The Adventures of Duke Waters: Chapter 3

A few months later on a late Friday afternoon, I tried calling Duke again. Duke was gracious enough to offer his services when I was in a bind, so I figured, “Why not see what this guy can really do?”

With “Miller Time” on his mind, Duke picked up the receiver, and strained to hear me tell him about my latest woe. I told him that I was the project engineer on a big water project down in Savannah.

“What trouble have you gotten into this time?” Duke asked, cheer in his tone.

“I’m not in trouble; it’s just that I’ve got clients hassling me because a brand-new water pump in Savannah is putting out 265 feet of head and only generating about half of the design flow.”

At this point, Duke quizzed me on a long list of potential problems, including power factor, motor voltage, supply head and possible pipeline restrictions such as a bad control valve.

I told Duke, “The pump was flow tested by the manufacturer, all of the power feeds checked out and I’ve been up and down the seven miles of 16-inch pipeline three times looking for problem valves.” I added, “The check valves are open, all the line valves are open, and the altitude valve at the tower is indicating full open.”

Duke asked, “Are there air valves on all the high points?”

“Yes, so where the heck is the extra headloss coming from?”

At a point in the conversation like this, Duke felt the need to assure me. “There is a logical explanation for the problem; there always is.”

“Duke, could I trouble you to fly up here in the morning and help me out? The owner is holding six figures on me until I can get this pump station to meet spec.”

Duke was gracious and replied, “Don’t sweat it; I’ll call you from the airport when I land in a couple of hours.”

I guess one of the perks of being a semi-retired, freelance engineer is that Duke had already wrapped up his 54 holes this week (probably by Tuesday) so he could leave the links to the duffers on the weekend and put in a couple of honest hours of work on Saturday. So he made a call to the airport and had them roll out his Cessna Citation X and gas it up. His Jag was humming smoothly on all 12. It was a 10-minute drive, barely enough time to get a Macanudo Cru Royale fired up. Before he knew it, his Cessna rolled onto the tarmac. He jumped up behind the controls and landed in Savannah in two hours and 650 miles later.

He found me in an anxious state. “Duke, thanks for making the trip,” I said. “Let’s zip over to the site and have a look.”

We entered the pump station and took the two flights of stairs down to the pump floor. There we found the 240 horsepower Worthington centrifugal pump straining to deliver flow to the grid. We surveyed the various suction, discharge, check and relief valves in the pump piping.

After completing his inspection, Duke said, “You were right in that all the valves were properly positioned,” and added, “Let’s take a trip out to the line and have a look at the air valve vault on that hill to the north.” Duke had a hunch.

Duke took one quick glance at the air valve to confirm his hunch and told me to come on up.

“Johnny B,” he quizzed, “Do you know what the three types of air valves are?”

I responded with, “What do you mean? An air valve is an air valve, right?”

Duke simply replied, “I’m hungry and you’re buying me dinner before we solve this problem.”

I drove us over to the Pirate House on the other side of the Historic District, away from the tourists on River Street. The story goes that Robert Louis Stevenson ate here and was inspired to write Treasure Island while in Savannah. I heard the place was haunted, so that was enough attraction for me.

We walked through the dimly lit entrance and found a table.

Moments later, a server arrived with a CC Manhattan for Duke and asked politely, “What can I bring for you, young man?”

Dumbfounded, I replied, “I’ll have what he’s having.” After the server left, I said, “You’ve been here before?”

Duke said, “Johnny B, let’s just say that I have been around the block quite a few times.”

And that is when I adopted Duke’s smooth Canadian Club Manhattan as my drink of choice. Sometime later, I learned in Wisconsin that they call them “Brown Mumblers,” because after one or two of them your diction becomes horribly scrambled. Not that I could ever notice.

After my first CC Manhattan, I got enough gumption to ask Duke, “So how did you get that ugly scar on your forehead?”

Duke was taken aback a little by my directness but replied, “It was a rookie mistake.”

He didn’t elaborate, so I said, “I’ve made a living making rookie mistakes. Once, I was testing an oil-powered butterfly valve controlled by a solenoid valve that wasn’t shifting properly. I shut off the 80 psig oil supply and proceeded to remove the pilot, not realizing that there was trapped air and oil under pressure in the hydraulic cylinder actuator. Needless to say, as I loosened the pilot, the trapped pressure gave me a bath in hydraulic oil covering my face and hair. I had to wash my hair with safety solvent. I won’t make that rookie mistake again.”

After his second CC Manhattan, Duke loosened up a bit and told his story. “When I was a rookie out on the road, I was testing a pressure relief valve on top of an enormous 15-foot diameter pressurized steel air tank. I was sitting on an equipment platform over the tank next to my test valve and saw that there was no pressure gauge on the tank. So I leaned over and removed a quarter-inch, square-head pipe plug with a crescent wrench while the tank was under 100 psig pressure. As a rookie, I had no clue that compressible gas would propel that pipe plug about 80 miles an hour off my noggin. It left a little mark that reminds me every day to work safely.”

“Damn, you were lucky!” I said. “Once I was down in the bottom of this dark, dank and smelly drywell of a sewage lift station in Dallas. Like an idiot, I looked up with my head back to examine the pump discharge piping and a huge slobber of sewage cascaded down and hit the back of my throat. I spit my guts out for ten minutes, but there is not enough whisky in Ireland to take that taste out of your mouth.”

Duke laughed and said, “I hear you Johnny B; I had a similar encounter with sewage while installing some 8-inch ball checks on a raw sewage lift pump. The welded steel flanges were cupped a bit, so I used quarter-inch thick red rubber gaskets to compensate for the uneven flanges. I figured, what the hell, these pumps only run at about 50 psig. All was going well until the pump shut off and a water hammer blew out a chunk of the gasket and soaked me in sewage from my shoulders down. I guess I learned that day that ball check valves tend to slam and thick rubber gaskets are not made for high pressure service.”

“OK,” I said, “all this talk of raw sewage is getting me hungry. Hey Duke, by the way, how is it an engineer can afford a plane and a Jaguar?”

Duke said, “Well, I can’t say,” and just laughed. He finally shut down the conversation with, “OK, here comes our chow.”

Over a fist-high plate of spaghetti, Duke explained the differences between air release, air/vacuum, and combination air valves as defined in American Water Works Standard AWWA C512 and asked, “And what type of air valve did you install on your pipeline?” knowing full well that the valve he saw in the vault had a large four-inch outlet port through which he could see the top of an air/vacuum valve float.

I smartly replied, “I thought it was an air/vacuum valve so as to provide good vacuum protection for the pipeline.”

Duke explained, “It was indeed an air/vacuum valve, but an air/vacuum valve exhausts and admits air rapidly during filling and draining of the pipeline, but once the pipeline is pressurized it will not open to relieve entrapped air. Only air release or combination air valves will relieve air while the pipeline is under pressure.”

He added, “When only air/vacuum valves are used, the trapped air will increase head loss at high points. The cumulative effect of increased head loss at several high points can be enough head loss to stop the pump flow all together.”

“Holy crap!” I muttered.

Duke concluded, “You need to add some air release valves to those air/vacuum valves and your mysterious headloss will disappear. The air release valve will release the entrained air when the pipeline is at full pressure. If you had used combination air valves in your design, you would have saved $2,500.”

“What $2,500?” I asked.

Duke left me with the invoice for a day’s service (and the check) and caught a cab back to the airport in time to catch Saturday Night Live before bed.

Up next in the series: Duke helps Johnny B troubleshoot galvanic corrosion in valves at a wastewater reclamation plant.