Hydraulic Flow Reducer - do they exist?

[turbo36]

Why do you think that?:confused2:

Look at how a cylinder is built; the displacement is different on each side of the piston due to the cylinder rod , the same amount of oil into a different amount of space will result in a change in speed ( and force as well) If you just use one needle valve the flow is equal to each side of the piston, it will retract faster then extend.

 

[kennyd]

Look at how a cylinder is built; the displacement is different on each side of the piston due to the cylinder rod , the same amount of oil into a different amount of space will result in a change in speed ( and force as well) If you just use one needle valve the flow is equal to each side of the piston, it will retract faster then extend.

Your reasoning is good, but does not apply to this application. It is true that the different displacement affects force, but not speed. The fluid will only move so fast through the restrictor, no matter which way it is moving-or how much of it there is.

 

[JD755]

Just FYI if interested. JD has used restrictors and they show as still available. No idea what size would be required, and those adjustable ones may be what you want instead but these would be a quick install.

 

[turbo36]

Your reasoning is good, but does not apply to this application. It is true that the different displacement affects force, but not speed. The fluid will only move so fast through the restrictor, no matter which way it is moving-or how much of it there is.

Kenny, this isn't a "Global Warming debate" actual science is at work here.
Flow in hydraulics is measured by displacement, usually Gallons per minute or Meters cubed per minute etc. the flow into each end of the cylinder is the same yet the displacement per inch of travel is different therefore the speed must be different. The larger the cylinder rod the greater the difference.


The reason for metering "out" of the cylinder is that by restricting the flow out of the cylinder you get smoother motion because the cylinder can not "free fall". Air or vacuum is compressible but oil is not.


HowStuffWorks "Log Splitters"

http://www.womack-machine.com/pdf/rb365/10p355.pdf

 

[kennyd]

Kenny, this isn't a "Global Warming debate" actual science is at work here.
Flow in hydraulics is measured by displacement, usually Gallons per minute or Meters cubed per minute etc. the flow into each end of the cylinder is the same yet the displacement per inch of travel is different therefore the speed must be different. The larger the cylinder rod the greater the difference.


The reason for metering "out" of the cylinder is that by restricting the flow out of the cylinder you get smoother motion because the cylinder can not "free fall". Air or vacuum is compressible but oil is not.


HowStuffWorks "Log Splitters"

http://www.womack-machine.com/pdf/rb365/10p355.pdf

OK, while I will concede that you are 100% technically correct-we are talking about a small cylinder on a snowblower chute. Real-life fact is the speed difference is VERY small, and in this non-precision application using just one adjustable restrictor is sufficient to do what the OP requested. Buying 2 of them would be a waste of money.My :2cents:

 

[turbo36]

OK, while I will concede that you are 100% technically correct-we are talking about a small cylinder on a snowblower chute. Real-life fact is the speed difference is VERY small, and in this non-precision application using just one adjustable restrictor is sufficient to do what the OP requested. Buying 2 of them would be a waste of money.My :2cents:

2 flow controls: $10.95 x 2 = $21.90

1 needle valve: $25.95

What is the waste?

 

[Spudland_Dave]

2 flow controls: $10.95 x 2 = $21.90

1 needle valve: $25.95

What is the waste?

Actually....

1 Needle Valve: $25.95
2 Flow Control Valves 24.95 ea = $49.90
Looking at the specs of posted valves before posting...Priceless


All kidding aside, the flow control valve posted was a 1/8" NPT 2000 psi unit, a "like for like" comparison would be this parker 1/4" NPT unit:
https://www.surpluscenter.com/item.asp?UID=2156122521021911&item=9-5300-25&catname=hydraulic

 

[turbo36]

Actually....

Looking at the specs of posted valves before posting...Priceless


All kidding aside, the flow control valve posted was a 1/8" NPT 2000 psi unit, a "like for like" comparison would be this parker 1/4" NPT unit:
https://www.surpluscenter.com/item.asp?UID=2156122521021911&item=9-5300-25&catname=hydraulic

How do you know the 1/8" won't work, no where did anyone list the port size needed whose not reading the specs correct?


Will a needle valve work? sure it will, but then the OP will come back and say "jeez it goes faster in one direction then the other, why is that?". I was just trying to be proactive.

Show me where any of my statements were wrong? The proper way to control motion in two directions is what I stated, if you want to cobble it go right ahead, but why even waste your time putting in a valve when a pair of vice grips will work just as well.:laughing:

 

[Spudland_Dave]

How do you know the 1/8" won't work, no where did anyone list the port size needed whose not reading the specs correct?


Will a needle valve work? sure it will, but then the OP will come back and say "jeez it goes faster in one direction then the other, why is that?". I was just trying to be proactive.

Show me where any of my statements were wrong? The proper way to control motion in two directions is what I stated, if you want to cobble it go right ahead, but why even waste your time putting in a valve when a pair of vice grips will work just as well.:laughing:

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:

 

[lwalsh]

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