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blowgun or sprinkler valve
Posted: Fri Jun 22, 2012 6:41 pm
by boyce123
i've been thinking of making a large piston pnuematic. would a blow gun have high enough flow for a decently efficient pilot release. If there wouldn't be a drastic difference in performance, i don't really want to buy, then deal with a sprinkler valve. Also, would it be possible to put a check valve in the piston as the chamber charging device.
Posted: Fri Jun 22, 2012 8:17 pm
by ramses
Depending on how much pilot volume you're talking about, you could have considerable "lock time" (Trigger lag). Furthermore, if the sealing face OD is small compared to the OD of the piston, your valve may open slowly, bounce, or even re-close.
Check valves have been used in pistons with much success. They can even be built into the O-ring groove.
To be honest, I would use a sprinkler valve or a QEV to pilot. That would then likely allow you to move the blowgun wherever you want on the cannon without any hit on performance. You should be able to find one (in the US) for under $15.00. One of the sponsors was selling them for less than $5.00 a while ago.
Posted: Fri Jun 22, 2012 10:25 pm
by jsefcik
ramses wrote:Depending on how much pilot volume you're talking about, you could have considerable "lock time" (Trigger lag). Furthermore, if the sealing face OD is small compared to the OD of the piston, your valve may open slowly, bounce, or even re-close.
Check valves have been used in pistons with much success. They can even be built into the O-ring groove.
To be honest, I would use a sprinkler valve or a QEV to pilot. That would then likely allow you to move the blowgun wherever you want on the cannon without any hit on performance. You should be able to find one (in the US) for under $15.00. One of the sponsors was selling them for less than $5.00 a while ago.
i do have a extra sprinkler valve, pm me if interested
Posted: Fri Jun 22, 2012 10:53 pm
by mattyzip77
If you are going to spend the money, I suggest a a qev for your pilot if its going to be a bigger sized pneumatic. A qev is pretty much the same amount of money and you dont have to modify it..
Posted: Fri Jun 22, 2012 11:41 pm
by jackssmirkingrevenge
mattyzip77 wrote:If you are going to spend the money, I suggest a a qev for your pilot if its going to be a bigger sized pneumatic. A qev is pretty much the same amount of money and you dont have to modify it..
Agreed, apart from the spending money part.
http://www.ebay.com/itm/Pneumatic-QE-04 ... 4166cb71ea
Less than $10 posted, why the heck
wouldn't you buy one? You fit this as the pilot, and pilot it with a blowgun, voila.
Also, would it be possible to put a check valve in the piston as the chamber charging device.
Unless you piston is o-ringed, you don't need any sort of valve. Air will simply leak around even the tightest of pistons, no need for an extra valve or equalisation hole.
Posted: Sat Jun 23, 2012 12:15 am
by boyce123
thanks for all the info, i'll see what i can come up with at my local hardware store tomarrow (i was hoping to suppliment fourth of july celebrations, and hong kong valves off ebay can't arrive for at least 25 days)
Posted: Sat Jun 23, 2012 5:25 pm
by waza8u
boyce123 wrote:thanks for all the info, i'll see what i can come up with at my local hardware store tomarrow (i was hoping to suppliment fourth of july celebrations, and hong kong valves off ebay can't arrive for at least 25 days)
Posted: Sat Jun 23, 2012 5:26 pm
by waza8u
boyce123 wrote:thanks for all the info, i'll see what i can come up with at my local hardware store tomarrow (i was hoping to suppliment fourth of july celebrations, and hong kong valves off ebay can't arrive for at least 25 days)
yea usually takes 25 days to a month for deliveries from hong kong but i got in 7 days just a week ago, i was very surprised