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Coriolis mass flowmeters measure the force resulting from the acceleration caused by mass moving toward (or away from) a center of rotation. This effect can be experienced when riding a merry-go-round, where moving toward the center will cause a person to have to “lean into” the rotation so as to maintain balance. As related to flowmeters, the effect can be demonstrated by flowing water in a loop of flexible hose that is “swung” back and forth in front of the body with both hands. Because the water is flowing toward and away from the hands, opposite forces are generated and cause the hose to twist.

In a Coriolis mass flowmeter, the “swinging” is generated by vibrating the tube(s) in which the fluid flows. The amount of twist is proportional to the mass flow rate of fluid passing through the tube(s). Sensors and a Coriolis mass flowmeter transmitter are used to measure the twist and generate a linear flow signal.
How to Use Coriolis Mass Flowmeters
Coriolis mass flowmeters measure the mass flow of liquids, such as water, acids, caustic, chemicals, and gases/vapors. Because mass flow is measured, the measurement is not affected by fluid density changes. Be particularly careful when using Coriolis mass flowmeters to measure gas/vapor flows because flow rates tend to be low in the flow range (where accuracy is degraded). Also, in gas/vapor applications, large pressure drops across the flowmeter and its associated piping can occur.
This flowmeter can be applied to sanitary, cryogenic, relatively clean, and corrosive liquids and gases/vapors in pipes smaller than 6-12 inches. General applications are found in the water, wastewater, mining, mineral processing, power, pulp and paper, petroleum, chemical, and petrochemical industries. Materials of construction are generally limited to stainless steel and Hastelloy C. Straight-tube designs are available to measure some dirty and/or abrasive liquids.

Many applications for Coriolis mass flowmeters are found in chemical processes where fluids can be corrosive and otherwise difficult to measure. In addition, the relative insensitivity to density allows Coriolis mass flowmeters to be applied in applications where the physical properties of the fluid are not well known. These flowmeters can also be used in chemical feed systems found in most industries.
Application Cautions for Coriolis Mass Flowmeters
If the pressure drop is acceptable, operate a Coriolis mass flowmeter in the upper part of its flow range because operation at low flow rates can degrade accuracy. Note that high viscosity fluids increase the pressure drop across the flowmeter. For liquid flows, make sure that the flowmeter is completely full of liquid. Be especially careful when measuring gas/vapor flow with Coriolis mass flowmeters. Pay special attention to installation because pipe vibration can cause operational problems.

Electricity figures everywhere in our lives. Electricity lights up our homes, cooks our food, powers our computers, television sets, and other electronic devices. Electricity from batteries keeps our cars running and makes our flashlights shine in the dark.

Here’s something you can do to see the importance of electricity. Take a walk through your school, house or apartment and write down all the different appliances, devices and machines that use electricity. You’ll be amazed at how many things we use each and every day that depend on electricity.

But what is electricity? Where does it come from? How does it work? Before we understand all that, we need to know a little bit about atoms and their structure.

All matter is made up of atoms, and atoms are made up of smaller particles. The three main particles making up an atom are the proton, the neutron and the electron.

Electrons spin around the center, or nucleus, of atoms, in the same way the moon spins around the earth. The nucleus is made up of neutrons and protons.

Electrons contain a negative charge, protons a positive charge. Neutrons are neutral — they have neither a positive nor a negative charge.

There are many different kinds of atoms, one for each type of element. An atom is a single part that makes up an element. There are 118 different known elements that make up every thing! Some elements like oxygen we breathe are essential to life.

Each atom has a specific number of electrons, protons and neutrons. But no matter how many particles an atom has, the number of electrons usually needs to be the same as the number of protons. If the numbers are the same, the atom is called balanced, and it is very stable.

So, if an atom had six protons, it should also have six electrons. The element with six protons and six electrons is called carbon. Carbon is found in abundance in the sun, stars, comets, atmospheres of most planets, and the food we eat. Coal is made of carbon; so are diamonds

Some kinds of atoms have loosely attached electrons. An atom that loses electrons has more protons than electrons and is positively charged. An atom that gains electrons has more negative particles and is negatively charge. A “charged” atom is called an “ion.”

Electrons can be made to move from one atom to another. When those electrons move between the atoms, a current of electricity is created. The electrons move from one atom to another in a “flow.” One electron is attached and another electron is lost.

This chain is similar to the fire fighter’s bucket brigades in olden times. But instead of passing one bucket from the start of the line of people to the other end, each person would have a bucket of water to pour from one bucket to another. The result was a lot of spilled water and not enough water to douse the fire. It is a situation that’s very similar to electricity passing along a wire and a circuit. The charge is passed from atom to atom when electricity is “passed.”

Scientists and engineers have learned many ways to move electrons off of atoms. That means that when you add up the electrons and protons, you would wind up with one more proton instead of being balanced.

Since all atoms want to be balanced, the atom that has been “unbalanced” will look for a free electron to fill the place of the missing one. We say that this unbalanced atom has a “positive charge” (+) because it has too many protons.

Since it got kicked off, the free electron moves around waiting for an unbalanced atom to give it a home. The free electron charge is negative, and has no proton to balance it out, so we say that it has a “negative charge” (-).

So what do positive and negative charges have to do with electricity?

STATIC ELECTRICITY

Electricity has been moving in the world forever. Lightning is a form of electricity. It is electrons moving from one cloud to another or jumping from a cloud to the ground. Have you ever felt a shock when you touched an object after walking across a carpet? A stream of electrons jumped to you from that object. This is called static electricity.

Have you ever made your hair stand straight up by rubbing a balloon on it? If so, you rubbed some electrons off the balloon. The electrons moved into your hair from the balloon. They tried to get far away from each other by moving to the ends of your hair.

They pushed against each other and made your hair move—they repelled each other. Just as opposite charges attract each other, like charges repel each other.

MAGNETS AND ELECTRICITY

The spinning of the electrons around the nucleus of an atom creates a tiny magnetic field. Most objects are not magnetic because the atoms are arranged so that the electrons spin in different, random directions, and cancel out each other.

Magnets are different; the molecules in magnets are arranged so that the electrons spin in the same direction. This arrangement of atoms creates two poles in a magnet, a North-seeking pole and a South-seeking pole.

Bar Magnet

A magnet is labeled with North (N) and South (S) poles. The magnetic force in a magnet flows from the North pole to the South pole. This creates a magnetic field around a magnet.

Have you ever held two magnets close to each other? They don’t act like most objects. If you try to push the South poles together, they repel each other. Two North poles also repel each other.

Turn one magnet around and the North (N) and the South (S) poles are attracted to each other. The magnets come together with a strong force. Just like protons and electrons, opposites attract.

These special properties of magnets can be used to make electricity. Moving magnetic fields can pull and push electrons. Some metals, like copper have electrons that are loosely held. They can be pushed from their shells by moving magnets. Magnets and wire are used together in electric generators.

BATTERIES PRODUCE ELECTRICITY

A battery produces electricity using two different metals in a chemical solution. A chemical reaction between the metals and the chemicals frees more electrons in one metal than in the other. One end of the battery is attached to one of the metals; the other end is attached to the other metal. The end that frees more electrons develops a positive charge and the other end develops a negative charge. If a wire is attached from one end of the battery to the other, electrons flow through the wire to balance the electrical charge. A load is a device that does work or performs a job. If a load––such as a lightbulb––is placed along the wire, the electricity can do work as it flows through the wire. In the picture above, electrons flow from the negative end of the battery through the wire to the lightbulb. The electricity flows through the wire in the lightbulb and back to the battery.

ELECTRICITY TRAVELS IN CIRCUITS

Electricity travels in closed loops, or circuits (from the word circle). It must have a complete path before the electrons can move. If a circuit is open, the electrons cannot flow. When we flip on a light switch, we close a circuit. The electricity flows from the electric wire through the light and back into the wire. When we flip the switch off, we open the circuit. No electricity flows to the light. When we turn a light switch on, electricity flows through a tiny wire in the bulb. The wire gets very hot. It makes the gas in the bulb glow. When the bulb burns out, the tiny wire has broken. The path through the bulb is gone. When we turn on the TV, electricity flows through wires inside the set, producing pictures and sound. Sometimes electricity runs motors—in washers or mixers. Electricity does a lot of work for us. We use it many times each day.

HOW ELECTRICITY IS GENERATED

A generator is a device that converts mechanical energy into electrical energy.  The process is based on the relationship between magnetism and electricity.  In 1831, Faraday discovered that when a magnet is moved inside a coil of wire, electrical current flows in the wire.

A typical generator at a power plant uses an electromagnet—a magnet produced by electricity—not a traditional magnet. The generator has a series of insulated coils of wire that form a stationary cylinder.  This cylinder surrounds a rotary electromagnetic shaft.  When the electromagnetic shaft rotates, it induces a small electric current in each section of the wire coil.   Each section of the wire becomes a small, separate electric conductor. The small currents of individual sections are added together to form one large current. This current is the electric power that is transmitted from the power company to the consumer.

An electric utility power station uses either a turbine, engine, water wheel, or other similar machine to drive an electric generator or a device that converts mechanical or chemical energy to generate electricity. Steam turbines, internal-combustion engines, gas combustion turbines, water turbines, and wind turbines are the most common methods to generate electricity.  Most power plants are about 35 percent efficient. That means that for every 100 units of energy that go into a plant, only 35 units are converted to usable electrical energy.

Most of the electricity in the United States is produced in steam turbines. A turbine converts the kinetic energy of a moving fluid (liquid or gas) to mechanical energy. Steam turbines have a series of blades mounted on a shaft against which steam is forced, thus rotating the shaft connected to the generator. In a fossil-fueled steam turbine, the fuel is burned in a furnace to heat water in a boiler to produce steam. Coal, petroleum (oil), and natural gas are burned in large furnaces to heat water to make steam that in turn pushes on the blades of a turbine.

Did you know that most electricity generated in the United State comes from burning coal? In 2006, nearly half (49%) of the country’s 4.1 trillion kilowatthours of electricity used coal as its source of energy.

Natural gas, in addition to being burned to heat water for steam, can also be burned to produce hot combustion gases that pass directly through a turbine, spinning the blades of the turbine to generate electricity. Gas turbines are commonly used when electricity utility usage is in high demand. In 2006, 20% of the nation’s electricity was fueled by natural gas.

Petroleum can also be used to make steam to turn a turbine. Residual fuel oil, a product refined from crude oil, is often the petroleum product used in electric plants that use petroleum to make steam. Petroleum was used to generate about two percent (2%) of all electricity generated in U.S. electricity plants in 2006.

Nuclear power is a method in which steam is produced by heating water through a process called nuclear fission. In a nuclear power plant, a reactor contains a core of nuclear fuel, primarily enriched uranium. When atoms of uranium fuel are hit by neutrons they fission (split), releasing heat and more neutrons. Under controlled conditions, these other neutrons can strike more uranium atoms, splitting more atoms, and so on. Thereby, continuous fission can take place, forming a chain reaction releasing heat. The heat is used to turn water into steam, that, in turn, spins a turbine that generates electricity. Nuclear power was used to generate 19% of all the country’s electricity in 2006.

Hydropower, the source for almost 7% of U.S. electricity generation in 2006, is a process in which flowing water is used to spin a turbine connected to a generator. There are two basic types of hydroelectric systems that produce electricity. In the first system, flowing water accumulates in reservoirs created by the use of dams. The water falls through a pipe called a penstock and applies pressure against the turbine blades to drive the generator to produce electricity. In the second system, called run-of-river, the force of the river current (rather than falling water) applies pressure to the turbine blades to produce electricity.

Geothermal power comes from heat energy buried beneath the surface of the earth. In some areas of the country, enough heat rises close to the surface of the earth to heat underground water into steam, which can be tapped for use at steam-turbine plants. This energy source generated less than 1% of the electricity in the country in 2006.

Solar power is derived from the energy of the sun.  However, the sun’s energy is not available full-time and it is widely scattered. The processes used to produce electricity using the sun’s energy have historically been more expensive than using conventional fossil fuels. Photovoltaic conversion generates electric power directly from the light of the sun in a photovoltaic (solar) cell. Solar-thermal electric generators use the radiant energy from the sun to produce steam to drive turbines. In 2006, less than 1% of the nation’s electricity was based on solar power.

Wind power is derived from the conversion of the energy contained in wind into electricity. Wind power, less than 1% of the nation’s electricity in 2006, is a rapidly growing source of electricity. A wind turbine is similar to a typical wind mill.

Biomass includes wood, municipal solid waste (garbage), and agricultural waste, such as corn cobs and wheat straw. These are some other energy sources for producing electricity. These sources replace fossil fuels in the boiler. The combustion of wood and waste creates steam that is typically used in conventional steam-electric plants. Biomass accounts for about 1% of the electricity generated in the United States.

THE TRANSFORMER – MOVING ELECTRICITY

To solve the problem of sending electricity over long distances, William Stanley developed a device called a transformer. The transformer allowed electricity to be efficiently transmitted over long distances. This made it possible to supply electricity to homes and businesses located far from the electric generating plant.

The electricity produced by a generator travels along cables to a transformer, which changes electricity from low voltage to high voltage. Electricity can be moved long distances more efficiently using high voltage. Transmission lines are used to carry the electricity to a substation. Substations have transformers that change the high voltage electricity into lower voltage electricity. From the substation, distribution lines carry the electricity to homes, offices and factories, which require low voltage electricity.

MEASURING ELECTRICITY

Electricity is measured in units of power called watts. It was named to honor James Watt, the inventor of the steam engine. One watt is a very small amount of power. It would require nearly 750 watts to equal one horsepower. A kilowatt represents 1,000 watts. A kilowatthour (kWh) is equal to the energy of 1,000 watts working for one hour. The amount of electricity a power plant generates or a customer uses over a period of time is measured in kilowatthours (kWh). Kilowatthours are determined by multiplying the number of kW’s required by the number of hours of use. For example, if you use a 40-watt light bulb 5 hours a day, you have used 200 watthours, or 0.2 kilowatthours, of electrical energy. See our Energy Calculator section to learn more about converting units.

Electricity Timeline

Energy Is the Ability to Do Work.

Energy can be found in a number of different forms. It can be chemical energy, electrical energy, heat (thermal energy), light (radiant energy), mechanical energy, and nuclear energy.

Stored and Moving Energy

Energy makes everything happen and can be divided into two types:

• Stored energy is called potential energy.
• Moving energy is called kinetic energy.
• With a pencil, try this example to know the two types of energy

Put the pencil at the edge of the desk and push it off to the floor. The moving pencil uses kinetic energy.

Now, pick up the pencil and put it back on the desk. You used your own energy to lift and move the pencil. Moving it higher than the floor adds energy to it. As it rests on the desk, the pencil has potential energy. The higher it is, the further it could fall. That means the pencil has more potential energy.

How Do We Measure Energy?

Energy is measured in many ways.

One of the basic measuring blocks is called a Btu. This stands for British thermal unit and was invented by, of course, the English.

Btu is the amount of heat energy it takes to raise the temperature of one pound of water by one degree Fahrenheit, at sea level.

One Btu equals about one blue-tip kitchen match.

One thousand Btus roughly equals: One average candy bar or 4/5 of a peanut butter and jelly sandwich.

It takes about 2,000 Btus to make a pot of coffee.

Energy also can be measured in joules. Joules sounds exactly like the word jewels, as in diamonds and emeralds. A thousand joules is equal to a British thermal unit.

1,000 joules = 1 Btu

So, it would take 2 million joules to make a pot of coffee.

The term “joule” is named after an English scientist James Prescott Joule who lived from 1818 to 1889. He discovered that heat is a type of energy.

One joule is the amount of energy needed to lift something weighing one pound to a height of nine inches. So, if you lifted a five-pound sack of sugar from the floor to the top of a counter (27 inches), you would use about 15 joules of energy.

Around the world, scientists measure energy in joules rather than Btus. It’s much like people around the world using the metric system of meters and kilograms, instead of the English system of feet and pounds.

Like in the metric system, you can have kilojoules — “kilo” means 1,000.

1,000 joules = 1 kilojoule = 1 Btu

A piece of buttered toast contains about 315 kilojoules (315,000 joules) of energy. With that energy you could:

• Jog for 6 minutes
• Bicycle for 10 minutes
• Walk briskly for 15 minutes
• Sleep for 1-1/2 hours
• Run a car for 7 seconds at 80 kilometers per hour (about 50 miles per hour)
• Light a 60-watt light bulb for 1-1/2 hours
• Or lift that sack of sugar from the floor to the counter 21,000 times!

Changing Energy

Energy can be transformed into another sort of energy. But it cannot be created AND it cannot be destroyed. Energy has always existed in one form or another.

Here are some changes in energy from one form to another.

Stored energy in a flashlight’s batteries becomes light energy when the flashlight is turned on.

Food is stored energy. It is stored as a chemical with potential energy. When your body uses that stored energy to do work, it becomes kinetic energy.

If you overeat, the energy in food is not “burned” but is stored as potential energy in fat cells.

When you talk on the phone, your voice is transformed into electrical energy, which passes over wires (or is transmitted through the air). The phone on the other end changes the electrical energy into sound energy through the speaker.

A car uses stored chemical energy in gasoline to move. The engine changes the chemical energy into heat and kinetic energy to power the car.

A toaster changes electrical energy into heat and light energy. (If you look into the toaster, you’ll see the glowing wires.)

A television changes electrical energy into light and sound energy.

Heat Energy

Heat is a form of energy. We use it for a lot of things, like warming our homes and cooking our food.

Heat energy moves in three ways:

1. Conduction
2. Convection
3. Radiation

Conduction occurs when energy is passed directly from one item to another. If you stirred a pan of soup on the stove with a metal spoon, the spoon will heat up. The heat is being conducted from the hot area of the soup to the colder area of spoon.

Metals are excellent conductors of heat energy. Wood or plastics are not. These “bad” conductors are called insulators. That’s why a pan is usually made of metal while the handle is made of a strong plastic.

Convection is the movement of gases or liquids from a cooler spot to a warmer spot. If a soup pan is made of glass, we could see the movement of convection currents in the pan. The warmer soup moves up from the heated area at the bottom of the pan to the top where it is cooler. The cooler soup then moves to take the warmer soup’s place. The movement is in a circular pattern within the pan (see picture above).

The wind we feel outside is often the result of convection currents. You can understand this by the winds you feel near an ocean. Warm air is lighter than cold air and so it rises. During the daytime, cool air over water moves to replace the air rising up as the land warms the air over it. During the nighttime, the directions change — the surface of the water is sometimes warmer and the land is cooler.

Radiation is the final form of movement of heat energy. The sun’s light and heat cannot reach us by conduction or convection because space is almost completely empty. There is nothing to transfer the energy from the sun to the earth.

The sun’s rays travel in straight lines called heat rays. When it moves that way, it is called radiation.

When sunlight hits the earth, its radiation is absorbed or reflected. Darker surfaces absorb more of the radiation and lighter surfaces reflect the radiation. So you would be cooler if you wear light or white clothes in the summer.

When we eat, our bodies transform the energy stored in the food into energy to do work. When we run or walk, we “burn” food energy in our bodies. When we think or read or write, we are also doing work. Many times it’s really hard work!

Cars, planes, light bulbs, boats and machinery also transform energy into work.

Work means moving something, lifting something, warming something, lighting something. All these are a few of the various types of work. But where does energy come from?
There are many sources of energy. In The Energy Story, we will look at the energy that makes our world work. Energy is an important part of our daily lives.
The forms of energy we will look at include:
* Electricity
* Biomass Energy – energy from plants
* Geothermal Energy
* Fossil Fuels – Coal, Oil and Natural Gas
* Hydro Power and Ocean Energy
* Nuclear Energy
* Solar Energy
* Wind Energy
* Transportation Energy
We will also look at turbines and generators, at what electricity is, how energy is sent to users, and how we can decrease or conserve the energy we use. Finally, we’ll look at the “newer” forms of energy…and take a look at energy in the future.