Tuesday, June 01, 2010
Well now I know why nobody’s building calliopes: the correct valves cost $120 apiece! With tax that works out to about $1,500 per octave!! Despite assurances from ‘country cousins’ that economic forecast is rosy in future I’d still like to build #5 using the OPM principle: “Other People’s Money”, don’t ya know.. So open up those wallets friends and neighbors! Maybe it’s time for a slightly more snazzy donation station in the shop.
Wednesday, June 02, 2010, 11:21 AM:
–Continuing last night’s thoughts this morning I thot I might construct one of those ‘donation thermometers’ that I’ve seen outside of the local hospital and our local ASPCA, with goals plainly stated and status indicated as a climbing red bar on the white painted thermometer. Maybe it could be rendered in some webpage-friendly format, along with a link to paypal? Must ask Noelle and maybe Rich.
Well maybe Grainger will have something cheaper? Will have to do a little rummaging. Not sure if there’s a difference in price between brass or SS these days but will investigate that angle as well. And then there’s the possibility of re-re-engineering the high pressure ones Tsutomu gave me; gotta see if I can make a larger ‘piston’ and enlarge the orifice still more.
Another test I need to do: get some pipe plugs and drill ‘em out to different diameters to determine just how large the whistle air entry hole has to be for it to be blow-able with vacuum cleaner exhaust. A favorable outcome there might mean it’s barely possible to use existing valves or cheaper renditions of same with larger orifices.
The other thing I need to do is to figure out just how those green ones come apart: so far all attempts to dismantle one have been in vain. Will have to get a little more aggro in future; i.e. the place where one would expect to have a nut is, in fact, a rounded-over shaft end (I think) and I’ll have to try grinding off the nub to see if the solenoid can then be removed from the valve assy. Said valve assy is topped by a massive nut but it can’t be removed by anything other than an especially thin wrench that I don’t have. Don’t want to modify the one I’ve got to do the deed either, but that may be the final answer; forceful disassembly of first one will tell.
Noodling while waiting for camper shell place to redo wiring in truck so that camper shell transferred from old Ranger still works with new Ranger; i.e. red ‘taillight’ and internal lighting which is sorely missed at present.
Ah! Good old ebay comes to the rescue! Took Rich’s advice and searched over there. First hit: exactly what I need for a third of the store-bought price. Still and all I want to get some more input B4 I spend a grand on two octaves worth. These look good:
3/8”, 12vDC, $30.95
http://cgi.ebay.com/3-8-Electric-Solenoid-Valve-12-Volt-Air-Diesel-B21N-/290439374847?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item439f8927ff
They’re a bit bigger than I really need: 1/4″ NTP is plenty big enough but I guess I can bush ’em down if nothing smaller is available.
Thursday, June 3:
Had an idea this morning: if I replaced unions with quick-connects (the kind intended for plastic tubing) maybe I could connect the dots with short pieces of copper or even stainless tube (I’ve got lots left over from another project) then I’d have a rigid system with a very small footprint and it’d probably cost less than unions too. Will first test the quick connects on metal tube: it’s an easy thing to do, yes?
Well what fun! Kris came by to work on her car and I got her help to get the semi-dismantled calliope #4 out of the RV (a tight squeeze!) and onto the workbench. I got Rich to come over and together the three of us did some kanoodling on what should come next.
First up was what to do with #4. After talking to the pros I decided the best thing I could do is give #4, sans whistles, to Rich who has an idea that it could be used either as some sort of MIDI-controlled flame effect device or as a multiple air-rocket launching carousel. Either way it sounds like a fun challenge and I can’t wait to see what comes next!
Before dragging the old mechanics and electronics to Rich’s ‘shop’ Kris and I did a rough calculation to determine manifold volume. Working the numbers seperately we both came up with a piddly 95 cu in. for the steel torus. Although more than the 48 cu in of calliope #3 it was still a bit less than I would desire for a proper plenum.
The goal in making calliope #5 is umpty fold, but the change in layout will make the design compact enough to be carried by one person, which also means it might actually fit atop the boiler in my fairly narrow steamboat. The plenum will be made from 4″ square 1/8″ wall steel tube. It will have an internal volume of at least 235 cu in, even tho footprint of the whole device will be about half what it was. Routing of wiring will be greatly simplified as well and that increases the likelihood that #5 will be capable of running propane. Now that I understand the importance of maximizing valve orifice area I’m going to search for off-the-shelf valves that operate more like organ valves rather than solenoid valves that depend on a small piston sealing an even smaller hole. The trick will be finding them with 1/4” NPT thread; to get the smallest footprint I can manage.
After remachining the existing valves on #4 I managed to cut plenum pressure from 80psi to 20psi. The valves I have been using look like this:
http://www.ascovalve.com/Common/PDFFiles/Product/8262_8263_HSeries_GP_R1.pdf
What I want to find and/or build is something that’s still solenoid operated but that toggles a plug of some kind to lift (or better fall into plenum), exposing a much larger opening. By having valve fall into plenum area the gas flow would help reseat it to give a crisper cutoff, yes? The valves closest to this concept that I’ve found so far look like this:
http://www.ascovalve.com/Common/PDFFiles/Product/8210R1.pdf
The goal is to get the silly thing to work on as little pressure as possible; say 5psi or less… The kicker, of course, is that 24 solenoid valves won’t be cheap; I figure a thousand bucks at least and although I’m told my economic forecast is a little rosier these days I’m still waiting for the check, so to speak…
After talking with Rich and Kris I gather that the electronics for 24 pipes is not much more complex than those for 12 so the idea is to combine the 1” dia pipes made for calliope #3 with the 1-1/2” dia ones from #4, giving me 2 octaves and the ability to play more MIDI tunes with less tune ‘squeezing’ needed.
Anywayyyy the first step is to start sketching out a top view so that I can get an idea of just how closely I can pack valves, to determine the length of 4” square tube I’ll buy to make the plenum. In #4 I put the solenoid valves far enough apart so that they could be screwed into their corresponding fittings on the plenum; i.e. about 4” apart. But by using unions instead of straight pipe nipples I can reduce this distance to maybe 3”. By staggering the pipes in the Y direction I can decrease the X separation still further. An added benefit of staggering pipes in a double row: if I decide to use propane I can make a much more compact, straight pilot light that will nest between pipes in staggered rows.