[AT] Hydraulic flow question?

[Carl Gogol]

James,
The circuit is simple.  It is a three spool mono block open center valve.
It is good for about 20 GPM and the tractor's pump is about 12 GPM>
High pressure oil from pump is first going through the valve's pressure
relief valve; 
1-  next in line is the motor control spool, a 4-way with detents with oil
returning to its companion port.  
2- Oil then flows to a 4-way port to ram #1. power extend, gravity return
both on one of the spool's ports.  I'm not sure it is needed but this
spool's companion port is never-the less connected to the return flow line.
I used it on a similar mower and don't remember if this connection was
required.  Don't see how it hurts even if it is unnecessary.
3- second ram is identical to #2 above but downstream from #2.
4- Finally oil is returned to the reservoir
Carl
Manlius, NY

-----Original Message-----
From: AT <at-bounces at lists.antique-tractor.com> On Behalf Of James Peck
Sent: Thursday, October 10, 2019 11:18 AM
To: Antique Tractor Email Discussion Group <at at lists.antique-tractor.com>
Subject: Re: [AT] Hydraulic flow question?

I believe some hydraulic valves use orifices to limit spool speed. Can you
sketch the circuit for us?

[Carl Gogol] I just finished replacing a triple valve on my International
140 that controls a side mount Alamo (triumph) sickle bar mower.  I did it
because I had the valve and the motor control on the "new" valve would
reverse the
motor where the original would not.  This is handy when the mower jams.   
The problem I created is the two controls for the hydraulic rams for
positioning the cutter bar are connected with ¼" hoses but the valve's ports
are all ½', -- but so were the original valve's.  
Problem - just moving one of the control's levers for a ram will stall the
tractor if opened all or most of the way.  
One solution - Limit the movement of the ram spools in some manner like
using a spacer to limit spool travel.
Question - Is there a more hydraulicy correct way -  the original valve did
not suffer this issue.  BTW- system is open center.
Carl
Manlius, NY

Humm- I wonder if the valve's high pressure bypass is not working or set too
high?

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