Alternative & Renewable Energy Blog

Hey I'm so jealous... I don't have any machining facilities...us cats are only alowed to play with wood.
Can't wait to hear more.
Del

I am currently working on a "new" style steam engine.

First, some history-

A typical steam engine has full pressure applied through the full power stroke, then it is dumped either to atmosphere (like the old locomotives) or to a condenser. The condensers do not need to be large because the "high volume" of steam will almost immediately become a much smaller volume of water- only the inlet needs to be large. The condenser will typically have many small tubes in it to condense the gas with water running through the tubes. The water can be "direct", like domestic hot water or circulated through a radiator to throw away the unneeded heat.

Now- if you look at a typical steam engine, you will see that it takes a lot of steam to fill the active cylinders for the continuous power stroke. NOW- if you have a chamber above the piston at Top Dead Center to receive a fixed quantity of steam at sime pressure, and allowed that steam to expand all the way to 0 PSIG at the bottom of the stroke, the actual pressure on the cylinder will be 50% of the inlet pressure (assuming that the chamber was fully charged at teh top of the stroke). That means a 50% drop in Horsepower, but it also means an 80% drop in steam volume required.

If the available steam is not enough to fully charge the chamber, the HP rating pressure will be 50% of the actual charge pressure. For example- if the chamber would require 3,000 Pounds of 200 PSIG steam per hour (PPH), but the amount of steam available is only 1,500 PPH, then the starting pressure will be 1500/3000 x 200, or 100 PSIG. The HP calculation will be based on the 50 PSIG average pressure, PLUS- if the discharge is into a vacuum chamber, the vacuum rated in PSIG. If the vacuum is, say, 20 inches, the vacuum is about 10 PSIG, so the HP will be based on 50 average PSIG power adn 10 PSIG vacuum, or about 20% more than with just the power stroke. Thus- you can get 60% of the power with only 20% of the steam. AND you still get all of the residual latent heat of the steam to heat water or even a building- 20 inch vacuum steam has a temperature of 161F, so relatively warm water can be available.

This is nothing new!

In the 1960s to 1970s the then Morris motor company started to experiment with steam engines for road vehicles, these were all uniflow engines (triple-expansion).

The cylinder blocks were of aluminium with mehinite cylinder liners, there were three cylinders. Their boilers were of the once through flash steam type with 260ft of coiled SS tubing of 3/8th of an inch I.D.

Spencer.

Really? I never heard that Morris got into steam cars at any point. All I knew about was Saab. Do you have any links to more info? I would love to see some pictures!

Hi, I'm sorry but a lot of my books, paper work etc got caught in the fire at my last address.

It was not only Morris that was interested in steam-engines for cars in the 1970s, British Leyland and BMC were also experimenting with steam. The BMC engine was a triple expansion single acting steam engine with three cylinders, each piston was stepped three times ie. the top part was one and a quarter inc diameter, the second part was two and a half ins diameter, and the bottom third part was three and a half ins diameter.

The Morris engine was very similar as far as I can remember, and both engines top working pressure was 150bar.

Spencer

1. Do not use stainless steel for flash boilers, it does not last and changes its strength throughout heat and cycling. 2. Use heavy wall, pierced carbon steel, made for flash boilers. 3. Consult Abner Doble's work and plagiarize all you see. 4. Consult all works of the Williams Engine Company of Ambler, PA. Plagiarize. 5. Encase the flash tubing in a porous ceramic and mix propane/air to combust within the ceramic foam, holding the heat to the tubing. 6. Use the Williams engine design for near or over unity operation. 7. Flash tube control was nettlesome 'then', however, new high temp sensors are available for the high pressure and heat ranges. 8. Special carbon ceramic slugs can be machined into great pistons and seals. 9. Fluorocarbons, not chlorofluorocarbons are available for sealed, condensing systems if you are willing to put in the search time. 3M made a slue of them in the 1970s. Check on carbon, aluminum, brass/copper and iron with high temp fluorocarbons. I have been where you are now. The knowledge you will gain from the material searches, machining, electronics and dynamics of fluids in high pressure and high heat will take you to places of thought and practice, that few scientist have gotten a chance to challenge. Youth is on your side. Lunge for the brass ring.