Caged Ball Valves

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No. 44
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Caged Ball Valves

Post by No. 44 » Wed Feb 25, 2009 5:29 am

I was thinking about the biggest problem with valved pulsejets today while at school, that the valves wear out so quickly, when it dawned on me that there was a valve used in early artificial hearts that had to work on changes in pressure in a way not too dissimilar to valved pulsejets and couldn't wear out quickly or the patient would die. I was wondering if any of you have built valved pulsejets using caged ball valves and if so, how did they perform?

larry cottrill
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Re: Caged Ball Valves

Post by larry cottrill » Wed Feb 25, 2009 12:24 pm

I have one, but sadly, never finished it. My theory was that if a ball bearing was small enough that I could set it on a table and get it moving by blowing on it, it would work as a valve. Highly sophisticated design. Ha.

But, it is one of the FEW examples of actual lathe work by me. Ha again.

http://www.cottrillcyclodyne.com/SFOA1.html

L Cottrill

Sebastian LFT
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Re: Caged Ball Valves

Post by Sebastian LFT » Wed Feb 25, 2009 2:27 pm

I tried to make a tiny one last year. Thinking the same as Larry with going small on a ball valve. My thought was spurred on by blowing on a ball whistle.



I have this 1-1/8" bearing laying around and it weighs a ton. If that actually got going I can imagine it beating the snot out of the valve seat and cage.



So, as usual with me I went tiny using the same dimensions as my micro mini Lockwood type pulse jet and a caged 3/16" (think it was a wee bit smaller) ball bearing. I experimented till I got about the right length for locking in. When it did the ball got red hot. Second time the ball disintegrated. Both run times were only seconds. Never got a video of it. C'est la vie :|



Maybe a cluster of tiny ball valves on a 24 inch long pulse jet would allow enough air to keep them relatively cool. 8)
You'll never know 'till you try it.

larry cottrill
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Re: Caged Ball Valves

Post by larry cottrill » Wed Feb 25, 2009 5:59 pm

The point of changing to my second design was to get significant "blast shielding". Not the bent washer, which takes up most of the cross-section of the chamber at that point. Of course, at the moment, I have no idea as to how well it works.

L Cottrill

No. 44
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Re: Caged Ball Valves

Post by No. 44 » Thu Feb 26, 2009 1:47 am

I think that so far the direction has been a bit wrong. One big valve probably won't allow sufficient air in for a good run and making them too small will just cause them to burn up no matter how many you have because iron burns pretty easily when it doesn't have anywhere for the heat to spread out to. Maybe a larger diameter engine with a circular array of valves would get better result. Also, I'm not sure they need to be balls, maybe they could be a kind of pivoting flap or some other kind of pressure-triggered valve.

Image
This is what I just threw together during the lecture tonight and I'm thinking that with 6 more arranged around this in a single valve plate you might get something that works. It'd be a bitch building anything like what I'm describing but my hope is you'd only have to do it once in a great while or at least a greater while than tradtional and suprisingly fragile reed valves.

Mark
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Re: Caged Ball Valves

Post by Mark » Thu Feb 26, 2009 2:57 am

I was wondering if you could sequester the ball valves from the heat in a channel of some sort. I recall racketmotorman had those synthetic fabric reeds and the US Navy used a rubber laminate between reeds and rubber bumpers. There might even be a way to use rubber superballs ricocheting back and forth, a long shot I know.
Here's a few heart valve ideas just for some food for thought. I bought a new heart valve sealed in an acrylic case/package on ebay for $20.00 just to play with it. It is a white ball in a cage with three metal spokes to confine the ball and a white gauze-like fabric skirt/base to sew into the the heart. Funny the stuff you can buy on eBay.
Anyway, here's a few odd designs, just to illustrate some different philosophies, not that they were designed for pulsejets. ha

"Well, below you can see scans of a Starr-Edwards heart valves from a 67-year-old Montreal woman. The valves have been functioning flawlessly 38 years after surgeons implanted them."
http://www.heart-valve-surgery.com/hear ... ars-later/

"Natural heart valves allow blood to flow straight through the center of the valve." I wonder if pulsejets would like that idea/motif? ha
http://www.heart-valve-surgery.com/mech ... -valve.php

The bi-leaflet design seems interesting. It might be fun to design something intricate like that for a pulsejet, just to be different, to be the first on your block. Or those tilting valves look good and quirky too.
http://www.pages.drexel.edu/~nag38/Types.html
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Al Belli
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Re: Caged Ball Valves

Post by Al Belli » Thu Feb 26, 2009 2:18 pm

Hi,

McMaster Carr has a hollow stainless steel 1" ball that may be useful as a valve component.

Part Number: 9327K33
$8.83 Each
Material
Tough Wear-Resistant Stainless Steel (Type 440A)


Ball Type
Hollow
Diameter
1"
Diameter Tolerance
±.005"
Sphericity
.001"

Rockwell C54-60

Al Belli

Sebastian LFT
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Re: Caged Ball Valves

Post by Sebastian LFT » Thu Feb 26, 2009 2:35 pm

No. 44, The problem I see with an open "wire" cage is that its right out there going commando in the heat. And you got the hammering of the ball to boot. What I was thinking was automotive. The valve has a valve seat transferring heat from it. Take that idea and make a socket shaped stop. Now you have the other end transferring heat. Drawback is that the cage will be saturated with heat already. Perhaps that could be overcome by injecting fuel directly into the cage.
Maybe a larger diameter engine with a circular array of valves would get better result
That's what I was getting at but failed to go into detail.
You'll never know 'till you try it.

Sebastian LFT
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Re: Caged Ball Valves

Post by Sebastian LFT » Thu Feb 26, 2009 2:42 pm

Larry, Where is your Ball Valve PJ now a days?? Great design BTW. :mrgreen: I think it would be great to see you fire it up...

Some fancy torch welding there with that thin washer and thick steel ball. I feel more at home and satisfied with oxy/acetylene. Ya gotta love it.
You'll never know 'till you try it.

Sebastian LFT
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Re: Caged Ball Valves

Post by Sebastian LFT » Thu Feb 26, 2009 2:45 pm

On Marks heart valve research, I like the bi-shutter flap idea. One could make the flaps a bit thicker with a stout pivot pins . With that( as with the ball valve) I can imagine increased pressures resulting in a very angry sounding pulse jet wanting to kick some other PJs ass. :twisted:
You'll never know 'till you try it.

Sebastian LFT
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Re: Caged Ball Valves

Post by Sebastian LFT » Thu Feb 26, 2009 2:58 pm

Here are smoe stills of my crispy fried ball valve. :(
Attachments

[The extension wmv has been deactivated and can no longer be displayed.]

You'll never know 'till you try it.

Mark
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Re: Caged Ball Valves

Post by Mark » Fri Feb 27, 2009 12:37 am

Perhaps one way that might work for a hollow/light steel sphere valve would be to have delicately precise springs at both ends to slow the impact and to provide a bit of return response to the feedback going on. Again, you would probably have to sequester the springs and ball valve from the heat in some way, but that wouldn't be insurmountable. And too, I guess you could pad the ends of the springs with rubber to minimize wear on the sphere.
It brings to mind some kind of gas gun with the steel sphere acting as some sort of ultra-fast, bolt-action, air-slug loading device, machine-gunning back and forth, "if" it were to work.
Presentation is Everything

alex smikle
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Re: Caged Ball Valves

Post by alex smikle » Tue Mar 03, 2009 4:43 am

I was looking on the design and its a nice concept. What could help with the heat is having the balls with an aluminum core, or a quick melting metal. Maybe the heat will go in latent heat to melt the core instead of the ball. Similar to sodium in car valves. One other idea is using ceramic ball bearings.

Sebastian LFT
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Re: Caged Ball Valves

Post by Sebastian LFT » Tue Mar 03, 2009 2:09 pm

One other idea is using ceramic ball bearings.

Now that sounds like a step in the right direction. Heat resistant and light. Though one would need to find a way to keep it from breaking apart. I,m sure it's possible to find a frequency (so to speak) for it to run with out pounding its self to chunks. I can't see it being any different then keeping a very thin piece of spring steel alive in a very harsh environment.
You'll never know 'till you try it.

ace_fedde
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Re: Caged Ball Valves

Post by ace_fedde » Sat May 16, 2009 11:10 pm

Hello all,
Normally wandering on the valveless forum but this topic attrackted my attention because I've also been thinking about this problem (never build something though).
Do you guys now that there are ceramic ball bearings? These balls are lighter :D and heat resistant :D :D :D
Also there are (nice little) ceramic cutting blades for lathe tools, vibrating resistant. I happen to have a few blunt ones. I was thinking to, once in the future, make something out of them.
Fedde
Your scepticism is fuel for my brain.

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