Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Builds, Repairs, Show Your Machines! => Technical Tips, Builds, and Help => Topic started by: KNO3 on July 08, 2019, 03:23:31 pm

Title: Re: Feedwater, to heat or not to heat?
Post by: Hero on July 21, 2019, 12:51:47 pm: Quote from: CBWho on July 10, 2019, 09:04:34 pm
> ...a crew of mice...
I’d like to see that!

I have dozens of potential crew members in my barn. Come and get them!
Title: Re: Feedwater, to heat or not to heat?
Post by: KNO3 on July 13, 2019, 03:39:05 am: Thanks for the link, very interesting. Your preheater is actually a secondary water boiler with it's own burner!
No room for such a beast in my little steam ship though. I'll have to stick with using waste steam for preheating the feed water.
Title: Re: Feedwater, to heat or not to heat?
Post by: Jim on July 10, 2019, 09:20:34 pm: Quote from: KNO3 on July 09, 2019, 06:57:20 am
Thanks, this sounds very interesting. What type of feed water heater did you make? Could your share some pictures of the steam plant please ?

Here's the link -

https://www.officeofsteamforum.com/technical-tips-builds-and-help/boiler-preheater/msg7897/#msg7897
Title: Re: Feedwater, to heat or not to heat?
Post by: SeeSteam on July 10, 2019, 09:04:34 pm: > ...a crew of mice...
I’d like to see that!
Title: Re: Feedwater, to heat or not to heat?
Post by: KNO3 on July 10, 2019, 04:20:24 pm: Thanks for the suggestion. I have found the Clayton Wagon plans and they show a feed water heater using exhaust steam. I could build one along those lines.
Title: Re: Feedwater, to heat or not to heat?
Post by: frazer heslop on July 10, 2019, 02:51:40 pm: Have a look on the john=tom site for the Clayton Wagon drawings as it has a feed water heater
I fitted one to my Clayton and it made a difference
In the book Steam and Stirling Engines you can build is a full plant that has a single acting V4 wobbler and a feed water heater fitted
It maybe book 1 not sure
Title: Re: Feedwater, to heat or not to heat?
Post by: Stoker on July 10, 2019, 01:04:48 pm: Quote from: St Paul Steam on July 10, 2019, 12:56:18 pm
simple and effective 😉👍

Not so simple and effective if it is a boat out on the water however!
Title: Re: Feedwater, to heat or not to heat?
Post by: St Paul Steam on July 10, 2019, 12:56:18 pm: Quote from: Belugawhaleman on July 10, 2019, 12:23:36 pm
I simply heat my feed water on the stove before filling my feed water tank and continue to add hot water during
the run
simple and effective 😉👍
Title: Re: Feedwater, to heat or not to heat?
Post by: KNO3 on July 10, 2019, 12:43:56 pm: That won't work in a r/c ship though, unless I build a mini stove and hire a crew of mice ;D
Title: Re: Feedwater, to heat or not to heat?
Post by: Belugawhaleman on July 10, 2019, 12:23:36 pm: I simply heat my feed water on the stove before filling my feed water tank and continue to add hot water during
the run
Title: Re: Feedwater, to heat or not to heat?
Post by: KNO3 on July 10, 2019, 10:44:02 am: I am using a pump. No experience with injectors.
Anyway, I think it would be hard separate the oil from the water in model size condensers. The exhaust of my steam engines looks like an emulsion and it takes a while for the oil to separate from the water.
Title: Re: Feedwater, to heat or not to heat?
Post by: SeeSteam on July 09, 2019, 01:28:29 pm: If using a pump, I suspect preheating based on the condenser would work best but if using an injector, I would avoid a preheater.

Is there a reliable manner to separate the water and the oil from the condensate? Perhaps always maintain some water level, so the oil floats?
Title: Re: Feedwater, to heat or not to heat?
Post by: KNO3 on July 09, 2019, 06:57:20 am: Thanks, this sounds very interesting. What type of feed water heater did you make? Could your share some pictures of the steam plant please ?
Title: Re: Feedwater, to heat or not to heat?
Post by: Jim on July 08, 2019, 05:59:39 pm: I made one and it made a big difference in boiler efficiency for thirsty engines and stopped the boiler 'going off the boil' so to speak when hand pumping a lot of replacement cold water into the boiler.
Title: Re: Feedwater, to heat or not to heat?
Post by: KNO3 on July 08, 2019, 04:14:00 pm: Thanks for the answers. I want the steam plant to run efficiently and to avoid the cold feedwater reducing boiler performance. That's why I asked if preheating feed water is advisable in our small scales. I am yet undecided, as it adds a level of complexity to an already very small and rather complicated steam plant.
Title: Re: Feedwater, to heat or not to heat?
Post by: Stoker on July 08, 2019, 03:41:30 pm: Depends entirely upon the level of efficiency that your operational paradigm requires, or conversely what features you want your steam plant to represent and display.

I would use some care if you choose to preheat in the chimney, as the temperatures found there may well create steam in the feedwater pipe, which would be a most undesirable occurrence.
Title: Re: Feedwater, to heat or not to heat?
Post by: St Paul Steam on July 08, 2019, 03:31:40 pm: I think a pre-heater condenser looks cool and all , but honestly I've never had the need for such things as I don't run my engines long enough or often enough to get the full benefit from it.
Title: Feedwater, to heat or not to heat?
Post by: KNO3 on July 08, 2019, 03:23:31 pm: Hello all,
Being in the middle of a steam plant build, I have come to the point in which I should decide how to best feed the boiler with water from the pump. I thought of drawing upon the forum knowledge, as I am sure others have tried this before. Is it worth the trouble heating the boiler feed water in a model steam plant? I am thinking of perhaps building a coil in the condenser, so the feed water gets heated by the spent steam. An alternative would be to place the coil in the chimney, to heat it with the exhaust gases.
What are your recommendations?