Why's That: A Straight Answer On Bending Pipes
Western Michigan University’s Robert M. Beam Power Plant is easy to miss in the summer when leaves obscure the view from Kalamazoo’s Stadium Drive. But earlier this year, when the trees were bare, Paul Toth of Kalamazoo noticed something curious about big metal pipes that come out of the plant near the road.
“I don’t know a whole lot about plumbing but I do know you try to go pretty much in a straight line whenever possible,” Paul said.
These pipes start out in a straight line. Then they take a series of bends - like a staple, or a letter U with square corners - before they straighten out again. They cross over Arcadia Creek and disappear under Stadium Drive on their way to Western’s campus across the street.
“As I saw these my initial question was, why the big bends?” Paul said. “I can’t imagine that it was done just for fun.”
To find out, we called Western’s facilities department. That’s how Paul and I ended up at the power plant and then in the control room, taking in the knobs, dials, and green and red lights.
“Fortunately there’s nobody that looks like Homer Simpson running this so that’s a good thing,” Paul observed as we look around.
“No, we have no Homer Simpsons here,” Western Associate Vice President of Facilities Management Pete Strazdas said. “As a matter of fact on the way out you will see a Board of Excellence.”
The plant was built in the 1920s not by the university, but the Kalamazoo State Hospital, now known as the Kalamazoo Psychiatric Hospital. In the 1990s Western bought the plant and finished converting it from coal to natural gas. Strazdas says it provides 70 to 80 percent of Western’s electricity in a year.
He adds that it’s mainly in the summer with the air conditioning on that Western needs power from the larger grid. On this day, says plant director George Jarvis,
“We’re powering all of campus and the hospital and selling a little bit back to your house maybe. We get a few cents from Consumers on that.”
The plant generates that power with turbines that Strazdas says have much in common with the ones you’d find on an airplane.
We leave the control room and a few steps away, Strazdas and Jarvis open a panel. The turbine sounds like a saw - a loud one - and it does look like airplane guts. All the movement must be inside the metal casing draped that’s in tubes and wires.
As they make electricity, the turbines generate heat. Instead of throwing it away, the plant uses that extra heat to boil water. That’s this plant’s other big product: steam that’s piped to campus and the psychiatric hospital to heat the buildings. Strazdas says the pipes that caught Paul Toth’s eye outside the plant are steam pipes. We gather around for a closer look.
“It’s steam for the entire west campus,” Strazdas said.
Paul wants to know why these pipes have that odd, staple-shaped bend in their otherwise straight path to campus. Why would you make that path less direct? But Strazdas says the bend is necessary because of a familiar property of metal: that it shrinks when it’s cold and expands when it’s hot.
“As it expands it’s going to be pushing the pipe in both directions,” Strazdas explained.
But you don’t want the ends of that pipe moving back and forth and maybe pulling out of the wall. So you have to do something to absorb the expansion. That’s what this bend, or expansion loop in technical terms, does for the steam pipes at Western. Strazdas compares it to an archer’s bow.
“You can flex that back and forth because the ends are fixed. So it’s going to push it in or pull it out and that ‘U’ is going to be flexing just like a bow flexes,” Strazdas said.
You might not see anything as dramatic as this loop on your pipes at home. But power plant director George Jarvis says subtler bends in a house’s hot water pipes play a similar protective role.
“Even in your house you probably have a hot water heater, you’re going to have to have certain elbows to account for that pipe movement. Otherwise that pipe will move, believe me,” he said.
Most of Western’s steam pipes are buried, but Strazdas says if you could see them, you’d find expansion loops throughout the system.
Paul Toth says the bendy pipes he spotted from Stadium Drive now make sense.
“It’s a good thing that folks that know what they’re doing are doing this because it was be dangerous otherwise,” he said.
And, he adds, he’s impressed that the power plant recycles heat from electricity-making into steam.
“I thought I was being very efficient by having a geothermal unit at home, and pulling the heat off that for my water heater, you guys are doing that about a million times past that.”