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Throttle design

Posted by James Deitrick 
Jim Crank
Re: Throttle design
September 07, 2003 10:57AM
You say Peter may have used a ball valve throttle for a while. Has he changed? It has been years since I saw his car.

No, the Stanley throttle was before the superheater, perhaps because they didn't know how to make one that would survive superheat. Even so, the saturate temperature at 600 psi, is enough to make brass/bronze quite fragile.
Peter Brow
Re: Throttle design
September 07, 2003 05:50PM
Thanks Terry! Wish I could find a version of the drawing on the internet so people could see what we're talking about. I, too, wonder if Peter Barrett is using a different type of throttle now.

Jim: I am leaning toward an updated/improved Stanley/Doble-type throttle with Stellite or similar sealing faces. This type has an extensive steam car track record and is easily designed/built/modified for gradual opening. Does a ball/globe valve, used as a throttle, last as long (before leaking) as an improved Stanley/Doble type throttle? The wise old-timers (White, Stanley, Doble, etc) insisted on throttling and shutting off the steam at different points.

Jim Crank
Re: Throttle design
September 08, 2003 10:07AM
My experience has been, and even with a high temperature version with graphite seats and a Stellite ball, that the ball type throttle does not last very long until it starts leaking and sometimes jamming.
Absolutely right. Throttling and sealing are done in two separate places.
Don't ignore the White throttle, it is so much easier to get off the seat than the Stanley/Doble version.
Jim Crank
Re: Throttle design
September 08, 2003 10:08AM
My experience has been, and even with a high temperature version with graphite seats and a Stellite ball, that the ball type throttle does not last very long until it starts leaking and sometimes jamming.
Absolutely right. Throttling and sealing are done in two separate places.
Don't ignore the White throttle, it is so much easier to get off the seat than the Stanley/Doble version.
Peter Brow
Re: Throttle design
September 09, 2003 05:21AM
The White throttle has gone into the mental file with mental Post-Its attached. I'm keeping those threads and the tapered section in mind, if a practical way for me to make those pops up (eg, thru equipment/skills upgrades) then that will be the throttle. I think a professional shop would charge me a small fortune to make one.

One possibility is to use a large-diameter commercial threaded bolt/nut inside the throttle steam chamber, and put a lever between that and the valve. Bolt on the short end of lever, valve (centered by guides) on the long end. Stuffing box on turned down & chromed/ground bolt stem. I'll keep the White throttle in mind. Maybe something will "click". Yeesh, I'm starting to write like the Corn Burner guy.

Re: Throttle design
September 02, 2005 11:43PM
Were all the White thottles made like this and does anyone know if they varied in size between the large and small engines?

Re: Throttle design
December 22, 2008 07:34PM
Interesting pic Kevin,

(he hasnt been around for sometime.)

Seems to me, the details of item '74' in that picture, would explain, why one model[of throttle] would work for a varing cross-reference of several different engines.

-Or, '174' not quite sure from the picture, theres a smudge.-



-edit- added statement-

Edited 1 time(s). Last edit at 12/22/2008 07:36PM by Jeremy Holmes.
Re: Throttle design
December 23, 2008 10:08AM

The first White car throttles, If I can recall one years ago, used a disk with a hole in it.
They quickly went to the one pictured for all models from then on. The same one for all horsepower models

Just remember, the Doble foot throttle has a double cam in the box below the actual throttle valve. The mechanical advantage Warren put in was very high at the start of movement. Getting that poppet valve off the seat with 1200 psi was not easy. Then the actual throttling was by the sleeve below the poppet with holes in it, just exactly like the Stanley.
Why they went to this for the Series D, E and F cars is curious, because the Model B used a White type of throttle and Abner wrote that it is very linear and easy to use. Possibly a material problem then.
The original Doble throttle had a hardened poppet, and now we always face both surfaces with Stellite as the original one develops leaks over time.

The White is via the throttle wheel shaft, which pokes out of the steering gear at the bottom, right to that lever (# 177) you see on the throttle with a simple connecting link, one to one. It is an extremely good throttle, does not give any problems in service and is much more linear than the Doble-Stanley type.
The actual throttling is done by a slight taper on the tip (#180) The seal is against the seat on the stem.
#176 is the bronze packing gland and the female threaded part, the stem itself is hardened steel. I had mine hard chromed and then ground to size.
Using the White throttle design with a foot pedal is as simple as you could ever want. 80° or 90° is the full movement from closed to full open. Use it.

We have the drawings, patterns and such for the White throttle. I think Don Sable has the special tap and die for making the threaded part.
Look on the White Owners web site on Woodson's web site.


Edited 1 time(s). Last edit at 12/23/2008 10:12AM by James D. Crank.
Re: Throttle design
January 03, 2009 01:12AM
Has anyone used a throttle with Stellite (or other improved sealing materials) in a Stanley?

Re: Throttle design
January 03, 2009 07:16AM
(metallurgy) A hard, wear- and corrosion-resistant family of nonferrous alloys of cobalt (20-65), chromium (11-32), and tungsten (2-5); resistance to softening is exceptionally high at high temperature.

Peter I have my doubts
John Packard in North Grafton Mass is making new Stanley throttles, very high quality work. I believe he is using hard stainless seats. There all precision ground and tight.
Re: Throttle design
January 03, 2009 10:20AM

I would think that today with all the neat metals we have at our fingertips, a definite improvement in the Stanley-Doble type throttle is available with material changes.
My Stanley had leak problems once in a while, and the steam temperature was all over the place at times, a Baker boiler. I used to see pitting on the sealing surfaces.

Quite right, throttling and final sealing are definitely in two places.
The White throttle stem has a sealing face; but before it closes, there is a small straight section right after the tapered part that does the actual throttling. It is a very close fit to the bore in that removable seat in the main casting.
Anyhow, it is a lovely throttle in use.

My concern would be getting that poppet off the seat in the first place, 600 psi is one thing; but 1200-1500 psi is quite another, thus Doble's double cam idea.
Today one has good hydraulic throttle actuators available and they work well.
Something that allows one to gently push on the pedal and not have to stamp on it to get the throttle to open, and start up with a lurch.


Edited 1 time(s). Last edit at 01/03/2009 10:22AM by James D. Crank.
Re: Throttle design
January 03, 2009 12:44PM
Jim I see no reason why more exotic metals can’t be used, I just haven’t seen it done. There is just not that large market to tool up and invest in making high ends Throttles.
John Packard has a high-end shop and could use any material specified by a customer.

When I put the Derr boiler in my Stanley I installed a 4000-PSI ball valve between the throttle and the boiler with a separate extended handle under the dash for positive shutoff.
I just didn’t like leaving an open car in the parking lot of a restaurant with 600 PSI in the boiler and all some one needed to do was lift the throttle leaver.

Re: Throttle design
January 03, 2009 04:13PM
I've done the same on the Model H but between the throttle and the superheater. It has a spring loaded over centre action so it's either open or closed and is operated by a Stanley valve handle to the passenger's side of the dash. Haven't yet had the situation where the passenger becomes so frightened that he turns the steam off but it could happen!

Re: Throttle design
January 03, 2009 04:26PM
Re: Throttle design
January 03, 2009 07:02PM
Thanks guys; lots of interesting possibilities and good ideas here.

Rolly, is that a Cruban-style relief throttle? Looks like a 3rd lagged pipe connected to it.

Mike, I like the "passenger panic valve" in your H. LOL

Lots of things brewing in the mental cauldron here. I am drawing up a 440C stainless ball on a small IC engine valve seat (HARD, unleaded-fuel type) for the poppet/shutoff part. Probably chromed/ground rod & Garlock 98 packing, looks like 7-8 rings of 1/8".

Still not sure what material & clearance to use for the throttling sleeve. No oil and about 470F (saturated) makes it worrisome, despite near-zero sliding surface speed and cyclic rate. I don't want to be the one who finally discovers an innovative and ingenious way to make this type of throttle stick. Maybe FE & FO got it right in that particular section of the throttle -- but what sleeve material/clearance did they (or Doble) use? Notched sleeve port & other dimensions mostly worked out.

Jim, the White-style throttle is still subconsciously brewing in a separate cauldron. That's the "surprise pot"; things have a way of popping out of there fully-formed when least expected, and superceding all previous plans.


Re: Throttle design
January 03, 2009 07:23PM
In the January 9th, 1958 Machine Design magazine there is an illustration of a "Taper-vee orifice valve design".

It is but a cylinderical casting with a T shape, having the inlet at the middle of the T.

There is a seal at one end of the cylinder and the outlet at the other. There is a sloted plug that moves back and forth and has a V cut in it that is around four times as long as the diameter of the plug. The plug slides in a tight fitting bushing threaded into the cylinder.

The V never exits the bushing and is sealed when closed by a chamfer on the plug and bushing(ala White throttle design). The flow path past the V slotted plug is a triangle type opening. This was devised to make a sealing point that is seperate from the regulation section and the tapered V section inhibits the deposit of solids in the sealing section and also wear on the regulation area. It was devised to handle sludge that conatained solids to replace the neddle type valve.

The pressure produces no force on the valve plug when it is closed, only when it is open and the pressure tries to force the plug out when it is open, via an ubalanced pressure.

I will try to get a scan of it uploaded here sometime.

As an aside my, "What is steam power?" article has now officially taken over a year to write! wry grin. . .

Caleb Ramsby

Edited 1 time(s). Last edit at 01/03/2009 07:27PM by Caleb Ramsby.
Re: Throttle design
January 03, 2009 07:41PM
Peter the Cruban Throttle is three valves in one housing and movement.
It has the puppet or main disk for shut off then a piston valve with a series of holes for controlling the steam to the engine, and then a D valve (Slide valve) to vent the steam in the pipe to the engine when the Throttle is closed. Un like a Stanley, you close the Throttle and wait till you run out of steam in the pipe.
See attachment

Re: Throttle design
January 03, 2009 08:40PM

Fran Duveneck had one of these Cruban throttles on his condensing Stanley and it really worked perfectly.
Much better than flaying for the drain valve on the side of the car in a panic when you are trying to double park the car and jamming both feet on the brake pedal.

Re: Throttle design
January 03, 2009 10:16PM
The Cruban throttle is an ingenious design. Interesting that it has poppet, piston, and D-slide valves, all in one unit. The multi-port piston valve section could be tuned to give very linear opening. My only concerns about it are the possibility of leakage from the D-slide vent valve, and the depositing of oil & carbon in the superheater while venting. That would not be an issue if the throttle were downline from the superheater. On the plus side, venting brings some oil up into the throttle to lube/protect the D-valve and rod/packing. If oriented with the poppet at bottom, then some of that oil might droozle down to the piston/poppet valve section too.

I am thinking of cast iron billet for the piston valve section of the throttle. Bore out a chunk of ~1" iron "billet" for the body, and turn/drill a smaller chunk for the hollow piston. Maybe .001 to .002 clearance all around. Not a tricky machine job, and cast iron on cast iron is usually good for sliding things in saturated steam. Less chance of differential expansion and electrolytic corrosion problems too. Malleable iron is also a possibility. Don't know if it soaks up and holds oil like gray cast iron.

Maybe the piston valve could be set up something like the Cruban, with progressively-opening ports.

I wish you success with your steam article, Caleb. My brain is elsewhere, so at present I can't quite visualize the throttle you describe.

Re: Throttle design
January 04, 2009 05:06AM
Where are you getting the oil from, your coming off the boiler with clean saturated steam, unless your using a drumless mono tube boiler and get oil carried over from contaminated water. Any other boiler with a drum will retain all contaminates within. The throttle is used before the supper heater. Dry supper heated steam can be hard on moving parts. Oil in injected before the engine.
It was cast bronze with a steel poppet valve, and bronze D valve on a bronze port face.
D valves where in, piston valves wear out.

I keep thinking conventional steam cars (antiques).
There is no reason you can’t install the throttle after the boiler and supper heater and before the engine and inject the oil before the throttle.

Jim, I could have used one with the Derr boiler. It had a sixty-foot supper heater. You needed to plan your stops a week in advance. The supper heater is located two rows above the combustion chamber and gives constant 750 F supper heat.

Edited 1 time(s). Last edit at 01/04/2009 05:26AM by Rolly.
Re: Throttle design
January 04, 2009 08:14AM
Hi Rolly,

Sorry, I should have explained; trying to keep my posts from getting too long. I was referring to the steam that is vented when the Cruban throttle is closed. Some of this steam comes from the steam line downline from the oil injection point, and from the valve chest & cylinders. Loaded with oil & oil vapor, which have to pass through the superheater to get to the vent valve in the Cruban throttle (if upline from the superheater). Stanley put a vertical hairpin in the steam line between superheater and oil entry, to keep oil out of superheater; I plan to do the same.

Throttle upline from superheater is the standard setup, except for monotubes, and I plan to stick with the upline location with my water-level boiler. I think it will keep any traces of oil etc in the boiler and out of superheater, as you say.

My current plan is to link the valve chest drain valve to the handbrake, and use that for engine pressure relief also, instead of using a Cruban-style relief throttle. The handbrake lever handle will be close to the hand throttle for quick pressure relief. Also, this way, setting the handbrake for parking releases any steam in engine, and prevents engine pressure buildup and "wandering car syndrome" if the throttle leaks while car is parked -- an old Doble trick. This setup allows handy engine pressure relief without oiling the superheater, and with throttle upline from superheater, which is easier on throttle.

Control key shuts off fuel and blows off boiler to water tank in case throttle sticks/jams open. Relatively small storage capacity in boiler, pressure dump should be quick. I also plan a fuel pressure dump valve (to fuel tank) on dash in case of leaks, fires, control failure, etc..

Thanks for the info on the bronze relief valve and casting in the Cruban throttle. I hadn't known that before, always figured it was cast iron or steel due to the temperature.

I remembered your monel engine rods (valves & pistons), and am thinking of using a polished monel rod on the throttle valve. The short length and small diameter needed makes a monel rod here cheap. Noncorrosive, wear-resistant, no pitting or cracked plating, won't chew packing or seize up.

Re: Throttle design
January 04, 2009 09:11AM
Dear Peter, In using your emergency fuel pressure dump valve, remember to have a big enough air vent for your fuel tank. If you do not have a big enough fuel tank air vent, an emergency fuel pressure dump of fuel at 140 pounds can quickly blow a seam in your fuel tank. Try to have your emergency fuel pressure dump valve accessible from the outside of your car without having to crawl under the car. The best place that I have found to place my hand valve is at the rear of the car under the fuel tank. A long enough hand valve stem makes it an easy reach during an emergency. A broken fuel line under pressure can quickly spit out a lot of fuel, and with the fuel on fire it make a hell of a big fire real quickly too. I only had to repaint my hood on that one. Been there, done that.
Re: Throttle design
January 04, 2009 10:01AM

Patent 2208736 is the first throttle I have found that mentions stellite. The patent is from around 1940 and it mentions that it is common to use stellite.

In a throttle that has a poppet and sleeve, it would seem that the sleeve clearance is not very critical. If the poppet (or ball) seals the valve in the off position, then the sleeve only varies the flow after steam is flowing. The leakage around the sleeve doesn't matter until it is greater than the lowest throttle setting. I have thought leakage could even be the first throttle position.

I have somewhere seen an article on a restoration where the throttle worked well but when they opened it up the wear on the parts was heavy.

The valve seats I mentioned are not stellite, but they have better wear capabilities, take higher temps, and are easier to machine. Im not sure how small they go though.

Peter Heid
Re: Throttle design
January 04, 2009 12:20PM

You mentioned that with the Derr boilers 60 ft of super heater that there could be too much steam left in after the throttle to make a nice stop.

How much volume of super heated steam after the throttle is starting to get to be too much? I am wondering at what point one might need to consider a throttle at the engine side.

Best Regards, ---- Bill G.
Re: Throttle design
January 04, 2009 01:17PM
I was exaggerating the problem. You learn to drive differently with a steam car.
The volume of 60 feet of 3/8 IPS is around 137.5 Cu inches. The volume of a Stanley engine in one RPM is 251 Cu inches.
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?
Re: Throttle design
January 04, 2009 07:51PM
Hi Pat,

Important safety tip; thanks, will do. I have to dig up the simplified fuel system I worked out ~2-3 years ago, before the endless intricacies of engine design & fabrication planning displac1ed a lot of previous data from memory. As I recall, the fuel pressure dump control ended up on the dashboard somehow for quick "panic operation", and also had a fusible link inside the "boiler room" to dump fuel pressure automatically in case of fire under the hood.

One thing I plan to try is a nitrile/fabric air bladder inside the pressure tank, to avoid air top-offs and air absorption/fuel pressure loss on standby, or at least minimize them. Possibly filled with argon to reduce permeability. If the bladder breaks, the air/gas can still be topped off thru a tire valve. With a good bladder, at least the fuel from a pressure tank dump won't be fizzing air like soda pop, but dumping that volume of fuel into the fuel tank, fast, will displace air & fuel vapor from inside the main tank, so either way a good main fuel tank vent is needed for safety.

I have wondered if there is a connection between dissolved air in fuel and carbon deposits in fuel vaporizing tubes. Maybe using inert argon gas instead of air would help.

Jim mentioned a self-acting fuel check valve on the White steam cars, which closes if fuel velocity exceeds a certain rate, indicating a broken fuel line or fast leak. I am looking into that too. Sounds very designable & buildable, and shuts off fuel _before_ fire. Right on, Rollin & Jim.

Fuel pressure line will be vibration-rated steel hydraulic tubing with 37° flare fittings, as short as possible and with as few fittings as possible. I am paying special attention to fuel line mounts, clearances, line flex, and padding due to "learning experiences" with gasoline lines in older cars. It is ironic that as cars age, they often get both more precious to those who love them, and peskier.


Re: Throttle design
January 04, 2009 08:13PM
Thanks for the valve seat info, Peter H. Any further info on where to get these, how to order, etc would be much appreciated. I need one with a 5/8" port/bore. I have no idea what kind of engine uses something this small, but they are listed in the catalog. Probably any modern IC engine valve seat would be either Stellite, or made of something better than Stellite. When they "unleaded" gasoline, they had to replace the old "soft" valve seats. My bug engine was last rebuilt in 1980, and is probably one of the last few gassers still on the road with soft seats. I use a gas additive.

The Stanley/Doble type throttle seems to press the piston valve part sideways against the bore, around the outlet port. Sort of a "round slide valve". Right, slight leaks here should be no problem, as it seals at the poppet. A couple thou clearance should do.

Peter B

Re: Throttle design
January 05, 2009 07:57AM
Hi,,,My take on the new gas is that it burns MUCH hotter,,therefore the valves need more clearence to stay on the seats,,,,double or triple maybee,,,hydraulic lifter cars are o-k I think,,,,not sure how fast they can leak down,,,Re throttle,,,Some Stanley throttles have a recess around the port,,so as to have pressure all around,,,not just one side,,Clearence,,the body is bronze,,so expands away from the cast iron sleeve,,neat trick eh,,Cheers,,,Ben
Re: Throttle design
January 05, 2009 05:42PM
Here is a scan of the valve that I mentioned.

This valve reminds me of the White flow motor.

If one were to make the notch with two different angles, such as the first part to open rather shallow and then a second angle that was more aggresive then there would be a very small initial opening with an exponentially greater opening after that.

The notch could be cut with an end mill, shaper or even hand filed with a nice gradual curve to it.

There is still of course the issue with actuation of the valve, be it eccentric, cam or threaded rod.

Making the notched section shorter would be of great benefit as in shortening the valve travel.

Caleb Ramsby

Edited 1 time(s). Last edit at 01/05/2009 05:48PM by Caleb Ramsby.

Re: Throttle design
January 05, 2009 08:12PM

That looks like a dandy and simple valve.

I am wondering about the pressure differences on the valve. With the valve closed there would be no particular force on the stem. As the valve opened pressure would then build up on the outlet end of the stem and tend to force the valve open further.

If, however the steam exit end of the stem were to go through another packing and the steam to then exit sideways to the stem the pressure differences on the valve would be small and constant.

Best, ---- Bill G.
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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