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Post by yorkshireman on May 1, 2019 7:03:09 GMT
Hallo One interesting question here is whether ceramic fibre insulation is hygroscopic or not. I guess it might be as a Silicate Wool. This means that droplets of boiler feed water once in the insulation will stay there for a very long time, promoting corrosion. The article www.ceceramicfiber.com/Article/Hygroscopicityofhigh_1.html night be relevant here. When working with ceramic fibre insulation material, one MUST also consider pulmonary risks. The insulation of the Side Tanks on my own Speedy is just ordinary AIR, and I am satisfied with it. regards Johannes
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Post by Roger on May 1, 2019 7:24:31 GMT
Hallo One interesting question here is whether ceramic fibre insulation is hygroscopic or not. I guess it might be as a Silicate Wool. This means that droplets of boiler feed water once in the insulation will stay there for a very long time, promoting corrosion. The article www.ceceramicfiber.com/Article/Hygroscopicityofhigh_1.html night be relevant here. When working with ceramic fibre insulation material, one MUST also consider pulmonary risks. The insulation of the Side Tanks on my own Speedy is just ordinary AIR, and I am satisfied with it. regards Johannes Hi Johannes, Those are interesting points. Ceramic fibre is horrible stuff to handle, I always use gloves and try not to disturb it more than necessary. It's only really necessary to use something like that when the temperatures are high, you don't need it when insulating tanks. Polystyrene won't absorb water and that makes it ideal since it's quite likely to get the odd wetting if the tanks are overfilled or there's a spill when removing the filling pipe. Air is probably good enough on SPEEDY with the tanks as drawn because there's a huge gap between the boiler and the water, at least at the front. I still think it's worth insulating though since it's so easy to do.
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Post by 92220 on May 1, 2019 11:26:42 GMT
Hallo One interesting question here is whether ceramic fibre insulation is hygroscopic or not. I guess it might be as a Silicate Wool. This means that droplets of boiler feed water once in the insulation will stay there for a very long time, promoting corrosion. The article www.ceceramicfiber.com/Article/Hygroscopicityofhigh_1.html night be relevant here. When working with ceramic fibre insulation material, one MUST also consider pulmonary risks. The insulation of the Side Tanks on my own Speedy is just ordinary AIR, and I am satisfied with it. regards Johannes I used to sell Morganite Kaowool ceramic fibre but before I did, I investigated the health risks because asbestos had been banned for health reasons and that made me very cautious. Ceramic fibre has no heath risks that I could find. The fibtres don't break down small enough to be a pulmonary risk and if it breaks down to dust, that has no known health risks either. The only proviso I would add to that is that when I was investigating it, Kaowool was the only brand available. There are many others now and ceramic fibre produced to a price rather than a quality, may not be as good. Interestingly, I bought some cheap ceramic fibre for an experiment, a couple of months ago, and it was nowhere near as good as the equivalent thickness Kaowool I used to stock. Incidentally, I sold a lot of it to model engineers, for boiler insulation, and never had a single complaint or any indication that it was hygroscopic. In any case, with a boiler reaching up to 160C at 90psi, any dampness in the ceramic fibre would be driven off rather rapidly, so corrosion wouldn't be a problem. In any case, boilers are generally copper and cladding is generally brass, though steel is occasionally used. Bob. Edit: I've just read that website page that Johannes has quoted. The English is a little confusing, and obviously written by someone who's English is not their first language, in places so the writer may not have got everything correct. One glaring error is that heading saying that ceramic fibre wool blanket is a new product. I hardly think so as I was selling it in 1982.....some 36 years ago!!
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Post by jon38r80 on May 1, 2019 16:30:41 GMT
I was reading backwards through your posts trying to remember exactly what insulation you were using. It appears that it is thin sheet polystyrene which is pretty good insulation if inflammable and prone to melting. Dont think it will in your case but an errant spark?. no matter. The reasomn I was looking was on one of the last projects I worked on I used some stuff call Aerogel which is purported to be a result of space craft insulation development. In terms of insulation for a given thickness it outperforms anything else I have come across. I used it because an Architect had ommitted to leave any space for insulation around an unheated lift shaft backing on to and below apartments resulting in Building regulation problems. Trouble with it is that it was VERY expensive but solved the problem in a space of about 10mm which would normaly have had 150mm of foil faced Kingspan insulation. At the time getting performance figures to carry out your own thermal calcs was difficult as the importer/manufacturer/supplier was very protective. It seems to be easier now, they even sell small quantities on Ebay in thin sheets. Interesting stuff but probably overkill on a model engine but if you really have a problem with water getting too hot for the injectors to work satisfactorily it might be a solution..
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Post by Roger on May 1, 2019 18:16:24 GMT
I was reading backwards through your posts trying to remember exactly what insulation you were using. It appears that it is thin sheet polystyrene which is pretty good insulation if inflammable and prone to melting. Dont think it will in your case but an errant spark?. no matter. The reasomn I was looking was on one of the last projects I worked on I used some stuff call Aerogel which is purported to be a result of space craft insulation development. In terms of insulation for a given thickness it outperforms anything else I have come across. I used it because an Architect had ommitted to leave any space for insulation around an unheated lift shaft backing on to and below apartments resulting in Building regulation problems. Trouble with it is that it was VERY expensive but solved the problem in a space of about 10mm which would normaly have had 150mm of foil faced Kingspan insulation. At the time getting performance figures to carry out your own thermal calcs was difficult as the importer/manufacturer/supplier was very protective. It seems to be easier now, they even sell small quantities on Ebay in thin sheets. Interesting stuff but probably overkill on a model engine but if you really have a problem with water getting too hot for the injectors to work satisfactorily it might be a solution.. Hi Jon, A quick search on eBay reveals that you can get Aerogel insulation in many different thicknesses at very reasonable prices. It would appear that it's between 2-3 times better than the Expanded Polystyrene I have with the added Graphite. The good thing about it is that it's good for high temperatures too, which makes me wonder why we're using anything else for our lagging? I don't think melting or sparks lighting Expanded Polystyrene between the tanks and boiler cladding is of any concern, but I might get some of the Aerogel anyway since it certainly looks to be better. Thanks for pointing me to this, I'd not heard of it before.
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Post by andyhigham on May 1, 2019 18:48:21 GMT
I have just had a look on t'internet Aerogel is also hydrophobic which is ideal in our situation
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Post by 92220 on May 1, 2019 18:54:37 GMT
Ignore what I wrote in my last post, above! Sorry, I am somewhat behind the times, and health issues HAVE been found with ceramic fibre, that I had no knowledge of as the info has all come about since I retired from the business. Thanks to Malcolm (rrmrd66) for steering me to the necessary info I was sadly lacking. From Jon's post above, it looks as if he has found a possibly safe alternative in Aerogel.
Bob.
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kipford
Statesman
Building a Don Young 5" Gauge Aspinall Class 27
Posts: 571
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Post by kipford on May 1, 2019 21:26:20 GMT
On EBay 200mm x 150mm x3mm thick is £3.59.£5.18 for 6mm. My Aspinall needs 3mm thick so it would need about 8 sheets or roughly £29, in the grand scheme of things it is not a lot and is certainly on my list as a solution. Dave
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Post by Roger on May 1, 2019 22:12:18 GMT
This is all 1501 has for checking the water level in the Pannier Tanks, just three test cocks. A bit naff really. 20180110_111928 by Anne Froud, on Flickr I've found the works drawing of the standard valve and modelled it below. I'm not convinced that the length of the body is the same at that fitted to 1501, it looks a bit long. The Works Drawing shows a really short version and this one, but it wouldn't surprise me to find that they hadn't modified it a bit. I'd really like to be able to see the water level in the tank without ruining the appearance in the cab. At the moment I'm toying with the idea of using the top one of these to serve as an indicator, the idea being that the valve handle rotates by half a turn as the water level changes. The arrangement would require a float and bevel gears to move the handle and a seal where the shaft comes out. There would be some kind of access panel with the mechanism mounted on it, the whole thing being attached to the end of the tank with a seal of some kind. Watch this space! Test cock assembly by Anne Froud, on Flickr
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Post by ettingtonliam on May 1, 2019 22:36:37 GMT
Is it too simplistic to suggest that you peep into the tank via the filler lid? Thats what, as far as I know, you do on tender locos because any water gauge would be facing towards the cab, and not visible to a driver sitting behind?
I don't think a gauge operated by a float, gears, shafts, seals etc would be very accurate in this sort of size, but if anyone can prove me wrong, I'd be happy for it to be you, Roger.
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baldric
E-xcellent poster
Posts: 210
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Post by baldric on May 2, 2019 6:51:13 GMT
Roger,
In full size those valves to show the level work quite well, the pressure from the "head" above the valve does give a reasonable idea as to how much water you have, however as in model form the "head" will be much smaller I can see that this is something that does not scale well.
You mention that the valve looks to long, in your photo part of the valve will be behind the cab front sheet, and I think the end of the tank may be recessed as well so there may be a fair amount hidden. It may just be how I am viewing it but your 3d model does not look that far out.
Baldric.
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Post by steamer5 on May 2, 2019 6:58:04 GMT
Hi Roger, The Speedy I drove years ago had a sight glass in the cab for the tanks, which sure made keeping an eye on water level easy. My loco has a float indicator on the tender which allows easy monitoring of the level. I’ll be watching to on how you solve this one!
Cheers Kerrin
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Post by Roger on May 2, 2019 7:58:27 GMT
Is it too simplistic to suggest that you peep into the tank via the filler lid? Thats what, as far as I know, you do on tender locos because any water gauge would be facing towards the cab, and not visible to a driver sitting behind? I don't think a gauge operated by a float, gears, shafts, seals etc would be very accurate in this sort of size, but if anyone can prove me wrong, I'd be happy for it to be you, Roger. There's a secondary reason for wanting to know the level while on the run, and that's because the axle pump can be used to refill the tanks from the riding truck. It would be possible to overfill the tank if you forgot to close the valve. I think that the technical challenge is not one of accuracy, it doesn't have to be amazingly accurate, but sealing the indicator shaft with only a small amount of friction. I'll probably carry out an experiment with a small 'O' ring on a 1.6mm shaft which is what it would be. The other issue is whether limescale would be a problem. One option for the internal mechanical parts is to 3D print those. The arm would be Stainless Steel and the float probably a closed cell foam.
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Post by Roger on May 2, 2019 8:01:13 GMT
Roger, In full size those valves to show the level work quite well, the pressure from the "head" above the valve does give a reasonable idea as to how much water you have, however as in model form the "head" will be much smaller I can see that this is something that does not scale well. You mention that the valve looks to long, in your photo part of the valve will be behind the cab front sheet, and I think the end of the tank may be recessed as well so there may be a fair amount hidden. It may just be how I am viewing it but your 3d model does not look that far out. Baldric. The length of the Hex just looks too long to me. The Works Drawing shows that as I've modelled it, behind that is a threaded portion and lock nut. The ones on 1501 are plain after the hex, which makes me wonder if they've just turned down a section of the hex at the back to clear holes in the cab wall.
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Post by 92220 on May 2, 2019 8:23:34 GMT
Hi Roger.
I've just looked at your photo on Flickr and magnified it. It's much clearer than the forum photo. You are right. The hex has been turned down to go through a hole in the cab plate. The hole diam is just slightly larger than the across-corners of the hex.
Bob.
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Post by Roger on May 4, 2019 21:18:11 GMT
I've been quiet lately, but that doesn't mean that I've been idle. Here's an experimental fleshing out of the way I think I'm going to do the water level gauge. I've done a quick print of a quadrant to see if the gear teeth come out well enough for this to be a 3D printed item and it looks to be plenty good enough although at Module 1.5mm the gears are a bit big. 20190504_220312 by Anne Froud, on Flickr The gears modelled here are Module 1mm and these look to be of a more sensible size. The ratio is 4:1 so that 45 degree arm movement results in 180 degrees of movement on the handle which is the indicator. Water level gauge by Anne Froud, on Flickr I'm concerned that the shaft seal will be the achilles heel of this arrangement. Sealing it is easy, but doing it while imposing as little friction as possible is not. The arrangement below does away with the seal altogether by using Neodymium magnets to connect the output indicator to the bevel gear. The magnets are pretty powerful even though they are small, in this case 2mm diameter and 4mm long. You can just see the green end of the output shaft magnet which sits across the diameter of the Purple output shaft. There are two Blue magnets pressed into the bevel gear, although only one is shown at present. The Orange bearing for the bevel gear is Phosphor Bronze and is only 0.5mm wall thickness where the magnets are. The hope is that this will provide enough torque to turn the output shaft. The necked end of the Orange bearing is intended to have a clip to retain the gear, but it probably doesn't need that. The gear can't come off because the quadrant gear is in the way. I've ordered some magnets to play with, I don't have the size I need for this. Magnetic coupling by Anne Froud, on Flickr Anyway, it's a work in progress at the moment with a few experiments to be done. I can 3D print the necessary parts for that now it's got this far.
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Post by steamer5 on May 5, 2019 5:24:24 GMT
Hi Roger, Now that’s as Baldrick would say, “ I have a cunning plan” & this one has a tail on it & can be called a “Wessel”!
At work we have a couple of pumps that use a magnetic coupling, the drive end has a “can” over the magnet that side, the pump has an arm that has another magnet that curved up & over the can. These pump 7.5 m3/hr.
The only suggestion I can make is only use 1 magnet on the tank side so that the indicator side only has, hopefully, one orientation....
Cheers Kerrin
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Post by Roger on May 5, 2019 6:53:00 GMT
Hi Roger, Now that’s as Baldrick would say, “ I have a cunning plan” & this one has a tail on it & can be called a “Wessel”! At work we have a couple of pumps that use a magnetic coupling, the drive end has a “can” over the magnet that side, the pump has an arm that has another magnet that curved up & over the can. These pump 7.5 m3/hr. The only suggestion I can make is only use 1 magnet on the tank side so that the indicator side only has, hopefully, one orientation.... Cheers Kerrin Hi Kerrin, Hopefully this "cunning plan" will work. This idea is used on all domestic Central Heating pumps. The thin shell separating the poles of the stator from the armature is very thin but is kept in shape by being a very close fit in the stator. The two outside magnets are arranged so that there is a North on one side and a South on the other so they are both attracting the magnet in the middle on the output shaft. That means I could add a ring around the outside to connect the outer poles which might increase the flux through the middle. That would have to be a Ferritic Stainless or Iron perhaps that's coated, say electrolytically with Copper. I'll cross that bridge when I get there.
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Post by steamer5 on May 5, 2019 7:00:14 GMT
Hi Roger, Got you! Yep having the north / South Pole will make sure the indicator should only grab one way.
On the pumps at work I’m not sure how strong/big the magnets are......I don’t think they are that big. The issue we have as these pump “slops” & the sand wears groove thru the cans!
Cheers Kerrin
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Post by Roger on May 5, 2019 7:10:50 GMT
Hi Roger, Got you! Yep having the north / South Pole will make sure the indicator should only grab one way. On the pumps at work I’m not sure how strong/big the magnets are......I don’t think they are that big. The issue we have as these pump “slops” & the sand wears groove thru the cans! Cheers Kerrin I can see how that's going to be a problem pumping sand. The gaps in the magnetic field have to be as small as possible if you want to get the largest force, so that doesn't help. I'll have to reduce the gap if mine isn't strong enough. It's 0.5mm for the material plus whatever small clearance there has to be, so that might be on the large side. If I go much thinner though, the support for the bevel gear becomes less rigid. It's all a compromise, but hopefully I can get the proportions so it does the job.
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