The Steamboating Forum

Page 25 is the better image

Oilking, I think you are writing about cleaning the glass? The offset arrangement allows mechanical cleaning of the glass with the gauge set valves (connecting to the boiler or the boiler water column).

I far as I can understand this, the issue here is cleaning of the passage between the boiler and the gauge, not the glass itself. Evidently in UK, this passage must be made such that one can "rod-thru". All of the US gauge sets I could find (including the ones you just referenced) would not allow that process.

Hope that is clear as mud, and hopefully not gauge glass mud!

Here is a typical UK three cock reflex gauge;

Fred,
After looking at Gondolier's photo, I see what you mean. A system like shown would only be able to have a check on the lower valve if the ball was held above the valve bore. It dosen't look like that's the case here.

On the Navy boilers that I steamed only the lower valve on the gauge glass had a ball check. The valves had chain wheels that allowed them to be operated on the lower level. There were two sight glasses plus one or two Yarway remote level indicators depending on the ship. These were blown down once a watch (4-6hr) or when one was not in agreement with the others. These were on 600 & 1200 PSI systems in ships designed to operate after recieving battle damage. For most of us a properly installed and well maintaned gauge glass annd try cocks should do just fine.

Happy Thanks Giving To All!

Dave

There are no checks on this gauge, they are uncommon on UK boilers. On a quarter turn cock that can be isolated with a boathook from 6ft away, a check valve is an unnecessary luxury, however, on a globe valve based gauge system, I can understand the tendency to want to cover all bases as you can at maximum be only an arms-length away from the escape.

Greg

I can see a potential problem with check-ball types in that as they cannot be roded through any build up of crud on the ball seat could cause it not to shut off as required! Whoops!!!

All of the boilers I deal with are closed cycle condensing systems. I don't see any buildup that would need any sort of mechanical cleaning. Bart gave me a Hypro pump that had years of operation on it and, while the bearings were toast, the insides only needed a wipe with a clean rag.

I have seen some locomotive non-condensing systems running on bad water in the mid western U.S. that had alarming deposits but the lakes around here are drinking water sources. My own well water fouls my teapot and messes up my kitchen faucet over time. But my boiler makeup runs perhaps a pint per day so the total solids left behind are undetectable. And they don't get a chance to do any depositing as I blow down hot when I'm done operating for more than a week or so.

I'm happy with my built in flow check balls. And, as I said, I would be nervous without my glass blow down valve.

Mike

I of course have a drain on the bottom of the reflex gage; this allows me to blow the gage albeit w/o closing off one of the ports. But it's clear that the British are concerned with possible plugging of the gage connections, given the requirement for "rodding" capability. Right now the bottom of my reflex gage is plumbed via a union directly to the boiler.... since this seems to concern folks, I will replace the union with a 1/2" ball valve fitted with an fabricated extension handle; I'll also fit a 3/8" ball valve in the upper 3/8" stainless tube that connects the top of the gage to a steam fitting on the boiler.

This will permit closing the bottom valve, blowing down the gage, and then opening the bottom and closing the top, and repeating.
This would indeed subject any detritus in either of the ports to full steam pressure across the blockage - quite likely enough to remove any build up on a boiler that sees less than 50 hours/year of use, esp. if performed on every steamup.

My boat needs two more valves anyway .

- Bart

I'm kinda with Mike on this one.
We(Navy) didn't open the 600psi boilers untill ~2000 steaming hours, and the 1200psi's, with the low phosphate treatment, were almost double that. After this amount of steaming I never saw anything more than a black magnetite film on any of the none heated surfaces, ie. drums, headers, and trim piping. In the amount of steaming time most hobbie boilers see in a season, even a once through, would have to be drinking some really nasty water to make plugging the sight glass piping an issue. If the glass is mounted with flanges or unions, it should be easy to check and clean the passages at the end of a season during layup.
Also on the Penberthy valve I have, by removing the side plug on the lower valve the ball can be removed using a small magnet, and then you can remove the stem leaving a straight path thought the valve. Yes it's not full pipe ID, but a 1/4" rod will fit. This can be done without disassembling the glass. I would not recomend this unless you have had a problem with the glass, or if the idea of bilge diving after you have dropped the ball sounds appealing.

Dave

Folks,

I think we should put this one to bed?
The British concern regarding blocked passages is a historical one going back to the early days and should be viewed as such if you are maintaining your boiler correctly.
My comments above regarding rodding etc. are concerned with “traditional” type bronze gauge sets suitable up to say 200 PSI. high pressure boilers are a different kettle of fish and this includes double plate glass gauges, these are used for high pressures where a reflex glass is unsuitable as the glass requires a thin mica layer to protect it from dissolving. These are not usually fitted on hobby steam boats.
Regards
Jack