Heat Exchanger End Flange/Sheet Decapitation
Comments
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Pretty cool. Not a lot off PPE in that video!
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I assume where ever those folks work they don't need more than they are using. Gloves,eye protection and hearing protection, safety shoes and long pants. Not sure what else you'd be looking for in a place like they were filming. It doesn't look like field work so I wouldn't expect respiratory protection and that type of work doesn't require face shields as far as I can tell. I know my ppe varied by conditions we were expecting to be exposed to.
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@rickdelta
according to the video that I saw from 2 different places where they worked on these things the tubes are just expanded in the socket they are set in through the front and rear sheet plates. I believe its called "swaged or swage or swaging" i may have spelled it wrong. I think this technique is common in these types of heat exchangers. Higher pressure may require brazing or soldering but it doesn't seem like its needed in these styles.
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They are just expanded into the tube sheets.
If you put your finger into one of the tubes you can feel where it is expanded.
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Shorts, tank tops and trainers on your list of approved PPE? 😊
The guy doing the grinder in the opening scene was fully protected though. 👍
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i always saw it as swedging in catalogs with the tool to expand a piece of tubing so 2 pieces the same size would fit together but google seems to think swaging is more common
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Ok! ….. so do I understand this correctly?
The hole in the sheet is slightly larger than the tube O.D.
The tube is placed in the hole in the sheet.
You expand the tubes end up to the size of the larger hole in the sheet?
What are the merits in joint strength in this process?
ie: Are you creating a copper to copper molecular bond?
I do this with PVC pipe ….. its called MOPVC (Molecular Oriented PVC)
It creates a very strong "hoop" or "ring" strength.
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Maybe it falls into the Cold Welding category, maybe one reason the Sheet needs to be so thick.
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System1 -
Using the swaging tool to swell the ends of the copper tubing over the end plate assures a tight seal against the end plates.
Removing the copper tubing in the way described saves you a great deal of work.
The only issue is how much sediment/rust is in the copper tubing as the dirt will reduce its value to a scrapper and get you less money.
You should be looking for a scrapper that will take the full lengths of the copper tube.
A lot of scrappers use load cell equipped floor scales to weigh metals and be done with it and then send it to a smelter.
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It is not cold welding. The tubes are expanded into the tube sheet call it what you want.
On boiler tubes they do the same thing. On HP steam sometimes one end of the tube is welded to the tube sheet.
But they can't weld both ends expansion would tear it apart.
Tubes have to move with temperature change.
With chillers the temp change is small compared to boilers.
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So, .….. can it be said, it's a "slip joint" that moves in and out with expansion?
ie: Not a bonded joint
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@I guess they have to move. That is the reason they do not weld both ends of a boiler tube.
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so then is copalum cold welding or compression?
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I'm sure the answer depends on if its a chiller, hot water or steam boiler.
Of the two tanks im working with …..one is piped to a very large refrigerant compressor.
Im sure BOTH ends must be welded to the sheet ….. else the high pressure refrigerant gas would escape! : (
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Larger chillers use a low pressure refrigerant like R11. Even R22 is only like 300 psig. A cold formed connection in to an inch or 2 thick tube sheet can easily hold that.
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You can slice through the steel tube cleanly without needing full circular access, and it’ll make easy work of the flange and copper bulkhead too.
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i still think a hole hawg and a large twist drill would release the tubes pretty easily. Rig up the pipe handle to be supported on a pipe or rod in the other tubes so you don't have to hold against the torque.
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I would think shoving a Sawzall blade inside the tube and making 1 or 2 cuts would make the tube pull out pretty easily
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Demolition Regulatory Compliance
Diamond wire cutting is a preferred method of demolition in many instances because it utilizes water as a coolant and lubricant so there are no hazardous chemicals present, there are no sparks, dust is minimal, and operators are kept at a safe distance while operating remotely. - Hudson Demolition Inc.
Chiller Flange/Sheet Decapitation (Update):
I've talked with a few diamond grit cutting wire manufacturers and got some good feedback and helpful ideas from them.
As my intention is for a low duty cycle - demolition only cutter ….. I don't need to use their expensive and high precision drive and pulley components.
I'll be building my cutter with low cost standard cable pulleys and a motor drive sheave.
The "grit" coated cutting wire traction interface to a "plain Jane" motor drive sheave …. is poor as is.
I intend to add a rubber base to the bottom of the motor sheaves belt groove (think: rubber band).
In addition to this, as the wire enters the sheave, instead of immediately exiting the sheave, its wraps around the entire bottom groove several times before exiting the sheave.
This should provide an unslippable traction drive to wire interface.
Another suggestion was before I make my 12ft cutting loop with the ends coupler, …… is to add a slight "twist" to the wire before compressing the joining connector.
This will force the entire cable to rotate as it cuts ….. using all the available grit, all around the entire cutting wire (no flat spots).
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