Steam engine valve help please?

[hunter2379]

I built a small steam engine from hardware store parts.
Problem: Flywheel doesn't haven enough mass to push piston back into cylinder.
My solution: Attach some sort of valve between cylinder and boiler that regulates the steam. Example: open>close>open>close>open>close
Such that will open one second and then close long enough for the piston to come back down, then open again, thus allowing the steam to renter and push the piston.

Anyone know a valve like this or have any suggestions???

Here is a sample picture I drew on what I have now.

http://files.engineering.com/getfil...6e-896b6043b8ec&file=steam_engine_outline.jpg

 

[MikeHalloran]

What you have so far is 2/3 or less of a steam engine.

You do indeed need a valve. It has to admit steam to each face of the piston in turn, and release steam and condensate from the other face.

You can get incredibly detailed design instructions in any of several reprint books available from Lindsay Publications.



Mike Halloran
Pembroke Pines, FL, USA

 

[hunter2379]

Im not sure if I misunderstood but what you wrote sounds like a two stage steam engine. This is supposed to be a one stage. Steam enters, pushed piston, and then exits. I was thinking of using a poppet valve, but not sure if it would work.

 

[MikeHalloran]

What I described is a 'double acting' steam engine. You actually need two of them in quadrature to get smooth output.

Your 'single acting' steam engine will work, given the correct valve and a large flywheel and not too large a load. It won't be able to start itself from every crank position.



Mike Halloran
Pembroke Pines, FL, USA

 

[bimr]

Perhaps some of the plans on this site may assist:

http://www.john-tom.com/html/SteamPlans.html

 

[hunter2379]

Thank you.

 

[bimr]

Would think a valve of some sort is required.

Look at this animation:

http://science.howstuffworks.com/transport/engines-equipment/steam1.htm

 

[MikeHalloran]

Chances are that your idea won't work like you imagine that it will. ... or at all.

Please read and study at least some of the tons of historical material that's available on steam engines.





Mike Halloran
Pembroke Pines, FL, USA

 

[Artisi]

A detailed study of steam engine construction would go a long way in helping you understand a simple steam engine. You can not get anything much simpler than a single action steam engine - cylinder, piston, crank shaft, flywheel and a valve to direct steam.

Without to much thought being put into it, what you need is a slide valve connected to the crankshaft, timed to open to live steam for the power stroke which then closes as the exhaust port opens to atmosphere for the return stroke.



It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[MikeHalloran]

After closure of the intake valve, steam does not expand quite like the charge in an internal combustion engine does after the spark.

But since you are determined to learn everything the hard way, go ahead and build what you have proposed, instead of seeking affirmation here.

Try to do it with minimal investment, keep detailed notes, and you might learn something. We might learn something, too.



Mike Halloran
Pembroke Pines, FL, USA

 

[Artisi]

hunter2379, to answer your question re spring loaded valve gizmo, I don't know.


It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[Artisi]

I had nothing better to do this morning so I typed "steam engine slide valve" into google - surprise surprise - have a look sometime.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[rmw]

This thread is a nice trip down memory lane. Last engine I saw run was in about 1987. It pulled an entire sawmill. I never saw a piece of machinery run so much and require so little maintenance.

First engine I ever ran myself was 1968 or 69. It was in the ME Lab and had been placed there after being retired from the University's power plant quite a few years previously.

The head of the ME Dean had passed the word to ME students to go to the lab on Engineers day and demonstrate some piece of equipment, so I started up this engine. At the time I worked in the campus power house and the replacement engines to this engine were still there, so I knew a little about how to heat up the steam line, etc. I didn't know exactly how to time it to start it, but grabbing the flywheel and hanging on it to start it rolling did the trick. It rolled right off and ran up to the (flyball) governor. (I didn't synchronize it, however.)

I'll never forget the look on the Dean's face when he rounded the corner all proud of his 'boys' in the Lab showing off stuff and found me running this engine. He tried to act pleased, but I knew he wasn't. Large flywheel running open with civilian visitors in the lab...

That old engine was scrapped about 4 weeks later. And these engines weren't made of hardware store parts either.


rmw

 

[Artisi]

A trip down memory lane for me, probably 1957 / 58 as an apprentice I was involved in an overhaul of the triple expansion steam engine in the Lady Houpton. From memory at the time she was still running 100psi boiler pressure - not sure what she is rated at today.

http://www.shf.org.au/LdyHpt/LdyHpt.html

The "Power House" museum in Sydney runs a number of old steam engines on live steam, the highlight for anyone with the least interest in engineering is the Boulton and Watt steam engine built in 1785.

http://www.powerhousemuseum.com/collection/database/?irn=7177

Nothing like the smell of steam and lub oil and the quietness of a steam engines in operation.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[btrueblood]

Steam locomotives always make me stop and watch, and if possible go along for the ride. Last one was about 10 or 15 years ago.

http://www.mrsr.com/