Tuesday, June 11, 2013

The Exchanger.

Fossil-fuel power plant. (WKnight94. Wiki.)

Fred never even knew what an exchanger was until he climbed into one. It’s basically just a heat-exchanger. This one was for hot gases. The space they were in was for maintenance.

An exchanger is two plates of steel, punched full of two-inch holes, set so far apart. Between the two plates is a series of steel tubes, hundreds of them, all welded into place. Hot gases go through the pipes, cold air passes around them. The welds are inspected as the system must hold a given pressure and temperature. The exchanger is welded into a flue, and a cross-flue brings in cool outside air, which flows around the tubes and goes into the combustion chambers pre-heated. It boosts the efficiency of the system. At least that was what Fred thought.

He had dropped out of high school. Hot air from the smoke stack is cooled inside the tubes. Solids in the gas stream condense in the exchanger. It reduces emissions. Every so often guys like him get to suit up, wear goggles, work boots, ear plugs and a hard hat. They clip a respirator on their belts, and carry a couple thousand pounds of tools and equipment up catwalks and ladders. They bring it all in through an eighteen-inch hatch,. They squat and crawl around in a room four and a half feet high, ten feet wide and thirty feet long, with a floor and ceiling full of those damned two-inch holes, and clean them out with a snake. They get to make nine, or ten, or eleven bucks an hour if the guys around him were anything to go by. Starting off at nine, he’d get a buck an hour raise in about six months or so many hours worked. Fred knew the snake intimately by now. Once pink, it was now a grubby red. It was one-point-one inches in diameter and weighed about eighty pounds per fifty foot length. It leaked ‘x’ amount of air at every metallic snap-joint, which slowed the rate of rotation…but didn’t make it any easier on the hauling.

He was eating a lot lately and seemed to crave sleep.

They had all swapped stories over the lunch trailer table, and one or two of them seemed to know each other. They hung out on the weekends at some place up the lake with their wives and kids.

They knew a little bit about each other, but there was always a new face and you only shared what was comfortable. Fred was fitting in. He was drawing a pay cheque, and he had managed to survive the bull work and crappy shifts, always being called in at the last minute, up until now.

They were on the southeast side of the powerhouse, where a tangle of yellow-painted ductwork led into the bottom of Stack One. No one had even the slightest idea of what was in the crud. No one really cared. They just tried to keep it out of their eyes, and their mouths, and some wore dust masks in a forlorn effort to avoid breathing it in.

Macrofouling of exchanger tubes. (tapprogge.de. Wiki.)
There are two operations involved. A generator on the ground provides air pressure to a series of rotating ‘snakes,’ basically a wire bottle-brush on the end of a cable, enclosed inside of a greasy, laminated rubber tube, soft on the outside so it can be handled. It goes around and around and scrubs those tubes right out. There are two snakes and two pairs of guys working in the chamber. It also makes power for the lights, on the ends of hundreds of feet of extension cord. The crew consisted of eight labourers, an operator for the vacuum truck, and the foreman. Two or three are on the ground at any given time, watching over the truck and generator or just on break. The foreman comes and goes, checking on other jobs throughout the plant as the firm had a lot going on during the shutdown.

Guys sort of didn’t like him hanging around, looking over their shoulders all of the time, and all foremen knew that instinctively. He was there to problem-solve but not otherwise interfere. They knew he was around. This was a good crew. He knew it and they knew he knew it. Or so someone had figured only just the day before.

The men sit on a plastic milk crate, the only thing that has been found to be the right height and able to take the weight. Men shove that rubber snake up those tubes for twenty-five feet or so until it pops out into the open flue or chamber which lies, presumably, above the exchanger. Fred had never been up there. You could do fifteen or twenty holes in a half-hour shot. He’d only been working for the company for about three weeks.

Fred’s arms, shoulders and neck were aching, as he sat in the harsh shadows of the quartz-halogen working lights. It was the second of three shifts on nights. They were about four hours into it. He pulled the snake out and looked at his watch before shoving it up the next tube. His partner Lloyd pulled the screaming vacuum hose away and chalked an ‘x’ beside the tube he had just done.

The whine of the snake and the howl of the vacuum hose and the guys working on the other end, yelling back and forth, all combined to make talk difficult.

“Another ten minutes.” They were doing half-hour shots.

Lloyd nodded. Then it would be his turn, and Fred could sit there and rest so to speak. He would also have to hold their vacuum hose, the end of it securely taped to a four-foot length of hockey stick, and try to grab as much crud as he could when it fell out of the hole. Otherwise they would be knee-deep in it and have to shovel it out. Also, the next reactor, right underneath them, still had to be done. It was better than the snake. After that it would be Fred’s first break.

Vacuum Truck. (Remi Kaupp, Wiki.)
The whole crew was filthy with the yellowish crusty stuff that fell out of the tubes.

An inevitable question from one of the new guys, asking why they had to go in from the bottom, had been quickly answered. It prevented clogs and jams, which was what happened when tubes were bored out from above. The crud went down holes already half-plugged, and so they didn’t do it that way. Pulling the snakes back up wouldn’t have been much better anyway. It might have been worse, when he thought about it.

It was six of one and half a dozen of the other for the men involved.

It was killing work, and their twelve-hour shifts were carefully calculated to produce as much progress as possible, with the smallest possible crew, while at the same time just trying to survive for the next shift. They all took equal turns at each job. The safety man outside the hatch, walky-talky in his lap and seated on his own plastic box, would rotate though when his turn came too. There was another labourer down by the vacuum truck as the operator didn’t do unskilled labour, not at any price, and they might need something or someone.

Fred was just looking over at the other guys. Cursing, Davis yanked and tugged at the stiff hose, all curled up around his feet and kinking and moving on its own volition seemingly, as he gave the pink, fleshy-coloured thing another downward pull and a cloud of dust came down in his lap.

His helper Johnson caught Fred’s eye and he giggled like a schoolgirl. He winked at Fred. That’s when he put the end of the three-inch vacuum hose up to Davis’s crotch area. It snapped on with a sick gulping sound and the sounds in the room quickly went up to a higher wavelength.

That’s when they learned nine hundred pounds of vacuum pressure on a black plastic corrugated hose could suck a man’s guts right out of him in no time flat.

Davis was already dead by the time his face jerked down, as white in the gills and big in the eyes as any man ever seen before or since. His arms fell way from the snake, which hung motionless. His mouth was a big round ‘O.’ Johnson stopped laughing, yanked the hose aside in a pink cloud of nameless goo, flung it behind him, and then put his hands up to his mouth. The spreading red stain on the middle of Davis’s white coveralls, right in between the legs, began to drip and flow. No one said a word. Lloyd’s back was turned anyway. He didn’t know what was going on.

But Davis was already dead as he settled slowly backwards off of his perch, holding onto the middle of what was left of him, and making loud rasping sounds, the noise of his falling imperceptible in the roar and whine of the tools.

It just took a while to figure it out.


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