MadModder

The Craftmans Shop => New from Old => Topic started by: awemawson on August 20, 2020, 10:19:44 AM

Title: Trying to Quieten the 110KVA Generator
Post by: awemawson on August 20, 2020, 10:19:44 AM
Life is a bit challenging at the moment, being lived in one hour bursts, with the wife and myself doing shifts one hour on one hour off looking after new puppy so that severely limits what I can achieve or get committed to.
 
But I decided to tackle the noise from the generator. It sits in a semi open stable that is clad in 'Yorkshire Boarding' - that is 6" wide boards mounted with 1" gaps between them. My main issue is not causing a nuisance to our guests in the holiday cottages.

Using a sound 'app' on my 'phone I'm measuring 107 dBA adjacent to it, and 65 dBA in the court yard garden surrounding the cottages.

I'm using a two prong approach. Build a 6 metre long sound deadening wall parallel to the generator, with a flanking wall at 90 degrees to partially close off the entrance, and I'm going to direct the exhaust vertically, and thanks to Pete who got me some lengths of suitable pipe the exhaust modification is underway.

Yesterday I set a length of the pipe in the lathe ready to thread it 2.5" BSP but something was very odd about the steady rest - it wasn't running right. Eventually I found that one of the bearings that form the tips of the fingers had collapsed.

Very fortunately my box of odd squirrelled away bearings provided an exact match so I was able to turn the end down to 2.960" being the major diameter of 2.5" BSP, but then my time ran out!

This morning I was able to do the actual threading, and also a 'rain cap' for the vertical exhaust was delivered so things in that area are progressing in fits and starts.

I won a pile of 15 industrial partition sheets (Facebook Marketplace) that will provide sufficient material for the walls - these were delivered Monday but I've not been able to start on them. They are a 70 mm thick sandwich of steel facing and insulating foam core. I will fix a 6 metre length of 80 x 80 x 6 mm angle iron to the frame of the stable at roof height, and to the concrete floor below, and use self drilling sheeting screws to fix them (as I have a few hundred left over from another project)

FH Brundles delivered the angle iron this morning and I managed to give them a coat of Red Oxide primer (as rain is threatened) - there should have been three but one was bent like a banana and I rejected it - replacement due in the next day of two.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: Brass_Machine on August 20, 2020, 10:52:06 AM
Looks like you are off to a good start.

How often does the generator run?
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on August 20, 2020, 11:01:42 AM
Eric, VERY rarely as I'm inhibited by the noise ! This is what powers my induction furnace.

A few pictures omitted off last post due to rushing:

The existing 'collar' that terminated the exhaust currently is going to be a b***r to remove - I know as I tried before I installed it.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: Brass_Machine on August 20, 2020, 11:38:33 AM
Sounds like a good plan.  <-- See what I did there?  :doh:


I need to build an enclosure for the CNC router and the shop vac. Both are very loud when running...
Title: Re: Trying to Quieten the 110KVA Generator
Post by: vintageandclassicrepairs on August 20, 2020, 07:04:50 PM
Hi Andrew,
I have fitted some "flue" silencers that proved quite effective quietening noisy oil fired boiler installations
If they have stainless stacks the pipes can amplify the noise alarmingly
Of course most modern units are now condensing low level outlets
A coarse stainless steel mesh is formed into a tube shape about 3 ft long and a couple of inches smaller than the flue, this is wrapped tightly with ceramic insulation blanket and bound with stainless binding wire, then a wrap of lagger's foil tape. This is fed down the SS flue and reduces the noise noticeably, extra units can also be added to
reduce the noise even more
Same principal silencers(?) are used on competition motorcycles and cars

John
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on August 21, 2020, 03:12:17 AM
John I made one of similar construction for a little 2.2 kVA generator that I've had for years - not stainless but mild steel but it's still going strong.

I've been cogitating how to cut this sandwich panel - the core is no problem but what about the steel outer layers :scratch: Then I remembered how, using my welding bench to support a sheet of plywood for cutting, I'd cut a slit in the 3/4" steel accidentally with my old Hitachi Skill Saw.

So this morning I did a quick trial cut and it's definitely the way to go  :thumbup: The blade is already old with at least one chipped tungsten carbide tip so if it has eventually to be replaced it's due anyway.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on August 21, 2020, 06:43:33 AM
So in another of my permitted one hour bursts of activity I've pretty well 'cleared the decks' in the Stable to prepare for wall building - just a couple of feed bins to move but they can be shunted about in the stable as work progresses.

The rest has found a temporary home in the tractor shed despite NOT being tractors!

Thank goodness for Pallets and Forklift Trucks  :clap:
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on August 23, 2020, 01:20:35 PM
Not much done due to puppy syndrome, BUT a major achievement was getting the upper angle iron in place.

Six meters long and weighing 75 kgs I dragged it out with the fork lift at the beginning of one of my 60 minutes sessions. Couldnít lift it into place as the mast of the forklift would need to go 3 foot through the roof ! I was scratching my head how to build a frame onto the forks when one of our cottage guests happened by to see what I was up to. In no time at all he had volunteered, and as a two man lift it was relatively easy to rest one end on the first RSJ then walk the other up a ladder and slide it into place. The rest of the wall should be easy now that first angle is in place
Title: Re: Trying to Quieten the 110KVA Generator
Post by: djc on August 23, 2020, 03:26:47 PM
Classic way to lift stuff with a forklift near to the roof is as:

https://fleggprojects.co.uk/wp-content/uploads/deliver-install-link.jpg

These are also good: http://www.sumner.com/sumner/sub/productb/main.21.7.8.21.0.0.html

Can do similar on a Genie lift by turning the forks upside down.

Anyway, on the sandwich panel cutting, be careful it does not close up on you at the end of the cut and pinch the blade. I cut the same style of insulated panels for walk-in cold rooms (craftsmen of wood, look away now - I use a Festool TS55) and even when fully supported on a sheet of ply, within about 3 inches of the end, it will grab. When I get near the end of the cut, I lift the panel and put an offcut of ply directly under the cut, so the outer edges of the sheet are in mid-air. Then the self-weight of the panel makes the cut open up.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on August 23, 2020, 03:33:28 PM
Good point about the panels closing up, I had a 9" angle grinder pinch when cutting channel section that resulted in me seeing bare leg bone  :bugeye: Fortunately my son was there to cut the power as the grinder flew through the air. He was about 12 then and is now 40 but I still have the angle grinder  and the scar!

A chap who rents one of my containers has a Genie Lift in it, but is rarely here to scrounge from!
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on August 24, 2020, 06:51:07 AM
This is progressing in tiny little steps for the reason already mentioned but I did manage to move the upper angle and re-fix it, and bolt down the lower angle directly below it set by plumb-bob.

I decided to move the upper angle (and hence whole wall) nearer the generator for two reasons - firstly the wider gang way inside was a waste of space, and secondly the space from the outer face of the insulated panels to the next timber beam would have been insufficient to get my drill in with a long series drill on it.

Lower angle bolted down with 'Thunder Bolts' which are excellent when they work - I did manage to shear some off when building the Pig Palaces !

- next step measure and cut some panels, but not until the long series drills arrive.


Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on August 25, 2020, 01:15:59 PM
What with Puppy, a visit from three grand children all under eight, and a simultaneous visit from a friend with two under two year olds not much got done

BUT the replacement steel angle iron got delivered in the pouring rain, and set in the hopefully dry stable for a few hours 'angle up' to dry, and I've just wiped it down with white spirit and roller coated it in Red Oxide in the 25 minutes I've been allowed  :bugeye:

This angle will be cut to form the top and bottom braces of the second wall in the position shown in the picture

Title: Re: Trying to Quieten the 110KVA Generator
Post by: chipenter on August 25, 2020, 02:45:19 PM
I agree about the thunder bolts the trick is not to use a worn drill bit , this can get expensive  with the torx heads .
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on August 26, 2020, 07:50:09 AM
4 mm long series drills arrived so time to do a test fit.

Big failure  :bang:

Much to my amazement 4 mm is not large enough as a pilot despite these screws being self drilling. The plastic 'star head' spins on the screw meaning I could only remove it by squashing in the vice - lucky it's not on a full size panel !

Drilling to 5 mm from the rear showed that is big enough - so it should be the screws are only 5.5 mm ! One successful fixing and 5 mm long seriies added to the buying list - oddly 1/3 rd the price of the 4 mm - more common I suppose ?

The screws are 50 mm too long, but being hardened snap off cleanly with a tap of the hammer :thumbup:
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on August 26, 2020, 10:50:12 AM
This is turning into one of those 'why did I ever start' jobs :bugeye:

I thought I'd cut one panel to size, offer it up and clamp it in place to mark out cut outs for it to tessellate with various bits of the stable structure .

First problem: cutting with the circular saw the lower cladding tends to sag away and not be cut, and as the off cut falls away the cladding de-laminates. Also lost more teeth from the saw. Finished the cuts with a 9" angle grinder that only just cuts deeply enough - be ok laying flat on a sacrificial board maybe

Second problem: the tressels that I set up keep collapsing - not really man enough for the job

Third problem: Having cut the sheet nicely to size with a 1/2" wiggle room I can't get it in place due to angles, beams etc and had to cut a further 1 - 1/2" off to get it in.

Going to have to cogitate before cutting any more. I do have spares but it would be nice not to waste them

Anyway, it's roughly in place and held with clamps - if I decide to use it I will raise the base the 1 - 1/2" rather than leave a top gap


Title: Re: Trying to Quieten the 110KVA Generator
Post by: Spurry on August 26, 2020, 01:57:50 PM
That's looks like the foam gun could make a very useful contribution to that top gap.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on August 26, 2020, 02:34:42 PM
Yes it's difficult to decide how fussy to be. There is a (needed) 2" gap from partition top to corrugations otherwise getting them in is practically impossible single handed.

There are foam 'eaves fillers' available that fill the corrugations but still leave the 2" gap. I was on the point of pressing 'buy it now' earlier but decided to wait and see what the effect is without them - if I do fit them I can fit a bit of 2x2 to the top with the eaves filler glued to it. Ideally I'd lift the panel to the corrugations to loose the gap and keep the foam out of any ground dampness but that may not be possible.

If I get the chance tomorrow I'll cut a second panel to the 1/2" wiggle room and try another approach angle - the trouble is that both the floor and the roof slope, and what 'should fit' below the angle iron doesn't clear the rest of the roof.

(I need to bring the panel in horizontal (due to height of entrance) turn it 90 degrees, advance in to the point it's going, then incline it at 45 degrees up slope towards the generator, and tilt it up until it engages with the top angle making the angle steeper as I go until vertical by which time it should be in place. Trouble is I can't lift it easily and have to have it on my back Ninja style!)

Title: Re: Trying to Quieten the 110KVA Generator
Post by: vtsteam on August 26, 2020, 10:24:53 PM
Andrew I have a distant memory of some articles about silencing 4 cycle motors with tuned pipe lengths (straight, not automotive header/collector pipes) And increasing exhaust extraction efficiency at the same time. It's a really dim recollection, but I think it was actually in experimental aircraft design.

Pipes were quite long, related to RPM and wavelength of exhaust gas, and it gave calculations. Extremely simple and low cost exhaust systems. Since your generator runs no doubt at fixed RPM, a simple straight tuned pipe might be doable, especially if vertical. Wish I could remember where I saw that -- about 25 years ago. Maybe an older EAA publication which I collected. If I get a chance (and if of interest to you) I'll take a look at my old EAA books.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on August 27, 2020, 07:00:28 AM
I gave up with the circular saw and reverted to the 9" angle grinder - oh that it was 10" as it only just cuts deeply enough if it is held at precisely the right angle. I cut the next panel (panel #2) with just the 1/2" wiggle room and it went in very nicely, doing a dance I described in my previous post.

By counter weighting cut panels I was able to move them on the pallet truck which made things much easier.

Panel #3 cut to the same loose fit wasn't loose enough and had to have another inch removed. I still haven't cut the first panel round the beams as I ran out of allotted time.

By the way, no there won't be big gaps between panels - they are just clamped roughly in place, and when I can screw them will be shunted along to fit tightly - probably have to pull them together with a strap.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on August 27, 2020, 10:08:38 AM
So in anticipation of a friend probably coming round this afternoon I have raised panel #1 about 1 1/2" to close the top gap and marked up for cutting setting in relief for the three structural members that need insetting.

Double manned it will be easy to set it on tressels and cut the bits out and put it in it's final position, - probably only take 20 minutes, but single handed would be quite different.

Poor chap will be press ganged if he turns up !
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on August 27, 2020, 02:55:34 PM
Well my friend did indeed arrive and taking the panel down, cutting the reliefs, and putting it back, as expected was a very quick job - it's now in place to receive the screws just as soon as the 5 mm long series drills turn up.

I've deliberately cut the slots on the large side and the gaps will be filled with expanding foam. I thought it useful to have something that the foam DOESN'T stick to to use less foam and leave a fairer face so I posed the question to Google:

"what doesn't expanding foam stick to?"

And it seems that I asked the same question in 2005 - the answer being 'waxed paper' but the thread I found on RCGroups, which sweeps up threads from Newsgroups was rather sobering as no fewer than four of the contributors to the thread are no longer with us  :bugeye:

Thread here:

https://www.rcgroups.com/forums/showthread.php?341842-What-DOESN-T-expanding-foam-stick-to
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on August 29, 2020, 09:27:17 AM
A progress report:

I have five panels now in place, four of which are pretty well fixed, the fifth being held by clamps. I tried pulling the second panel into the first using a ratchet strap but frankly it was no better than thumping it with a baulk of timber and a big hammer so I gave that idea up!

I'm again limited by shortage of long series drills - it's taken 10 to get so far  :bugeye: Now admittedly two were my fault, one I dropped the drill, and two I trod on the drill, but the other 8 were in use breakages - mainly on the angle on the floor - there are distinct hard spots in it so goodness knows what went into the pot when it was rolled. Now at 135 mm long they are long wobbly drills, and mostly unsupported as it passes through the insulation but it starts penetrating the angle and suddenly grabs, and it's not just before breakthrough it's in the middle of the web.

Today I took delivery of a pack of 'eaves fillers' and a pack of expanding foam cartridges and a gun to apply them.

. . . more drills on order !!!!!!

Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on August 29, 2020, 11:39:54 AM
I opened up the pack of 'Eaves Filler' and did a trial fit.

I think that it will be OK but may need a bit of squirty foam behind it to secure it in place/
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on August 30, 2020, 11:54:35 AM
No wonder I couldn't unscrew the collar on the end of the exhaust pipe - the thread has been WELDED  :bang:

Probably have to cut it off somehow, but I still want a bit of thread for the elbow to screw onto  :scratch:

(Pipe extends as far as the chalk mark inside the collar)
Title: Re: Trying to Quieten the 110KVA Generator
Post by: russ57 on August 31, 2020, 03:26:36 AM
Just hi temp loctite...


Maybe you can just grind the beads off and leave the bulk of the pipe?

-russ

Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on August 31, 2020, 04:53:33 AM
The plan (when I can escape from Puppy - double cottage change over today so a bit hectic here :bugeye:) Is to remove the tail stock from my 40" Colchester Master, fit the Fixed steady down the tail stock end, and gripping the collar in the chuck carefully turn off the weld. This is only going to work if the collar is reasonably concentric.

Depending on how good the penetration is I may not have to go much deeper than the minor thread diameter but it all needs a good rotary wire brushing before it goes near my nice lathe !
Title: Re: Trying to Quieten the 110KVA Generator
Post by: djc on August 31, 2020, 10:58:25 AM
I must have missed it somewhere, but why does the joiner need to come off at all?

It is possible to buy a street elbow to go in its female thread or a close nipple to convert it back to male thread for a standard elbow.

Even if unthreaded or damaged threads, could you turn the threads off one end of a close or standard nipple and use 6013 or 7018 loctite to secure it in the joiner?
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on August 31, 2020, 01:50:19 PM
The pipe would be too far off the wall, and the coupler thread is not very good  and not even round at the exposed end :(

Anyway things have moved on -  managed to escape for an hour this afternoon (guests running late  :thumbup:) so removed the lathe tail stock and mounted up the pipe, coupler in the chuck.

Initially I turned the pipe up to the shoulder down to the minor thread diameter, then about 50 thou below, and even tried to undercut the shoulder but it wasn't having it, the weld penetration must have been good!

So I decided to part it off, and see if the remaining thread would work with the elbow (It's a BSPT thread so tapered)

Sadly not - I can get about half a turn on. So I decided to mount it up and re-thread it on the lathe. Carriage to extreme right which involved removing the taper turner bracket and RH stop mechanism but still I couldn't get the threading tool far enough to the right.

Now  I must study pictures, but I think the I can shorten the pipe at least 1" maybe 1.5" which will solve the problem, but time caught up with me and I had to go 'meeting and greeting' !

. . . .so hopefully a job for tomorrow
Title: Re: Trying to Quieten the 110KVA Generator
Post by: chipenter on August 31, 2020, 02:06:46 PM
Turn the tool end for end and mount it on the other side of the tool post .
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on August 31, 2020, 02:13:51 PM
Good thinking  :thumbup:
Title: Re: Trying to Quieten the 110KVA Generator
Post by: vtsteam on August 31, 2020, 10:09:40 PM
Andrew, did you see my post earlier asking you if you wanted info about tuned pipes?
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on September 01, 2020, 02:15:16 AM
Steve yes I did thank you. Not much option here to tune as apart from the last vertical section lengths are pretty well dictated.

Without proper threading kit for this size of pipe Iím limited to what will fit in the lathe .
Title: Re: Trying to Quieten the 110KVA Generator
Post by: djc on September 01, 2020, 04:10:47 AM
Turn the tool end for end and mount it on the other side of the tool post .

And for really serious length increase, a boring bar facing backwards, used externally.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on September 01, 2020, 05:56:41 AM
So as Jeff said the OBVIOUS thing to do is mount the tool on the RH face of the tool post, but in my rush yesterday it didn't occur to me  :nrocks:

So this morning once things were calm on the canine front I re-threaded the end of the pipe. Nasty horrible job as the pipe is far from straight with a 50 thou eccentricity from where I could fit the roller steady to the end, so the re-cut thread is  far from concentric but that doesn't matter in this application. It fits and is mechanically strong - I'm sure that it would leak like a sieve under pressure !

I'd expected picking up the thread would be the hard part, but it was a doddle.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: mattinker on September 01, 2020, 06:53:44 AM
Andrew,

A long time ago, I worked in a Quarry with a welder who taught me a lot about fabrication. We had a dust suppression system to install, no threading equipment available. Trevor's solution was to collect stubs of threaded pipe in the scrap pile and weld them on when we needed them!  Sometimes, if I need a pipe thread, I'll buy black pipe nipples and weld them on, even though I have a lathe!

Cheers, Matthew
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on September 01, 2020, 07:32:20 AM
All done (hopefully!) now Matthew.

So I've just fitted the exhaust stack and proved that the generator opens it OK - which it does  :thumbup:
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on September 01, 2020, 10:53:56 AM
My long series 5 mm drills came this morning, so while a friend was entertaining puppy I managed to cut and fix panel #6 and complete the fixing of panel #5

Annoyingly, when I'd carefully cut panel #6 to height and cut round the RSJ and fixed it in place, I found that it was only 35 inches wide, unlike the rest that are a 1 metre coverage. It doesn't really matter except that I now have 4 inches of angle iron sticking out at the end of the wall. I'll probably cut it off with an angle grinder at some stage.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: modeng200023 on September 01, 2020, 11:54:32 AM
Don't forget to instal some lighting in the generator room.

John
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on September 01, 2020, 12:27:43 PM
Yes John my friend the ex-fireman keeps nagging me about that  :clap:

The only lighting originally in the stable are two halogen PIRs, one of which will be in the "generator room" but long term I will put some LED floodlights, both for the Generator and also for the rest of the stable.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: kayzed1 on September 01, 2020, 02:53:54 PM
Do you have a drain hole in the elbow o/s to drain the stack?
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on September 01, 2020, 03:13:19 PM
No I donít but drilling one would be easy. Theoretically it should stay dry, the rain cap should keep the rain out and condensation should evaporate as it will be hot but now you mention it Iíll drill one  :thumbup:

Iím now looking for used welding blankets to hang up as sound absorbers so if anyone has a pile please let me know.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on September 02, 2020, 03:52:49 AM
Guests arriving this morning so not much will be done, however I managed to 'clear the decks' ready for the second (return) wall to be built. I've only two full height panels left, one being a metre wide and the other 35 inches, so that dictates the wall length!

Also I've drilled a drain hole in the exhaust stack as suggested by Kayzed1 - thanks  :thumbup:
Title: Re: Trying to Quieten the 110KVA Generator
Post by: jiihoo on September 02, 2020, 07:45:29 AM
Hi Andrew,

Annoyingly, when I'd carefully cut panel #6 to height and cut round the RSJ and fixed it in place, I found that it was only 35 inches wide, unlike the rest that are a 1 metre coverage. It doesn't really matter except that I now have 4 inches of angle iron sticking out at the end of the wall. I'll probably cut it off with an angle grinder at some stage.

Assuming this is not a corner but end of the wall: Maybe fix a 2 x 4 or 2 x 5 vertically on the end of the wall, fixed to the extra length of angle iron. Do a roundover on the outer corners if you want to be fancy and then start calling it a design feature to "protect the frail edge of the paneling".
You could also install a light switch, electrical outlets or hooks for extension cords etc. on it.

So definitely seeing this more of a design feature than a mistake here  :wave:

Cheers,

Jari
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on September 02, 2020, 08:59:05 AM
Yes nice touch!

Iím following some strip pvc curtains in eBay and if I win them they will form the  ďdooríí between the two walls so a vertical there is probably needed anyway
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on September 02, 2020, 12:48:31 PM
After the guests had left I was able to escape for 5 minutes and cut the top and bottom angles for the second wall.

(Top angle is much longer as it needs to span three rafters)
Title: Re: Trying to Quieten the 110KVA Generator
Post by: kayzed1 on September 02, 2020, 03:20:06 PM
Guests arriving this morning so not much will be done, however I managed to 'clear the decks' ready for the second (return) wall to be built. I've only two full height panels left, one being a metre wide and the other 35 inches, so that dictates the wall length!

Also I've drilled a drain hole in the exhaust stack as suggested by Kayzed1 - thanks  :thumbup:

 :clap: :thumbup:
Title: Re: Trying to Quieten the 110KVA Generator
Post by: kayzed1 on September 02, 2020, 03:23:14 PM
I have had a few expensive Motorcycle exhausts go because they for got to do the hole at the low point.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: WeldingRod on September 02, 2020, 10:25:25 PM
You haven't lived until you've started a big diesel with no rain cap or drain hole!

Black oily crud EVERYWHERE...

Sent from my SM-G892A using Tapatalk

Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on September 03, 2020, 11:47:14 AM
I managed to get the angle iron for the return wall screwed up to the rafters, and hence drop a vertical to locate and fix down the floor angle.

It was great fun holding that one up under the rafters and screwing at the same time - it weighs about 30 kg - a combination of ropes and ladder balancing -  though I only dropped it once  :bugeye:

So next is to mark out and fix the two remaining panels - not really looking forward to it as both top and bottom slope AND the rafters need cutting round. Might need to make templates  :scratch:
Title: Re: Trying to Quieten the 110KVA Generator
Post by: kayzed1 on September 03, 2020, 07:47:04 PM
Could you not use U channel top and bottom..infill the top and then slid the ends in, a couple of self tappers to hold them in place.
That would make it easy for when you need extra light to change the oil....and stuff. 
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on September 04, 2020, 01:52:50 AM
Iíd intended to use U channel initially, indeed the fellow I got the panels from was going to bend some up from zintec for me as he has an 8 foot folder. But in the end I decided putting a single 6 meter long angle iron was simpler and easier.

Last night I cut a 3 x 3 inch infill from an old 5 x 4  fence post  to make the wall that Iím working off a simple vertical (upper feather boarding sticks out 3Ē from lower masonry) the plan is to fix a horizontal batten sticking out from this wall at an arbitrary height, and use it as a datum to take measurements up an down to transfer onto the panel for cutting..
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on September 04, 2020, 09:17:41 AM
Depressingly little done today (cottage guests leaving, cleaners on holiday, cottage guests arriving - you get the jist !) But I did manage to fix the 3x3 timber wall packing piece in place. All of three 10 mm clearance holes in the timber and 10 mm into the masonry for the frame anchors, but it came at a cost . . .

My Bridgeport milling machine doubles up as a drill press, and drilling the first 10 mm hole in the timber resulted in a dramatic bang and flash of flame with a tripped main breaker  :bugeye: Holes had to be completed on the drill press in the woodwork shop, but that's another fault that needs tracking down. I had a very brief look in it's control box and I suspect the motor contactor as a bit of it's insulation is now missing, but that will have to wait until later to be properly looked at as I'm back 'on duty'  :bang:












Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on September 04, 2020, 12:53:24 PM
I LOVE it when our cottage guests actually ring up and say that they will be arriving late -  suddenly I have another 90 minutes of TIME  :clap:

So I devised a way of supporting a horizontal lath as a datum line, and took 'soundings' up and down from it having marked the widths of the two (different) panels on the lath. This allowed me to transfer the datum onto the one remaining 1 metre wide panel, mark off it's odd shape and that of the rafter and cut it to size.

Still with time in hand I decided to try and fit it - it fitted like a glove  :ddb: Just clamped no time to screw it as they'll hove over the horizon any moment now - but that's the PENULTIMATE  panel in place - so definite progress.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on September 05, 2020, 06:39:29 AM
I finally got ALL the panels fitted this morning - no major dramas.

I nearly forgot that as the panel engages 50 mm into the one on the left I needed to leave an extra 50 mm on the rafter 'notch' for this to happen - just remembered it time.

Having won the auction last night for the PVC strip door parts on eBay then the door closing is now determined  :thumbup:
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on September 12, 2020, 04:41:55 AM
At long last I managed to find a few minutes to hang the PVC strip curtains. Simple enough once I'd mounted a piece of wood up top to act as a transom.

As the strips have been roiled for quite some time the bottoms are very curly. Hopefully this will 'hang out' given time - if not I'll dunk them in a bucket of hot water to encourage them.

I'll eventually secure the two outer strips to the panels with strips of 2 x 1 to keep them close to the wall, but I can't do that until they uncurl.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: russ57 on September 12, 2020, 05:07:17 AM
So, does it work....

-russ

Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on September 12, 2020, 05:13:16 AM
Got 'cottage guests' sitting in their courtyard garden eating breakfast, so daren't try it yet !
Title: Re: Trying to Quieten the 110KVA Generator
Post by: John Rudd on September 12, 2020, 05:48:46 AM
Got 'cottage guests' sitting in their courtyard garden eating breakfast, so daren't try it yet !

Lol.....go for it!.... :lol:
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on September 12, 2020, 07:26:43 AM
Well I did . . but not until they all went out  :clap:

Seems that the curtains have reduced the noise by the cottages courtyard by about 3 dBa to 68/69 dBa. The background noise at that point (road / animals / etc is about 60/61 dBa.

But noise perception is a funny thing - it still sounds pretty loud to me !
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on September 20, 2020, 11:06:11 AM
When I bought the job lot of PVC strip curtains for the generator enclosure I was aware that there might JUST be enough left over to span the eastern entrance to the stable.

At last yesterday I managed to get the 'curtain rail' up and today I hung the strips - they have an absolute minimal overlap of 'one hook' as I don't have enough for more overlap, but in the future if any more turn up it's just a case of hanging and cutting to length.

No doubt they will blow all over the place when it's windy, but there is a noticeable noise reduction over towards the tractor shed now that they are up.

With neither the floor nor the lintel being horizontal positioning the rail was fun - it IS horizontal but doesn't look it!
Title: Re: Trying to Quieten the 110KVA Generator
Post by: Muzzerboy on September 20, 2020, 03:55:46 PM
I'd be thinking about slapping some of that horrible rock wool insulation around the generator room itself. I hate handling it, as it seems to make me itchy before I've even touched it but the sound deadening is pretty good bang for buck.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on September 20, 2020, 04:44:00 PM
Itís not too bad To handle in Ďslabí form intended for cavity walls, but with 25 square meters to cover it gets expensive . And thatís without doing the ceiling - another 21 sq m

Fair old breeze through the generator room when itís running, and the Ďoff the rollí stuff would be blowing all over the place, and need a mesh to retain it.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: Muzzerboy on September 20, 2020, 05:08:36 PM
Yes, that's a big old room. On the other hand, you probably don't need to completely cover every surface to absorb a lot of it.

I guess you can get an idea how good/bad it is from your feedback reviews!
Title: Re: Trying to Quieten the 110KVA Generator
Post by: tom osselton on September 20, 2020, 07:12:38 PM
I put rockwool in the garage walls covered with chipboard and you can barely hear the compressor running.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on September 21, 2020, 02:09:17 AM
Remember that the partition panels are themselves a 70 mm thick sandwich of foam core with 0.5 mm steel facings. Were the room hermetically sealed it would probably be acceptability quiet outside. But of course it needs airflow, lots of it !
Title: Re: Trying to Quieten the 110KVA Generator
Post by: nrml on September 21, 2020, 02:59:25 AM
Acoustic foam panels are fairly cheap on ebay and are less messy than rock wool. If you place a few on surfaces that reflect towards sound apertures, it could go a long way.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: Muzzerboy on September 21, 2020, 03:08:41 AM
The point I was trying to make was that you can deaden a lot of noise with sound absorbent foam without needing to cover every surface and fill every hole. A good example is fitting a carpet or large curtain in an otherwise empty room. The relative silence can be deafening. The steel coverings over the foam will provide very little dampening of sound within the space. Similarly, painting a wall a dark colour can reduce the light levels in an otherwise well lit room. True, sound won't pass through the panels so well but that isn't going to be the dominant mechanism here.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on September 21, 2020, 07:14:52 AM
Yes I take your point entirely - just waiting for a job lot of something suitable to turn up  :thumbup:
Title: Re: Trying to Quieten the 110KVA Generator
Post by: WeldingRod on September 21, 2020, 02:03:03 PM
Compressed fiberglass duct board is excellent for this application...

Sent from my SM-G892A using Tapatalk

Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on September 21, 2020, 04:04:43 PM
Yes you mentioned that before as I recall, but it doesnít seem to be available this side of the pond. I had a search when you previously recommended it. Domestic ducted heating systems went out of fashion here in the mid Ď70s so perhaps that explains it.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: nrml on September 26, 2020, 02:28:08 AM
Some interesting experiments on sound absorption.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on September 26, 2020, 05:56:58 AM
Some interesting points raised in that video, thank you.

It reinforces my opinion that lining the walls and ceiling with rock wool cavity batts is the way forward if only I can find a job lot at an affordable price, they donít need to be as thick as a standard 100 mm batt, probably 25 mm would quite adequate, but itís not practical to split them. Rock wool by the roll is of course available but mounting it brings more issues.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on October 15, 2020, 07:42:02 AM
At last I've sourced a load of Rockwool Acoustic insulation in 25 mm thick slabs - supposedly 'semi-rigid'  - we'll see if it is or not when fixing!

Fixing to three different types of substrate:

Steel partition - self drilling screws

Timber cladding - 2" No 10 wood screws

Concrete Blocks - 50 mm x 5 mm 'hammer fixings'

All using 60 mm nylon washers. No doubt this is going to be one of those 'fun jubs' !

Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on October 15, 2020, 09:58:30 AM
I thought that I'd experiment fixing a slab to the partition wall, in the end it went so well I actually got nine fixed before I was called away to rescue the wife from the puppy :bugeye:

Initial marking out was a pain then I hit on the idea of making a jig - speeded things up considerably.

Then starting the self drilling screws wasn't easy - they wander as of course the point is the wrong side of 25 mm of soft insulation - they need centre punching, but you'll never find the centre pop through the insulation :bang:

Simple solution, clout the screw with a hammer and carry on screwing - went like a dream.

. . . so nine sheets done out of a total of 96 so about 10% - but it's the easy 10% I reckon.

Too early for noise tests as guests are present and anyway much more probably needs doing before the effect will be  noticeable though I can tell it's already less echo-y.

 
Title: Re: Trying to Quieten the 110KVA Generator
Post by: tom osselton on October 15, 2020, 03:27:02 PM
Looking good that will help out a fare bit.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on October 15, 2020, 04:05:10 PM
Yes I'm hoping so Tom!

I've now got sixteen slabs fixed to that long partition wall, so it is pretty well covered - just four to go at the far end.

I've just done a very quick 'start it and turn it off' test (before anyone notices  :clap:) and the noise in the generator enclosure has dropped from 107 dBA  to 103 dba

Tomorrow I hope to complete that wall and the end wall near the PVC strip curtain.

I've just ordered a bolt of heavy duty waxed cotton canvas to make the air duct from the radiator to the outside world - this will be about 2 metres long and a metre by 1.5 metres square. Hopefully this will absorb some of the sound of the emerging fan driven air which can then be prevented from re-circulating back round the radiator as it does at the moment.

Downside is I need to open negotiations to use the sewing machine as the canvas is 60" (1.5 metres) and I need 2.8 metres to wrap round the radiator cowl  :clap:

Title: Re: Trying to Quieten the 110KVA Generator
Post by: nrml on October 15, 2020, 04:37:24 PM
I'm surprised you don't have an industrial sewing machine tucked away in one of your workshops waiting for it's moment to emerge and shine. The insulation job is looking good. :thumbup:
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on October 15, 2020, 04:49:56 PM
Well I did years ago! I do have a light duty one sold to me as industrial but it isnít, they lied !

(Back in my youth I had a holiday job in a haberdashers on the Fulham Road in Chelsea. (Tulleys) They had a side line making rather rectangular sofas and I was involved at all stages from making the wooden frames, upholstering them and making their covers. So when I left home at the tender age of 17 and went to live in Southampton and needed a sofa for my flat, I made one. From that it grew into me making one or two a month, and I got registered as a manufacturing upholsterer ! Even had an exhibition at the Southampton Show one year ! Still got my magnetic tack hammer and staple gun from those days)
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on October 16, 2020, 09:56:20 AM
Cracking on today I got the north wall covered in acoustic insulation apart from where it abuts the west wall, and I got the south wall insulated over the wooden cladding, again leaving a gap next to the west wall. The east wall is finished so I am left with the lower (masonry) half of the south wall and the west wall to complete.

The west wall is where the radiator air leaves the enclosure, and I need to bend up the cowl arrangement and insert it through the wall before fitting the sound insulation.

I also want to sound insulate the ceiling - probably using wire mesh of some form with the Rockwool resting on it - I have two unevenly spaced rafters to fix it to so it needs to be stiff enough to carry it's weight and that of the Rockwool over a cantilever of 600 mm and a 'both ends supported' span of a metre. 50 mm mesh with 2.5 mm wire is looking like the best candidate at the moment but £12 a sheet and 6 sheets takes the shine off it. If I could get over the cantilever somehow I'd use 1/2" mesh chicken wire but by the time I've messed around with batten etc I think probably I'll go for the simpler solution of stout mesh!
Title: Re: Trying to Quieten the 110KVA Generator
Post by: russ57 on October 16, 2020, 06:37:13 PM
I would think, guessing a bit about the rockwool stiffness, that a mesh of even 150x would be fine, more like concrete reo than a mesh fabric. I guess you wouldn't get it in galvanised, but a coat of spray paint would fix that as well as seal the rockwool preventing fibre shedding.


-russ

Title: Re: Trying to Quieten the 110KVA Generator
Post by: tom osselton on October 16, 2020, 07:49:53 PM
You could try one of these off of Amazon Iíve been looking at them for a while. ( thinking canvas)

https://www.amazon.ca/YaeMarine-Cobbler-Repair-Machine-Mending/dp/B07NC3F3M6/ref=sr_1_9?crid=MAHNLMGR4CIS&dchild=1&keywords=hand+crank+sewing+machine&qid=1602891750&sprefix=Hand+crank+sew%2Caps%2C199&sr=8-9
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on October 17, 2020, 06:31:34 AM
A burst of intense sheet metal bashing this morning produced a radiator cowl to be fixed to the the west wall of the stable when I've cut a suitable hole.

When it is in situ and therefore somewhat more rigid I will add either some louvers or a mesh to stop wild life entering.

I've spot welded pre-drilled flanges on with the upper one 1-1/2" displaced from the lower one to make the horizontal surfaces of the cowl actually slope outwards to shed rain.

Next job - mark out and cut a darn great hole in the stable wall  :bugeye:

Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on October 17, 2020, 08:32:13 AM
Measuring up the wall to cut a hole for the cowl showed me that the generator was not quite parallel to the south wall - the radiator end needed to move south two inches, and if it did that the required hole EXACTLY lined up with four of the stable wall planks.

So shift the generator - it's only about three tons and the direction of travel is slightly up hill - just do it  :scratch:

Roller crow bar to the rescue and it's amazing what you can shift single handed with a bit of grunt  :clap: So now the potential hole is in a more conveient place cut it out - so I did with my jigsaw.

Not only was the hole in the right place but the cowl actually fitted through it, so I set too screwing the flanges in place.


 . . it was then the I discovered a major cock up  - I'd offset the flanges in the wrong direction so the 'horizontal' surfaces slope towards the wall not away from it  :bang: :bang:

Theoretically it's just a class of 'un-spot-welding'  three of the flanges and re-fixing them in the right place, but I was rather enthusiastic welding them and they are rather robust welds.

. . I'll cogitate on it for a bit, and maybe experiment undoing spot welds on some scrap - you can get a special drill to remove spot welds, but I don't have one.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on October 17, 2020, 01:23:24 PM
My experiments removing spot welds confirmed that buying the proper drill was sensible so I have some on order.

I also in anticipation  of removing the wrongly located flanges bent up the replacements

Then I started blocking up the slits in the Yorkshire boarded stable by over boarding with 25 x 50 roofing battens, and as it's not practical to get them under the barge board to keep rain out of the upper end grain I've given each of them a little lead rain cap.

Obviously I can't complete this until the cowl issue is resolved as the battens interfere with the cowl, but I've managed to do all the rest.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: hermetic on October 17, 2020, 01:45:34 PM
My preffered spot welding removal tool was the "zipcut". It has a spring loaded hardened centre pin, surrounded by a double ended screw on cutter with some wickedly hard and sharp teeth which cut round the outside of the spot weld, which means you only have a hole in the upper panel, and you can grind the weld off the lower panel, refit it and plug weld them back together.
Phil
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on October 18, 2020, 07:05:21 AM
Thanks Phil, yes that's the sort I've ordered along with a conventional stubby flat ended drill.


. . . .BUT . . .do I fancy removing 40 odd spot welds and possibly end up with a messed up main cowl body . . NO !

So I decided just to abandon the original and make another - I had the materials and it undoubtedly took less time than drilling out the spot welds. So it's (re) made and fitted and the Yorkshire boarding weather strips are finished.

Now I'm off to measure up for ceiling mesh  :thumbup:

(anyone want a redundant cowl ???)
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on October 18, 2020, 11:22:37 AM
This afternoon I finished off fixing the Rockwool acoustic slabs to the lower half of the south wall.

I'd been putting this off as the substrate is rather variable cement blocks peppered with hard bits of slag and I knew that it wasn't going to be straightforward.

The fixings I'm using are miniature 'frame fixings' 5 mm diameter by 50 mm long and are intended to be inserted into a 5 mm drilled hole, and the metal screw tapped home to expand the plastic plug. I rapidly found that the screws all too easily bend when even lightly tapped and that driving them home with an electric screwdriver improved the success rate enormously !

Just the west wall round the recently installed cowl to be lined and when that's done I can start the ceiling. Six 1250 x 2400 x 5 mm galvanised weld mesh ordered from F H Brundel which should arrive in the coming week.

Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on October 19, 2020, 04:36:27 AM
I've been cogitating on how to seal off the lower edge of the west wall. In its original incarnation as a stable the Yorkshire Boarding deliberately didn't stretch down to the concrete floor. This was to prevent rain wicking up the end grain and rotting out. The planks stop about four inches short, with the lowest horizontal beam being about seven inches from it's lower edge.

I considered a couple of courses of brickwork and a bit of damp proof course under the timber, but water will still puddle on the DPC.

Then I remembered that I had a few spare lengths of six inch 'twin wall' electric cable ducting that not only had an outer diameter of seven inches (ideal!) but was obviously made from rot proof plastic, AND the curvature would shed water from outside BACK outside. Perfect  :thumbup:

Cutting a suitable length this morning it proved to fit very nicely. Just in case it wants to pop out I've run some expanding foam along the inner / lower edge to keep it in place. This can be trimmed later today when it's 'gone off'

Unconventional I suppose but I think that it will be effective.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on October 19, 2020, 01:24:57 PM
Later this morning, in a nod to Health and Safety, I built a safety barrier round the projecting cowl to stop people bumping into it. (Pete. you will recognise the bits !!!)

Then after lunch I was able to finish the bits of the South and North walls abutting the West wall that previously I'd had to leave, and then finally finished fixing acoustic slabs to the West Wall.

So that's all vertical surfaces covered in 25 mm Rockwool Acoustic Slab - just the ceiling to do which is going to require a bit of ingenuity, but that will have to wait until the 50 x 50 mm mesh arrives so time to think about it.

(That's 58 slabs fitted or 41.76 square metres, the ceiling is a further theoretical 23.4 square metres or another 32 slabs which is lucky as I have 38 left!)

The canvas for the 'radiator exhaust air tunnel' has arrived, but I won't fit that until the ceiling is done or it will get in the way of ladders etc.


Title: Re: Trying to Quieten the 110KVA Generator
Post by: kayzed1 on October 19, 2020, 07:34:53 PM
one assumes a grill and mesh to keep out the critters.. :beer:
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on October 20, 2020, 02:45:10 AM
Oh yes !
Title: Re: Trying to Quieten the 110KVA Generator
Post by: russ57 on October 20, 2020, 03:08:14 AM
Are you sure it's not just a padded cell....

-russ

Title: Re: Trying to Quieten the 110KVA Generator
Post by: AdeV on October 20, 2020, 04:04:29 AM
Are you sure it's not just a padded cell....

A padded cell with a honking great diesel engine in it! Luxury!  :lol:
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on October 20, 2020, 05:43:05 AM
It does sound very peculiar in there when the Generator is not running, and if your ear is within about a foot of the wall itís even stranger  :clap:

All that disappears though when the engine starts !

I thought that I had thinking time before the ceiling mesh is delivered, but Brundels have email to say itís coming today  :bugeye:
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on October 20, 2020, 10:19:13 AM
True to their promise, Brundles have just delivered a bankrupting load of steel to me  :bugeye:

The six 50 x 50 x 2400 x 1220 galvanised mesh panels to hold the ceiling acoustic material up, but also . .

Three off 6 mm x 100 mm x 6 metre mild steel bars and . .
Two off 25 mm x 25 mm x 3 mm x 6 metres angles

. . .to make Copes and Drags for the Foundry - but more of that later in an another thread probably.

Meanwhile I feel singularly disinclined to start fixing the mesh, and anyway first I need to reduce the three light fittings to dangling cables in order to get the mesh up (lights will fix up under the mesh)
Title: Re: Trying to Quieten the 110KVA Generator
Post by: AdeV on October 20, 2020, 02:05:22 PM
...a bankrupting load of steel...

I know the feeling: I recently bought 7 lengths of 25mm square box, a length of 25mm equal angle & a 25x3mm flat bar; nearly £200 delivered! I misheard him on the phone, thought it was £90odd (thinking, that's quite reasonable)... didn't hear the 1 on the front of it!!

Still... all my orange "B&Q-like" shelving no longer sags, with 3 steel reinforcement bars under each shelf  :thumbup:
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on October 20, 2020, 02:22:34 PM
That lot listed above, plus two off 2 metre x 1 metre x 1.6 mm Zintec steel sheets was £247  :bugeye:

Steel has risen enormously in the last couple of years.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on October 21, 2020, 08:13:38 AM
As soon as I could escape from other duties this morning I isolated the lighting supply to the generator room and took down the two LED strip lights and one LED flood light. Leaving the cables dangling (but taped off) I will have to work the mesh sheets round them.

To start the first mesh I put screws into the side of the two joists near the west wall, and fixed short lengths of fencing wire to them to initially suspend the mesh (trimmed to width) at an angle so that I could then 'load' it with Rockwool, pivot it into place and screw it up. To help this process I made a suitable temporary prop.

Needless to say it wasn't quite as simple as that - but  I got a tolerable result fixing the first too meshes. The mesh size is about 50 mm longer than the Rockwool length so 1200 mm x 50 mm bits have to be packed on the exposed edge as I work from West to East.

The next mesh will incorporate the lighting cables, and I'm tempted to cut it lengthwise where the cable emerges and put it up as two bits.



Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on October 21, 2020, 12:31:39 PM
This afternoon when I was released from Puppy sentry duty I managed to get a further one and a half more meshes up.

As I thought that I might have to, I ran a partial sheet up to the lighting cables and a full sheet beyond which worked out quite well, though obviously the room must taper a bit as the sheets are getting too long - next one wil need to be shorter by one mesh I think to avoid scaring the walls too much as it's moved into place.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: Muzzerboy on October 21, 2020, 02:58:23 PM
....avoid scaring the walls too much as it's moved into place.

Yes, they must be petrified by now ;-)

IIRC, the building regs for noise control recommend / require a gap between rockwool and the next panel for most effective noise reduction. So the gap between the panels and the roof certainly wouldn't be a bad thing on that basis, assuming they are correct.

Looking forward to the acid test ie dBA measurement of the final system! I suppose you might argue the acid test is avoiding a bad review on Tripadvisor or whatever.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on October 21, 2020, 03:26:44 PM
Well throwing caution to the wind I did fire it up with a full compliment of Ďinmatesí ensconced in their cottages. With the incomplete ceiling I am measuring 60 dBa at the gate to their courtyard occasionally dropping to 59 dBa.

There is a noticeable decrease in the noise which presumably will continue to improve as I finish the ceiling. Iím expecting the exhaust radiator air tunnel to improve things as well.

However Iím conscience not to run the generator too long at the moment as there is masses of Rockwool bits around to clog air filters.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on October 22, 2020, 03:28:35 PM
Today I got the last of the Rockwool sound insulation installed. The last panel was a bit of a pain as it needed a 50 mm 'extra' bit fitting that for the life of me I couldn't get to stay put as I fixed the mesh. Cosmetically not ideal but probably has zero effect on the sound deadening!

So what's the results?

Well when I began I was measuring 107 dBa adjacent to the generator, and 71 dBa by the cottages courtyard (this last figure seems to have been recorded optimistically low by me on earlier posts)

Now I am measuring on brief tests today 95 dBa inside the generator room, and 59/60 dBa by the cottages courtyard.

The 12 dBa reduction in the generator room is obviously very significant but I'm surprised the the remote reading isn't less, though it IS the same 11/12 dBa reduction.

. . . still got the canvas 'radiator exhaust tunnel' to go !

Apart from the canvas, re-installing a spot light fitting, and a major hoovering up that's about it for the generator room.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: russ57 on October 22, 2020, 05:35:36 PM
12db is pretty good - a subjective reduction to 1/4 if I recall my acoustics.

Are you planning to seal the rockwool in any way? Even a light spray paint would help I would think, without affecting the performance.


A walk around the enclosure with the meter may pinpoint any significant 'spot' leaks. Covering those with lead sheet ought to help.

Last question - does the generator noise vary with load?



-russ

Title: Re: Trying to Quieten the 110KVA Generator
Post by: AdeV on October 23, 2020, 02:52:19 AM
Apparently, 60dbA is about the equivalent noise level to a conversation in a restaurant.... so not bad, considering the size of the engine. If you've got a few quid left over, you could always add a layer of AcoustiBlok (tm) sheet - this is (apparently) seriously sound-deadening stuff - their 6mm sheet is claimed to reduce sound levels by 32dbA, which would get you nicely below "Library" sound levels (40dbA). Since their website doesn't quote prices, you know it's going to be dear...

I was planning to use this to keep a generator quiet on my transporter; but after I stopped racing some mumbleteen years ago, the project lost any sense of urgency it might have had in the first place...
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on October 23, 2020, 02:56:09 AM
Russ Iíve been considering some sort of spray to make it less friable but paint would be inflammable so my thought at the moment are along the lines of a solution of sodium silicate.

Iím sure that the generator note will change with load, in fact I know it does, but the actual noise level subjectivity seems the same.

To biggest escape point is probably the door where I have those pvc strips, but I canít block it as loads of air is needed for cooling and combustion.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: RussellT on October 23, 2020, 04:53:00 AM
That sounds like a good result to me.

Can you do anything to the floor?

Russell
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on October 23, 2020, 05:03:25 AM
Probably not Russell, itís very uneven concrete, about all I could possibly do is lay some cork tiles, but theyíd not lay flat and be a trip hazard
Title: Re: Trying to Quieten the 110KVA Generator
Post by: russ57 on October 23, 2020, 05:27:22 AM
You need some sort of 'labyrinth' or baffle so the noise has to bounce around to escape.

Like this
 - - - -   - - - -
     -  - - - -
------       - - - - - -

This technique is used eg to reduce sound from a dust extraction enclosure.

Would paint really be flammable once it dries? I thought after the solvent is gone, it's mainly pigment and binder especially water based.

For the floor, what about that soft-fall used in playgrounds? Some sort of crumb rubber.

Or carpet / outdoor carpet / artificial grass..

Really make the cell comfy...



-russ

Title: Re: Trying to Quieten the 110KVA Generator
Post by: Muzzerboy on October 23, 2020, 08:15:46 AM
Seems the new thing in sound engineering is "psychoacoustics". Fancy sounding stuff but it refers to the nature of the noise as much as the absolute noise level itself. For example, a leaf blower may not be massively noisy but could get you killed, whereas a serene throbbing noise at the same level might make you friends. I suspect I have a fairly good idea what a loaded diesel generator sounds like ie not too unpleasant.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on October 23, 2020, 08:48:55 AM
Well a friend popped round yesterday and I demonstrated the generator and itís noise and he, being an ex HGV driver was  ecstatic about the sound. Thought it sounded great!

But I can imagine that if you are on a long awaited paid for holiday itís perhaps not what you want while dining al fresco in the courtyard  :clap:
Title: Re: Trying to Quieten the 110KVA Generator
Post by: russ57 on October 23, 2020, 09:06:34 AM
Offer the guests a custom cast souvenir...
Maybe cast iron earmuffs...

-russ

Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on October 24, 2020, 11:26:18 AM
Today I extended the radiator surround forwards towards the west wall by about eight inches.

This will allow me to use a single width of the canvas as a wrap and give sufficient overlap for fixing, otherwise I'd have had to join two strips of canvas which would have been a bind.

Need to make and fix a grill to keep insects out, then the canvas can go on.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: hermetic on October 24, 2020, 11:45:02 AM
Neat work on the radiator extension Andrew, but we wouldn't expect anything less from you! How about some industrial rubber conveyor belt between the woods that the genny is standing on and the floor, might stop the floor becoming so much of a transfer medium for the sound.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on October 25, 2020, 10:09:16 AM
With the help of  a friend I managed to get the canvas wrapped round the wall flange and  radiator extension, and fixed with 25 mm strips of Zintec pop riveted through the canvas. Prior to wrapping I put gaffer tape over the raw edges of the wall cowl and radiator extension to hopefully prevent the canvas chaffing.

Needless to say it was not ever so easy, but rare earth magnets came to the rescue holding the canvas while I fixed the strips on. I'd intended to use double sided carpet tape to hold  it temporarily in place, but as the canvas is waxed it didn't stick!

Once it was in place and the seam crimped together with clothes pegs I was able to tack stitch the seam with rather crude tacks and the pegs could be removed.

Starting the generator it was immediately apparent that the airflow was now completely different. Before the radiator air was re-circulating but now the hot air is expelled and fresh drawn in through the PVC door strips, which now billow inwards. I feared that the door being partly open would increase the external noise but I'm still measuring 60 dBa at the cottage courtyard.

It's amusing to see how the 'tunnel' inflates as the generator is running.

. . . just the outer grill to make and fit, but it's pouring down so it will have to wait.
Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on October 25, 2020, 12:42:40 PM
Rain barely stopped all afternoon, but as I have the original cowl, where I cocked up the flange, I was able to use it to model the vermin mesh.

Mesh cut and bent and ready to fit when weather permits!

It is slightly finer than I would have chosen as no doubt it will give a bit of air resistance, but I had it in stock so have used it. Can always re-make it  later in a coarser mesh if it gives problems, but I think that the engine is adequately cooled and anyway will only be used for short(ish) runs.

Title: Re: Trying to Quieten the 110KVA Generator
Post by: awemawson on October 26, 2020, 06:40:38 AM
A slight respite from the rain this morning, I even spotted the sun at one time - so I sprang into action and fitted the 'rodent mesh' into the radiator exhaust flange. Just a drilling and bolting affair - nothing too complicated.

Air flow doesn't seem to be unduly affected - no doubt the over pressure in the canvas tunnel will be greater, however having a 45 degree cut off on the cowl has increased the discharge area by about 40% so the impedance of the mesh perhaps isn't anything to worry about!