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Diaphragm Piston

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Diaphragm Piston

Unread postAuthor: frocksie » Wed Jan 16, 2008 5:41 pm

I was thinking today about pistons and diaphragms, when I started thinking about combining the two, due to the popular belief that diaphragms open faster and pistons give better airflow. I came up with this design, with no idea how well it would work.

I'm wondering if this would give any appreciable advantage over a regular piston or diaphragm.

This drawing isn't to scale, although it may be close. Certain features may need tweaking, such as the thickness of the diaphragm, or the diameter of the diaphragm.

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Brown--Bumper
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Blue--3" endcap piston
Black--Diaphragm
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Aqua--1.5" Sch. 21
Tan--Golf Ball
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Unread postAuthor: elitesniper » Wed Jan 16, 2008 5:47 pm

the only problem is that you need a washer behind that diaphram or it will blow tear or rip just like a burst disk, but looks like it will just perform the same.
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Last edited by elitesniper on Wed Jan 16, 2008 5:50 pm, edited 2 times in total.
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Unread postAuthor: Hubb » Wed Jan 16, 2008 5:47 pm

From looking, it appears as if the piston has to open, which will release the diaphragm, correct? If so, I don't see any advantages, just an extra step.

If that's not how it works, please explain it.
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Unread postAuthor: ALIHISGREAT » Wed Jan 16, 2008 5:51 pm

hubb017 wrote:From looking, it appears as if the piston has to open, which will release the diaphragm, correct? If so, I don't see any advantages, just an extra step.

If that's not how it works, please explain it.


its a moving diaphgram, the piston has a hole in the the diaphgram can move back and as it is mounted on a piston when the piston moves back it gives extra flow.

why not just make a QEV style diaphgram piston?
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Unread postAuthor: frocksie » Wed Jan 16, 2008 6:00 pm

Hubb,
the way I saw it, when the pilot valve is opened, the diaphram will open, and then the piston.
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Attachments
diaphram piston3.JPG
piston and diaphragm open
diaphram piston3.JPG (20.11 KiB) Viewed 765 times
diaphram piston2.JPG
pilot opened, diaphragm opens
diaphram piston2.JPG (20.48 KiB) Viewed 765 times
diaphram piston.JPG
diaphragm sealed
diaphram piston.JPG (20.54 KiB) Viewed 765 times
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Unread postAuthor: ALIHISGREAT » Wed Jan 16, 2008 6:05 pm

Another point is that how much more power will you gain if any? because the extra pilot volume will make the diaphgram open slower.
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Unread postAuthor: frocksie » Wed Jan 16, 2008 7:28 pm

ALIHISGREAT,
The increase in pilot volume would be relatively small, less than 6 cubic inches. The only way to figure this out may be to make it.
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Unread postAuthor: bigbob12345 » Wed Jan 16, 2008 7:37 pm

I would assume that the power increase wouldnt even be noticeable it just isnt worth all that extra work.And I think normal pistons open fast enough this is not needed.
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Unread postAuthor: clide » Wed Jan 16, 2008 8:55 pm

Unless you are using a very light projectile (much lighter than a golf ball) then you probably wouldn't even be able to measure the difference with a chrony.
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Unread postAuthor: Hubb » Thu Jan 17, 2008 5:51 am

frocksie wrote:Hubb,
the way I saw it, when the pilot valve is opened, the diaphram will open, and then the piston.


I got ya. In order for the diaphragm to open first, the equalization hole in the piston will have to be large, which will basically make it useless. I see no advantage in the design. It's good, though, that the cogs are turning.
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