Dear Viewers of this blog,
More than half the people who view this blog are seeking information about hydrostatic testing tubular heat exchangers.
In response to people who request a copy, I will email a PDF version of MGT Inc.'s proprietary hydrostatic testing procedure.
Wednesday, February 15, 2012
Sunday, February 12, 2012
MORE BOOKS BY STANLEY YOKELL
Recently written and submitted to Vantage Point Publishing for review:
A Boy Grows in Brooklyn
Beneath the Surface.
Here is the first story in the book called A Strange Dive:
A Boy Grows in Brooklyn
Beneath the Surface.
Here is the first story in the book called A Strange Dive:
Joe Steen and Thura served two hitches as Navy divers. Working together, they became good friends with trust in each other’s competence. Now civilians, they quickly became certified PADI and NAUI Scuba Instructors. For a while they worked for a small New Jersey Scuba party boat operation. But when it failed, owing them each a month’s pay, they decided to try to find places in warmer waters as Divemasters caring for tourist divers. They soon found an operation on Bonaire in the Netherlands Antilles that was happy to take advantage of their experience.
Although Bonaire had become a tourist destination, they fell in love with the place and its people, even learning enough of the native tongue Papiamento to communicate with the local population, none of whom seemed to think it strange that a blue-eyed, tall, blond-haired man and a short darker skinned, black-eyed oriental one should be fast friends. Joe and Thura were enthusiastic about the island’s policy of protecting the reef and keeping its pristine environment for wildlife to flourish in the surrounding waters. They became strong supporters of STINAPA, Bonaire’s reef protection organization.
Joe, the son of retired Navy Seal Max Steen, spent an ideal boyhood with a father whose gruff ways hid his deep affection for his son. His mother Rose, whose obvious devotion to her husband and son, did not interfere with her prowess as a competitive swimmer on the U.S. Olympic team thought he was the brightest, most wonderful son. Although Max’s duties often took him away from wife and child, his return each time was cause for a celebration.
Joe’s parents had him swimming before he could walk. Their life experiences had freed them from prejudices about people’s origins, religious preferences, skin color and ethnicity. It was the most natural thing for Joe’s dad to teach his son how to dive and how to take care of himself in the rough and tumble world. Because Max and Rose placed a premium on education, learning and physical fitness Joe grew up to be self-confident, well-educated and physically fit. His announcement on graduating from MIT with a degree in physics that he was seeking a commission in the Navy as a diving officer brought smiles to his adoring parents and an admonition from his dad not to be seduced into becoming a Navy Seal.
Max Steen told his son, “Despite the public perception, there is not much glamour, but lots of hard work and danger in being a seal. You don’t get to enjoy the underwater environment except in the small amount of spare time the Navy allows you. Besides, you never know if some stupid politician is going to have you sent on a mission with which you disagree. You’d be lots better off serving a hitch or two as a Navy diver, spending some time as a Scuba instructor and then settling down to a career in physics. You might even want to go back and get a doctorate in the subject.”
Joe took this advice to heart, especially because his dad had earned his doctorate in mechanical engineering after ending his career as a Navy Seal.
Single named Thura was the son of escapees from Myanmar who had succeeded in achieving refugee status in the United States. His father Saya Naing had been an officer in the Myanmar army who refused to carry out an order to fire on a small group of protestors. With his pregnant wife Daw Mya Aye, Saya Naing took a roundabout route that finally led to the United States where they settled into small community of other Burmese escapees in San Francisco. Thura was born shortly after their arrival.
Saya Naing quickly found work that suited his nimble mind. He never talked to his son about life in Myanmar. But he made sure that his son would be educated, and like many other Asian immigrants, insisted that Thura learn his parents’ language and study hard. Thura was an obedient and respectful son. He spoke English without accent, Myana Bhasa (the official language of Myanmar), and Spanish. His parents never discussed their country of origin. But Thura made himself aware of its history. He took pride in the work of U Thant at the United Nations. His hard work as a student took him easily through the University of California in Berkeley where he too studied physics. This gave him a common interest with Joe. At Berkeley, Thura swam competitively. On graduation, he decided to give back to the country that gave his family refuge and comfort and applied to become a U.S. Navy diving officer. It was a happy coincidence that the Navy assigned Thura and Joe to the same units for training and beyond. Over the occasional beer, they would talk about physics and their plans to go on to graduate school when they were ready to settle down.
For relaxation and to take a break from sometimes adoring women tourists Joe and Thura flew the short distance from Bonaire to Margarita Island off Venezuela. There they spent hours under water taking professional quality photographs and videos in the relatively shallow waters of La Pecha, Payape, La Punta, Cominoto, and El Infierno islands. On Payape they encountered Jesus Pinero a Cuban diver. The conversation was easy and relaxed because Joe and Thura both spoke Spanish fluently. Sitting over drinks with Jesus, they discussed various dive sites. Much of their talk was the talk of people who understood each other’s love of the physical pleasure and relaxation that only proficient Scuba divers can know.
Jesus sipped his drink and talked of his homeland. “You know that Dr, Fidel was a Scuba diver in his prime, don’t you?” he asked.
Thura was not much given to conversation and kept silent. Joe answered. “No, I don’t know much about Senor Castro”, he replied, “In fact, I don’t know much about Cuba except that there are restrictions on Americans traveling there”.
He did not want to get in to the history of relations between the United States and Cuba despite knowing a good deal more than he let on to Jesus.
Jesus continued. “Dr. Castro has done everything in his power to maintain the waters around my homeland as a region protected from pollution. Cuba maintains the reef as a marine park. It is one of the most beautiful places in the world”, he said proudly.
“Then what brings you here?” Joe asked, “The diving isn’t all that spectacular.”
Jesus answered with a smile, “We are friends with the Venezuelans and their women are beautiful and perhaps more available than in Cuba where morality is highly valued.”
Although both Joe and Thura had more or less continuing relations with women on Bonaire, neither they nor their female friends believed strongly in constancy. That was one of the reasons they had come to the Venezuelan islands. But Jose’s talk of the pristine reefs around Cuba caught their attention. They looked at each other and they knew that they were going to dive in Cuban waters.
Returned to their hotel, Joe fired up his notebook and began investigating Cuban dive sites. He Googled “Cuba Scuba”. Aware that the United States frowns on Americans visiting Cuba he took note of a statement on one of the first sites that popped up that read While American citizens can visit Cuba, passport warnings advise that it's "not recommended," and American companies cannot legally do business with Cuba because of a U.S. trade embargo. Most trips, therefore, are booked through Canadian or Mexican tour operators.
He thought there shouldn’t be any problem booking from Bonaire or even from this dinky island. Let’s see what kind of accommodations they offer.
He and Thura looked over the many Cuban places recommended for diving on the internet. They settled on the MeliĆ” Cayo Coco hotel complex. Incentives were its five-star rating and the fact that the website said for adults only (people aged 18 and over). They noted that it was fairly isolated being situated on Las Coloradas beach, in Cayo Coco, connected to the mainland by a 17 kilometer causeway. They anticipated that they would find a few newly-married honeymoon couples, unmarried couples enjoying amorous trips and Scuba divers who preferred places not populated by tourists looking for bargains in jewelry and watches.
They visited the spanking new dive shop, talked with the manager and arranged for a private dive boat, weights and tanks. They had brought their own BCs, jackets and skins, flippers, masks and snorkels. As in their Navy days, they had underwater communication modules. Typical of long-time dive partners, they communicated with each other only to call attention to an underwater sight or in the event of a difficulty. The dive shop manager was delighted to have two experienced divers patronizing his facility and he promised that they would not regret diving the waters of Cayo Coco.
Careful divers, they did a checkout dive off the beach before setting out with coxswain Mario Perez for their first boat dive. They brought three tanks each which they carefully stowed in the boat’s racks. Perez told them that he knew all the sites around Cayo Coco including where they could find sharks, octopuses, fish larger than inhabited other places and caves he had investigated. They had heard many such stories elsewhere and knew they would have to investigate for themselves.
Although they brought still and video cameras and lights, they followed their usual practice of doing the first boat dive free of equipment just to enjoy the relaxation and assess the underwater terrain. What they saw was as promised with large schools of fish, wrasses, butterfly fish, an octopus lying in wait for prey, Bermuda lobsters, the largest grouper they had ever seen, trunk fish, sea horses that had become rare in Bonaire, large Anemone, hard and soft corals, gorgonians, and sea worms. They called to each other when an interesting sight came into view. They were nearly at the end of air when at the limit of his vision Thura spotted something that he had never seen underwater.
“Joe”, he called, “Look where I’m pointing and tell me what you see.”
Joe followed the line of sight from Thura’s arm.
“Do you see what I see, what looks like two mermaids?” Thura asked.
Joe responded, “I haven’t smoked any of those funny cigarettes that cause hallucinations, but that’s what I think I see. Let’s get a little closer.”
As they finned toward what they thought they had seen the creatures disappeared from view. They were now out of air and came up, slowly snorkeling back to the boat. On board, they questioned Mario, “Has anyone ever seen a fish here that looks like a mermaid?” Joe asked him.
Perez shrugged his shoulders. “I never hear of such a fish”, he said.
The rest of the day’s diving was pleasant and interesting and Thura took still pictures while Joe held the lights and Joe made a video that he planned to edit when they got back to Bonaire. They did not see the mermaids again.
Back on the beach their conversation was about whether to bring down still or video gear on the next dive. They were sitting on the deck watching the sun set and sipping beers when Jesus Pinero sat down at their table. “Good to see you again Jesus”, Joe said, “Going to dive here for a while?”
“Si, Si”, Jesus responded, “I have connections with the hotel. Diving is good. You been down?” he asked.
“Burned up three tanks yesterday”, Joe answered.
“So what did you see I should look for?” Jesus asked.
Joe and Thura looked at each other.
“Jesus”, Joe asked, “You’ve been here before, right?”
“Si, Si”, Jesus responded.
“Did you ever see a fish that looked like a storybook mermaid?” Joe asked.
Jesus smiled but did not answer. Joe and Thura took his non-response to mean that he thought they were joking. They did not pursue the question of mermaids.
The next morning Joe and Thura were pleased to see that there was virtually no wind and no clouds overhead. No wind and bright sunshine would mean maximum underwater visibility. They ate an early breakfast and set out with four tanks each. They planned to take still pictures in the morning and videos in the afternoon dives. Diving makes people hungry, because even ‘though good divers are relaxed under water, diving burns up many more calories than idling on the beach. They brought high-calorie sandwiches of peanut butter and jelly, fruit and hard candies. The compressed air that the divers breathe on relatively shallow dives dries out the tissues, so they brought a cooler of water. Neither Joe nor Thura had it in mind to search for the “mermaids”. But it was in the back of their minds that if there was another sighting of the strange fish they would capture it with their cameras.
They had just gone over the side of the boat after lunch with the video camera and lights when Thura again called to Joe, “Joe, look straight in line with the bow of the boat and tell me what you see.”
Joe looked. “Mermaids”, he gasped, “Let’s get nearer and take some pictures.”
Toting the video camera and lights they headed toward the strange fish. But the fish disappeared, rising to the surface and swimming toward the beach. Frustrated, the pair continued videoing underwater wildlife. They turned their attention to a cluster of sharks that were patrolling a large coral head that looked like an island on the white seabed. Their two morning dives were at shallow depths – less than 100 feet below the surface. Nevertheless they decided to lie in the shade of the covered part of the boat for a couple of hours before making the afternoon dives.
Next morning was again clear and calm. Perez asked them, “You like wall dive?”
Joe and Thura had enjoyed many wall dives, most recently at Tongue of the Ocean where they made a deep dive using nitrox to minimize the problem of nitrogen accumulation and decompression. However, their tanks were filled with compressed air. Thura said, “We like.”
He asked, “How deep?”
“She go down more than 75 meter”, Perez answered, “but is long boat ride to site.
Ever careful Joe and Thura decided to limit their wall dive to 150 feet (a little more than 45 meters) and to do 10 minute decompression stops at 20 and 10 feet. Perez took them almost an hour away and dropped the anchor. “Este ayer”, he said.
They went over the side. Perez handed them the still and video cameras and the lights. The wall they approached was as sharp a drop off as they had ever seen and they drifted down photographing and videoing the different kinds of wildlife that live at different depths. A persistently curious and very large barracuda swam so close to their face masks that they laughed that the fish was trying to communicate with them. As they had done in the past, they discouraged the barracuda by taking out their regulators and blowing large bubbles of air. The barracuda left but hung around nearby. The wall dive was very satisfactory and they busied themselves writing notes about it on the long voyage back to Cayo Coco where they planned to spend the rest of the day photographing and videoing the abundant wildlife. Although they did not discuss it, each of them was hoping to capture the image of the pair of mermaid fish the thought they had seen there.
Joe and Thura planned the next day’s diving to be a day of looking around unencumbered by cameras and lights – a relaxed day to enjoy the sights and feel of being part of the sea. They were fortunate in having another calm, windless day with excellent visibility. They wandered idly down not staying close to each other but keeping each other in sight. If one saw something interesting he would talk to the other and lie still until his partner approached. It was thoroughly enjoyable. The two were watching an octopus change color when at the corner of his eye Thura saw the two mermaids. Without a word to Joe he finned over to them and grabbed the tail of the nearer one. To his amazement her skin slipped off from the waist down revealing two lovely female human legs surmounted by a bikini swim suit. The end of each leg was strapped to fins that had evidently been in the tail of the sheath. A light weight belt and small tank was strapped to her waist and he could see a very compact regulator. She quickly took the arm of her companion and they disappeared to the surface, rapidly swimming toward the beach. Thura called to Joe to join the chase but they could not catch up.
Now there were mysteries to be solved. Where would the two women get such costumes and such gear? Why would they don it and swim bare breasted underwater. Bare breasts at Cayo Coco were not an unusual sight. The lodge specifically advertised that there were no restrictions on nude sunbathing. But it was rare to see woman swimming nude in the blue water and they had only once seen a woman dive completely nude except for her Scuba gear. That was off Grand Bahamas Island. And they knew she was a member of the staff of the major Scuba organization on the island and that she was noted for her sometimes bizarre behavior.
They resumed their day’s activities, not discussing what they had seen with coxswain Mario Perez. That evening Jesus Pinero joined them as they sat at dinner. “Have a cervasa, Jesus”, Joe offered.
“Mucho gracias”, Jesus accepted, “You dove today?”
“Yes”, this was a non-picture and video day. We just went down to look and play”, Joe responded.
“See anything interesting?” Pinero asked.
“Would you believe that Thura actually made contact with a mermaid?” Joe answered.
Pinero became very serious. “Oh”, he said, “Tell me about it.
“Well he grabbed her tail and she swam out of it. Turns out the two women were in costume and, under sheaths of what looked like fish scales they were wearing weight belts, small tanks and mini-regulators.”
“And did they have masks?” Jesus asked.
Thura said, “They had tiny goggles so from a distance you could not see Scuba masks.”
“You must not talk about this to any other divers”, Jesus said.
“Why not?” Joe asked.
“Is a government project to entice tourists with a story about mermaids being sighted in Cayo Coco”, he said, “You reveal what you found there will be trouble. Best you just say nothing.” There was an implicit threat in Pinero’s words.
“And if we do?” asked Thura.
“You will be in big trouble with the authorities. Maybe even be arrested as American spies”, Pinero responded.
Joe Steen and Thura returned to Bonaire. They did not mention mermaids to anyone there. Who would believe them?
Saturday, October 22, 2011
Books by Stanley Yokell
Viewers if this blog can purchase an illustrated print copy of An Old Timer's Scuba Tales, by Stanley Yokell from Amazon.com. 
Amorous Publications subsidiary of Vantage Point Publications has published. Stanley Yokell's novelette, "House of Mirrors" under his pen name Stanley Israel. It is available for purchase on Kindle and Nook and in paperback from bookstores, Amazon.com.
Amorous Publications subsidiary of Vantage Point Publications will publish Stanley Israel's anthology, "Love, Sex and Erotica" in 2012..
Note to readers of these books
The genesis of House of Mirrors was a slip of the finger when I was searching for a book to read on my kindle. I inadvertently clicked on what was portrayed as an erotic story, mentally seeing the words as an exotic story. What I downloaded was a truly crude bit of pornography, written in language with which I am not comfortable. It was essentially street language that described sex acts in the crudest way, using crude language. I deleted it from my kindle.
That night, I began to think that over the years I have on occasion read erotic books, beginning as a boy with D. H. Lawrence’s “Lady Chatterley’s Lover” and later on one with a semi-erotic theme, “Being There” by Jerzy Kosinksi that was made into a movie starring Shirley McLane. I conflated that thought with the notion that I could write a more interesting erotic story than what I had inadvertently downloaded to my kindle. And that I could do it without using street language to describe self-love and other forms of amorous activity. I let my imagination rove and “House of Mirrors” is the result. This little book is the result. Subsequently I wrote the stories in the Anthology, "Love, Sex, and Erotica", which should be available for purchase shortly.
I submitted these works under my pen name, Stanley Israel to Vantage Point Publications and their subsidiary sent me contracts to publish the works. They are written under my pen name to avoid embarrassing family and friends who might be appalled that a man of my age and profession has and is capable of expressing such thoughts. Readers who might be offended by frank discussion of sexuality should not buy these books.
Vantage Point Publications will publish Stanley Yokell's murder mystery "Murder at Plato House" in 2012. It should be available for purchase shortly
Vantage Point Publicahtions will publish Stanley Yokell's murder mystery "The Murder on the Mall will be published later in 2012.
Amazon.com has published Stanley Yokell's book, "An Old Timer's Scuba Tales. It is available on paper back from Amazon.com and some bookstores and for download to Kindle and Nook.
Stanley Yokell's autobiography "A Happy Life", has been published by Amazon.com. It is available in paperback and on Kindle from Amazon.com and from some bookstores.
Stanley Yokell's books, "The Ride", "The Ship", and "Dog Stories" published by Xlibris are available in paper backe and hard cover for purchase from Amazon,com, book stores and Kindle
Edith Yokell's book, "My Life Stories" has been published by Amazon.com. It is available in paperback from Amazon.com and from some bookstores and on Kindle .
Stanley Yokell's book, "A Working Guide to Shell-and-Tube Heat Exchangers", McGraw-Hill, 1990 is out of print but used copies may be available on Amazon.Com.
"Tubular Heat Exchanger Inspection, Maintenance and Repair" written with Carl F. Andreone remains available from McGraw-Hill and other sources.
Sunday, July 24, 2011
PRESSURE TESTING FEEDWATER HEATERS AND POWER PLANT AUXILIARY HEAT EXCHANGERS
On July 20, 2011, the ASME published online Stanley Yokell' article "Pressure Testing Feedwater Heaters and Power Plant Auxiliary Heat Exchangers," in the Journal of Pressure Vessel Technology (Vol.133, Iss.5).
Viewers can access the article at:
URL: http://link.aip.org/link/?JPV/133/054502
DOI: 10.1115/1.4003468
Viewers can access the article at:
URL: http://link.aip.org/link/?JPV/133/054502
DOI: 10.1115/1.4003468
ASSURING TUBE-TO-TUBESHEET JOINT TIGHTNESS
Stanley Yokell presented his paper Assuring Tube-to-Tubesheet Joint Tightness and Strength on Wednesday, July 13, 2011 at the ASME Power Conference in Denver, Colorado. Readers who would like a copy of the PowerPoint presentation should request one by email to Info@mgt-inc.com.
Friday, April 15, 2011
A FEW TIPS ON CLOSED FEEDWATER HEATERS
In response to many inquiries about operating and troubleshooting closed feedwater heaters, we offer the following from the chapter "Achieving Reliability" of the course notes of our coppyrighted course, "Closed Feedwater Heaters-Mechanical Aspects":
Symptoms and Possible Causes of TTD and DCA Temperature Changes,
TTD Greater Than Design
A. Noncondensible buildup. Check Operating Vents.
B.Excessive pressure drop in desuperheating zone of horizontal heater.
Check condensing zone pressure.
C.Water leaking into DSH zone. Check for tube leaks or shroud leak in vertical channel head down heater. .
D. Shell side tube corrosion. Check for tube leaks.
E. Tubeside fouling. Check for snake skins inside tubes.
F. Tubeside pass-partition leaks. Check gasket on pass-partition covers or weld cracks at tubesheet.
DCA Greater Than Design
A. Low liquid leve. Check the liquid level.
B. Steam entering the drain cooler. Check for water hammer caused by steam collapsing in DC, It sounds like firecracker popping noise at the shroud welds and through tube holes at the end plate.
C. Horizontal split pass long drain cooler may have low liquid level or steam entering thrugh shoursd weld cracks, Check the liquid level. Check for shroud weld cracks. Listen for water hammer noise.
D. Vertical heater may have low liquid level or steam entering through shroud weld cracks. Check for shroud weld cracks. Listen for water hammer noise.
Check the Position of the Drain Valve Stem.
Knowing the position of the drain valve stem is useful because most drain lines and drain valve ststems are sized to carry much more flow than the normal drains flow rate. Consequently, if a minor tube break occurs, the drain system will probably be able to handle the extra drain flows. It is likely that the excessive drain flow will not have caused a noticable change in the DCA temperature, but it will be idicated by a cgange in the position of the drain valve stem.
Note: The HEI Closed Feedwater Heater Specification requires that the valve stem position should be checjed ib every shift.
Following are failures that can be repaired and ones that cannot be repaired but which can be treated so as to slow the rate of deterioration:
Repairable Feedwater Heater Failures
A. Tube-to-tubesheet joint attachment.
B. Impingement plate failures and damage.
C. Vibration failure damage.
D. Shroud weld failures when the flat divider plate is welded to the arcuate section.
Failures that are Not Repairable But Can be Treated so as to Slow the Rate of Deterioration
A. Tube failure in the top row of the DC in horizontal heaters at the end plate caused by steam entering the DC through the annular spaces betweeb the tube ODs and the tube hole IDs.
B. Tube failures in the top row of the DC in horizontal heaters at the back of the tubesheet caused by failure of the weld joining the DC flat divider plate to the back of the tubesheet.
C. Tube failures in the outer bends of U-tubes caused by vibration.
D. Tube failures in the inner bends of U-tubes caused by Stress Corrosion Cracking (SCC).
E. Tube failures at the back of the tubesheet caused by SCC and/or vibration.
Symptoms and Possible Causes of TTD and DCA Temperature Changes,
TTD Greater Than Design
A. Noncondensible buildup. Check Operating Vents.
B.
C.
D. Shell side tube corrosion. Check for tube leaks.
E. Tubeside fouling. Check for snake skins inside tubes.
F. Tubeside pass-partition leaks. Check gasket on pass-partition covers or weld cracks at tubesheet.
DCA Greater Than Design
A. Low liquid leve. Check the liquid level.
B. Steam entering the drain cooler. Check for water hammer caused by steam collapsing in DC, It sounds like firecracker popping noise at the shroud welds and through tube holes at the end plate.
C. Horizontal split pass long drain cooler may have low liquid level or steam entering thrugh shoursd weld cracks, Check the liquid level. Check for shroud weld cracks. Listen for water hammer noise.
D. Vertical heater may have low liquid level or steam entering through shroud weld cracks. Check for shroud weld cracks. Listen for water hammer noise.
Check the Position of the Drain Valve Stem.
Knowing the position of the drain valve stem is useful because most drain lines and drain valve ststems are sized to carry much more flow than the normal drains flow rate. Consequently, if a minor tube break occurs, the drain system will probably be able to handle the extra drain flows. It is likely that the excessive drain flow will not have caused a noticable change in the DCA temperature, but it will be idicated by a cgange in the position of the drain valve stem.
Note: The HEI Closed Feedwater Heater Specification requires that the valve stem position should be checjed ib every shift.
Following are failures that can be repaired and ones that cannot be repaired but which can be treated so as to slow the rate of deterioration:
Repairable Feedwater Heater Failures
A. Tube-to-tubesheet joint attachment.
B. Impingement plate failures and damage.
C. Vibration failure damage.
D. Shroud weld failures when the flat divider plate is welded to the arcuate section.
Failures that are Not Repairable But Can be Treated so as to Slow the Rate of Deterioration
A. Tube failure in the top row of the DC in horizontal heaters at the end plate caused by steam entering the DC through the annular spaces betweeb the tube ODs and the tube hole IDs.
B. Tube failures in the top row of the DC in horizontal heaters at the back of the tubesheet caused by failure of the weld joining the DC flat divider plate to the back of the tubesheet.
C. Tube failures in the outer bends of U-tubes caused by vibration.
D. Tube failures in the inner bends of U-tubes caused by Stress Corrosion Cracking (SCC).
E. Tube failures at the back of the tubesheet caused by SCC and/or vibration.
Tuesday, March 22, 2011
On Line Feedwater Heater Replacemment
Recently a question was circulated about how to safely install a feedwater heater on line. This consultant simply stated that it is necessary to have double block valves to protect pesonnel. However, Mr. Steven Kidwell,Project manager of Burns and McDonnal made a more informative comment. It is repeated here. This consultant is in complete agreement with Mr. Kidwell.
Here is Mr. Kidwell's comment
Double block and bleed is the only safe way of performing an on-line replacement. And it needs to be on all the pressurized (or vacuum) pipes, not just the mahor ones. The second block can be a spectacle flange to save money, but those spectacle flanges need to be installed ahead of time at an outage.
The other consideration is that normally the heater serves as an anchor for the pipe when the thermal stress analysis is done. If the heater is removed while the pipe is hog, the pipe will spring when the cut is made. So large temporary restraints need to be designed to hold the pipes in place so the new heater nozzles will mate up. Vof feedwater pipes and extraction pipes, these restraints will be massive. Commonwealth Edison pulled this off years ago, but because of the expense involved,they never considered it again.
Here is Mr. Kidwell's comment
Double block and bleed is the only safe way of performing an on-line replacement. And it needs to be on all the pressurized (or vacuum) pipes, not just the mahor ones. The second block can be a spectacle flange to save money, but those spectacle flanges need to be installed ahead of time at an outage.
The other consideration is that normally the heater serves as an anchor for the pipe when the thermal stress analysis is done. If the heater is removed while the pipe is hog, the pipe will spring when the cut is made. So large temporary restraints need to be designed to hold the pipes in place so the new heater nozzles will mate up. Vof feedwater pipes and extraction pipes, these restraints will be massive. Commonwealth Edison pulled this off years ago, but because of the expense involved,they never considered it again.
Subscribe to:
Posts (Atom)
