OK, basic question for any a youse what work on hydraulics...
I know you can use a double acting cylinder with a single
acting valve by putting a breather in the unused port. But can
you run a single acting cylinder from a dual action spool by
plugging the other port? Would you need to add an extra relief
return before the valve for a standard dual action open center
valve, or would the OC or the valve internal relief take care
of that for you?

Working on a small project, and trying to minimize expense by
designing to what I can scrounge...

Thanks,
--Glenn Lyford

wrote:
OK, basic question for any a youse what work on hydraulics...
I know you can use a double acting cylinder with a single
acting valve by putting a breather in the unused port. But can
you run a single acting cylinder from a dual action spool by
plugging the other port? Would you need to add an extra relief
return before the valve for a standard dual action open center
valve, or would the OC or the valve internal relief take care
of that for you?

Working on a small project, and trying to minimize expense by
designing to what I can scrounge...

Thanks,
--Glenn Lyford

You can do it a couple of ways . Change the internal spool . Block the
handle so it will only move one way . Plumb from the unused port back
into your return line . Plug the port is fine , just hard on the relief
valve if you inadvertently shift to that port . Changing the spool is
the right way . So may different style of valves out there now I would
not say any advice other then direct from the manufacturer is gospel .
Most of them have free tech support so why not make use . Luck
Ken Cutt

Plumb from the unused port back into your return line.

That certainly sounds doable enough.

Plug the port is fine , just hard on the relief valve if
you inadvertently shift to that port.

But aren't you going to shift to it every time you go to let
the other side down?

Thanks for you answers, that's a big help.
--Glenn Lyford

wrote:
Plumb from the unused port back into your return line.


That certainly sounds doable enough.


Plug the port is fine , just hard on the relief valve if
you inadvertently shift to that port.


But aren't you going to shift to it every time you go to let
the other side down?

Thanks for you answers, that's a big help.
--Glenn Lyford

Well the valves I am familiar with have a center neutral position . As
long as you only shift from center one way and back to center it should
not be an issue . Inadvertently shift the wrong way though you will hear
your relief valve complaining . A replacement spool should be around 20
bucks in the more common size valves or make up your own . Luck
Ken Cutt .

On Sun, 25 Sep 2005 00:23:48 -0700, Ken Cutt
wrote:

wrote:
Plumb from the unused port back into your return line.


That certainly sounds doable enough.


Plug the port is fine , just hard on the relief valve if
you inadvertently shift to that port.


But aren't you going to shift to it every time you go to let
the other side down?

Thanks for you answers, that's a big help.
--Glenn Lyford

Well the valves I am familiar with have a center neutral position . As
long as you only shift from center one way and back to center it should
not be an issue . Inadvertently shift the wrong way though you will hear
your relief valve complaining . A replacement spool should be around 20
bucks in the more common size valves or make up your own . Luck

But has to be shifted the other way to let the cylinder back down.

Wayne Cook
Shamrock, TX
http://members.dslextreme.com/users/waynecook/index.htm

Wayne Cook wrote:
On Sun, 25 Sep 2005 00:23:48 -0700, Ken Cutt
wrote:


wrote:

Plumb from the unused port back into your return line.


That certainly sounds doable enough.



Plug the port is fine , just hard on the relief valve if
you inadvertently shift to that port.


But aren't you going to shift to it every time you go to let
the other side down?

Thanks for you answers, that's a big help.
--Glenn Lyford


Well the valves I am familiar with have a center neutral position . As
long as you only shift from center one way and back to center it should
not be an issue . Inadvertently shift the wrong way though you will hear
your relief valve complaining . A replacement spool should be around 20
bucks in the more common size valves or make up your own . Luck


But has to be shifted the other way to let the cylinder back down.

Wayne Cook

Brain dead at times . Yikes . Yes has to be shifted to get it back down
.. Good call Wayne . In that case a new spool seems the solution . I
only have a few prices at hand for new spools . Seems to run from $25 up
TO $39 Can for single acting replacement . Luck
Ken Cutt

I built a bucket loader last fall using porta-power-type cylinders
controlled by a valve made for double-acting cylinders. All I had to do
was run the unused ports into the return line with low-pressure stiff
plastic tubing. They see some back pressure from the filter so the
connection needed to be solid.

jw

wrote:
I built a bucket loader last fall using porta-power-type cylinders
controlled by a valve made for double-acting cylinders. All I had to do
was run the unused ports into the return line with low-pressure stiff
plastic tubing. They see some back pressure from the filter so the
connection needed to be solid.

Thanks guys. After some more digging, the guys at
Eaton seem to recommend this solution as well, assuming
I'm reading their diagrams right.

--Glenn Lyford

OK, next silly question:

What's the functional difference between a motor
control spool and a cylinder control spool?

Can use one on the other with some reduction in
functionality, or does it make it pretty much a
no-go? (Thinking of using a motor spool on a
cylinder if it's possible).

--Glenn Lyford

On 26 Sep 2005 14:02:07 -0700, wrote:

OK, next silly question:

What's the functional difference between a motor
control spool and a cylinder control spool?

Can use one on the other with some reduction in
functionality, or does it make it pretty much a
no-go? (Thinking of using a motor spool on a
cylinder if it's possible).

I believe the main difference is the absence of load checks on a
motor spool. Thus if you're trying to just move the cylinder up a
smidgen the load may actually drop some before you get all the way to
lift mode.

Wayne Cook
Shamrock, TX
http://members.dslextreme.com/users/waynecook/index.htm

On 26 Sep 2005 14:02:07 -0700, wrote:

OK, next silly question:

What's the functional difference between a motor
control spool and a cylinder control spool?

Can use one on the other with some reduction in
functionality, or does it make it pretty much a
no-go? (Thinking of using a motor spool on a
cylinder if it's possible).

--Glenn Lyford
A motor control spool usually has a "sppol down" feature - kind of
like a reverse pressure relief valve, to allow the motor to slow down
instead of stopping dead, IIRC.

wrote:

OK, next silly question:

What's the functional difference between a motor
control spool and a cylinder control spool?

Can use one on the other with some reduction in
functionality, or does it make it pretty much a
no-go? (Thinking of using a motor spool on a
cylinder if it's possible).

--Glenn Lyford

Open center vs closed center? One stops a piston, the other allows
free wheeling. Gotta think about inertial loads.

Wes S
--
Reply to:
Whiskey Echo Sierra Sierra AT Alpha Charlie Echo Golf Romeo Oscar Paul dot Charlie Charlie
Lycos address is a spam trap.

wrote:

(Thinking of using a motor spool on a
cylinder if it's possible).

Just re-read that. If the cylinder can fall due to load or gravity it
is a bad choice.

Wes
--
Reply to:
Whiskey Echo Sierra Sierra AT Alpha Charlie Echo Golf Romeo Oscar Paul dot Charlie Charlie
Lycos address is a spam trap.

Another issue to think about:

What happens if some large external force is applied to the cylinder
rod while the valve is closed?

If this is a vehicle the hydraulics could absorb the force of a crash,
for instance.

You might need another relief valve between the control valve and the
cylinder.

jw