Grizzly
21-10-2014, 06:46 PM
Hi Guys.
Please excuse the puns above, only as an Engineer fast approaching being put out to graze!
I rarely get the chance to justify some of the "Old School" comments that I have made in the past to Younger colleagues.
1 of my favourites has been " A Good Engineer that knows his plant, can tell if there is a problem when he walks into his plant room. Just by listening"!
I guarantee there are plenty reading this that know what I mean? Especially if they are site based!
Secondly there will be loads who even if they don't do Industrial, Supermarket Packs etc. that have seen what 2 pipes / surfaces rubbing together can do!
AC guys I bet have seen more than me!
So a few weeks ago I was on a site where I was to do what we call a "look and Log".
Basically the minimum attendance a customer can get away with but still comply with the relevant EN378 regs and have a Refcom 24/7 company provide back-up to their on-site Engineers / Electricians / Maintenance Staff.
So having booked in and reported to the relevant staff etc. I walk through the one plant room
With very, very old J&E Hall recips! Into the newer Annex with a Sabroe SMC116 Pac
Both are on Ammonia.
Listening to the Sabroe Recip load up and unload. I could hear something we have discussed a few times on the Forum Lately.
Basically I could hear the discharge gases pulsing / surging along the discharge pipes up towards the overhead Condenser and Receiver. This pulsing / surging was intermittently causing the relevant pipework to shake.
There was a resonance that was emanating from the system, but within this noise there was
the noise of something vibrating. I wasn't sure but my guess was it was something metallic?
As we are hopefully still taught? Not a Good Sound.
There where various things like cladding / Ally insulation which could be the culprit?
Following the shaking discharge line up through the roof on it's way to the condenser and Receiver ... Nothing!
Checking the returning 2" Steel liquid line however on the horizontal run that ran across the back of the pack. Halfway along I saw what I can only describe as a broken bracket which was once the bottom half of a 2" steel pipe saddle.
Because the centre line of this bracket was for some reason no longer in line with the Liquid line pipework. It had been snapped in half and was sat to the side of the 2" pipe.
Imagine the word LO, L being the bracket and O being the pipe. The toe of the L was against the pipe, both appeared to be rubbing together?
Because of the long unsupported pipe run I was able to gently push them apart. Instead of red oxide surfaces I saw shinny Metal. At this point I went and got one of the site shift Engineers.
He then went and fetched a cordless disc cutter and cutting off the remaining 1/4 bracket below the pipe at the point where it was welded to it's support stanchion.
The below Picture show what I saw!
11806
The Indent matches the toe of the bracket so perfectly that it's almost as if someone has got a cold chisel and driven it into the pipe!
You can even see the paint difference of the 2nd coat applied after the bracket!
Given that the system charge was (Unknown to me.) but would likely be something like 200 / 300kg Ammonia and the bulk was feeding this line from the receiver above.
I politely advised the customer that I would not be continuing with my service inspection. The damaged pipe would need a coded welder repair with agreement from the Insurance Surveyor.
This having been done the system needed topping up.
Myself and a colleague will be going back to isolate and purge the Liquid line and once the pipe has been welded. To add more ammonia and set the plant to work.
Long winded I know Guys, but a lesson all the same. Imagine no-one finding the damage, how long before a catastrophic Failure?
Not a bad days work Just for listening!
The Plant room that was maybe my 5th or 6th Visit in about 2 years.
So maybe you don't have to know the plant room so much after all?
Just don't ignore the noises
I like to pass these situations on, not for self glory. But someone reading this will apply the same one day and hopefully have a similar positive result. Because this stuff isn't in any text book. WE learn from talking to each other!!!!
Grizzly
Please excuse the puns above, only as an Engineer fast approaching being put out to graze!
I rarely get the chance to justify some of the "Old School" comments that I have made in the past to Younger colleagues.
1 of my favourites has been " A Good Engineer that knows his plant, can tell if there is a problem when he walks into his plant room. Just by listening"!
I guarantee there are plenty reading this that know what I mean? Especially if they are site based!
Secondly there will be loads who even if they don't do Industrial, Supermarket Packs etc. that have seen what 2 pipes / surfaces rubbing together can do!
AC guys I bet have seen more than me!
So a few weeks ago I was on a site where I was to do what we call a "look and Log".
Basically the minimum attendance a customer can get away with but still comply with the relevant EN378 regs and have a Refcom 24/7 company provide back-up to their on-site Engineers / Electricians / Maintenance Staff.
So having booked in and reported to the relevant staff etc. I walk through the one plant room
With very, very old J&E Hall recips! Into the newer Annex with a Sabroe SMC116 Pac
Both are on Ammonia.
Listening to the Sabroe Recip load up and unload. I could hear something we have discussed a few times on the Forum Lately.
Basically I could hear the discharge gases pulsing / surging along the discharge pipes up towards the overhead Condenser and Receiver. This pulsing / surging was intermittently causing the relevant pipework to shake.
There was a resonance that was emanating from the system, but within this noise there was
the noise of something vibrating. I wasn't sure but my guess was it was something metallic?
As we are hopefully still taught? Not a Good Sound.
There where various things like cladding / Ally insulation which could be the culprit?
Following the shaking discharge line up through the roof on it's way to the condenser and Receiver ... Nothing!
Checking the returning 2" Steel liquid line however on the horizontal run that ran across the back of the pack. Halfway along I saw what I can only describe as a broken bracket which was once the bottom half of a 2" steel pipe saddle.
Because the centre line of this bracket was for some reason no longer in line with the Liquid line pipework. It had been snapped in half and was sat to the side of the 2" pipe.
Imagine the word LO, L being the bracket and O being the pipe. The toe of the L was against the pipe, both appeared to be rubbing together?
Because of the long unsupported pipe run I was able to gently push them apart. Instead of red oxide surfaces I saw shinny Metal. At this point I went and got one of the site shift Engineers.
He then went and fetched a cordless disc cutter and cutting off the remaining 1/4 bracket below the pipe at the point where it was welded to it's support stanchion.
The below Picture show what I saw!
11806
The Indent matches the toe of the bracket so perfectly that it's almost as if someone has got a cold chisel and driven it into the pipe!
You can even see the paint difference of the 2nd coat applied after the bracket!
Given that the system charge was (Unknown to me.) but would likely be something like 200 / 300kg Ammonia and the bulk was feeding this line from the receiver above.
I politely advised the customer that I would not be continuing with my service inspection. The damaged pipe would need a coded welder repair with agreement from the Insurance Surveyor.
This having been done the system needed topping up.
Myself and a colleague will be going back to isolate and purge the Liquid line and once the pipe has been welded. To add more ammonia and set the plant to work.
Long winded I know Guys, but a lesson all the same. Imagine no-one finding the damage, how long before a catastrophic Failure?
Not a bad days work Just for listening!
The Plant room that was maybe my 5th or 6th Visit in about 2 years.
So maybe you don't have to know the plant room so much after all?
Just don't ignore the noises
I like to pass these situations on, not for self glory. But someone reading this will apply the same one day and hopefully have a similar positive result. Because this stuff isn't in any text book. WE learn from talking to each other!!!!
Grizzly