Water Treatment

A special section just for steam engines and boilers, as without these you may as well fit a sail.
User avatar
cyberbadger
Full Steam Ahead
Full Steam Ahead
Posts: 1123
Joined: Thu Nov 07, 2013 9:16 pm
Boat Name: SL Nyitra
Location: Northeast Ohio, USA

Re: Water Treatment

Post by cyberbadger » Sat Mar 28, 2015 1:55 am

DetroiTug wrote:Completely full is supposed to be another method of preservation, but I've seen lots of steel rust badly totally submerged.
I'd avoid that method like the plaque personally. One: The dissolved oxygen in the water. Two: If you forget about it when winter comes and it's in unheated area it will be a piece of junk as that water turns to ice.

Some Steam traction folks do another trick for winter layup. After completely draining and drying the boiler they nitrogen/argon blanket it. The noble gas displaces the air, so there is basically no oxygen available. And the Noble gas doesn't interact with any of the metal.

A little overkill maybe, but I'd probably do that if I had cylinders of nitrogen/argon around.

-CB
User avatar
Lopez Mike
Full Steam Ahead
Full Steam Ahead
Posts: 1903
Joined: Wed Dec 07, 2011 6:41 am
Boat Name: S.L. Spiffy
Location: Lopez Island, Washington State, USA

Re: Water Treatment

Post by Lopez Mike » Sat Mar 28, 2015 2:36 am

I sometimes need to seal up pressure vessels that I have made for clients for storage and shipping. I flush and fill with welding gasses. Usually my MIG gas. It's moisture I'm trying to exclude so pretty much any dry gas will do.

That said, just blowing my boiler down hot and closing all of the valves seems to have kept any visual damage to zero.
If you think you are too small to make a difference, try sleeping with a mosquito.
Dalai Lama
User avatar
DetroiTug
Full Steam Ahead
Full Steam Ahead
Posts: 1863
Joined: Fri Nov 27, 2009 5:56 pm
Boat Name: Iron Chief
Location: Northwest Detroit

Re: Water Treatment

Post by DetroiTug » Sat Mar 28, 2015 12:10 pm

The inert gas is a good way to go.

I think it is imperative to ascertain that the boiler is completely dry before it is closed up with or without gas.

I haven't seen one lately, but years ago (before computers) people used to build terrariums. It was a small sealed ecosystem. They used a big water jug and fished dirt and plants through the neck, watered it all, put a cork in it and watched it grow. The "fun" part of it is it never needed water. The downside is they typically had condensed moisture on the inside of the glass.

A boiler closed up with a little bit of water would be the same thing. Unless the temperature is held constant, the dissipation of moisture, condensing running back to the bottom to repeat the cycle is going to happen. When warmed the water will dissipate, when the steel is cooled, the moisture in the air will condense on the shell. The daily wetting of the steel is the most damaging situation in my opinion.

I've worked with steel extensively. One thing I've noticed in regards to it's longevity in service, it's much like wood. If it's coated it holds up pretty well, but left bare and exposed to moisture and where it cannot dry out or off, it deteriorates rapidly.

I leave the valves open on the boiler. So far so good on that.

-Ron
User avatar
Lopez Mike
Full Steam Ahead
Full Steam Ahead
Posts: 1903
Joined: Wed Dec 07, 2011 6:41 am
Boat Name: S.L. Spiffy
Location: Lopez Island, Washington State, USA

Re: Water Treatment

Post by Lopez Mike » Sat Mar 28, 2015 2:04 pm

When I blow down hot, there are usually some coals in the firebox so there is no chance of any moisture been left behind. Also, when I am done for the season, I use my wet or dry vacuum to make sure there are no pockets of water hiding somewhere in the piping to freeze and break things before Spring.

So far I have found that my valves are tight enough to hold a small vacuum on the boiler over the Winter. Keeps the stinking mud wasps out too.
If you think you are too small to make a difference, try sleeping with a mosquito.
Dalai Lama
User avatar
fredrosse
Full Steam Ahead
Full Steam Ahead
Posts: 1906
Joined: Fri Nov 20, 2009 5:34 am
Boat Name: Margaret S.
Location: Phila PA USA
Contact:

Re: Water Treatment

Post by fredrosse » Sat Mar 28, 2015 2:45 pm

Steel will rust quickly if exposed to the oxygen in air, and water/wetness speeds this process very much. Steel will corrode much more slowly if submerged in water which contains dissolved oxygen. If a boiler is bottled up with water having dissolved oxygen, then there is a little rusting, this consumes the dissolved oxygen, then corrosion stops.

Steel will not corrode if submerged in water that has no disolved oxygen, and it is standard practice to fill industrial boilers completely full of deaerated water (no dissolved oxygen) for layups that will be for several days or several weeks.

I have attempted to get my VFT completely dry, with hot blowdown, opening several bottom blow valves, and opening the top mounted steam outlets. This method never seems to get all the wetness out, and that makes for ideal corrosion conditions, wetness and air circulation. Running a mild fire to evaporate all of the wetness is risky business in a dry boiler, especially a VFT. Differential expansion may cause damage, the mild fire may overheat a thin wall tube well before the thick boiler shell metal is heated.

As a result, I always fill my boiler completely full with deaerated water on every shutdown during the operating season. In winter, with the possibility of freezing, I drain and dry the boiler, applying a high vacuum to boil away all wetness within the system before bottling up the boiler. This takes a long time with a refrigeration high vacuum pump.

I think the best approach is to put an inert gas (Nitrogen) blanket on a drained boiler, regulated to 1/2 PSIG. This will keep air out, but the purge process to get all the air out before blanketing needs proper attention. Previous forum posts here describe methods, either apply the Nitrogen while there is still nothing but steam in the boiler (immediately after a hot blowdown), or purge the boiler interior with about 15 volumes of Nitrogen, to sweep out all the air before bottling up the boiler.
Jack Innes
Warming the Engine
Warming the Engine
Posts: 84
Joined: Mon Sep 30, 2013 9:12 pm
Boat Name: Mazeppa
Location: Brooklin, Ontario, Canada

Re: Water Treatment

Post by Jack Innes » Sat Mar 28, 2015 5:27 pm

An interesting aside regarding the nitrogen idea is that the Cloud series Rolls Royce cars have a sealed box section frame that is filled with nitrogen under a slight positive pressure to prevent rust from attacking the steel from within. This works well until someone leaves a bolt out somewhere thus loosing the pressure & ultimately the nitrogen. A RR that has been maintained by less than RR mechanics can prove to be an expensive disappointment.


On the boiler front, is it acceptable to fill the boiler & piping with plumbing antifreeze for the winter? In the case of my Balckstaffe boiler the volume is only about 3 gallons & it is set up so it can be rinsed well before use in the spring.


A third point, how does one use the TSP in treating the boiler ?

Jack
User avatar
Lopez Mike
Full Steam Ahead
Full Steam Ahead
Posts: 1903
Joined: Wed Dec 07, 2011 6:41 am
Boat Name: S.L. Spiffy
Location: Lopez Island, Washington State, USA

Re: Water Treatment

Post by Lopez Mike » Sat Mar 28, 2015 6:57 pm

If I were to use antifreeze for protection, I would be inclined to use the stuff sold for the drinking water system in R.V.s. To be quite honest, I don't know that much about either the usual automotive OR the RV stuff.

I put the TSP in my hot well.
If you think you are too small to make a difference, try sleeping with a mosquito.
Dalai Lama
User avatar
fredrosse
Full Steam Ahead
Full Steam Ahead
Posts: 1906
Joined: Fri Nov 20, 2009 5:34 am
Boat Name: Margaret S.
Location: Phila PA USA
Contact:

Re: Water Treatment

Post by fredrosse » Sat Mar 28, 2015 7:06 pm

I use RV (Recreational Vehicle) Antifreeze in my piping during winter, as much of this piping has pockets that might hold water. The RV stuff is non-toxic, intended to winterproof RV water systems.

For winter layup, first disconnect the feedwater line from the boiler. I have a 15 gallon feedwater tank, which is empty. Put in 1 gallon of RV antifreeze, then work the hand pump to get the antifreeze thru the valves, etc. Then turn over the engine to get the engine driven pump filled with the antifreeze. All this time the feedwater discharge line is emptying into a jug. Then close the feedwater discharge valve and continue pumping, lifting the feedwater pump relief valve, filling that line with antifreeze, then open the feedwater bypass line to flush that with antifreeze. I have done this for four years now, everything is satisfactory when the steaming season arrives. You can save and re-use the antifreeze every year. Flush well with water before hooking up to the boiler.

TSP (Trisodium phosphate) sold at super markets and home supply stores, a white powder. Mix about 1 teaspoon into a few ounces of water, stir until all dissolved. I fill several small medicine bottles with the solution, and dump one into the feed tank at the beginning of the season (1 teaspoon per 10 gallons of water). Also about 1 teaspoon into a typical launch boiler on initial filling. Beware, some stores are now selling "Phosphate free" TSP, not what you want.

Buy Ph test strips, available at fish tank stores, or thru the internet, about $5 for 100 test strips. Keep the boiler water at a Ph of 9 to 11, adding TSP increases Ph. Blowdown will require replenishment of some TSP to maintain this ideal akalinity.
Jack Innes
Warming the Engine
Warming the Engine
Posts: 84
Joined: Mon Sep 30, 2013 9:12 pm
Boat Name: Mazeppa
Location: Brooklin, Ontario, Canada

Re: Water Treatment

Post by Jack Innes » Sat Mar 28, 2015 7:42 pm

Thank you Fred & Mike.

I think the advantage of the RV antifreeze is in that it is unlikely to leave any deposits inside the system.

I have done as you described to fill all of the lines & valves plus I have filled the boiler as well. Is there any reason to not fill the boiler? Remember my boiler holds less than 3 gallons.

On TSP I forgot to ask if it is safe with my boiler with copper tubes & steel drums?

Thank you,
Jack
User avatar
Lopez Mike
Full Steam Ahead
Full Steam Ahead
Posts: 1903
Joined: Wed Dec 07, 2011 6:41 am
Boat Name: S.L. Spiffy
Location: Lopez Island, Washington State, USA

Re: Water Treatment

Post by Lopez Mike » Sat Mar 28, 2015 9:09 pm

As far as I know there would be no problem with copper and steel and TSP.
If you think you are too small to make a difference, try sleeping with a mosquito.
Dalai Lama
Post Reply