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Throttle design

Posted by James Deitrick 
Jim Crank
Re: Throttle design
September 01, 2003 11:09AM
Peter,
Back from a superb Mars observing session with the telescopes.

Starting with yours of the 30th. Yes the White throttle is a precise and well made item, common to all White hardware. Tricky to to make unless you have good and advanced machining equipment, maybe best left to a precision machine shop to make; but more than well worth the cost.

Why Doble didn't use this White design has been a question for me too, since the Model B did use a screw operated throttle. Plus his experience, no doubt, with the family 1906 White his father bought.
The Stellite surfaces in the E throttle are to eliminate the wire drawing problem when you use the car often just creeping along. They last for over thirty years without having to touch them, good enough!
On the White, there is an absolute minimum of flow passage when the throttle is closed, so even if the cone section starts leaking, it is minor.
Stellite surfaces would cure this today. They are Stellite faced surfaces, because the Doble throttle stem is more complicated and the seat is directly in the throttle body forging. Stellite welding rod is commercially available.
Remember, the Dobles only had case hardening available to them. Yes the throttle poppet was hardened; but Stellite is much better.

White did indeed use lots of tapered surfaces, especially the fuel valve needle, which is the very devil to make correctly. I think White did this because he wanted precise control and in those days, this was one sure way to get it. Also the White Co. was very well equipped to make such things on a production basis, remember their sewing machine business, and all the other things of similar precise nature they made in large quantities.

The actual sealing when shut off is the cone section after the slight taper section. That cone on the tip is just for flow considerations.
Looking at it from the end of the threaded section, the sealing surface, then the throttling section and finally that flow tip.

Andy,
White used a thread actuator for precise control of throttle opening, it gave a good mechanical advantage that results in a two finger throttle control, works with about a 60° movement of the arm, so it is easy to use it with a foot pedal. Dobles used a two faced set of cams when they went to a foot throttle. Nice; but a stinker to adjust precisely when setting it up.
Try a White throttle when it is at 1,000 psi, easy. I defy you to do this with a Stanley type throttle. Even the Doble takes a good foot push to get it open. If the cams are not set just right, a heavy stamp by the foot.
Certainly some other actuator can be used in place of the threads, like an eccentric, just as long as it is under total control of the throttle pedal.

On thing about a White throttle, if the packing is not really tight, considering the angle of the threads, it will open itself wide open. Happened to me, I thought the counterweight on the crankshaft would come out the side, until I got it shut off. Not nice!!

George,
The Stanley and Doble sleeve-poppet throttle has to have a lot of flow resistance, a LOT more than the White. The throttling is through holes in the sleeve, with too much sharp angling of the flow to get from the inlet to the outlet. The turbulant flow must be awful and the Doble throttle sleeve and poppet is smaller than the Stanley. Consider this with a steam flow in the Doble that can get to 1500 lbs/hr.
I do think the White design, using an eccentric actuator, is the best one yet.

Jim
George
Re: Throttle design
September 01, 2003 11:37AM
Jim,
How was the Mars viewing? The best night up here was Friday night around 12-1AM and I could finally see some color differentials of the surface---atmosphere was not very cooperative!
Thanks for the White input---ever know of someone using a White throttle on a 20HP Stanley? A 30HP Stanley can easily draw off more than 2000#/hr steam for a short period of time.
Craig's S-10 uses a Stanley throttle with a small hydraulic cylinder from a clutch system---it is foot actuated and is very easy to operate and overcome the opening resistance.
Hope you had good viewing, George
Jim Crank
Re: Throttle design
September 01, 2003 05:50PM
George,
Viewing was the best I have ever seen. Milky Way from horizon to horizon, and from 5° up, absolutely rock steady all night, 6th magnitude visual alone. This is supposed to now be the best viewing site in the U.S. Pushed the 12" to 1200 X and it still was holding up. Saturn filled the eyepiece. Cannot recall ever having it this good. 15 miles of very rough dirt road to get to the observatory.

Back to White throttles.
One thing I forgot to mention about the White throttle. The main thing that is wrong with it, is that the packing gland is attached with a big nut. This gets loose at times. Also the gland is too short, three more rings of packing would help; but then the friction goes up. Modern type packing, like a spring loaded carbon face seal, would sure help seal it without too much friction, backed up with a few rings of carbon packing.
Also today, old throttles are often corroded very badly. The cylinder oil is injected after the throttle, perhaps it should have been into the throttle. Just an observation from 14 years of running a nice OO White.
Never heard of anyone using a White throttle on anything except a White. They are just too hard to get these days. One other thing is that the connections are their own thread size and the throttle body is hard to hold and cut the threads on a lathe. One orders a special die and uses it in a mill.
Although, some of the White community have remade them. See the White Owners web site and ask on there who is doing this.

I think we will use the White throttle; larger for 2500 lbs/hr flow, with the thread actuator; but in a new housing with a better packing gland design, lightly spring loaded shut, already have it designed in my mind. The seat comes out, screwed in, just like White did it.
Remember in the White car, the steam is coming into the bottom and trying to push the stem back and open the throttle, which it sure does if the packing is not really tight. The reverse of the Stanley and Doble throttles, where the steam holds the poppets down on their seats.
Whatever, it still is better than the Doble or Stanley by miles.

Jim
Peter Brow
Re: Throttle design
September 02, 2003 04:35AM
Hi Jim,

Thanks for the info. Not much to add there. White's sewing machine experience would definitely come in handy building the kind of equipment used in the White cars, but of course fabrication capabilities often determine design choices.

George and Jim: glad you guys got a good look at Mars. The past couple weeks it has been hard not to notice the Red Planet in the skies. However, the night skies have been overcast around here the past few days (prime viewing times), so hopefully I'll get a shot at it in the next week or so with the 3.5" refractor. Maybe I should pack up the bug and head for Mt. Palomar observatory, or the deep desert.

--------------

I scaled the throttle drawing at the stanleymotorcarriage.com webpage. I love scaling drawings. The thrill of discovery! Of course, if the drawings are pixely and tremendously blown up, with thick lines, the results will not be too accurate, and there are often doubts about the scale used. But I am not trying to get an accurate copy of a Stanley throttle. The dimensions could be a bit different here and there and it would still work well, in this part at least.

Anyway, I scaled it assuming that the outlet port is about the 1/2" ID I want. This gives about a 7/8" diameter poppet which @ 500 psig would require ~300 lbs opening force. The valve stem scaled out to 1/2" OD, which is about 98 lbs of constant pressure trying to push the stem out of the housing and close the valve. This should give people an idea of the forces involved.

Valve travel from fully closed to fully open scaled to 5/8". If this were actuated by a 5/8" crank and a link barely over 5/8", an ~9" throttle lever at the driver's end of the crankshaft, pivoting 90°, would take about 8 oz of friction to keep the steam from closing the throttle, and just over that to move the lever. Opening force at the end of the lever, I have not calculated yet. As soon as the poppet is cracked just a bit off the seat, the pressure should equalize and it should go down to the moving force of just over 8 oz..

The opening force at the valve stem (300 lbs) would be about 3x the moving force once open. However, the opening force at the end of the throttle lever would be less than 3x the opened force if the actuating crank, link, and valve stem were set up to be in line when the throttle is closed. This would give considerable mechanical advantage during the initial opening, as it would require a good angle of crank travel to give a tiny bit of valve lift. Not sure what kind of actuating linkage the Stanley throttle used; one of many small steam car details that never seems to make it into articles, illustrations, etc..

I figure that a throttle pedal would have about 1/4 the travel of a 9" hand throttle lever with about 90° of pivot. So the forces would be ~4x, or about 2 lbs to move the throttle. I need to do a measurement of the accelerator pedal spring pressure on some of the gas cars around here for comparison. If the 2 lbs pedal force, or the opening force (whatever it is) with this setup were substantially more than a typical accelerator pedal, this might be a good reason to use a hand throttle, which I would set up so that the brake pedal closes it (not an original idea).

Comments on hand throttle vs. foot throttle are welcome. I remember reading a few letters and articles in old issues of The Steam Automobile where foot throttles were derided as clumsy and dangerous, and the Stanley hand throttle praised as a much more convenient, precise, and pleasant method of vehicle control.

I am leaning toward a foot throttle, but a hand throttle might reduce the possibility of accidental acceleration -- an issue in the news in recent years. A certain carmaker, accused of selling defective accelerators, claimed that people were pushing the wrong pedal; an alarming mistake which I have made on a couple occasions over the years, and which I suspect an oldtimer friend did several times, leading to collisions, though he swore up and down it was a defect in the car.

Somebody once told me that some gas cars were made with hand throttles optional as late as the 1940s, and I know that many handicapped folks have aftermarket hand throttles installed on their automatic transmission vehicles. A couple wheelchair friends have a van so equipped; one of these days I'm going to have to bug them for a look at the throttle. Hand braking too! Maybe a hand throttle isn't such an outdated idea after all.

In "The Modern Steam Car" (Lindsay Books) Thomas Derr discusses an adjustable-friction device to keep steam pressure from closing the throttle. I seem to recall seeing a little twiddly knob connecting throttle lever to quadrant in pictures of some Stanley throttles, and have wondered if those were (optional? aftermarket?) throttle-friction adjusting devices, safety locks, or both.

Another type of throttle to consider is the ball throttle designed & built by Peter Barrett for his 1000 psi/1000°F steam car. It does not shut off and throttle steam at different points. Not sure how long it would go without leaking, as it hasn't seen extended road service to my knowledge, but it does look like actuating force would be low and consistent with very simple actuating mechanism, and he reports that it is very satisfactory in operation. Plans are available for the Barrett throttle, and it is illustrated at Karl Peterson's website, for which there is a link at my links page:

[www.geocities.com]

Peter
Peter Brow
Re: Throttle design
September 02, 2003 04:50AM
Barrett steam car drawings:

[www.firedragon.com]

There is not a drawing of the throttle at this page, but the drawings are $15.00 from the SACA Storeroom. This page does list the Barrett components, and has pictures and data on many of them.

Peter
Andy Patterson
Re: Throttle design
September 02, 2003 09:36AM
Sorry this is a bit garboled:

Ine could balance the valve with steam in some as well

should have read:

One could balance the valve with steam in some way as well.

Andy
Mike Clark
Re: Throttle design
September 02, 2003 05:02PM


Peter,

As it happens I’ve just been looking at the throttle on my Stanley Model H. It is a bit smaller than you have concluded from your scaling. The stem of the valve is 0.275 inch diameter and the head of the poppet about 0.575 at the inner rim of the face – (the same as the valve sleeve). The steam outlet from the throttle is about 3/8 bore, feeding a ½ inch bore superheater and steam pipe to the engine. This throttle is for the dry 3 5/8 x 5 inch 20hp engine. Don’t know whether the 4 x 5 had a bigger throttle.

The mechanical advantage of the throttle hand lever over the throttle rod is about 17 to 1, a six inch arc movement of the hand lever moving the throttle rod through its full travel of 3/8 inch. (3/8th is also the diameter of the metering hole in the valve sleeve). The force on the finger grip on the lever to start to move the linkage is about 3-4 pounds with no steam pressure, translating to about 50 or 60 pounds at the throttle, less once the “stiction” has been overcome. It doesn’t seem to need significantly more pressure to open the throttle with 600psi up, presumably because the closing pressure is applied only to the cross sectional area of the valve stem and would therefore be about 35 pounds, i.e. a good deal less than the frictional load of the gland which is why the throttle doesn’t close when you let go of the lever!

The reason for looking at all this is that I entered the car for some vintage car driving tests next weekend and found that the regulations required a return spring on the throttle to close it should the linkage fail – appropriate for i/c cars but impossible for me! This spurred me into doing what I had intended for some time which was to put an emergency shut off valve in the steam pipe to the superheater – this seemed to satisfy the scrutineers who check the thing over before the event although it doesn’t truly fit the requirement.

In thinking up your modern steam car you need to consider legislative requirements on the throttle mechanism – I am sure you will not be allowed any kind of throttle which stays open and has to be positively shut by the driver to slow the car. You would at least have to link it to the brake, possibly even arranging to dump the steam from the pipe and valve chest. Think of the hassle which manufacturers have gone through to get “drive by wire” throttles.

Mike
Peter Brow
Re: Throttle design
September 03, 2003 05:20AM
Hi Mike,

Thanks for the data, much appreciated. What we have here is a classic example of what I call a "choice of scale error". I assumed (there's that word again) that the throttle port would be 1/2", same as the steam line bore. But no, 3/8" -- flow restriction -- I guess they don't call it a "throttle" for nothing!

Re-scaled it for 3/8" throttle port, and the figures from the scaled drawing now agree very closely with yours. Drawing shows approx 3/8" diameter stem, though; wonder if yours was turned down or modified at some time in the past, or was designed/built different, or if the drawing isn't entirely accurate. I am also not sure what year/model the drawing is from.

This led to the realization that if the steam velocities should stay the same in ports, pipes, etc for different sized systems, then my throttle should be much smaller. So I scaled it to a 1/4" throttle port, and figure a 3/8" bore superheater and main steam line are more appropriate than the 1/2" previously considered. This makes the throttle valve quite small, with very small opening/closing forces.

It may be that hand throttles are only allowed in specially-modified vehicles for the handicapped. I will look into that. I've been making changes to the design all over the place with regulations in mind. I'm a long way from a production vehicle, if ever, and the requirements are much more lax in my area for custom vehicles than for new production vehicles, but the higher the standard the car is built to, the better.

Another reason to go with a foot throttle is simply that people are used to them. If I ever hand someone the keys and tell them to take it for a spin, they'd probably be more comfortable -- and perhaps safer -- with a standard-style "go pedal" than with some unfamiliar lever under the steering wheel.

Automatic cylinder/steam line pressure relief during throttle closing is already in my design. That's a safety/convenience item which I insist upon, whatever the law says. Even with a spring-return foot throttle, I will still add a linkage to make sure the brake pedal positively shuts the throttle in case it sticks. An auxiliary shutoff valve is a good idea too, will look into that.

How is your throttle linked to the throttle lever shaft? I think it must be some kind of crank on the lever shaft, perhaps with a link to the throttle valve stem. The few drawings and photos which I have are none too clear, and I never got a good look on the few occasions I have seen Stanleys.

For a foot throttle, I might go with a roller follower in a slotted cam, profiled for easy opening. This could be put in a small grease box with a boot to exclude dirt and minimize wear.

It seems odd that the rules for the vintage car driving tests require spring-return throttles. Many vintage gas cars, like Model T's, have hand throttles too, and a spring-return hand throttle is actually less safe than the "cruise control" type, especially in antique cars with heavy steering where both hands should be free to control the wheel. I'm a stickler for rules, but alas some rules are not written by the most knowledgeable or reasonable people.

Peter
Peter Heid
Re: Throttle design
September 03, 2003 10:17AM
All,

"Thanks for the mention of stellite seats and valves for Stanley/Doble type throttles. Do these eliminate the wear/leakage problem, or do the stellite seal faces eventually wear/leak too? I wonder if some newer materials like technical ceramic or diamond coatings might be worth a look in this department. Stellite it is, unless something better turns up."

Stellite has generally been replaced in automotive use with other alloys that have greater wear resistance and can tolorate higher heat loads. They are available from any compentent automotive machine shop under several trade names. They cost a little more than stellite, but only a dollar or two. Though stellite can be machined with carbide, the harder seats are best ground.
Andy Patterson
Re: Throttle design
September 03, 2003 11:05AM
Hi Peter

I was think about your point that a safety valve should be operated once in a while just to keep it functioning ...

Whell how about an electric control tied to the key. Key on valve open Key off valve closed. A panic button could also break the circuit to close the valve in an emergency.

I am still planing on using electric controled valves. So would need no pressure release when the breaks are applied. The inlet valves would cess to open when breaking.

Andy
George
Re: Throttle design
September 03, 2003 02:30PM
Peter H.,
Thanks for the input on new materials, some of us "old timers" are not exposed to such things as you are in the racing motorcycle shop.
I think the success with new materials/coatings would have to do with erosion from very high velocity steam and corrosion as well. The differential in coefficient of expansion of the face and sub material is also important.
But if they are used in motorcycle exhaust valves with success that would answere that question.
George
Mike Clark
Re: Throttle design
September 03, 2003 04:25PM
Peter,

The Model H throttle linkage is a bit different to other Stanleys as the throttle is behind the boiler rather than alongside. However the principle is the same and from memory the lever at the bottom of the throttle rod on the steering column is about 1.75”, connected with a link to a 3.5” lever keyed to a shaft, at the other end of which is another lever of about 7/8” connected to the throttle rod. The mechanical advantage through the whole setup including the hand lever is about 17 to 1. The short travel of the throttle and slight flexibility of the throttle rod itself allows it to cope with the geometrical error of the connection between the final lever and the throttle rod - shades of the old beam engines here! The 0.275” diameter of the throttle rod is the same on two throttle units I have here.

Mike
Scott Finegan
Re: Throttle design
September 03, 2003 04:44PM

The "Green Monster", at the first SACA time trial suffered from a stuck throttle, and passed the finish line still accelerating. It was finally stopped with a secondary shutoff valve and/or a dump valve. Ideally you would have both.
Peter Brow
Re: Throttle design
September 04, 2003 04:29AM
Andy: Good solutions to both backup shutoff and cylinder steam shutoff. Depending on how the engine is designed and geared, it may be desireable to actually vent steam from the cylinders to exhaust when throttle is closed. Consider backing into a tight parking place, or maneuvering in close quarters, especially around darting pedestrians. If the throttle is closed immediately after one of the cylinder inlet valves closes, and if the steam in the cylinder is not vented, then the steam left in that cylinder could move the car a few more inches, or even a few feet. This could lead to bumper taps, fender benders, collisions, or even pedestrian injuries.

A good steam car should be able to stop on a dime. A direct-drive counterflow engine with separate inlet and exhaust valves could do this by opening all the exhaust valves. I plan to use one piston valve per DA cylinder, and add tiny inlet and exhaust vents at each end of each cylinder for quick warmup and quick stopping. When the throttle is closed, a linkage opens both of these valves on each end of each cylinder, instantly venting both the cylinders and the steam line to the exhaust line.

Peter H: Thanks for the note on new hi-temp alloys; could you give some examples of trade names to inquire about? Any favorites to recommend? George has a point about corrosion and differential expansion; steam conditions are different from IC conditions in some ways. Stellite has a steam track record, but perhaps some of the other alloys do too, such as in marine or stationary steam turbine plants. I'll look into this.

Mike: Thanks. Interesting that the Stanley throttles don't use a link between the lever and throttle valve stem. The Stanley brothers seem to have loved flexing metal in their designs. Deflecting/flexing the throttle valve stem and/or the valve body support rod would increase friction on the valve stem -- which is exactly what is needed to help keep the steam from closing the throttle! Any time you can solve a problem by eliminating a design element instead of adding one, there you have ingenious design.

Scott: Some kind of backup shutoff seems adviseable in case of stuck throttles. But all the extra valves in an improved steam car are really adding up; it would be nice to avoid as many as possible. Wonder if rocking a Stephenson link to its "neutral" midpoint would shut off inlet to both ends of a double-acting cylinder? If so, a steam car could be set up to shift into "neutral" whenever the throttle pedal is released, and with this plus vented cylinders there would be little danger from a stuck-open throttle. Wouldn't take much extra mechanism. I'll have to look into that.

Corrosion-resistant throttle materials might reduce the odds of sticking. Chromed/ground sleeve and bore? Stainless? Monel? Does oily water/steam help? How common is throttle sticking anyway? Was the Green Monster's stuck throttle a fluke, or the result of some fabrication or maintenance error? Here's an inherent safety advantage of the White throttle.

Peter
SSsssteamer
Re: Stuck Throttle
September 04, 2003 09:54AM
In 18 years of over 22,000 miles of driving a Stanley, I have never had the slightest problem of a stuck throttle from binding. A hard chromed throttle stem would make a smoother operating throttle though. Over the winter storage, I have seen stem packing sieze the throttle stem solid on a few of my friends' Stanley throttles. I once lost the clevis pin from my throttle linkage while driving along at 45 m.p.h.. It was a good thing that the road was straight because it took me an eigth of a mile to get the steam chest openned, the fuel shut off, and the brakes dragging enough to overcome the steam's power to a complete stop. Now, I make sure that the cotter pin in the throttle's clevis pin now is new and properly bent over every time that it is replaced. With the steam throttle fully openned in forward valving, because of the steam pressure on the slide valves and on the linkage, it is very difficult to move your hook up pedal to the mid position from forward. It is also impossible to get the pedal out of reverse for the same reason. I have to lap my throttle seat once a year, or about every two thousand miles to keep it from leaking. The seat is brass on brass and it doesn't take much to make it leak. I have my throttle adjusted so that when I set my throttle locking pin on a closed throttle, it is also pulling the throttle seat tightly closed. This helps the throttle seat last longer by not wiring it with a slow leak.
Jim Crank
Re: Throttle design
September 04, 2003 10:19AM
Pat,
Also never heard of a Stanley throttle jamming wide open, nor one on a Doble. Although, Warren Doble did put two cams on the foot throttle design, so if it did stick open, you put your toe under the throttle pedal and lifted up.
Never happened to any of the eight Dobles I know; but he had his reasons. CARBON was the culprit. That is why the later Dobles had scale traps and you were supposed to use the toe operated blowdown often.
I did break the stem on my Stanley's throttle once; but with a friend at the wheel and me on the fender holding the pieces together with vice grips in one hand and holding on with the other, we got home in good, if dramatic, style.
Jim
Mike Clark
Re: Throttle design
September 04, 2003 04:43PM
It was just the possibility of dropped out clevis or broken throttle rod that set me off to fit a secondary valve in the steam pipe. It seems to work perfectly on a short test and as I fitted it in place of the siphon valve which is mounted on the dash I can actually drive the car on it with a bit of a stretch or more easily with the assistance of a passenger. I used a modern globe valve which I am told has been successfully used before on other cars.

Mike
Peter Brow
Re: Throttle design
September 05, 2003 01:55AM
Pat: Yes, hard chromed/ground throttle stems are a good idea. Sounds like authentic brass seats are okay in original classics with proper adjustment and maintenance. Though brass is far from an ideal valve seat material. One of my properties has old brass seats in all the faucets, and some tenants have developed the habit of closing them loosely, letting them leak and not telling me for weeks or even months, until they're streaming water and driving up the water bill. Then they need grinding or new seats. (The faucets, not the tenants.) Just replaced such a seat a couple days ago; reground to a tiny nub and with laughably deep grooves. Hardware store guy said he'd never seen one that bad; almost suggested framing it. And that is with cold water @~65psi; I can only imagine how fast 500-600 psi steam would groove a brass valve seat.

Thanks for the valve linkage operational info; throttle-linked shifter to "valve neutral" was a dumb idea, prob even with piston valves. Unnecessary, too; see next.

Jim: Sounds like seized throttles are rare as hen's teeth. Demon Carbon the villain again. Scale traps are a must for monotubes. Just realized I've already solved this problem anyway; my control key design already includes a "blowoff" position (besides "on", "pilot/standby", and "off", then "blowoff", where a panicked ultra-offety-offward twist of key will land it), which shuts off all fuel and dumps all steam/water from (small) boiler in short order. Big cloud of steam out the tailpipe, but a throttle stuck wide open for whatever blue-moon reason would only require a key twist and a few seconds of panic braking until the steam pressure went away. On top of that, the brake-linked cylinder vents would be wide open, and as soon as the boiler dump started, the water control would start pumping in cold water like crazy, accelerating the boiler cooldown (thermal shock, ugh). Great vise grip/fender story, btw. smiling smiley

Mike: The Barrett throttle is a globe valve. Probably the ultimate modern valve type. Barrett has reported no problems in the thousands of miles he's put on it.

Peter
David K. Nergaard
Re: Throttle design
September 05, 2003 07:46AM
I have recently given up trying to regrind the seat of my old Stanley throttle. It is nearly impossible to insure there is no grinding compound left on the seat when you are done. So, I have made a new throttle, based on the Stanley, but with the poppet seat accessable. I intend writing it up for the SACA Bulletin in the near future, as soon as I am convinced it is a successful design.
It has a triangular notch in the sleeve hole, to make gradual starting easy. This notch is about 1/12 of an inch high. In normal driving, the notch is all the opening needed! I just drove my car nearly 800 miles over the weekend, and, excepting steep grades, rarely moved the lever more than half way up the quadrant. Yesterday, I disconnected the outlet tube and checked how much opening that position of the lever provided; just a hair more than the notch!
Jim Crank
Re: Throttle design
September 05, 2003 10:03AM
Peter,
The idea of using brass or bronze throttle in any steam car with high pressure and superheat is totally absurd. Even cast iron in those days would have been better. White knew this, I wonder why Stanley did not.
Breaking or sticking throttles are just so rare an occasion that I stopped worrying about it years ago. Be more concerned about breaking that steam line between the boiler and the throttle. That gets REALLY exciting.
Happened with E-14 once, a fractured three way valve, right next to a golf driving range. BANG and I saw his driver and the ball heading down the range at high altitude. Must have scared the guy out of his wits.

David,
I have seen quite a few Doble throttle sleeves that had been ground out into a pear shape for precisely the same reason. It works.
Jim
Peter Brow
Re: Throttle design
September 06, 2003 06:22AM
David: Thanks for the notes; I will plan on a notched throttle sleeve and will look into replaceable (& Stellite?) valve seat when the time comes. Looking forward to your report on the new throttle design; good idea. Downsizing my throttle port seems adviseable. With high pressure steam, it seems a good bit of horsepower will squeeze through a very small opening.

Jim: I wouldn't even consider a brass throttle for a new steamer, and the Stanley bros shouldn't have either. But for existing antiques, originality is often an issue for historical preservation purposes, even with hasslesome invisible features that virtually nobody would appreciate. It's each antique owners' decision, though; none of my beeswax, and I'm not taking sides. My own almost-antique is 100% stock, even annoying things like the points, oil cooler, solid lifters, etc, for which much better and lower-maintenance equipment is available. My project steam car is a whole nother thing, every single part subject to change at any time.

I live 4 blocks from a golf course, and often drive through it; hope I never get a chance to repeat your broken steam line experience around the duffers (or anywhere else). ¡Ay carumba! LOL. Another emergency use for a one-key shutoff/blowoff control. Fortunately, good steamers seem to go a few decades (?) before steam lines break. Flexibility is another good reason not to oversize the steam line.

Peter
George
Re: Throttle design
September 06, 2003 07:35AM
Peter B,
I remember from years ago that Peter Barret was using a ball balve design,
is your mentioning of a globe valve an updated valve version?
Thanks, George
George
Re: Throttle design
September 06, 2003 07:36AM
Peter B,
I remember from years ago that Peter Barret was using a ball balve design,
is your mentioning of a globe valve an updated valve version?
Thanks, George
George
Re: Throttle design
September 06, 2003 07:37AM
Peter B,
I remember from years ago that Peter Barret was using a ball balve design,
is your mentioning of a globe valve an updated valve version?
Thanks, George
Peter Brow
Re: Throttle design
September 07, 2003 06:57AM
Hi George,

Do you mean a lifting ball valve as a throttle? Peter Barrett may have used such a valve in one of his earlier systems. If I recall correctly(?), the Barrett ball throttle (current design) for which plans are available has a pivoting ball with a port drilled through it, IE a globe valve, rather than a lifting-ball design. I also seem to recall a slot milled in the top of the ball, for actuation via a key on the end of a pivoting shaft. I have seen a drawing of it somewhere. I think it was at Karl Peterson's website, but I couldn't find it when I checked a few days ago (removed?). I just dug through some steam magazines, and didn't find it there either.

I hope I'm not "remembering" some other design! It is annoying not knowing where to go for a memory check on this.

Perhaps someone here has the Barrett throttle blueprint, or has seen it, and can comment.

Peter
Jim Crank
Re: Throttle design
September 07, 2003 10:26AM
Peter,
Why go to all the trouble to try to make a ball valve, when you can buy a steam ball valve in 1/2"-1" sizes right off the shelf? Just go to "high temperature steam ball valves" on Goggle and look there. Up to 2,000 psi and 1100°F. Available right here in town, and I have used them and they work.
Don't make what you can buy.
Jim
Jim Crank
Re: Throttle design
September 07, 2003 10:27AM
Peter,
Why go to all the trouble to try to make a ball valve, when you can buy a steam ball valve in 1/2"-1" sizes right off the shelf? Just go to "high temperature steam ball valves" on Goggle and look there. Up to 2,000 psi and 1100°F. Available right here in town, and I have used them and they work.
Don't make what you can buy.
Jim
Terry Williams
Re: Throttle design
September 07, 2003 10:34AM
Jim Crank wrote:
>
> Peter,
> The idea of using brass or bronze throttle in any steam car
> with high pressure and superheat is totally absurd. Even cast
> iron in those days would have been better. White knew this, I
> wonder why Stanley did not.
> Jim

It's true that brass is not for superheat, but Stanleys didn't superheat before the throttle. Did they?
Terry Williams
Re: Throttle design
September 07, 2003 10:38AM
Yes, Peter Barrett used a ball throttle valve, for a while. It was as you describe.

Peter Brow wrote:
>
> Hi George,
>
> Do you mean a lifting ball valve as a throttle? Peter
> Barrett may have used such a valve in one of his earlier
> systems. If I recall correctly(?), the Barrett ball throttle
> (current design) for which plans are available has a pivoting
> ball with a port drilled through it, IE a globe valve, rather
> than a lifting-ball design. I also seem to recall a slot
> milled in the top of the ball, for actuation via a key on the
> end of a pivoting shaft. I have seen a drawing of it
> somewhere. I think it was at Karl Peterson's website, but I
> couldn't find it when I checked a few days ago (removed?). I
> just dug through some steam magazines, and didn't find it
> there either.
>
> I hope I'm not "remembering" some other design! It is
> annoying not knowing where to go for a memory check on this.
>
> Perhaps someone here has the Barrett throttle blueprint, or
> has seen it, and can comment.
>
> Peter
Jim Crank
Re: Throttle design
September 07, 2003 10:56AM
Terry,
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.
Jim
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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