Sound Insulation

[Andrew Mawson]

I need to >>SOUND

[Doctor Drivel]

Use Warmcell. You can build a frame, mix it, apply it and board up. It also makes the frame air-tightish. Making something air-tight reduces sound a hell of a lot.

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "Andrew Mawson" saying something like:

Go out to the nearest Aggreko depot and have a look at how they construct their soundproof gensets. There's quite a bit to it, not just sticking stuff on the walls.

[Rumble]

Andrew Mawson said the following on 20/11/2005 17:46:

AIUI (don't have one handy to inspect closely!) super silent generators generally have the following features: -

1. The engine compartment is air tight (or very nearly so).

1. The panels for the engine compartment have sound insulation to both insulate and dampen vibrations in the panels.

2. All the doors and access panels have rubber seals (both to help with the airtighness and to stop vibrations).

1. An extensively baffled exhaust system.

2. The engine is mounted on rubber shock absorbers (kind of obvious!).

The radiator and air intake obviously have to be outside the airtight engine compartment.

Don't forget to consider the fire risk of additional insulation.

Google for: car soundproofing

Have fun!

[Doctor Drivel]

Insulation doesn't easily catch fire.

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "Doctor Drivel" saying something like:

You have to balance the needs of the airflow for cooling and combustion and the necessity of sound insulation.

Combustion air and exhaust are ducted in and out, and the radiator can be mounted externally. Even so, the temperature build-up inside a closed insulated container with a genset in it can be dramatic. Add to that the possibility of a fractured fuel line spraying fuel over insulation material. There's always a chance some of the insulation material might come loose and fall on a hot turbo casing, for example.

Insulation might not easily catch fire, but soak it in diesel and apply an ignition source.

[Andrew Mawson]

combustion

container

Dave,

For all the reasons you mention I have 'probably' settled on using bog standard 100mm rockwool retained by a custom made cage of wire meshing. Both the radiator outward flowing air and the combustion air are currently ducted but the input air to the radiator is drawn from the totally open bottom of the trailer chassis. I will probably enclose the bottom but leaving a largish entry port at the alternator end so that cool air is available for its cooling as well as the radiator. Currently kicking ideas arround about what to do under the engine sump - I'll probably enclose it in sheet steel with rockwool above, but incorporate a drip tray with a funnel shape leading to a drain so any oil drips and fuel leaks don't accumulate in the enclosure.

AWEM

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "Andrew Mawson" saying something like:

It's certainly going in the right direction; what size is the enclosure and what's it made of?

As I said, have a gander at how Aggreko and others do it; no point in re-inventing the wheel.

[Andrew Mawson]

alternator

enclosure

Dave,

This is a twin axle trailer mounted Aggreko 100KVA set made towards the end of the 1980's. Its is a steel box about 2.6m long, 1m wide and

1.3m high. The engine / alternator are close coulpled and mounted directly on the chassis rails which are open to the world below. The only concession to noise originally was 'anti drumming' tar paper 3mm thick on the panels inner surfaces ! I intend to line the panels with 100mm rockwool retained by I'm not quite sure what !

Todays problem is the engine has started running far too fast. It's a SIMMS injector pump, with the 'stop lever' controlled by solenoid, and the throttle fixed by stops and it suddendly started running about 15% fast, so if anyone knows about SIMMS pumps gen would be appreciated.

AWEM