Feathering?

[NCMau]

I hear the word "Feathering" when applied to FEL. Are there types of valves that allow to do that or they all have the same built-in mechanism?
The reason I am asking this is because when I had a loader on my 8N few years ago, I was able to apply little pressure to one side of the valve handle and be able to get smooth slow FEL movements. At least that 's what it seemed like.
Right now, after installing a PTO pump on my 35hp old iron, I don't get smooth slow movements, especially arms down (bucket empty).
As it was pointed out by members in a previous post, the likely culprit is my 40 years+ valve. I guess eventually I have to bite the bullet and buy one. (BTW there are no suction leaks)

 

[oldnslo]

Feathering to me is just as you describe it. Moving the lever on your directional valve slowly to allow for slow smooth motion/operation of the function.

Feathering is affected by:
How how valve is built, some have more or better metering than others.
Flow rate through the valve Vs the valves flow rating.
Pressure required to move the load.

Roy

 

[J_J]

You can change the feather operation by the amount of fluid going to the valve.

How many GPM does the PTO pump provide?

If you had maybe 8 GPM [ estimate ] to the 8N valve before, and now you are providing around 15 GPM with the PTO pump, by the time you are half way with the lever, you are providing about half of the PTO pump flow, which is half of the 8N pump volume.

You can feather with lever type valves. Solenoid valves are either full on or off.

 

[dstig1]

This is a point has bothered me about any hydraulic equipment I have every used. Why are the valves so touchy? Even my tractor loader is that way. With a couple hundred hours of experience, I have gotten better at it, but the design of these valves seems to follow the "bang-bang" school of thought that the designers think people only really want them fully opened or closed and feathering is very touchy to do. I know if I am moving my tractor when trying to lower the bucket I am almost guaranteed that any slight bump in the ground will cause my hand to move the lever a slight bit and WHAM the bucket comes slamming down. On things like a loader I doubt they are fully opened more than 10% of the time, so why not design a valve that works better with the common use pattern? If it worked as smoothly as the HST pedal, I would be a very happy guy. And yes I know those are 2 very different types of hydraulic systems.

Just a pet peeve of mine...

 

[NCMau]

This is a point has bothered me about any hydraulic equipment I have every used. Why are the valves so touchy? Even my tractor loader is that way. With a couple hundred hours of experience, I have gotten better at it, but the design of these valves seems to follow the "bang-bang" school of thought that the designers think people only really want them fully opened or closed and feathering is very touchy to do. I know if I am moving my tractor when trying to lower the bucket I am almost guaranteed that any slight bump in the ground will cause my hand to move the lever a slight bit and WHAM the bucket comes slamming down. On things like a loader I doubt they are fully opened more than 10% of the time, so why not design a valve that works better with the common use pattern? If it worked as smoothly as the HST pedal, I would be a very happy guy. And yes I know those are 2 very different types of hydraulic systems.

Just a pet peeve of mine...

Yea, I hear you Dave! Well at least I'm finding out that I'm not alone in this world. Just debating if I really should have a new valve. As I stated previously, pushing the arms up is not as bad as going down. I'm planning to put a side 30" deck on the loader for trimming trail hedges, but I need a little smoother control.

 

[NCMau]

You can change the feather operation by the amount of fluid going to the valve.

How many GPM does the PTO pump provide?

If you had maybe 8 GPM [ estimate ] to the 8N valve before, and now you are providing around 15 GPM with the PTO pump, by the time you are half way with the lever, you are providing about half of the PTO pump flow, which is half of the 8N pump volume.

You can feather with lever type valves. Solenoid valves are either full on or off.

My old 8N I had a puny 4 gpm pump to operate the ram, no bucket cylinder. My 35 now has 7 gpm to work the ram and bucket cylinders. I don't think is too much flow is it?

 

[J_J]

Short levers are more sensitive to maovment. The longer the lever, the more finesse you have.

The valve should be matched to the volume of fluid the pump is putting out.

If you double the flow, you will have less of a feather mode, because the feather is in about the first 1/4 or 1/3 of valve movement.

If you want slow, just add a flow control valve in the cyl circuit. Reach up and adjust the flow to your satisfaction.

Some of the flow controls will restrict in one direction and full flow in the other. So you can restrict going down and full flow raising the arms.

Here is that valve.

Surplus Center - 3/8 NPT 8 GPM PRINCE WFC-600 IN-LINE FLOW CONTROL

 

[oldnslo]

You can change the feather operation by the amount of fluid going to the valve.

What I was trying to say is that if the valve is rated for 10 GPM and you putting 20 GPM through it you now have greater pressure drop across the valve which creates a higher inlet pressure. Since feathering is a function of pressure drop across the metering lands this increased pressure drop makes feathering much more difficult.

Example: In the above scenario at 10 GPM you have 100 PSI at the valve inlet from pressure drop through the system. To lower an FEL requires 0 PSI so my pressure drop is 100 PSI from inlet to work port.

Same system at 20 GPM creates 1000 PSI drop in the system so you have 1000 PSI pressure drop from inlet to work port to lower the FEL.

Above Numbers are just for examples...

If feathering or metering a load is critical and you have to do it frequently invest in valve that is designed to provide metering. Valve companies like Husco, Sauer Danfoss, Eaton, Rexroth ,etc. all make valves that have metering notches and pressure compensation modules designed for this purpose. They are not your inexpensive $180 valves but they will give you feathering control.

Prince , brand, etc. may but I am not familiar with there product line.

Roy

 

[NCMau]

Interesting. Tank you.

 

[CJONE]

Also alot of the cheap monoblock valves do not have reliefs cut into the spool so they are harder to "feather" than a premium valve with the flow cuts in the spool. CJ