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Throttle design

Posted by James Deitrick 
Re: Throttle design
January 05, 2009 08:40PM

Those were my concerns also, great idea on a fix.

Then it would look more like a U shape instead of the T shape.

For a sealing pressure, one could turn down the stem end of the valve smaller then the od of the sealing face.

It looks like the White throttle is being pushed open by the steam even when it is closed, so it has a sort of negative sealing force, combine that with the fast pitch thread and you get Jim's rather disturbing story.

One could replace the V notch part of this valve with just a necked down section Ala White, that diverges back to the original od of the valve stem which with the addition of your idea which would exit the other end of the valve body with packings. This would give one the capacity to make a perfectly balanced valve if the two ends of the valve steam were of the same od. The packing should give on the resistance that would be required to keep the throttle in place, an exterior coil spring around the valve stem ala poppet valve design, could return the valve for a foot throttle design.

For easy closed throttle venting, the steam exit end of the valve stem could uncover a small port in the throttle body when it was closed, this may waste a bit of steam via leakage past the valve stem but it sure would be simple.

Caleb Ramsby
Re: Throttle design
January 05, 2009 11:15PM
Hi Caleb and Bill,

Thanks for posting the scan of this throttle valve, looks like a goodie. Good ideas for modifications too. Some closing force is nice to have in the shutoff section of throttle. If the operating mecha breaks, it shuts itself.

I think Jim's throttle adventure was with a Stanley throttle(?).

Cast iron in a bronze body, and recessed, interesting stuff Ben. I could do it that way ... easily. I did many hours of websearching on IC engine valve seats & Stellite last night, got fed up with all the issues & incunabula involved, came up with new closing-valve seat for a 500psi saturated steam throttle. Drill 3 holes in bar stock; one is countersunk/ball-lapped. 440C bar stock if I can work out the heat treating, 304L otherwise. With about the same steam conditions, either way should be a big durability improvement over Stanley's bronze seat. Extremely easy to remove this cheap chunk-o-bar for replacement or seat regrinding (throttle built in sections, bolted together, a bit different from Stanley), and the parking brake vents the engine, so achieving eternal service life with the throttle shutoff valve seat is not crucial. What is crucial is actually building and driving it. Anybody with a hacksaw and drill press could make a replacement seat block for this thing quite easily.

Notched port in sleeve valve for gradual opening.

And now is the time on Sprockets when we blueprint.

Re: Throttle design
January 05, 2009 11:49PM
Hi Caleb,

I would like to reflect on some of my intital design's related to very high-pressure steam-injection valves.

Im dealing with a 60*included angle, actual 30(*) degrees, the pintle is set at 29/62* respectively with regards to seat-mate. This is the configuration that I use today. In this way, internal pressure cannot develope across the seat surface area- itself.

The one thing I found most perplexing, was seat area related to distance or width of the seat(fixed) itself.

To me, this mean's, according to diesel fuel injector semantics, the 'popping pressure'(if you will), is directly/inversely related to the [fixed]seats actual surface area. In other words, hence, the less the surface area, of the 'seat', non-moving area. The more sharp the resolution per-reaction unreated to system handling pressure. However the moving cone/pintle may be wide by comparison of the fixed seat yeilding consistant results.

I had this undesired effect of self-opening at a given internal system pressure, regardless of external controlling mechanisms(it actually could overcome very strong spring tension). 'ie' I wanted to open the valve at a pressure higher than it would self open, considering operating parameters. I found that it was most easy, to control, by reducing the width of the stationary seat(cone). In contrast, the moving part of the seat can be wider yet maintian the same divergent angle. And self-opening popping pressure is mostly dependant on the fixed seat surface area.



-edit- correcting divergent angle from 29*/58* to 29*/62* -

Edited 1 time(s). Last edit at 01/05/2009 11:59PM by Jeremy Holmes.
Re: Throttle design
January 06, 2009 06:31AM
A warning about the "jinx factor". Never use the word "easy" several times in the same email or discussion board post. This seems to cause the opposite.

Re: Throttle design
January 06, 2009 11:31AM
Peter B,

The Valve seat Part number SB1000-3 has a 1/2 inch ID and a 1 inch OD, while the depth is 7/16. You can easily machine these seats in the lathe to get your 5/8 bore and any seat angle you wish. The SB1125-11 has a 5/8 bore but a bigger 1-1/8 inch OD and the same depth.

For installation into cast iron or steel a interference fit of 0.001 to 0.002 will work fine.

The seats are about $5.00 Each and I think I can order individually, even on the tiny sizes. That size is special order and it would take about a week to get to me.

Let me know what you want and I will order it for you.

Peter Heid
Re: Throttle design
January 06, 2009 04:02PM
Hi Peter H,

Thanks! Can these be ordered in Stellite? One of the screwy things I ran into was that different makers use different alloys, many of which only develop their rated hardness in IC valve service through work hardening (heated and hammered tough by the valves). Hard to tell exactly what you're getting, and how they'd last in steam service. Doubtful if many of the proprietary valve seat alloys have ever been tried with steam. Stellite, we know about. 45° and 1/2" port would be fine.

Peter B
Re: Throttle design
January 29, 2009 04:58PM

"Solve the problem, how much will steam 137.5 Cu inches expand from 600 PSI at 750F to 0 when the throttle is closed and push a 4200 Lb car? How many revaluation will the engine turn?"

How far does the vehicle travel with one engine rotation, and what do you figure the rolling resistance to be ?

I will assume the steam acts like a perfect gas because of the superheat, and that no heat is lost, other than doing work.

Peter Heid
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All files from this thread

File Name File Size   Posted by Date  
white throttle web.jpg 73.5 KB open | download Kevin Harpham 09/02/2005 Read message
1920 Stanley.jpg 269.1 KB open | download Rolly 01/03/2009 Read message
drw-a.jpg 119.1 KB open | download Rolly 01/03/2009 Read message
Notched Vee valve 001.jpg 280.7 KB open | download Caleb Ramsby 01/05/2009 Read message