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Discussion Starter · #1 ·
Since I completely took over Richard Kapuaala's thread on Goodall valves, I decided to put my own thread up about the Schwinky valve.

What's a Schwinky valve you might ask? It's a quick acting valve to allow easier, more accurate reading of your sight glass. Most people are aware of the issue of air bubbles or capillary resistance causing problems with reading the actual level of the boiler with the small bore glass tubes that are common in these scales. Some folks here have done many different things to address this issue. Electronic sensors, larger sight glass tubes, blow down valves, etc. My solution was to create a small purge valve that mounts on the top of the sight glass water column. It's the opposite of a blow down valve, since the steam actually blows up, but I didn't want to call it a blow up valve for obvious reasons. All you need to do is press on the top of the valve, a slight bit of pressure is released through the very small gap between the pushrod and the hole drilled through the sight glass plug. The water column bounces and 9 time out of 10 settles at the true water level inside the boiler.

Here's one of my first conceptual drawings:



I like how Richard explains it, "looks like a reverse safety valve."

Of course some will say it's dangerous, or you might get burned. I've been using one on my Regner Willi for months and have more issues with heat moving the reverser on my Willi or my Aster CLIMAX.

Here's a pic of the valve I made for my 3 cylinder shay:



Here's one with the valve open.


It's pretty easy to make, I built these on my mini-lathe, but it can most likely be made on a drill press. The only part that really needs to be fabricated is the disk that pulls the o-ring against the modified sight glass plug. The hardest step is finding the o-ring small enough. The disk on the end of the push rod is soft soldered after I peen the end of the rod enough to mechanically hold it in place. If anywhere along the way you decide to back out, just fit a small piece of brass rod into the hole that's drilled in the plug and braze it shut. The springs don't need to be that long, and height could be a problem for some closed cabs, but those are the springs I had available.

Here's a picture of the Schwinky valve installed on my Willi.


As I stated in Richard's post "Please ignore the fireman, it's a "King Cake Baby' from Diamondhead, and there are no child labor laws being violated." (and I'm still looking for some scale asbestos diapers)
 

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Discussion Starter · #3 ·
Posted By steamboatmodel on 03/06/2009 8:03 AM
Just looking at this I thought would a tire valve work?
Regards,
Gerald


It's got the same internal parts. They might be a good source for the seal.
 

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Interesting, still you have to push the button to get an accurate reading, so the only thing it has going over a proper blown valve is that it is easy for the operator to use.
It seams like a lever operated one would reduce the chance of steam heated digits.
John
 

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Dave,
No problem with taking over the thread, I liked your suggestion, but there is more detail here and its given me some ideas on some mods to the swinky valve that I'm gona work on to metigate the risk of burn.
BTW, I found some metalic heat resistive tape that might work good for diapers ;)
 

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Seems like a good idea to address a very real problem. Where did the name come from?

How far are you pushing the rod down to open?

I am looking at the length and guessing that you are only wanting the long length to keep heat and steam away from your finger. If you had a lever at right angles that would depress the rod, you would make the rod and spring short and put length into the lever? Do I understand correctly?




Ed
 

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The whistle valve in "Steam Trains in Your Garden" by Brian Wilson pg.128 is a lever operated side discharge version of this type of valve that makes use of the short style of Shrader valve core. Real quick and simple to make.
John
 

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Posted By Dwight Ennis on 03/06/2009 9:34 AM
I"m wondering if a cone and cone seat would work instead of the o-ring. I guess a lot would depend on the machining precision of the mating surfaces and having sufficient tension imparted by the spring.


Dwight, what is wrong with an O-ring? The good old Mamod has one in it's safety valve and mine is now close to 15 years old with no sign of decay.
Regards
 

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This is exactly the type of valve idea that I have been looking for to use on my Accucraft WD Baldwin. Now, does any one know where to get a Schrader valve tap in the US. BTW, I checked the Australian web site given above and i could not find the tap. I have Googled for the tap, but I have come up negative.

Any help would be greatly appreciated.

Dan
 

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Dan,
Try Discount tools. I just spotted this searching for ( "Schrader valve" tap )

Name: Steve
Date: January 18, 19105 at 12:21:48
Homepage: Discount-Tools.com
Subject: Schrader valve thread

Reply:
We carry these as specials. Normal delivery is just one day. They are not on our website, but if you go to http://www.Discount-Tools.com you can send an email or call 714-751-3844.
 

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For a Schrader valve tap I found a tire valve repair kit at a hardware store. It has a tapered end to start taping and the other end to complete tapping. While not a perfect tool it will work for experimentation with Schrader valves.

 

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Hi Rob'
The tapered end on that tool is an Easy Out, used to remove Shrader Valves that have broken off. The other end is to clean up the threads after you get the broken off one out.
Seadawg'
I have use these valves. You don't have to push them down, just a bit of pressure with anything on the side of the sprung shaft to unseat the seal & it will blow it down.
 

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This looks neat. I have always had the problem of wondering when my sight glass is not telling me the truth. Sometimes even with a blow down it lies.
 
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