The Big Bang Theory!

[Grizzly]

Having been asked to give my opinion (whilst on-site) on a Very large Sabroe recip.
That having been restarted, following a oil diff switch reset. Did not sound to good!
On restart whilst in attendance there was no adverse noise but there was bad vibration on start and shutdown.

I in agreement with the site returned to investigate>

The following photos are quite shocking considering that this comp was runnable.
How long before an oil diff shutdown was never determined.

As discovered....

Grizzly

[monkey spanners]

WOW! thats bad!

Not in the same league but years ago i was called to a 3hp prestcold that wasn't cooling well. It ran nice and quite with no virbration, but didn't seem to be pumping too well so i shut the sucction valve in to see what it could do. As the pressure droped a light tapping noise started and very quickly turned into a heavy hammering, so bad i ran for cover! Turned out it had snapped a rod (twin cyl comp) and had knocked the piston up to the top of the bore, as the crank case pressure dropped the piston was pushed back down into the crank!

Was a fixed orifice syatem and customer had been running it with no load....

[Magoo]

Hi Grizzly
a definite mess inside and a major cost to rebuild total compressor. Check that a new bare shafted compressor could be a cheaper option. Use old unit as a mouring for your 40 foot boat/ launch. ( joke )

[HVACRsaurus]

Interesting photos, its not often we get to see them in such a state.

[mark957]

no pistons connected ehehehe no noise .........

[josef]

Grizzly, has seen many accidents with thermopump, but not so in your case, not a pretty sight.

[flyinkiwi]

That's not a Sabroe - it's a BITZER!

[HallsEngineer]

Pwned! Thats outta here!!!

[Grizzly]

Ok Guys!
Having studied the remains and discussed with colleagues.
I call this the big bang, because the most likely scenario is!

The jammed piston crown was a result of stress failure around the piston little end.
Were the recess is for the scraper ring, on the remaining peice a fracture can be seen running around the ring recess.

My supposition is that the piston for whatever reason cracked internally around the bottom ring recess. Causeing the bottom portion of the piston (ie its skirt) parted with the top half.
The comp was reported as haveing an issue (making strange noises) by their very experianced Engineer. Who was ignored.
At some point the remaining attached but shortened piston twisted / jammed as it reached BDC.
Resulting in the big bang that snapped the bottom half on the bigend.
Bent the con rod, snapped the bottom section of the liner as the piston skirt pusshed into it.
All of this ripped the big end shell and journal scrapping the crank. (it was reground for oversize shells 2.1/2 years ago).
The repair bill is astronomical to the point where the site may just chance running on the 2 remaining machines which together only just meet the duty of the brocken one.

Suffice to say I would not of wanted to be stood near it when it went bang!

Grizzly

[mrfrze]

Cant be a Bitzer - they dont break up that easy! Must be a Copeland..

[mikeref]

Situation always comes down to costs. What happens when one of the other 2 need repairs?
One can plan preventative maintenance however, Murphy's law only recognises the exact opposite.
Crankshafts/ etc: are costly but surely the business owner can organise staged repairs. Budget from month to month. Thinking... costs aren't going to get any cheaper as time rolls on.

[Grizzly]

The comp has since been rebuilt.
The owners sourced a second hand comp from somewhere in Europe.
And used a French company to ship it across, who then stripped the replacement and did a selective rebuild.
It took 2 men 5 days and then back online.

As they say time will tell!
Grizzly

[Tycho]

is that an hct 8075 or hct 8100?
We bought one from somewhere in the UK, some factory that had shut down and was selling the plant of in pieces, the compressor was as new.

usually a complete overhaul of this type of compressor takes 2 days, one day to strip it and clean all the parts, then 1 day to put it together, (16 hours) add 4 hours for preparation and running it afterwards, it should be done in 20 hours tops (brag brag brag )

[Grizzly]

is that an hct 8075 or hct 8100?
We bought one from somewhere in the UK, some factory that had shut down and was selling the plant of in pieces, the compressor was as new.

usually a complete overhaul of this type of compressor takes 2 days, one day to strip it and clean all the parts, then 1 day to put it together, (16 hours) add 4 hours for preparation and running it afterwards, it should be done in 20 hours tops (brag brag brag )

Maybe Tyco.
Now try the same with a SMC 188. You won't be throwing them together.
The cylinder heads weigh around 80Kg. A Piston and liner assy are 40plus KG.
I know the French guys worked hard, given that the crankshaft which was replaced weighs 240Kg alone.
Smaller stuff is easy but this is big boy league and it was a total rebuild by the way.
So respect to them that did it, I know I have done it in the past myself.
And you know when you have done so believe me.
By the way as this is on ammonia it can take a morning just to purge off the Gas prior to stripping it.

Therefore I dispute whether your flippant timings are relevant!
Grizzly

[Tycho]

hey now, I wasnt putting anyone down,
and I asked you if it was a HCT 8075 or 8100 wich are smaller compressors, because all I had to go by was the picture of the inside of the crankshaft.

and the time frame I put for the HCT 8075/8100 is correct for a major overhaul, doesn't matter if it's nh3 or *****, I'd add a few hours if the crankshaft would have been replaced...

[shoorik]

hello!
We had similar problem with Frascold. 3 compressors died simultaneously. From 3 comps we made 1. Powerlifting

[Grizzly]

hey now, I wasnt putting anyone down,
and I asked you if it was a HCT 8075 or 8100 wich are smaller compressors, because all I had to go by was the picture of the inside of the crankshaft.

and the time frame I put for the HCT 8075/8100 is correct for a major overhaul, doesn't matter if it's nh3 or *****, I'd add a few hours if the crankshaft would have been replaced...

Sorry Tyco.
I must have misread your post, In my defence I had just done 18hrs straight.

Just finished 21 hrs.
Time for bed!
Grizzly.

[Tycho]

Sorry Tyco.
I must have misread your post, In my defence I had just done 18hrs straight.

Just finished 21 hrs.
Time for bed!
Grizzly.

Hope you had sweet dreams

I know the feeling, and after 21 hours going you sleep so deep that when you wake up you feel even more exhausted than before going to bed