Yankee Dryer

[HFRH28]

No, not the northerners.... The machine used in the paper industry to dry the paper. I was in a discussion the other day about Yankee Dryers rupturing and even leveling buildings when being cooled too rapidly during firefighting operations. I don't have one in my district, so i don't have the ability to pay a "pre-plan" visit to one. From what I found on my Google search, even stopping the Yankee from spinning can be dangerous, and that the maximum water flow that can be applied is roughly 25 GPM. I heard there are some pictures floating around of a site where a yankee ruptured, but no such luck in finding these pictures so far. Anybody?

And for those of you who wish to know what a yankee dryer is: http://www.globalequip.com/photos/bg_901299.jpg

[doughesson]

I learned in my short term as a Navy boiler technician before striking for bosun's mate that spraying cold water on a hot boiler is not a good thing.
Was that dryer insulated?Like you,I cannot go up close and personal to see for myself and ask questions.

[SWLAFireDawg]

I am not entirely familiar with waht this equipment does, but from the looks of the general design I would say it incorporates centrifugal motion and heat. If the operating temp was hot enough, I see where dousing it with water would cause uneven thermal contraction of the metal parts. This would likely further lead to a failure of a linkage or part, or separation of a mechanical component. The end result would likely be the rotating parts flying loose at what may be as much as 2000 to 5000 rpm's. Not pretty. If the operating temp was around 1000 degrees or so, you would also have a tremendous amount of steam expansion, basicly creating a water explosion.

I have seen an industrial furnace destroyed in a similar manner as to the boiler mentioned. A liquid fire occured in the fire box, and the snuffing steam used to put it out had a malfunctioning steam trap on it, so straight condensate (water) was thrown into the furnace thus creating a loud boom......

[Firegod32]

Check with FM Global's Forest Products group. They are in Dallas, TX and can be reached at 972-377-4808. Tell them you are with a FD and are looking for information on Yankee Dryers. If nothing else, ask to speak to one of the account or field engineers as they should be able to help. I know they have a LARGE loss history and likely some "UTH" (Understanding the Hazards) on these dryers.

[captainactivity]

Is someone looking for pictures of Yankee Dryer explosions?

In a fire I wouldn't go close to one of these things if it is operational. Just stay well back, too many unknowns.

Here is a link which may help.

http://www.vcos.org/resources/Yankee%20Safety.pdf

[PaperDoll]

Although I do not have photos of any failures of Yankee Dryers, I can give you a little information on them. They are cast iron, operate at over 400 degrees, and rotate at 40-50 mph. They are not to be stopped on a dime because the condensate will cause fractures which can result in an explosion. We have back ups to the back up to vent should everything fail and it stop quickly (or slowly for that matter). I would hope, as our facility has incorporated, any factory operating a Yankee would have their own fire crew who is specially trained on this beast. In my training, I was told the explosion from one would leave our entire site a crater. My safety records show an explosion of a Yankee once every 80 years on average worldwide.

Hope this is beneficial to you, even without photos.

[fouellette]

I have worked in a 3 paper mills that had Yankee Dryers and was responsible for inspection, maintenance & safety around the dryers. They are usually used in mills that manufacture tissue or other fine paper.

I don't have a picture of an exploded Yankee dryer, but I have seen some. Below is a link so you can at least see what they look like.

http://www.byronsoftware.org.uk/QA/by05001.htm

They are made of cast iron, usually weighing in range of 60 to 100 tons. The main parts are the "shell", which looks like a really bid pipe. The ends of the shell are capped with "heads". When an explosion occurs, it is usually the shell that fails, or the connection of the shell to the head.

They are used to dry paper. Steam is injected into the dryer and becomes condensate as heat is taken away by drying the paper. They experience a lot of thermal stress just from their daily operation. A cold, wet sheet is laid on the outside of the dryer as it rotates.

From the explosion photos I've seen, the heads don't move very far, but pieces of the shell fly everywhere, lifting off the roof, and riping the paper machine apart.

There are a a few reasons why they explode thermal stress from either warming up too fast or cooling one spot when the dryer is hot. It is OK to use a hose around the Yankee dryer as long as it is TURNING. The operations staff do this everyday when the hose up around the machine while it is running.

However, if you use a hose on it while it is hot..and stopped...there is a very good chance the shell will crack and explode. One exploded in Italy in the 90's. A brand new machine with inexperienced operators. There was a fire around the Yankee....they hit the stop button..and pointed their hoses at it. They cracked the shell, heard some hissing and took off. They were able to clear the building before it exploded.

The reason it explodes is because the steam in the shell is under pressure (or compressed) and expands when the shell fails.

The other reason they can explode is from being operated too long and with poor inspection procedures. The maintenance staff in these mills are supposed to complete a variety of inspections to try to predict when it is time to take them out of service.

The rate of explosion is higher than every 80 years. I believe it is more like every 5 years.

So in summary, it is fine to use a hose around a Yankee dryer. Just make sure it is turning (if it is hot).

If it has been down for a while and is at room temperarure, it is also OK to use a hose then too.

There are a small books that may be of use.

"Guidelines for the Safe Operation of Yankee Dryers" by William Corboy. It is available from TAPPI press.

[baileycd1]

I currently work at a papermaking plant with 8 Yankee dryers, running for the most part 24/7. I work on a papermachine with a Yankee Dryer 15 feet in diamater, weighing 80 tons, and am also on the plant fire brigade. Our Yankees are pressurized with steam @ 135 psi, and are limited by plant policy to run at no more than 380 degrees fahrenheit. Our max speed is 3000 feet per minute, or about 35 mph. We have other yankees on our site that are 18 feet in diameter and run 3000-4000 feet per minute. The Yankees have a venting system so that with the turn of a hand valve, the pressure can be relieved for firefighting operations. Each of our Yankees has a blade running the length of the cylinder which is used to free the paper sheet from the yankee. This blade is changed every 12 hours, and the first thing we do before we remove the blade is rinse it with water from a 1 1/2 inch washdown hose, while the Yanke is running and pressurized. This requires that water hit the yankee, although not in a direct stream or in a focused location, for a few seconds at least a couple times a day, yet this process has never led to a Yankee failure on a papermachine to my knowledge. So those of you afraid to go anywhere near one in a firefighting operation can relax your fears slightly, its not that black and white. Our plant does have its own fire brigade, who receive specialized training in fighting Yankee fires, as do all technicians who work on the papermachines. We very rarely have a fire on one of our machines that the machine operators are not able to extinguish on their own with no more than washdown hoses. Our training dictates that for firefighting episodes, once the steam is vented from the Yankee, it should be kept rotating, but can be sprayed with water, although it is still not recommended that you hit it with a straight jet or in a focused location for extended time. Best practice is a fanned out nozzle, and moving the nozzle around over the surface of the dryer. Information given us in our training is that there is an average of one Yankee failure worldwide in the paper industry every 3 years. In the history of our company, we have only had 3 failures worldwide, which i would guess is pretty good since we have 8 yankees just at this site, and several plants around the world.
Our training materials state that the explosive force of a 15 foot Yankee suffering thermal failure is equal to 55 pounds of TNT; An 18 foot Yankee equal to 80 pounds.