Force circulation steam generator design
Posted by SteveW
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Re: Force circulation steam generator design March 13, 2022 03:59PM |
Registered: 14 years ago Posts: 134 |
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Re: Force circulation steam generator design March 13, 2022 04:42PM |
Registered: 17 years ago Posts: 1,680 |
Steve
It all depends in what state you are using the pressure vessel in and where. States like New York and Road Island all pressure vessel are required to be code stamped by a holder of an S stamp. (A license pressure vessel builder holding a federally issued S stamp) Unless the law has changed in Massachusetts only stationary pressure vessel fall under the boiler laws. Cars boats tractors and cranes do not fall under the law, however if you have liability insurance they may require inspection by a certified boiler inspector
The federal code changed in 1995 to reduce the build pressure under the ASME to 3.5 times operating pressure. All material used have to meet the ASME code as well.
The ASME is a privet group of engineers that design and write codes as they see it and sale codes to States and business’s for there use, not all sections of the codes are used in many State’s the States may only use sections of them.
Insurance companies also get involved as was the electrical codes. The insurance Co changed the code in many States on electrical panels requiring all circuit backers must be the same manufacturer as the panel.
Rolly
It all depends in what state you are using the pressure vessel in and where. States like New York and Road Island all pressure vessel are required to be code stamped by a holder of an S stamp. (A license pressure vessel builder holding a federally issued S stamp) Unless the law has changed in Massachusetts only stationary pressure vessel fall under the boiler laws. Cars boats tractors and cranes do not fall under the law, however if you have liability insurance they may require inspection by a certified boiler inspector
The federal code changed in 1995 to reduce the build pressure under the ASME to 3.5 times operating pressure. All material used have to meet the ASME code as well.
The ASME is a privet group of engineers that design and write codes as they see it and sale codes to States and business’s for there use, not all sections of the codes are used in many State’s the States may only use sections of them.
Insurance companies also get involved as was the electrical codes. The insurance Co changed the code in many States on electrical panels requiring all circuit backers must be the same manufacturer as the panel.
Rolly
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Re: Force circulation steam generator design March 15, 2022 11:29AM |
Registered: 5 years ago Posts: 611 |
Rolly,
I often wondered and perhaps you can clarify that the boilers we make and use on steam cars would be classified as a M boiler (miniture boiler)?
ASME Boiler Code Website
Kind regards,
Rick
I often wondered and perhaps you can clarify that the boilers we make and use on steam cars would be classified as a M boiler (miniture boiler)?
ASME Boiler Code Website
Kind regards,
Rick
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Re: Force circulation steam generator design March 15, 2022 12:03PM |
Registered: 17 years ago Posts: 1,680 |
Rick
As far as I know they are not.
I believe there was two court cases in NY regarding Stanley boilers.
They do not meet the code as it is written. Min head plate thickness on fire tube boilers by the code twenty years ago was 3/8” most Stanley boilers as built only use ¼ inch plate. The code requires in NY the main stop valve to be ASME approved as well as gate valve and two swing check valves on the feed water. Stanley uses neither. There is a section in the code for wire wrap pressure vessels. I am not sure if it applies to steam fired pressure vessels.
The two cases were found exempt from the code as there antique Motorcars. The late Brent Campbell was an adviser in the cases as he explanted them to me.
Stanley were exempt as being antique motor cars. Both cars were registered and insured.
Rolly
As far as I know they are not.
I believe there was two court cases in NY regarding Stanley boilers.
They do not meet the code as it is written. Min head plate thickness on fire tube boilers by the code twenty years ago was 3/8” most Stanley boilers as built only use ¼ inch plate. The code requires in NY the main stop valve to be ASME approved as well as gate valve and two swing check valves on the feed water. Stanley uses neither. There is a section in the code for wire wrap pressure vessels. I am not sure if it applies to steam fired pressure vessels.
The two cases were found exempt from the code as there antique Motorcars. The late Brent Campbell was an adviser in the cases as he explanted them to me.
Stanley were exempt as being antique motor cars. Both cars were registered and insured.
Rolly
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Re: Force circulation steam generator design March 16, 2022 07:27AM |
Admin Registered: 16 years ago Posts: 1,917 |
This certainly seems to be a state-by-state situation. As I understand it, Michigan has rules for boilers used in carnival rides, with the inspection standards being different if the ride accepts paying passengers.
Back when steam cars were actually common, the state passed a law (still in force) stating that automobiles were exempt from licensing. That said, when I inspected SE-101 at GM Design Staff about 25 years ago, it had an official inspection plate on the steam generator. That might have been a liability issue since a multi-tube, parallel path, once-through steam generator is even safer than a monotube of equal capacity
Back when steam cars were actually common, the state passed a law (still in force) stating that automobiles were exempt from licensing. That said, when I inspected SE-101 at GM Design Staff about 25 years ago, it had an official inspection plate on the steam generator. That might have been a liability issue since a multi-tube, parallel path, once-through steam generator is even safer than a monotube of equal capacity
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Re: Force circulation steam generator design March 16, 2022 07:48AM |
Registered: 11 years ago Posts: 235 |
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Re: Force circulation steam generator design March 16, 2022 11:53AM |
Registered: 5 years ago Posts: 611 |
Thanks Rolly,
One more thought...
Under Power Boilers is PP (pressure piping) stamp approval. My ponder is if this applies to a forced circulation steam generator in the size that would be used for a steam car. In the case of Zimirken, he uses a pipe as his separator drum. I would say this can fall under piping, just a bigger diameter, still a pipe.
On another note, John Baldwich has loaned the ASME boiler code book to me. It's a big green bonded book that I have yet to open. I have to admit my procrastination in not opening it and should just research this query on my own. However, that would be less fun!
Thanks,
Rick
One more thought...
Under Power Boilers is PP (pressure piping) stamp approval. My ponder is if this applies to a forced circulation steam generator in the size that would be used for a steam car. In the case of Zimirken, he uses a pipe as his separator drum. I would say this can fall under piping, just a bigger diameter, still a pipe.
On another note, John Baldwich has loaned the ASME boiler code book to me. It's a big green bonded book that I have yet to open. I have to admit my procrastination in not opening it and should just research this query on my own. However, that would be less fun!
Thanks,
Rick
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Re: Force circulation steam generator design March 16, 2022 01:04PM |
Registered: 17 years ago Posts: 1,680 |
Rick
I designed and had built two boilers to the code. It took me a year to go through all the math required to satisfy the requirements. Hartford boiler insurance no longer has in house PE in pressure vessel design to overlook or except your work. The drawings have to be stamped with a PE stamp. They have a list of engineers they will except for there approval if you hire one. I did for a thousand dollars to review and approve my cad drawings and math.32 two pages of math. The only thing I, we disagreed on was my calculations on the thickness of the bottom drum plates for ligament spacing. Not an easy calculation to understand. I had 3/8 thick plate he wanted ½ ‘ plate. The sides and bottom were OK at 3/8. The builder had to be a registered PE and licensed with the national board and hold liability insurance to use an S stamp, the one that gave me the right price also used Hartford boiler insurance for there insurance.
As a construction estimator and builder I estimated the cost without knowing the added cost to be applied for the liability insurance to be between $5500.00 and $6800.00 the price came in a $6200.00
On the drawings every piece of metal has to be tagged and sized per the code and every welded joint with the weld symbol. All tapped holes have to show five full threads.
I have not kept up with all the changes, I did get a copy of the changes adjusting the boiler code in 1999 reducing the allowable stress values based on material design value be s to reduced to 3.5 rather then the 4 used for over half a century.
Rolly
I designed and had built two boilers to the code. It took me a year to go through all the math required to satisfy the requirements. Hartford boiler insurance no longer has in house PE in pressure vessel design to overlook or except your work. The drawings have to be stamped with a PE stamp. They have a list of engineers they will except for there approval if you hire one. I did for a thousand dollars to review and approve my cad drawings and math.32 two pages of math. The only thing I, we disagreed on was my calculations on the thickness of the bottom drum plates for ligament spacing. Not an easy calculation to understand. I had 3/8 thick plate he wanted ½ ‘ plate. The sides and bottom were OK at 3/8. The builder had to be a registered PE and licensed with the national board and hold liability insurance to use an S stamp, the one that gave me the right price also used Hartford boiler insurance for there insurance.
As a construction estimator and builder I estimated the cost without knowing the added cost to be applied for the liability insurance to be between $5500.00 and $6800.00 the price came in a $6200.00
On the drawings every piece of metal has to be tagged and sized per the code and every welded joint with the weld symbol. All tapped holes have to show five full threads.
I have not kept up with all the changes, I did get a copy of the changes adjusting the boiler code in 1999 reducing the allowable stress values based on material design value be s to reduced to 3.5 rather then the 4 used for over half a century.
Rolly
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Re: Force circulation steam generator design March 16, 2022 03:31PM |
Registered: 14 years ago Posts: 134 |
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Re: Force circulation steam generator design March 21, 2022 07:09AM |
Registered: 11 years ago Posts: 235 |
It depends entirely on what state you're in. Most states have exceptions for boilers that power a vehicle. This is because stanley boilers aren't up to code because they use wire wrap for strength, and the state boiler regulators aren't going to force their owners to change them.
It's funny, the ASME boiler code is very expensive if you try to buy it. But pretty much every section of it is posted online somewhere on a corporate or government website if you google right. You might have to type in the specific numbers in to google to find them though.
On the forced circulation note, I found that my circulation pump was very economical to produce. It was inspired by someone's story I read online about a circulation pump they found in an industrial boiler. You have a series of check valves that are steam rated. Then you have a long tube from the middle of them to a piston pump. Because the tube is long, the pump itself isn't exposed to the high temperatures, similar to plumbing in a pressure gauge. This means you don't need a high temperature pump, it just needs to handle high pressure water. My pump was double acting, so the forces were mostly balanced (minus the piston rod area) so it required little power to run. You just need to make sure that the volume in the long tube is bigger than the pump displacement volume by about 2x, so the hot boiler water cools down before it makes it to the pump. This makes it WAY easier and cheaper to source the circulation pump.
It's funny, the ASME boiler code is very expensive if you try to buy it. But pretty much every section of it is posted online somewhere on a corporate or government website if you google right. You might have to type in the specific numbers in to google to find them though.
On the forced circulation note, I found that my circulation pump was very economical to produce. It was inspired by someone's story I read online about a circulation pump they found in an industrial boiler. You have a series of check valves that are steam rated. Then you have a long tube from the middle of them to a piston pump. Because the tube is long, the pump itself isn't exposed to the high temperatures, similar to plumbing in a pressure gauge. This means you don't need a high temperature pump, it just needs to handle high pressure water. My pump was double acting, so the forces were mostly balanced (minus the piston rod area) so it required little power to run. You just need to make sure that the volume in the long tube is bigger than the pump displacement volume by about 2x, so the hot boiler water cools down before it makes it to the pump. This makes it WAY easier and cheaper to source the circulation pump.
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Re: Force circulation steam generator design March 21, 2022 03:07PM |
Registered: 14 years ago Posts: 134 |
Zmirkin, sounds like an interesting design for the pump. Right now what I'm looking at is a pump that is internal and uses high temperature magnets with an electrical field to rotate the shaft. This will work around the problem of pressure while the magnets will take the heat or so the company claims. As soon as my brother has corrected drawings we will see about putting them up. It's slow going for him to do the math. We have the radiant heat coils figured and now he is working on the hot air conduction.
SteveW
SteveW
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