Hydraulic Flow Reducer - do they exist?

[turbo36]

I think some people spend more time on this site than they do on their tractors.

That's because we drive computers and not tractors for a living!

 

[turbo36]

Turbo36...hope you know no ill will was intended in my post, just trying to be comical..... I've always gotten a kick from those discover card commercials (and the joke versions I've seen)...

To answer your questions...None of your statements were wrong...

How do I know the one posted "wont work"...well, its only rated to 2k PSI.. Spec sheet from Deere on the 4120 show the hydraulics being rated to 2500 psi...could you use it...yeah, probably...as for the size, well, 1/8" NPT isnt a common hose size. getting a 1/4" NPT hose assembly is cheap & easy.

Speed difference between extend & retract....I HIGHLY doubt even the most trained eye and sophisticated stopwatch could detect the difference. In theory your 100% right....but in reality how you apply the joystick would make more of a difference... I know I've never noticed a difference on the angle cylinder for my power rake...I use a Needle Valve for my Hydraulic motor rotator...so displacement is the same both ways...

As for the vice grips...well, back in the day when the vice grips were made in the USA, that would be a fine suggestion, but now with the Chinese Vice Grips...not so much :laughing:

Being the OCD engineer that I am, I ran calculations assuming 3" bore, 7/8" rod and 8" stroke - a few tenths of a second - you are right not much. I humbling concede on grounds of arguing the irrelevant!


Funny thing on the vice-grips, I was in Menard's maybe 6 months ago and the had both the USA and Chinese vice-grips in the same bin - The Chinese ones had a higher price tag on them

 

[OtterBrookStables]

Talked to my dealer this past weekend. He has never done any such flow reduction. He told me to learn to feather the chute lever! LOL! Not sure how much time and expense this is worth as I can live with it the way it is. I was just looking for a quick and easy fix.....

 

[radman1]

TSC has a 3/8" pipe thread (NPT) fitting with built in restrictor. I use them frequently. They cost around $5. Hydraulic fitting retailers will also have them. I use them frequently on cylinders, hydraulic side links ect. If it is too restrictive, (but I don't think it will be), you can drill out the tiny orifice slightly bigger.

 

[macles]

Both of you guys are sort of correct.
The proper way is to use flow controls on each port of the cylinder and and control the flow out of the cylinder "free flow in - meter out".

If you use a needle valve the cylinder will operate at different speeds when retracting or extending.

This advice seems dangerous. Restricting the output flow from the shaft port on a cylinder can create large hydraulic pressures. ex. 2" Bore with a 1" shaft at a working pressure of 2500psi under no load can produce 3333psi at the shaft port if its flow is restricted. It gets worse if there is a load pulling on the cylinder.

 

[turbo36]

This advice seems dangerous. Restricting the output flow from the shaft port on a cylinder can create large hydraulic pressures. ex. 2" Bore with a 1" shaft at a working pressure of 2500psi under no load can produce 3333psi at the shaft port if its flow is restricted. It gets worse if there is a load pulling on the cylinder.

Restricting the output flow is the normal practice in industrial machinery design, it is commonly referred to as "metering out".

 

[turbo36]

Turbo36...hope you know no ill will was intended in my post, just trying to be comical..... I've always gotten a kick from those discover card commercials (and the joke versions I've seen)...

To answer your questions...None of your statements were wrong...

How do I know the one posted "wont work"...well, its only rated to 2k PSI.. Spec sheet from Deere on the 4120 show the hydraulics being rated to 2500 psi...could you use it...yeah, probably...as for the size, well, 1/8" NPT isnt a common hose size. getting a 1/4" NPT hose assembly is cheap & easy.

Speed difference between extend & retract....I HIGHLY doubt even the most trained eye and sophisticated stopwatch could detect the difference. In theory your 100% right....but in reality how you apply the joystick would make more of a difference... I know I've never noticed a difference on the angle cylinder for my power rake...I use a Needle Valve for my Hydraulic motor rotator...so displacement is the same both ways...

As for the vice grips...well, back in the day when the vice grips were made in the USA, that would be a fine suggestion, but now with the Chinese Vice Grips...not so much :laughing:

Surprisingly the the variation in speed is quite noticeable, I put the snowblower on a few weeks ago and was surprised at the difference in speed from one direction to the other, I shoot a video next time i get up north.

 

[oldnslo]

Surprisingly the the variation in speed is quite noticeable, I put the snowblower on a few weeks ago and was surprised at the difference in speed from one direction to the other, I shoot a video next time i get up north.

Dumb question but... did you by chance get a flow control with the "free Flow reverse" option? This would explain control in one direction and not the other.

Roy