I really don't get this - Valve size vs flow and pressure

woodlandfarms · Jun 9, 2008

So, my PT produces 18 GPM at 3000 PSI. I have a valve in an aluminum block that turns on and off my PTO. I pulled this valve and now I am stumped. The valve has 4 small holes (3/16") and feeds from and to a maybe a 3/8" or 1/2"hole. The hose that supplies this is a 3/4" hose, and the hose from this is 3/4". So, doesn't a valve just kill my pressure and GPM? I mean I read in here how a flat face coupler will give you at least another 100 to 200 GPM so why would this valve appear to me to be so restrictive?

This is not to bash on my machine, it is to learn more about why hydraulics work the way they do. I have put a pressure gauge on the end of my pipe and get 3000 PSI so I know the valve works as advertisesd (I think).

Carl

Wayne County Hose · Jun 10, 2008

Carl, the valve will give you the pressure. That does seem small to pass 18 gpm. I would have to do the math. But, remember, even though you have a 3/4" hose, you are only passing about 1/2" worth of fluid. Look down the crimp fitting on a 3/4" hose, my crimps measure .597". -8 and -6 crimps cut the flow by even a larger percentage of the hode i.d.

You have been posting a lot. Are those lazy writers still on strike?

woodlandfarms · Jun 10, 2008

Writers are back. Actors are threatening so we are not making any movies. Too risky to try and start a movie then have your actors walk out. This applies for the studios. For independents you can make a side deal with the actors.

So, yes, I am up north waiting patiently for this to get over. I have a bunch of things I want to buy and nothing to buy it with.

Thanks for the info on the valves. It seems restrictive, but what do I know...

rdbrumfield · Jun 12, 2008

If that block is just for the hyd pto, would made sense to slow the engagement speed. as for the hoses, they are most likely 4wire for strength.
Personally I never cared for the hyd or elec pto system. Seems hard on equipment not to be able to feather in a bit to start rotation instead of the instant on.

woodlandfarms · Jun 16, 2008

rdbrumfield said:
If that block is just for the hyd pto, would made sense to slow the engagement speed. as for the hoses, they are most likely 4wire for strength.
Personally I never cared for the hyd or elec pto system. Seems hard on equipment not to be able to feather in a bit to start rotation instead of the instant on.

It is a bit of a jolt. With my system you need to have the engine at idle, then bring it up to speed to get the necessary RPM's.

Carl