Hello and welcome to another edition of "Behind the Park." I'm Park Ranger Dave
Byers and in just a moment we'll get to explore a really unique
part of the Park that not alot of visitors get to see. In just a moment we'll head
inside to the River Transformed exhibit.
We'll get look at a real operating turbine. We'll watch the water flowing through the
canal,
into the turbine, dropping down. It's turning gears, pulleys, leather belts,
operating all five floors of machinery in the mills like the Suffolk Mill standing
behind me.
So if you'll join me, we'll head inside the River Transformed exhibit and
explore Behind the Park.
We're here inside the River Transformed exhibit standing over
the secret to Lowell's success. As we look down, we see a turbine in operation.
In the early part of the 19th century most of the mills in America were
powered by water wheels- the big kind of
wheels you often see in gristmills, but they weren't very efficient. They can
only take
sixty-four percent of the power of falling water and convert them into
energy that can be used in the mills.
In the 1840s, Lowell's chief engineer, a man named James B. Francis
did some experiments to come up with a new kind of water wheel. it was called a
turbine
and that's what we see in the pit beneath us. Here the water is flowing in
from the canal on the other side where we just were.
That water is flowing through an underground tunnel called the penstock.
just beneath me.
The water flows in, drops down in the chute case underneath us,
drops about 15 feet, and hits that turbine,
spins it, and that's what's spinning the gears we can see at the top of the
turbine pit.
Now we can't see inside this chute case to see exactly what makes this work
so we've taken one apart and put it over on another side of the exhibit.
We're going to go take a look at exactly all the parts and pieces, the innovations in
technology that go into making this
system work. So follow me. So the water travels through the canal,
through the penstock, that underground tunnel, drops down fifteen feet,
heads to the guide vanes in the chute case towards a turbine runner.
The water then heads in and hits the blade of the turbine runner,
imparting its energy and spinning this turbine runner.
The turbine runner spins, it spins a drive shaft heading up to the top of the
turbine pit.
The drive shaft spins the bevel gear sitting at the top of the pit. That bevel
gear meshes its teeth with another bevel gear
that changes the direction of the energy and spins the drive shaft.
That drive shaft is connected to a large flywheel
that spins a leather belt that operates the machines in the mill.
So what controls this turbine system? What controls the amount of power available
to the machines in the mill?
Well, it's a fairly complicated nineteenth century engineering marvel. This is the
fly ball governor and it's down here at the
lower level of the turbine. This governor is attached to the turbine by a series of gears
and belts and as the turbine spins, it spins these fly balls.
That's why it's a fly ball governor. And as these spin faster and faster, they swing
out they open a valve. That valve sends hydraulic fluid through the governor
machine,
operates another valve operated by this wheel,
and as it spins the collar ring inside lifts up, lets more water in to the turbine
and it speeds up. So how does this fly ball work? Well it's really simple physics.
You take a ball, like this, hanging on a string and if I were to twirl this
over my head,
it's spinning around fairly low but as I increase the speed
that fly ball begins to lift itself up. [sound of ball hitting videographer's head]
The turbine technology developed here in Lowell has now spread
around the world.
Francis' turbine is tremendously efficient- about eighty-five percent
efficient
and the turbines that he developed are now used in places like Grand Coulee Dam,
Hoover Dam, and the Three Gorges project in China.
About 20 percent of the world's hydropower
is created using Francis turbines. It's a remarkable legacy that Lowell's
technology and innovations that took place here
have now spread around the world and gone global. Well, we hope that you
enjoyed our
inside look at the River Transformed exhibit. During the summer season we do
have this exhibit open on our
afternoon trolley tour. Check with our Visitor Center or check our website at
nps.gov/lowell for
details and until next time, we hope to see you "Behind the Park."