Micro CoGen.

Prime movers, diesel and gas engines => Listeroid/Petteroid/Clones => Topic started by: veggie on December 30, 2009, 09:36:07 PM

Title: Exhaust system - Pipe expansion
Post by: veggie on December 30, 2009, 09:36:07 PM

Well, I finally got around to putting headers on my 6/1  :D
My concern is how much linear growth I could get in the vertical pipe and could this put stress on the head.
The vertical pipe is anchored at the head and supported at the bottom.
Am I worrying too much about this ?
Have a look at the pictures...

I added a drain at the first turn so I could catch any liquids (or broken piston rings  ;D)

veggie
Title: Re: Exhaust system - Pipe expansion
Post by: BruceM on December 31, 2009, 04:28:50 AM
Nice rig, Veggie. Wish I had your mount system, and the air starter looks nice too.

Here's some thoughts, worth about 1 cent.

I also use a threaded 2" pipe 90 near the head- which I've been told is not so good, exhaust-flow wise.  I should have used a Rigid or  IMC (electrical conduit) 90 sweep.  With 2 inch pipe, it "seems to be OK."

A Tee is even more restrictive for flow- but I don't have enough experience to know if it's really an issue.  Instead, how about a downward Tee as a trap (if you must) after a sweep elbow? 

Hard to know if expansion of the hot pipe relative to engine/cylinder is going to be an issue- a soft mount (rubber auto exhaust hanger?) on the lower end might solve the problem, but there IS going to be some movement at the upper end from engine/cylinder vibration and movement-  so a SS flex section in the upper vertical exhaust section might be the safest, so this movement is isolated from the exhaust. 

Best Wishes,
BruceM


Title: Re: Exhaust system - Pipe expansion
Post by: Crumpite on December 31, 2009, 07:55:09 AM
Where are you folks finding those SS flex sections ???

Daryl
Title: Re: Exhaust system - Pipe expansion
Post by: quinnf on December 31, 2009, 11:50:24 AM
That's a nice clean starter installation.  

But I'm with Bruce about the exhaust system.  I can't recall precisely what the rule of thumb is for the restriction each 90 degree bend adds to an exhaust system, but it's something like one 90 degree bend restricts the exhaust flow the same as 10' (I think) of straight pipe.  Give a thought to using large radius bends in the exhaust lines.

And as for the expansion, if you have a temperature rise of 600 deg. F. (worst case) a 36" long straight section of steel pipe, the expansion should be about 0.157", or a little more than 1/8".  So it might be good to build in some flexibility.  Rubber hangers like Bruce mentioned are universal in car exhausts these days, and they also help to dampen mechanical noise that could be telegraphed through the exhaust system.
Quinn
Title: Re: Exhaust system - Pipe expansion
Post by: mobile_bob on December 31, 2009, 12:38:21 PM
pant legs and fire hydrants drive me crazy for some reason,

woof!

:)

bob g
Title: Re: Exhaust system - Pipe expansion
Post by: veggie on December 31, 2009, 01:29:40 PM
Fired her up with the new exhaust system today. Wooo Hooooo!!
The exhaust noise inside the building is virtually eliminated.
Outside the building, it's quite bearable also.

Here's a video of the unit running 80% loaded with the new automotive muffler.



http://www.youtube.com/watch?v=qx5qABD5WD0 (http://www.youtube.com/watch?v=qx5qABD5WD0)

PS: sorry for the poor sound quality. My garage really echo's when the cars are removed.
veggie
Title: Re: Exhaust system - Pipe expansion
Post by: veggie on December 31, 2009, 02:09:02 PM

Sounds like a good plan. Then nobody will hear it running. Even through the night.

PS: Although..... what we all really want is a "flower bed" muffler like yours  :D

veggie