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Large (6 3/4") mushroom vents?


FluffMagnet

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Hi all - my first post here, so please be gentle :)

 

I am fitting out a 45' barge and I'm desperately seeking six "large" (6¾" outer dia, 4¾" internal dia) mushroom vents* - colour and material irrelevant (I'll even accept plastic at this point!). It seems the only company who makes them is Black Country Metal Works, but they won't produce any unless they have an order for 25(!) pcs. Short of spending the £750 required to meet their minimum order quantity, what are my options?

 

*) It is important that the vents don't have any internal protrusions, such as a handle for closing; the vent base must be flush with the cabin roof even when screwed down. This is because I will have fans mounted on the inside, which any protrusion would interfere with.

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You've gone to a trade supplier - that's why there's a minimum quantity. Midland Chandlers sell direct to the public - and the price reflects that.

An alternative is - https://www.limekilnchandlers.co.uk/brass/4-brass-mushroom-vent.html

and there may be others The whole fitting should be flush to the roof, although the shallower variety may not (MC do both) - perhaps that's why you ask / specify? I'm sure there are other suppliers  - it's years since I needed some!

 

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Black Country Metal Works also sell directly to the public. And while "standard size" (6" x 4") mushroom vents are easy to find - either via search engine or on eBay etc - the only company I have been able to find that sells the "large" (6¾" x 4¾") type is Black Country Metal Works.

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2 hours ago, alan_fincher said:

Limekiln list the larger size, though I admit it shows as "out of stock".

https://www.limekilnchandlers.co.uk/large-brass-mushroom-vent.html

Have you had a conversation with them about whether they are likely to restock it?

Thanks, I now have, and they won't :( Apparently they "import them themselves", but stupid me forgot to ask from where! At least this means there are multiple sources of these things, which gives me some hope :)

 

39 minutes ago, Joe Bourke said:

Have a look at davey.co.uk. Be warned they are dear.

Dear? They're £276.52 plus VAT each. That's not "dear", that's daylight robbery! Times six, inc VAT, the bill would land on two grand ? Or to put it another way: I could buy seventy-two of them from Black Country Metal Works for the same amount...

 

12 minutes ago, Joe Bourke said:

Try ebay

Done. Long time ago. One of the first places I look for pretty much anything.

 

 

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5 hours ago, FluffMagnet said:

Black Country Metal Works also sell directly to the public. And while "standard size" (6" x 4") mushroom vents are easy to find - either via search engine or on eBay etc - the only company I have been able to find that sells the "large" (6¾" x 4¾") type is Black Country Metal Works.

I have no idea about their mushroom vents, but some items the Black Country Metalworks sell are decidedly substandard.  Their water cans are not fit for purpose, unless they have got their act together since I was daft enough to buy one.

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Hello FluffMagnet, could I ask why you need that size vent? I know you mention fans, perhaps there may be a way of fitting normal size mushroom vents, but alternative spec fans. You said you would consider plastic vents, surely there are suitable ones of the size you mention readily available. 

I warned you Davey & Co were expensive, but I thought you were loaded with cash like all boatowners. ?

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1 hour ago, Joe Bourke said:

Hello FluffMagnet, could I ask why you need that size vent? I know you mention fans, perhaps there may be a way of fitting normal size mushroom vents, but alternative spec fans.

I need that size because I want to use 120mm 12V "PC" fans for the ventilation; these fit neatly inside the roof insulation, with both being exactly 1" thick. Cheap as chips too, and relatively quiet (yet powerful) due to their large diameter. I could fit them under 4" i/d vents, but this would reduce the efficiency by ~50%. I'm kicking myself for not having purchased the vents when I designed the ventilation system last year - I think they were "in stock" then - I Just didn't take into account that the product might vanish between concept and implementation :( Lesson learned: don't hold fire on that "buy it now" click! 

 

1 hour ago, Joe Bourke said:

You said you would consider plastic vents, surely there are suitable ones of the size you mention readily available.

I think so too, but I haven't been able to find much, despite 120mm being a fairly standard ventilation pipe dimension. Suggestions?

 

1 hour ago, Joe Bourke said:

I warned you Davey & Co were expensive, but I thought you were loaded with cash like all boatowners. ?

So you did, and I made sure to have a stiff drink to hand before checking the price ;) As it is, it would make far more sense to order 25 pcs @ £750 from BCMW and try to flog the surplus 19 than spend £2k on the six.

 

Edit: Here's an animation I made, to illustrate the concept:

 

vent.gif.501521883ecffe9c86b7ad4efdc1126e.gif

 

Edited by FluffMagnet
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3 minutes ago, FluffMagnet said:

Please disregard them. They will not be fitted, and this is about finding 120mm roof vents.

Fair enough! Can't help you there, sorry, except to observe that fans are probably available in a larger range of sizes than mushrooms :(

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1 minute ago, AndrewIC said:

Fair enough! Can't help you there, sorry, except to observe that fans are probably available in a larger range of sizes than mushrooms :(

Not really; the next (standard) size down is 80mm, which would whine like a turbo-jet if you wanted to move any significant amount of air. :(  120mm is the sweetspot.

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When the fans failed in our extract-a-lites we replaced the fan with doubled up computer fans. They were circular casings with little tabs in each corner. I cut the tabs off and taped 2 together with duck tape and stuffed them up the mushroom and cowl vent ducting. I think they were 90 odd millimetre diameter, so a snug fit in the ducting. We have 2 in the galley, 1 in the heads, and one in the shower room. I think they were only a couple of quid each.

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1 hour ago, Joe Bourke said:

When the fans failed in our extract-a-lites we replaced the fan with doubled up computer fans. They were circular casings with little tabs in each corner. I cut the tabs off and taped 2 together with duck tape and stuffed them up the mushroom and cowl vent ducting. I think they were 90 odd millimetre diameter, so a snug fit in the ducting. We have 2 in the galley, 1 in the heads, and one in the shower room. I think they were only a couple of quid each.

Sounds like a nice and cheap solution. Not sure how well two co-rotating sets of blades will perform, though I'm sure I've seen some server computer case that used them (noisy as *&#!£$) There are round fans too, which cost quite a bit more, but are designed for ventilation use and a lot cheaper than the bulky bolt-on "marine" vent fans I've seen, one example being the San Ace "RF" (round frame?) series: http://uk.farnell.com/sanyo-denki-sanace-fans/9rf1312p3h001/axial-fan-136mm-12vdc-70-7cfm/dp/2679913 For larger fans, look at combustion engine cooling fans, which are available in surprisingly small sizes, e.g. https://www.ebay.co.uk/itm/153010395167

 

Edit: For the record, I will be using the Sunon EEC0251B1, of which I have already purchased 10pcs. 184m3/h, or 108 cfm, at 44.5dBA noise level and 0.45A current draw (5.4W). They will be individually controllable through PWM, so can run whisper quiet with very low power draw, while still providing meaningful air flow.

 

Edited by FluffMagnet
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At the risk of being flamed -

I question the real need for fans everywhere?

Fine - in the loo and kitchen area where they can be switched on as needed. That's what I did  - but they're quite noisy. If you run them slow, they aren't very effective.

If the ventilation in the boat is reasonable to good( we have drop back vents and opening sections in our bus windows) then natural convection is good enough.

Of course if your 'windows' are portholes - then that's another story....

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1 hour ago, OldGoat said:

I question the real need for fans everywhere?

Feel free! I think it's possible to question almost every design decision I make - and I do too :) I'm not, however, interested in having any lengthy discussion about this, suffice to say the fans are needed because of the size, shape, layout and existing ventilation of my boat. And the fans will be very effective even at whisper quiet speeds - already tested! This is one of the benefits of choosing a larger diameter fan. They will also be able to shift huge amounts of air when required - such as right now ?

 

I believe I have located the manufacturer of these vents; a company called Vertex Exports in Uttar Pradesh. I have sent them an inquiry.

Edited by FluffMagnet
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12 hours ago, FluffMagnet said:

For the record, I will be using the Sunon EEC0251B1, of which I have already purchased 10pcs. 184m3/h, or 108 cfm, at 44.5dBA noise level and 0.45A current draw (5.4W). They will be individually controllable through PWM, so can run whisper quiet with very low power draw, while still providing meaningful air flow.

I would not call 6 fans each drawing 0.45a 'minimal'

 

If running 24/7 that's 65Ah per day (or put another way, 2x 100Ah batteries dedicated to running fans, meaning another 2x 100Ah batteries that need to be charged for many hours every day)

65Ah is more than equivalent to running 2x fridges 24/7

 

Fine if you are permanently moored and on a landline, but if 'mobile' then you will be running the engine a lot.

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9 minutes ago, Alan de Enfield said:

I would not call 6 fans each drawing 0.45a 'minimal'

I already said I didn't want to go "in depth" on the design of my ventilation system, but I guess I'll have to explain a few things:

 

1) The fans are individually controlled. That is any fan can be on at any level independently from all others. For example, the forward bedroom can get a gentle flow of air while the bathroom fan is on half power and the galley fan on full blast.

 

2) The fans are controlled by PWM (Pulse-Width Modulation). This means that they draw less power the lower their speed. The fact that the fans have a maximum power rating of 5.4W only means that they are capable of moving more air as need arises.

 

3) The fans will not be "always on". While having manual controls (a simple momentary pushbutton), the PWM dimmer units are also controlled by the central computer, a Raspberry Pi, which is always on, and always online (using about 7.5W). This is also equipped with (several) temperature & humidity sensors, allowing some automation of climate control (it will also control a Webasto diesel heater and, when shore power is available, a Meaco dehumidifier).

 

 

4 minutes ago, BWM said:

Ah yes - I have looked at these. Definitely an option. But I would need to butcher the internal opening/closing handle, as it would interfere with the fan. I'm also concerned that the low height of the units mean what's left of the screw will still protrude inside the cabin when fully closed.

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2 minutes ago, FluffMagnet said:

I already said I didn't want to go "in depth" on the design of my ventilation system, but I guess I'll have to explain a few things:

 

1) The fans are individually controlled. That is any fan can be on at any level independently from all others. For example, the forward bedroom can get a gentle flow of air while the bathroom fan is on half power and the galley fan on full blast.

 

2) The fans are controlled by PWM (Pulse-Width Modulation). This means that they draw less power the lower their speed. The fact that the fans have a maximum power rating of 5.4W only means that they are capable of moving more air as need arises.

 

3) The fans will not be "always on". While having manual controls (a simple momentary pushbutton), the PWM dimmer units are also controlled by the central computer, a Raspberry Pi, which is always on, and always online (using about 7.5W). This is also equipped with (several) temperature & humidity sensors, allowing some automation of climate control (it will also control a Webasto diesel heater and, when shore power is available, a Meaco dehumidifier).

 

 

Fairy snuff - you obviously have a good understanding of electronics and climate control, I hope you have a similar level of knowledge re battery charging and maintenance.

Have you done a power audit yet ?

 

Good luck with it all.

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Just now, Alan de Enfield said:

Fairy snuff - you obviously have a good understanding of electronics and climate control.

I think I do.

1 minute ago, Alan de Enfield said:

I hope you have a similar level of knowledge re battery charging and maintenance.

I think I do.

1 minute ago, Alan de Enfield said:

Have you done a power audit yet ?

Yes. I keep a spreadsheet listing every single on-board consumer, its power draw, and estimated runtime / 24h. It also includes the distances to the distribution boards which each consumer is connected to, automating the calculation of the amount of wire of different dimensions that will be needed, and how many fuses (and what size) each distribution board will require.

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