Pneumatic cylinder

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Geochurchi
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Location: Concord ,NH / Naples, Fl

Pneumatic cylinder

Post by Geochurchi »

Hi All, still having issues with the gate arms, can anyone help with figuring out what the best size cylinder would be, things have changed over the years and we are thinking that the cylinder may not be large enough, any formulas we find are confusing.
Thanks
Geo 🇺🇸
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Bill Shields
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Re: Pneumatic cylinder

Post by Bill Shields »

Well...a bit of background would be helpful.

Since some of us haven't idea how large or heavy the item you appear to be trying to lift..not any idea the location of the center of gravity or the pivot distances or available air pressure..the answers to the question you are asking is indeterminate
Too many things going on to bother listing them.
Geochurchi
Posts: 153
Joined: Mon Feb 22, 2021 7:49 am
Location: Concord ,NH / Naples, Fl

Re: Pneumatic cylinder

Post by Geochurchi »

Hi, your right Sorry, what we have are 2 crossing gates, 2 cylinders , gate arms are 12’ , weigh 25lbs each, air pressure is 40 lbs, I will take some pics in the AM. I tried to post a video awhile back but the site won’t allow it, search Crossing Gates on this site to view other posts, we are now thinking maybe the cylinders are too small.
Geo 🇺🇸
If it ain’t broken keep working on it until it is .
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Bill Shields
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Re: Pneumatic cylinder

Post by Bill Shields »

cylinder diameter?

pivot dimensions? center of arm pivot to each end of the air cylinder -> when up and down. pictures not much good if they do not have actual dimensions included.

at what point is the 25' value determined? by lifting at the end of the 12' tip or by lifting at the mounting point of the cylinder? -> or elsewhere?

cylinder travel length?

what has changed since the gates last worked?

what sort of 'snubbing' do you have on the air cylinders? unlikely that the system is just air alone -> otherwise arm action would be very uncontrolled.

pictures must be below a certain size and are added as 'attachments'
Too many things going on to bother listing them.
Geochurchi
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Joined: Mon Feb 22, 2021 7:49 am
Location: Concord ,NH / Naples, Fl

Re: Pneumatic cylinder

Post by Geochurchi »

This AM I reinstalled the exhaust flow control valve in each valve, seems to work much better, (for now) what is the difference between using the flow control valves on the cylinder and the exhaust flow control on the valves? Cylinder is 1” Dia. 6” extension of rod, gate arm 25 lbs. this may be to much to sort out in a forum!
073FAE2A-0F7C-48AB-BCE2-278C760D0A52.jpeg
4FFF58DF-4EC6-4DD2-A209-6E0721822291.jpeg
Geo 🇺🇸
If it ain’t broken keep working on it until it is .
Geo 🇺🇸
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Bill Shields
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Re: Pneumatic cylinder

Post by Bill Shields »

Now getting somewhere.

I would disassemble the flow control valves unit and give it a good cleaning.

Most of your problems are probably related to dirt restricting flow
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Bob D.
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Re: Pneumatic cylinder

Post by Bob D. »

As I pointed out in your previous post about these gates and where you had a video link showing them bouncing, you already have flow control valves on both ports of the cylinder. Your only problem is the exhaust side of the down stroke is not restricted enough. You always control the flow to an air cylinder on the exhaust side. If after doing this and the gate goes up to slowly for your tastes you could utilize one of the solenoid valve ports to cut out a flow valve.
I think if you nearly close both flow controls you will have a slow and steady operation in both directions. Make small adjustments of the valves starting with just barely open.
3/4" Juliet II 0-4-0
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3/4" Hall Class 10 wheeler
3/4" Evans Caribou/Buffalo 2-8-0
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Bill Shields
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Re: Pneumatic cylinder

Post by Bill Shields »

Ah ha...access to additional info..😀
Too many things going on to bother listing them.
Geochurchi
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Re: Pneumatic cylinder

Post by Geochurchi »

Good point on cleaning the flow control devices, this system is less then sterile, I have disconnected the arm from the cylinder and it is very controllable using the flow control valves.
Geo 🇺🇸
If it ain’t broken keep working on it until it is .
Geo 🇺🇸
Bob D.
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Joined: Thu Jun 21, 2012 10:43 pm
Location: Saco, ME. USA

Re: Pneumatic cylinder

Post by Bob D. »

Plenty easy to control the position of an air cylinder with no mass acting upon it. If your not controlling the pressures on both sides of the piston during movement you end up with a big oscillating spring.
3/4" Juliet II 0-4-0
3/4" Purinton Mogul "Pogo"
3/4" Hall Class 10 wheeler
3/4" Evans Caribou/Buffalo 2-8-0
3/4" Sweet Violet 0-4-0
3/4" Hunslet 4-6-0
3/4" Kozo A3. Delayed construction project

1 1/2" A5 Camelback 0-4-0
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