize yourself with the Coriolis flow transmitter of the Instrumentation and Process Control Training System, and learn how to commission it.

The Discussion of this exercise covers the following points:

Introduction

Coriolis effect

How a Coriolis flowmeter works

Industrial applications

Advantages and limitations

Description of the supplied Coriolis flowmeter

Installing the Coriolis flowmeter

Calibration

Introduction

Flow measurement is essential in most industrial applications and the need for very accurate flow measurement devices is always present. One of the most versatile and accurate types of flowmeters used in modern plants is the Coriolis flowmeter. First introduced to the industry in the seventies, the Coriolis flowmeter was initially bulky, inaccurate, and expensive. Since its introduction, many improvements to the design of the Coriolis flowmeter have made it one of the most flexible flow measurement instruments of its time. Its design takes advantage of the Coriolis effect, first described by the French mathematician and engineer Gaspard-Gustave de Coriolis in 1835.

This type of flowmeter allows measurement of the mass flow rate instead of the volume flow rate like the other types of flowmeters. The sections below describe both the physical principles on which the design of the Coriolis flowmeter is based and how these principles are used for mass flow measurement.

Coriolis effect

This section provides the fundamental principles of classical mechanics required to understand the Coriolis effect. However, this brief introduction gives only the basics required to understand how Coriolis flowmeters work and is in no way a complete description of the Coriolis effect, nor is it a classical mechanics course. If you feel the need to increase your knowledge, consult one of the documents listed in the bibliography.

Fundamentals of the Coriolis Flowmeter

Exercise 1

EXERCISE OBJECTIVE

DISCUSSION OUTLINE

DISCUSSION

Figure 1. Gaspard-Gustave de Coriolis

(1792 – 1843).

Instrument symbol

Coriolis flow transmitter

Exercise 1 – Fundamentals of the Coriolis Flowmeter Discussion

2 © Festo Didactic 85995-00

Inertial frame of reference

The position and speed of an object are always given relative to a frame of reference. For example, the velocity of a car is measured relative to the surface of the Earth which, in this case, is the frame of reference. In an inertial frame of reference, a body obeys Newton’s first law of motion, that is: Every object persists in its state of rest or uniform motion in a straight line unless it is compelled to change that state by forces impressed on it.

In an inertial frame of reference, a body also obeys Newton’s second law as written in Equation (1).

(1)

where is the force vector

is the mass of the body is the acceleration vector

An inertial frame of reference is essentially a frame that either does not move or moves in a straight line at a constant speed. We will see later that, although the Earth can be approximated as an inertial frame of reference for most applications of physics, Earth is a non-inertial frame of reference.

Non-inertial frame of reference

A non-inertial frame of reference is an accelerated frame of reference. An accelerating car is an example of a non-inertial frame of reference. From the point of view of the passenger of an accelerating car, a pair of fuzzy dice hanging from the rear view mirror seems pulled towards the back of the car by some kind of force. However, for an observer outside the car, it is clear that the dice are accelerated and that there is no real force at work (Figure 2).

Hence, for an observer in a non-inertial frame of reference, the only way to make the movement of objects fit with Newton’s laws of motion is to introduce a fictitious force that does not really exist, but that compensates for the acceleration of the frame of reference.



Figure 2. Non-inertial frame of reference.

Coriolis force

The Coriolis force is a fictitious force introduced to describe the motion of bodies in rotating non-inertial frames of reference. Take for example a baseball pitching machine in the center of a big rotating carousel. If it pitches a ball toward the edge of the carousel, the trajectory of the ball can be viewed differently depending upon whether the ground or the carousel is used as the frame of reference. Figure 3 shows the trajectory of the ball for both frames of reference.

x

y

x'

y'

Acceleration

Inertial frame of reference

(the road)

Non-inertial frameof reference

(the car)



Figure 3. Inertial frame of reference vs. non-inertial frame of reference.

In the first case (Figure 3a), the ground is considered as an inertial frame of reference and the trajectory of the ball is straight. In the second case (Figure 3b), the carousel is the frame of reference; it is also the point of view of someone beside the pitching machine. Since the carousel is rotating, it is a non-inertial frame of reference. For an observer beside the pitching machine, the ball has a curved trajectory and seems pulled toward the left by an unknown force. The movement of the ball in this case can be explained to the observer by introducing a fictitious force called the Coriolis force. Equation (2) gives the mathematical definition of the Coriolis force. As shown in this equation, there is no Coriolis force if the velocity vector is null.

(2)

where is the Coriolis force

is the mass of the body is the angular velocity of the rotating frame of reference

is the velocity vector of the moving body of mass

x

y

x'

y'

Inertial frame of reference(the ground)

Non-inertial frame of reference

(the carousel)

(a) The ground is the frame of reference.

Direction of rotationof the non-inertial

frame of reference

(b) The carousel is the frame of reference.

Trajectory of theball in the inertial

frame of reference

Trajectory of the ball in the non-inertial frame of reference



As illustrated in the example above, the Coriolis force is a convenient way to describe the apparent deflection of the trajectory of a body moving in a non-inertial rotating frame of reference. The Earth is also a non-inertial rotating frame of reference. However, because of the relatively slow rotational velocity of the Earth (about 7.3 x 10-5 rad/s), the Coriolis force due to Earth’s rotation affects only large systems such as large air masses.

The Coriolis effect plays an important role in the formation of cyclones. For a rotating spherical object like Earth, the Coriolis force has a different effect on a moving object depending upon whether it is located in the Northern hemisphere or in the Southern hemisphere. In the Northern hemisphere, the trajectory of particles is deflected to the right which, conjugated with a low air-pressure area, leads to the formation of cyclones spinning counter clockwise (Figure 4a). On the other hand, in the Southern hemisphere, moving air is deflected toward the left, thus leading to the creation of cyclones spinning clockwise (Figure 4b).

Figure 4. Air flow around a low air-pressure area.

Figure 5 shows photographs of two cyclones, one that occurred in the Northern hemisphere and another that evolved in the Southern hemisphere. The first photograph shows hurricane Ike over the Gulf of Mexico spinning counter clockwise (Figure 5a) and the second shows tropical cyclone Edzani, over the Southern Indian ocean, spinning clockwise (Figure 5b).

(a) Northern hemisphere. (b) Southern hemisphere.

Low-pressure area



Figure 5. Cyclones direction of rotation.

Coriolis effect myths

It is a common belief that the Coriolis force influences the direction of rotation of the water vortex formed when flushing a toilet and that this vortex will turn counter clockwise in the Northern hemisphere and clockwise in the Southern hemisphere. This is a very romantic view of how a physics principle can explain an everyday phenomenon, but it is all wrong! The Coriolis force is far too weak to have any influence whatsoever on the direction of rotation of the water in a draining toilet or sink. The acceleration imparted by the Coriolis force to a moving particle in the middle of the Northern hemisphere is of the order of 10-6 m/s2 (about the same magnitude in ft/s2); this is ludicrously small compared to the other disturbances influencing the way the water drains out of a toilet. The design of the toilet or sink and the way it has been filled determines the direction of rotation of the drained water.

The Coriolis force is also too weak to influence the direction of rotation of tornadoes and dust swirls. In these cases, the direction of the winds plays a much more important role.

(a) Hurricane Ike (September 2008). (b) Tropical cyclone Edzani (January 2010).



Aside from the direction of rotation of cyclones, you can observe the Coriolis effect in one of the many museums around the world that displays a Foucault pendulum (Figure 6).

Figure 6. Foucault pendulum in the Panthéon (Paris).

How a Coriolis flowmeter works

Now, how can one take advantage of the Coriolis effect to build a flowmeter? Everything starts with the idea of making a fluid flow in a rotating frame of reference. As mentioned above, a moving body viewed from a rotating frame of reference seems to have a deflected trajectory. This fact has inspired the design of the Coriolis flowmeter, which is described below.

The flow tubes

A Coriolis flowmeter usually consists of two flow tubes1. For the sake of clarity, the flow tubes are represented with a U-shape in this section. However, there are almost as many shapes of flow tubes as there are Coriolis flowmeters manufacturers.

The ingenious idea of using the Coriolis force to measure a flow rate is to transform the flow tubes into a rotating frame of reference. But, unlike the Earth or the carousel examples, a full rotation around an axis is not acceptable since it will transform the flowmeter into a monster of bulkiness. The solution is to make the tubes vibrate around an axis in order to generate controlled Coriolis forces. The vibrations are generated using an electromagnetic driver.

1 Some models have only one flow tube. The working principle of a Coriolis flowmeter with one flow tube is the same as for a Coriolis flowmeter with two flow tubes, the main difference being that the model with one flow tube is bigger.



As implied in Equation (2), there is no Coriolis force if a body or particle is not

moving ( ) in the rotating frame of reference. Therefore, if there is no flow in a flow tube, it will oscillate normally as shown in Figure 7 and Figure 8.

Figure 7. Flow tube with no flow.

Figure 8. Flow tube with no flow (front view).

When a fluid flows in a vibrating flow tube however, its velocity is no longer zero ( and the effects of the Coriolis force appear. Because of the shape of the tube, the effects of the Coriolis force are not constant over the length of the flow tube. Similar to the difference in the direction of rotation of the cyclones, depending upon whether they appeared in the Northern hemisphere or in the Southern hemisphere, the effects of the generated Coriolis force are different depending on which side of the twist axis we look at. As Figure 9 shows, when a fluid flows from the inlet to the outlet of the tube, it moves away from the rotation axis in the first half of the tube (i.e., before the twist axis) and it moves toward the rotation axis in the second half of the tube.

Drive force

Drive force

Inlet

Outlet Vibration direction

(a) Side view. (b) Front view.



Figure 9. Twist axis and rotation axis of a flow tube.

The twist axis passes through the point where the oscillation amplitude is maximal when there is no flow. The way the generated Coriolis force acts is different before and after the twist axis. In the inlet section, the Coriolis force goes against the drive force, so the tube lags behind the position it normally assumes when there is no flow. In the outlet section, the Coriolis force has the opposite effect and adds to the drive force. Figure 10 shows how the Coriolis force twists the oscillating tube when a fluid is flowing through it.

Figure 10. Twisting of the flow tube when a fluid is flowing.

When a fluid is flowing in the U-shaped flow tube of a Coriolis flowmeter, Figure 10 shows that the left and right sides of the tube do not move together. Figure 11 shows the amplitude of oscillation of each side plotted against time. In this figure,

you can observe a time lag ( ) between the two curves. This time lag is caused by a phase shift between the readings of the two detectors measuring the deformation of the tube due to the effect of the Coriolis force.

Whatever the shape of the

tube, the Coriolis force is

null at the peak oscillation

point.

InletOutlet

Rotation axis

Twist axis

Flow direction

Drive force

Drive force Fluid reactive

force (inlet)

Fluid reactive force (inlet)

Fluid reactive force (outlet)

Fluid reactive force (outlet)

(a) Drive force upward. (b) Drive force downward.

Fluid flows awayfrom the rotation

axis

Fluid flows toward the rotation axis



Figure 11. Phase shift.

With the help of a little bit of mathematics and physics, it can be proved that the

mass flow rate of the fluid passing through the tube ( is proportional to the

time lag between the two sensors. Equation (3) shows the relationship between the time lag and the mass flow rate.

(3)

where is the mass flow rate is a constant that does not depend on the fluid properties

is the time lag between the two sensors is the phase shift between the two sensors is the first resonance frequency of the tube

Dual-tubes Coriolis flowmeter

For a dual-tube flowmeter, the two tubes vibrate in counter phase and the phase difference is measured using two sensors installed as shown in Figure 12.

Figure 12. Dual-tube Coriolis flowmeter.

Left side

Right side

Time

Amplitude

Driver

Sensors



Industrial applications

Coriolis flowmeters measure the mass flow rate and are not affected by changes in the temperature, pressure, viscosity, or density of the measured fluid. They can measure the quantity of matter flowing in a pipe with high precision. This is very significant for many industrial applications, such as custody transfer or monitoring of pharmaceuticals, where measuring the quantity of manipulated matter is crucial.

The use of Coriolis flowmeters is not limited to the applications mentioned above. This type of flowmeter is widely used in the food and beverage, chemical, petrochemical, pharmaceutical, and paper industries where it is used to measure the mass flow of beer, honey, ketchup, peanut butter, acids, ammonia, latex, solvents, asphalt, oil, fuel, soap, vitamins, cellulose slurry, and paper pulp, just to mention a few examples.

Advantages and limitations

Coriolis flowmeters are versatile and reliable measuring instruments. Some of their advantages have already been described. Nevertheless, these advantages are listed below, along with others not already mentioned:

Direct mass flow measurement

High accuracy (typically between ±0.1% and ±0.3% error)

Low maintenance

Insensitivity or low sensitivity to temperature, pressure, conductivity,

viscosity, or density changes

Direct measurement of multiple variables (mass flow, density,

temperature)

Independent of the fluid flow profile (laminar or turbulent)

No moving parts requiring maintenance

Can be made to be resistant to corrosive fluid

Most Coriolis flowmeters can detect two-phase flow (gas/liquid)

Coriolis flowmeters also have limitations and disadvantages that must be considered:

High initial cost

The actual design of the Coriolis flowmeter limits the line size to a

maximum diameter of 150 mm (6 in)

Unable to measure two-phase flow accurately, therefore it is not suitable

for measuring the mass flow rate of liquids with high gas content.

Not suitable for measuring low in-line pressure gas flow.

Some designs are sensitive to vibrations

High pressure drop for high-density fluids

Bulky compared to some types of flowmeters



Description of the supplied Coriolis flowmeter

The Coriolis flow transmitter (Model 46924) is shown in Figure 13. It consists of a sensor/transmitter and a bracket for mounting the device on the process workstation. Table 1 describes the main components of the Coriolis flow transmitter.

Figure 13. Coriolis flow transmitter (Model 46924).



Table 1. Components of the Coriolis flow transmitter.

Component Description

Inlet Fluid must enter the flowmeter through this port.

Sensor The sensor assembly containing the flow tubes.

Flow orientation arrow

Indicates the required direction of flow. Be sure to follow this instruction.

Outlet Fluid must exit the flowmeter through this port.

24 V dc input Power input for the flowmeter. Used to energize the Coriolis flowmeter with a 24 V dc signal.

Fault panel Contains one switch used to simulate a fault with the apparatus.

Analog output / HART communication port

Sends a 4-20 mA signal proportional to the measured mass flow rate. HART communication can also be established with various devices such as a handheld or portable computer, a controller, or a programmable logic controller (PLC) using this port.

Digital display Displays the measured flow rate and other information related to the operation of the flowmeter. The protective cover can be removed to gain access to the control keys.

The display can be used to configure several parameters and to read the flow rate directly. The function of each button is described below:

go backward in a menu or modify a value

go forward in a menu or modify a value

select an item from a menu or store an entry

ESC press the + and – buttons simultaneously to return to the previous menu or display

Summary of technical specifications

Some technical specifications are summarized in this section. For details, please refer to the documentation provided with the system.

Device name Promass 80 Measured variables Mass flow rate, density,

and temperature Power supply 24 V dc Communication protocols HART Pipe diameter 1.27 cm (0.5 in) Range for full scale value (liquids) 0 kg/h to 6500 kg/h

(0 lb/min to 238 lb/min) Mass flow accuracy ±0.3% Operating temperature of the sensor

-40°C to 140°C (-40°F to 284°F)

Temperature of the process -50°C to 150°C (-58°F to 302°F)



Installing the Coriolis flowmeter

The Coriolis flowmeter is heavy. Use proper techniques to lift it and request help

whenever necessary. Always wear safety shoes when working with this

equipment and make sure it is properly secured to the workstation.

Equipment required

The following equipment and tools are required to install the Coriolis flowmeter on the process workstation:

Coriolis flowmeter

A spring nut and bolt for attachment to the support strut

Ratchet with ½ in sockets or equivalent wrenches

Installation procedure

The Coriolis flowmeter is designed to be installed at the end of the workstation above the pump so that the pipe is aligned with the axis of valve HV2. The arrow cut on the back plate of the mounting bracket must point in the direction of the flow.

The sensor of the Coriolis flowmeter consists of two curved tubes and the reading depends on the mass of fluid flowing in these tubes. Therefore, it is essential to position the flowmeter so that no gas bubbles remain in the sensor tubes. Avoid installing the flowmeter horizontally at the highest point of a pipeline or vertically upstream from a free pipe outlet.

Also, be aware that the shape of the sensor tubes may allow the accumulation of gas or solid if the transmitter is installed horizontally. For process fluids likely to contain an excess of gas, the flowmeter should be installed so that the curved part of the sensor is pointing downward. For process fluids with suspended solids, the curved part of the sensor should point upward.

Calibration

The Coriolis flowmeter is calibrated by the manufacturer at the factory. The unit cannot be calibrated by the user. If necessary, it must be returned to the manufacturer for calibration.

Exercise 1 – Fundamentals of the Coriolis Flowmeter Procedure Outline


The Procedure is divided into the following sections:

Set up and connections

Commissioning the Coriolis flow transmitter

Set up and connections

1. Connect the equipment according to the piping and instrumentation diagram (P&ID) shown in Figure 14 and use Figure 15 to position the equipment correctly on the frame of the training system. To set up your system for this exercise, start with the basic setup presented in the Familiarization with the Instrumentation and Process Control Training System manual and add the equipment listed in Table 2.

Table 2. Material to add to the basic setup for this exercise.

Name Model Identification

Coriolis flow transmitter 46924 FIT 1

Electrical unit 46970

Pneumatic unit 46971

Accessories 46993

Figure 14. P&ID.

PROCEDURE OUTLINE

PROCEDURE

Calibrator

(4-20 mA)

Exercise 1 – Fundamentals of the Coriolis Flowmeter Procedure


Figure 15. Setup.

2. Connect the control valve to the pneumatic unit. Details about the installation and operation of the control valve are available in the Familiarization with the Instrumentation and Process Control Training System manual.

3. Connect the pneumatic unit to a dry-air source with an output pressure of at least 700 kPa (100 psi).

4. Wire the emergency push-button so that you can cut power in case of emergency. The Familiarization with the Instrumentation and Process Control Training System manual covers the security issues related to the use of electricity with the system as well as the wiring of the emergency push-button.



5. Do not power up the instrumentation workstation yet. You should not turn the electrical panel on before your instructor has validated your setup—that is, not before step 9.

6. Be sure to install the transmitter as shown in Figure 15 and connect it to a 24 V dc power outlet on the electrical unit. Use one of the direct outputs to keep the transmitter from shutting off in case the emergency push-button or the OFF button (S2) is used.

7. Before proceeding further, complete the following checklist to make sure you have set up the system properly. The points on this checklist are crucial elements for the proper completion of this exercise. This checklist is not exhaustive, so be sure to follow the instructions in the Familiarization with the Instrumentation and Process Control Training System manual as well.

f

All unused male adapters on the column are capped and the flange is

properly tightened.

The ball valves are in the positions shown in the P&ID.

The three-way valve at the suction of the pump (HV1) is set so that the

flow is directed toward the pump inlet.

The control valve is fully open.

The pneumatic connections are correct.

8. Ask your instructor to check and approve your setup.

9. Make sure it is safe to energize the system for you and for the team working on the other side of the system, if any. When ready, turn on the main power by pushing the handle of the safety switch in the ON position. Do not press the S1 button yet.

The transmitter initializes and the remote display turns on after a few seconds.

Commissioning the Coriolis flow transmitter

a Note: The following procedure assumes you are using the display to program the transmitter. If you want to configure your transmitter from a computer, you can do so by accessing the same menus and inputting the same values in the appropriate fields of the Fieldcare software. Please refer to the HART Software Configurator student manual (P/N 86050) for more information on how to connect your transmitter to a computer.

Enabling programming mode (access code)

10. In many plant applications, it is crucial to the process that the settings of transmitters remain unchanged unless change is properly authorized. To avoid inadvertent changes to their settings, most devices use a numerical code to



protect their settings. The Coriolis flow transmitter has such a protection system and requires that the user enters a numerical code to enable the programming mode.

The programming mode is disabled automatically at boot or if no key has been pressed within 60 seconds. If the programming mode is disabled and you try to change a protected setting, the transmitter prompts you to enter the ACCESS CODE.

ACCESS CODE ***

11. The default access code is 80. Use the + and – buttons to enter this code and enable the programming mode.

ACCESS CODE 80 *

12. Once the correct access code is entered, the transmitter displays a message that indicates that the programming mode is enabled.

PROGRAMMING ENABLED

Quick setup commissioning

13. The easiest way to configure the Coriolis flow transmitter is via the functions of the QUICK SETUP group. Press the E button to access the GROUP SELECT menu and use the + and – buttons to select the QUICK SETUP function group.

14. Press the + button to change the value of the QS-COMMISSION function to YES and press the E button two times to confirm the change and proceed with the quick setup commissioning.

a If the programming mode is not already enabled, the transmitter will ask for the access code. Proceed as described above and then change the value of the quick setup commissioning function to yes.

15. The quick setup commissioning consists of several functions for which parameters must be set. Use the + and – buttons to select the parameters of the function as indicated in Table 3 and press the E button to confirm each selection. Each time a parameter is set, the transmitter confirms by displaying ENTRY STORED.



Table 3. Quick setup commissioning.



Function Parameter Description

LANGUAGE ENGLISH Sets the language used to configure the transmitter.

PRE-SETTING DELIVERY SETTING

Resets the transmitter to the factory settings.

SURE? YES Confirms the reset action.

SYSTEM UNITS MASS FLOW The SYSTEM UNITS function enables the units for mass flow, volume flow, corrected volume flow, density, and temperature to be set.

UNIT MASS FLOW kg/m (lb/m)

Enables the units to be set for mass flow.

UNIT TOTALIZER kg (lb)

The transmitter calculates the total mass of fluid that has passed through the flow meter since the last reset of the totalizer.

OTHER UNIT? YES If set to yes, enables the units for another of the measured variables to be set.

SYSTEM UNITS VOLUME FLOW

UNIT VOLUME FLOW

l/m (US gal/m)

Enables the units to be set for volume flow.

UNIT TOTALIZER l (US gal)

The transmitter calculates the total volume of fluid that has passed through the flow meter since the last reset of the totalizer.

OTHER UNIT? YES

SYSTEM UNITs DENSITY

UNIT DENSITY kg/m3 (lb/ft3)

Enables the units to be set for density.

OTHER UNIT? YES

SYSTEM UNITs TEMPERATURE

UNIT TEMPERATURE

°C (CELCIUS) °F (FAHRENHEIT)

Enables the units to be set for temperature.

MEASURING MODE

STANDARD When set to standard, the output signal is proportional to the measured variable.

SELECT OUTPUT CURRENT OUTPUT 1

Enables the configuration of output 1.

ASSIGN CURRENT

MASS FLOW Assign one of the measured variables to the current output.

CURRENT SPAN 4-20mA Enables the current span of the transmitter to be set.

VALUE 20mA +60.000 kg/min (+133.4 lb/min)

Sets the value of the measured variable that corresponds to 100% of the span.

TIME CONSTANT 1.00 s Determines how fast the current output reacts to a change in the measured variable (i.e., damping).

FAILSAFE MODE MIN. CURRENT Determines the current output in case of a fault.

OTHER OUTPUT? Yes Enables the configuration of additional outputs if available. The pulse output will be turned off to avoid unnecessary error messages.

SELECT OUTPUT PULS/FREQ. OUT. 1

Enables the configuration of pulse or frequency output 1.

OPERATION MODE

PULSE Sets the operation mode of the pulse/frequency output to the pulse mode.

ASIGN PULSE OFF Turns pulse mode off.

Function Parameter Description



AUTOCONF. DISPL?

YES Automatically configures the transmitter so that it displays the mass flow on line one and the totalizer 1 on line 2 of the display. You can change the units of the totalizer or reset it by changing the parameter in the TOTALIZER 1 function group, available from the GROUP SELECT menu.

16. Once the quick setup commissioning is completed, the transmitter displays SETUP COMPLETE.

17. Use the ball valve HV2 to adjust the flow rate so that the rotameter reading is 4 L/min (1 gal/min).

18. Record the flow rate reading of the Coriolis flow transmitter in Table 4. To switch between the mass flow rate reading and the volume flow rate reading, as well as display the other measured variables such as temperature and density, press the E button to access the GROUP SELECT menu. From this menu select MEASURING VALUES and the E button. In the MEASURING VALUES function, you can switch between the various measured variables using the E button.

Table 4. Coriolis flow meter and rotameter flow rate reading.

Flow rate (Rotameter)

L/min (gal/min)

Flow rate (Coriolis TX)

L/min (gal/min)

Flow rate (Coriolis TX)

kg/min (lb/min)

4 (1)

19. Use the ball valve HV2 to increase the flow rate (as read on the rotameter) by steps of 4 L/min (or 1 gal/min) until you reach 60 L/min (1 gal/min). For each flow rate, record the flow rate reading of the Coriolis flow transmitter in Table 4.

20. Compare the flow rate reading of the Coriolis flow transmitter to the flow rate reading of the rotameter.

Exercise 1 – Fundamentals of the Coriolis Flowmeter Conclusion


In this exercise, you have learned how to commission a radar level transmitter for use on the Instrumentation and Process Control system. You learned the principles of echo detection and the use of a filter mapping.

1. What is the Coriolis force?

2. Does the Coriolis force influence the direction of rotation of the water vortex formed when flushing a toilet?

3. How does a Coriolis flow meter work?

4. Name three industrial applications for the Coriolis flow meter.

5. Name two advantages and two limitations of the Coriolis flow meter.

CONCLUSION

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