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 Post subject: Re: Steam Actuated Inlet Valves?
PostPosted: Wed Apr 11, 2018 6:20 am 
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Joined: Wed Dec 07, 2011 6:41 am
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Location: Lopez Island, Washington State, USA
Boat Name: S.L. Folly
Poor Tom. Maybe we'd best get back to his question. About those steam operated valves . . .

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 Post subject: Re: Steam Actuated Inlet Valves?
PostPosted: Wed Apr 11, 2018 6:20 am 
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Joined: Fri May 13, 2016 2:42 am
Posts: 146
Location: Da Nang City Vietnam
Boat Name: Alphington
Great looking boat Mike, lots of hard work there.

I will start glass sheathing the outside of mine next week. I am currently working out how to vacuum bag the mahogany veneer onto my curved transom, so far I have discovered 127 ways to make the bag leak. I am hoping that Blu Tack will be the answer.

How about starting a post on your build so we can follow your progress.

Cheers

Lionel


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 Post subject: Re: Steam Actuated Inlet Valves?
PostPosted: Wed Apr 11, 2018 6:44 am 
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Joined: Mon Oct 31, 2016 5:57 pm
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Location: Norman, OK
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Wow, this took off way more than I expected it to.

To respond to a few of the observations:

1. It should be possible to run this at boiler pressure. All that should be necessary is that the surface area of the piston attached to the main valve be larger than that of the valve, and there will be sufficient pressure to open and close it regardless of boiler pressure.

2. Precision in terms of position of the valve shouldn't matter. From my understanding, the ideal steam engine (and the basis for the development of the Corliss valve system) should strive to open and close its valves as quickly as possible, so as to avoid unnecessary throttling of the steam during admission into the cylinder. Because of this, there shouldn't be an issue with position of the poppet valves as they will be either forced open by action of the steam cylinder or forced closed by the valvespring.

3. The reason I thought of using steam to move the primary cylinder valves while using a solenoid to control steam admission into the valve cylinders is to avoid the issues concerning power consumption of the solenoid that would arise if the solenoid were sized to open and close the cylinder valves directly.

4. The reason I think this may be an improvement over the balanced poppet valve is that, from my understanding, the balanced poppet valve has serious issues with steam leakage owing to different coefficients of thermal expansion causing a change in length of the valve relative to the steam chest, thereby allowing excessive leakage. However, I admit I have not found significant literature on this topic.

5. Condensation in the valve cylinders shouldn't be a huge issue. Even if the valve cylinder is completely filled with water, this would simply lock the valve open. Would the engine cease operation? Sure. But, unless it were an interference design, it shouldn't fail catastrophically.

This would obviously be a much different system than is currently used, but I'm not sure I would call it more complicated. Given the discussion on the intricacies of setting valve timing and control in the crankshaft lubrication thread, I think this may be a lot simpler in terms of adjusting the valves, as all that needs to be changed is a few settings in the engine management system.


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 Post subject: Re: Steam Actuated Inlet Valves?
PostPosted: Wed Apr 11, 2018 8:06 am 
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Joined: Fri Nov 27, 2009 5:56 pm
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Quote: "using steam to move the primary cylinder valves while using a solenoid to control steam admission into the valve cylinders is to avoid the issues concerning power consumption of the solenoid that would arise if the solenoid were sized to open and close the cylinder valves directly."

It's still going to require energy to actuate the valve, instead of solely electricity, it's steam. In a self contained plant that would be regenerating electricity consumed, the steam would be more efficient. Energy systems in series are rarely ever considered efficient. shortest distance between two points is a straight line etc.

Mechanical linkage is going to be the most efficient. It is the same as running a feedpump off of 12 volts DC, it can be done, but the power requirements are enormous in comparison to a simple crankshaft driven pump.

Quote: "I'm not sure I would call it more complicated. Given the discussion on the intricacies of setting valve timing and control in the crankshaft lubrication thread"

It would be far more complicated. Some of the potential issues, poor electrical connections,, electronics with much higher failure potential vs a simple eccentric, condensation - thermal insulation, It won't run until there is ample pressure to operate the valves, when it is up to pressure, it will probably be way more than needed causing the need for some sort of speed control/hysteresis on the valve travel.

-Ron


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 Post subject: Re: Steam Actuated Inlet Valves?
PostPosted: Wed Apr 11, 2018 3:00 pm 
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Joined: Thu Nov 07, 2013 9:16 pm
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Location: Northeast Ohio, USA
Boat Name: SL Nyitra
Lopez Mike wrote:
My new hull is long ways from the perfect design OR construction.

Mike,

Thanks so much for sharing some pictures!

I feel you may undersell yourself, because I think she's a beauty!

-CB


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 Post subject: Re: Steam Actuated Inlet Valves?
PostPosted: Wed Apr 11, 2018 8:17 pm 
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Joined: Mon Dec 14, 2015 2:12 pm
Posts: 165
Location: Very eastern England
Boat Name: Platypus, Shelduck
Lopez Mike wrote:
I strongly recommend the stitch and glue method. It was very gratifying to have so much progress from day to day. The material bill is up to around $4K. Epoxy hasn't gone down in price. $500 for a five gallon bucket.


I agree strongly with all of that. I have two stitch + tape boats: a 2-man kayak built over 50 years ago, and a (pole propelled) punt built 20 years ago. Both still appear to be in excellent condition. The canoe has it easy, being always stored under a roof and dry, but the punt stays in the water inside a wet boathouse, and seems to take no harm from that; it does have a double coat of epoxy varnish.

To my mind strip planking + epoxy/glass does produce a more elegant hull, and I built a big Canadian canoe that way two years ago. It's a lovely thing, and both light and strong, but the time taken for construction was at least 5 and maybe 10 times that for the plywood kayak.


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 Post subject: Re: Steam Actuated Inlet Valves?
PostPosted: Wed Apr 11, 2018 10:22 pm 
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Joined: Fri Mar 07, 2014 5:38 am
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Location: South Lake Tahoe, CA, USA
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Aren't most injectors in on-the-road common-rail compression-ignition engines activated by solenoid these days? That and the injectors in newer direct-injection gas vehicles? Those are systems firing well over 1,000 times per minute while on the road, and albeit small surface areas for the valves in them, dealing with tens of thousands of psi fuel pressure.

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 Post subject: Re: Steam Actuated Inlet Valves?
PostPosted: Wed Apr 11, 2018 10:37 pm 
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That is a good question Wes. It must be the size of the coil and the amount of work it is doing, which is much less than opening a poppet valve.

-Ron


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 Post subject: Re: Steam Actuated Inlet Valves?
PostPosted: Wed Apr 11, 2018 10:43 pm 
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Joined: Thu Nov 19, 2009 2:51 am
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TriangleTom wrote:
I've done some research and so far I haven't been able to find any information about this having been tried in the past, although I'm sure I'm not the first person with this idea.


This is a case were the technologies just didn't overlap. By the time the control system was capable of handing the speed & duty cycle steam had largely died out.

This should be some inspiration

[Youtube]https://www.youtube.com/watch?v=6HND4x22jXM[/Youtube]

The beauty of an electrically controlled valve like this is that it allows more flexibility in the placement of the valves as you are no longer tied to the physical limitations of a mechanical linkage between the output shaft and the valve actuation. Yes, it does introduce some other technical issues but it's always about tradeoffs isn't it?

Cheers

Ken


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 Post subject: Re: Steam Actuated Inlet Valves?
PostPosted: Wed Apr 11, 2018 11:18 pm 
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Joined: Wed Dec 07, 2011 6:41 am
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I think it's interesting to see how much more complex the overall scheme of things is compared to the obvious physical machinery.

With each improvement in steam engines we seem to have been taking a couple of steps forward and one back. Stevenson valve gear was supplanted in locomotives for more than one reason. The eccentrics were in a terrible place for maintenance. Filthy and hard to get at. And the space between the engine frames began to be needed for bracing as the power of the engines shot up. Very few U.S. engines were built with anything but Walshearts valve gear and inside admission piston valves in the last half century of their existence. Marine steam had none of these issues and never converted over to more sophisticated gears. Piston valves at higher pressures being the most notable exception.

There was a big increase in efficiency with the Corliss design where the ports only had to flow one direction. And the intake and exhaust events were largely independent. But they were only successful in stationary installations. There was no way that all that mechanism would survive hanging out on the side of a locomotive and reversing was not a trivial issue.

Uniflow designs had the advantage of, well, uniflow. Like the Corliss, the ports did't have to waste heat by heating up and down again. Combined with poppet valves and efficient ports, it was the wave of the future. Too bad that it still is. I crewed on a three cylinder uniflow boat and we whacked a few docks due to unpredictable reversing behavior.

Inventors tend to focus on the direct function of the 'improvements', but seldom seem to take into account indifferent maintenance and other issues that they would rather not face.

The cost of labor and fuel killed reciprocating steam as a commercial technology. We retro fools appreciate it for its elegance and simplicity. I don't have a problem with anyone building some wonderfully complex power plant for the sheer fun of it. But please don't expect me to believe that it will be particularly efficient by modern I.C. standards or be a joy to have in the boat on a sunny afternoon.

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