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It seems like it would massively complicate heat exchanger repair.. I learned of an obscure tool recently- a roller tube expander. You use this to tight-fit a

It seems like it would massively complicate heat exchanger repair.. I learned of an obscure tool recently- a roller tube expander. You use this to tight-fit a tube in a boiler's tube-sheet. So you can install or replace tubes in pressure vessels such as a boilers or heat exchangers. Check it out: https://www.youtube.com/watch?v=u7UQKNapTBE https://www.youtube.com/watch?v=u7UQKNapTBE Failure: https://youtu.be/HlXVP2HHTfo?t=696 https://youtu.be/HlXVP2HHTfo?t=696 Repair: https://www.youtube.com/watch?v=7znd-hpy2Vc&t=708s https://www.youtube.com/watch?v=7znd-hpy2Vc&t=708s

elil17 4y ago
This is for aerospace heat exchangers, where weight is the primary concern. This would not be used along-side tube-base heat exchangers, but rather with 3D printed heat exchangers.
- jhallenworld 4y ago
  Replacing tubes in aerospace heat exchangers seems to be a thing: https://www.meggitt.com/products-services/heat-exchangers/ https://www.meggitt.com/products-services/heat-exchangers/ "Its innovative design means that single tubes can be easily replaced during overhaul periods, minimising costs to operators. The operational lifetime of a tubular unit is 3 million flying hours and 50 million Serck Aviation bonded interfaces in the field have never failed." Even the patent mentions: "In addition to aerospace applications, the disclosed headers can be used generally in other transportation industries, as well as industrial applications." But actually I think the spreader could be contained within some kind of bell-shaped header, and not actually attached to the heat exchanger tubes, just immersed in the same fluid. So replacement might be easy. But any kind of spreader is adding weight compared with an empty header, so not sure if the easing of the fluid flow is worth the weight gain. No doubt this depends on the application.
  - elil17 4y ago
    1. This design would have to be 3D printed because there is not a good way to manufacture it using traditional methods, so it would probably be paired with a 3D printed heat exchanger. 3D printed heat exchangers do not typically have tubes. Rather, they employ more complex geometry such as gyroids. edit: actually I'm not sure this is true. I guess you could come up with a similar design that could be IM'd. 2. Just because you could use the design in "other transportation industries" doesn't mean anyone is actually planning to do it. With the technology as expensive as it is right now, it would not make economic sense. 3. Having a spreader is not primarily about "easing the fluid flow," it's about ensuring that the entire heat exchanger gets fluid flowing through it. Typically this is worth it in applications where weight matters (because you can't afford the dead weight of part of the heat exchanger which is not actually getting much fluid flowing through it), but it is not worth it in industrial or HVAC applications (because it's cheaper to just build a bit larger of a heat exchanger). I do like the idea of a "floating spreader" - I will have to see if that has been done before.
nixonpjoshua1 4y ago
I think this is why this application is a military helicopter part where weight savings are at a premium and budgets are not.

elil17 4y ago

This is for aerospace heat exchangers, where weight is the primary concern. This would not be used along-side tube-base heat exchangers, but rather with 3D printed heat exchangers.

jhallenworld 4y ago
Replacing tubes in aerospace heat exchangers seems to be a thing: https://www.meggitt.com/products-services/heat-exchangers/ https://www.meggitt.com/products-services/heat-exchangers/ "Its innovative design means that single tubes can be easily replaced during overhaul periods, minimising costs to operators. The operational lifetime of a tubular unit is 3 million flying hours and 50 million Serck Aviation bonded interfaces in the field have never failed." Even the patent mentions: "In addition to aerospace applications, the disclosed headers can be used generally in other transportation industries, as well as industrial applications." But actually I think the spreader could be contained within some kind of bell-shaped header, and not actually attached to the heat exchanger tubes, just immersed in the same fluid. So replacement might be easy. But any kind of spreader is adding weight compared with an empty header, so not sure if the easing of the fluid flow is worth the weight gain. No doubt this depends on the application.
- elil17 4y ago
  1. This design would have to be 3D printed because there is not a good way to manufacture it using traditional methods, so it would probably be paired with a 3D printed heat exchanger. 3D printed heat exchangers do not typically have tubes. Rather, they employ more complex geometry such as gyroids. edit: actually I'm not sure this is true. I guess you could come up with a similar design that could be IM'd. 2. Just because you could use the design in "other transportation industries" doesn't mean anyone is actually planning to do it. With the technology as expensive as it is right now, it would not make economic sense. 3. Having a spreader is not primarily about "easing the fluid flow," it's about ensuring that the entire heat exchanger gets fluid flowing through it. Typically this is worth it in applications where weight matters (because you can't afford the dead weight of part of the heat exchanger which is not actually getting much fluid flowing through it), but it is not worth it in industrial or HVAC applications (because it's cheaper to just build a bit larger of a heat exchanger). I do like the idea of a "floating spreader" - I will have to see if that has been done before.

nixonpjoshua1 4y ago

I think this is why this application is a military helicopter part where weight savings are at a premium and budgets are not.