Be not annoyed, oh mighty mods, I post here hoping for more suggestions on Presscilla...

MERLIncMan said:
or just pump it up with a Schrader valve once?
Click to expand...
That's an interesting idea, I think it could work. However, I think it would require a small air tank or chamber to contain the compressed air. The volume of the air side of the hydraulic cylinder when bottomed out would be relatively small and the air might get compressed to too high a pressure. Say, if you had 60 psi in the air side of the system, with the cylinder fully extended up (air side), and it was attached to a chamber of equal volume it might get to perhaps 120 psi when the cylinder was down, that would still be within safe range for air and a Schrader valve. But if there was no chamber the air might get compressed to pressures approaching hydraulic pressure and that would not be safe and would impede the downward force you are trying to achieve.
 
Nigel123 said:
I plumbed shop air to it
not a big deal for me had air closeby
never tried pumping it up once didnt want the air pressure to increase with the stroke of the cylinder
the regulator i use ibleeds off the air so it doesnt rise more than 10 to 20 lbs above set pressure
your cylinder looked like it had a port for return was it bought as a retractable type?
Click to expand...
The port you see in my video is just a sintered bronze muffler that I put on it to prevent bugs and junk from getting in that side of the piston - it's supposed to be a double acter.
 
Eddyde said:
That's an interesting idea, I think it could work. However, I think it would require a small air tank or chamber to contain the compressed air. The volume of the air side of the hydraulic cylinder when bottomed out would be relatively small and the air might get compressed to too high a pressure. Say, if you had 60 psi in the air side of the system, with the cylinder fully extended up (air side), and it was attached to a chamber of equal volume it might get to perhaps 120 psi when the cylinder was down, that would still be within safe range for air and a Schrader valve. But if there was no chamber the air might get compressed to pressures approaching hydraulic pressure and that would not be safe and would impede the downward force you are trying to achieve.
Click to expand...
A pony tank you say? Hmmmm.....
 
Another safety concern with over compressed air would be the potential dieseling of any oil residue in the cylinder.
 
You could just put a hydraulic accumulator on the bottom side or just use the simple external or internal mounted spring(s).
 
OTmachine said:
You could just put a hydraulic accumulator on the bottom side or just use the simple external or internal mounted spring(s).
Click to expand...
These are good ideas. I tried extension springs (as shown in the video), they did not work. I cannot find a compression spring of such dimension as to go inside the lower part of the piston. Perhaps I will look again - need something around 4"ID and 10" long - a car spring maybe so. As far as an accumulator, this is a neat thought, but that would be merely another piston/bladder with a spring/air in it wouldn't it? Seems redundant if I've already got a dead side of a piston to use.
 
MERLIncMan said:
These are good ideas. I tried extension springs (as shown in the video), they did not work. I cannot find a compression spring of such dimension as to go inside the lower part of the piston. Perhaps I will look again - need something around 4"ID and 10" long - a car spring maybe so. As far as an accumulator, this is a neat thought, but that would be merely another piston/bladder with a spring/air in it wouldn't it? Seems redundant if I've already got a dead side of a piston to use.
Click to expand...
It would be entirely hydraulic. No oxygen. Hence, no chance of KaBoom! Most accumulators are charged with an inert gas like nitrogen.
 
I watched the video again. It looks like there might be too much friction between the hammer and the column? If so, maybe some roller bearing guides could help?
Also, you might not need a new pump to use the double acting cylinder. It might be possible to just replace the spool valve to one that can toggle between the cylinder ports.
 
You must log in or register to reply here.
Back
Top