Quiet 12v Galley Blower?

[GordMay]

Oops; I could have read more carefully.

You done her right. Your idea for "squishier" is a good one.

[Canibul]

No problem. Any and all solutions gratefully considered.

[captmikem]

Originally Posted by Canibul

Yep.
All of the noise is fan noise. And this is now a new fan just installed last night.
Marine Inline Compact Blower 4" Inlet 12 Volt 120 CFM 3 Amp - - Amazon.com

Same installation, and only slightly quieter than the old one.

That is a 120 CFM fan, several computer muffin fans have that volume, and higher freq motors.
Here is $16 example:
BitFenix Spectre Pro All Black 140mm PWM Fan (BFF-SPRO-P14025KK-RP) - FrozenCPU.com

For quiet, you could take a high volume 24V fan and run it on 12 volts, it will run slower, and quieter, (like in your car, when you select a lower fan speed it is simply reducing the voltage to the fan) and move about half the CFM quoted at 24V.

[PuttingDoctor]

Experienced greatest joy in my last kitchen remodel when we replaced the built in exhaust fan / microwave with a cabinet mounted filter / light setup. Above the hood ran the ductwork first to a heavy baffle that weighted about 25 pounds, then the fan. One could not tell the fan was on even at high speed unless you noted the movement of the vapors.

Likely not a solution for the boat but there are many ways to relocate away from the immediate area to reduce sound.

Oh, actually the best idea in that remodel was the electric heat mat under the tile floor. ThermoSoft is amazingly efficient.

[Canibul]

Yes, I went with a lower CFM blower hoping that it would be quieter. It's not much quieter, although every little bit helps of course.

I've got several 12 volt computer fans here I can try out. My concern with those is that the motor is not really protected against any kind of liquid or splatter prone stuff. Like bacon grease or even steam. They're meant for dry environments, moving mostly warm (not hot) air over microprocessors to cool them off. They'll handle light dust and lint, but the motors are somewhat exposed in the airflow. The blowers like the ones I have are designed so the motor is shrouded behind a plastic cowling so the greasy fumes etc. blow past without going through the motor.

The squirrel cage design has the motor completely outside the air flow. But of course it has some foot print issues in most boat installations.

[msrcal36]

Our solution has worked well and is VERY quiet. This fan can be swiveled to aim any direction including vents, hatches, etc. It is the best fan we have ever used:

Sirocco DC Fans - Caframo | Fisheries Supply

[CC45]

Product Catalog – Computer Fan Outlet – Computer and Instrument Fans, custom Try this company. they have fans that can evac large area's .

[Canibul]

Thanks, and we do like Caframo fans. Have six on board already. But I'm looking for something to move the hot air and greasy etc. over the stove to outside the boat. Not an issue on the hook but in the marina down here we're all buttoned up with the air conditioner running and I want to evacuate the fumes and not circulate them around the boat.

[CC45]

Originally Posted by Canibul

Thanks, and we do like Caframo fans. Have six on board already. But I'm looking for something to move the hot air and greasy etc. over the stove to outside the boat. Not an issue on the hook but in the marina down here we're all buttoned up with the air conditioner running and I want to evacuate the fumes and not circulate them around the boat.

Hi, ok i'm going to look at that site also. Not sure at the moment on what fans to use for that. I'll be trying to acquire one that your trying too, for my Chris Craft. if i do find one i'll let you know..

[NahanniV]

I have a galley extractor fan.

Works great, but as noted, Very noisy.

My experiment this winter is to replace the 3" aluminium accordion ducting with exhaust hose and support the fan only with the exhaust hose.

Have not finished the install yet, but my tests seemed less noisy.

Cheers,
JM.

[leftbrainstuff]

Originally Posted by Canibul

Working our way through this boat I'm slowly improving things where I can. One real annoyance is a very noisy galley exhaust blower. It's so loud we have to shout to carry on a conversation over it. It came with the boat, and is one of those ducted fan type inline blowers, mostly advertised as bilge blowers. This one uses 4.8 amps and does a good job exhausting cooking fumes but dang it's deafening. It's hooked up with standar aluminum 4" dryer hose, and vents overhead through a screw-down mushroom cap kind of vent cover.

Does anyone here know of a good, quiet alternative to these jet engine things?

We have 2 12v computer fans in a board which nests in our port. Its not super quiet but does give sufficient airflow. They are quieter than other options.

The computer fans vent directly out the port. No ducting. They are not designed to cope with any ducting pressure loss. The opposite port to the cockpit is also opened. This gives a direct flow path maximising air flow and galley venting.

The small port space claim negates the use of small diameter hi speed fans. A quiet slow fan wont move enough air.

You need at least 20+ air changes per hour for kitchen / galley venting. When you do the math on your max fan size you'll be able to determine the min fan speed.

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[colemj]

Canibul, that blower you linked to looks just like the Rule versions that we found to be very loud from the start. There are others that are quieter, and I linked to one earlier.

This application is less about air flow and more about air flow through ducting and restrictions. Computer fans fail in this - they have the free air flow, but try to make them pull or push against a restriction and that air flow disappears. The motors just aren't strong enough - which is why you don't see them used for bilge blowers, etc.

Canibul and I are not talking about providing airflow in our galleys or moving more air out a side port. We have a somewhat unique application similar to what is found in houses in a range hood containing a ventilator fan to draw air through the hood and duct it outside. So Caframo's, cross-ventilation, computer fans in side ports, etc are not a solution to this. This application needs a blower.

Mark

[CarinaPDX]

For any fan the quality of the bearings is a major consideration for longevity and noise. Most fans use bushings - not true bearings - and thus have a short life and become very noisy rather quickly. This applies to bilge exhaust fans as well as the square "computer" fans. For moving air in the living spaces I use 120mm computer fans with bearings exclusively, and all of the more recent purchases have speed controls built in. The MTBF on such devices is typically 30k-50k hours. I have one screwed to the overhead opening of a mushroom vent in the galley, and it is not too noisy. I have a bronze screen over the intake (mostly to keep out insects) which needs regular cleaning. Of course it does not compare to the powerful modern range hoods for homes but it is adequate for the task.

By comparison, I was going through a Hella Turbo every year or two until I discovered that it was only rated for MTBF 2k hours. Regular failures were a result of the bushing design, not some defect. I also used a standard bilge blower until I discovered that it had an MTBF of 1.5k hours - it was really intended for blowing out the bilge for 5 minutes before starting, not continuous use. I now have a Delta-T.

The upshot is to look for real bearings (roller/needle/ball) instead of bushings and if at all possible find the MTBF numbers. Also, go the extra mile with the computer fans: there are large differences in air flow so only buy the high capacity ones, and with bearings of course.

Greg

[colemj]

Originally Posted by CarinaPDX

The upshot is to look for real bearings (roller/needle/ball) instead of bushings and if at all possible find the MTBF numbers. Also, go the extra mile with the computer fans: there are large differences in air flow so only buy the high capacity ones, and with bearings of course.

Greg

For applications like the range hood exhaust of the thread topic, the fan is only used an hour or so each day, so MTBF isn't much of an issue. We have never had a cheap bilge blower-type fail - only get too loud.

Again, computer fans just won't work in this application. It isn't about air flow per se - it is about air flow through ducting and restrictions. And a computer fan would need an appropriate housing to fit the duct work.

Mark

[CarinaPDX]

Originally Posted by colemj

the fan is only used an hour or so each day, so MTBF isn't much of an issue. We have never had a cheap bilge blower-type fail - only get too loud.

My point is that it gets loud because the bushings wear quickly, and that is the cause of the increased noise in many cases. Yes the fan still moves air for a long time after the bushings get noisy - it just isn't tolerable. That is what happened with my Hella fans.

It is quite possible to find, or at least make with a 3D printer, adapters that attach to computer fans and provide a tube for the duct hose to slide over. As I noted before, fans are available in a broad range of capacities. Just going to Frys and buying one is not likely to yield an adequate fan - look around on the internet and order the most powerful one and I think you may find it will serve. Still, probably not the airflow of a bilge blower but not the noise either.

Greg