Ways to limit flow for small cylinders?

   / Ways to limit flow for small cylinders? #1  

joea99

Platinum Member
Joined
Sep 8, 2014
Messages
670
Location
Marbletown NY
Tractor
Kubota B21, JD 240GT
Probably lots of threads on this but did not find any. I'm collecting parts to hook up a top and tilt kit. Got an 11gpm joystick valve coming which appears correct, from what I've read, as the tractor has an 8.5gpm pump and "they say" valves should be 25% greater capacity. So about right.

But, the cylinders are quite small, the tilt being not much larger than a soda can or one of those "monster" energy drink cans. So, I worry about the control being "twitchy" and/or "slamming" due to high flow rate.

I know there are needle valves for this which allow me to "fine tune", but wondering if there are cheaper alternatives, such as flow limiter, orifice fittings or like that. Besides being expensive(ish) it is not clear the needle valves will hold setting under use, vibration, etc.
 
   / Ways to limit flow for small cylinders? #2  
....Besides being expensive(ish) it is not clear the needle valves will hold setting under use, vibration, etc.
You'll need a "Check Valve" to hold a setting. I have a needle valve it work great on slowing things down to get the top and side link exactly where you want it.
 
   / Ways to limit flow for small cylinders? #3  
Yes, there are orifice fittings or also called restrictor fittings available that will do exactly what you want and it's most likely the cheapest solution.

However, I would try it out first to see how it will behave and then add the fittings since can be easily done after the fact.

Also, is this for the Kubota B21? They do list a total flow of 8.5 GPM, however this is the combination of the steering flow (1.3 GPM) and the rest of the flow actually works the loader, 3 pt and etc. In reality, you'll have 7.1 GPM at the joystick valve. Won't make much difference anyway.

Something like this:

 
   / Ways to limit flow for small cylinders? #4  
I'm running a restrictor fitting like ptsg ^ shows on my grapple cylinder.
 
   / Ways to limit flow for small cylinders?
  • Thread Starter
#5  
Thanks for the replies. Yes, it is for the B21 and happens to be the Kubota cylinders, glad it was still available.

Good idea to try it out first of course and be very careful first try. May not be till spring the way things are going.
 
   / Ways to limit flow for small cylinders? #6  
Probably lots of threads on this but did not find any. I'm collecting parts to hook up a top and tilt kit. Got an 11gpm joystick valve coming which appears correct, from what I've read, as the tractor has an 8.5gpm pump and "they say" valves should be 25% greater capacity. So about right.

But, the cylinders are quite small, the tilt being not much larger than a soda can or one of those "monster" energy drink cans. So, I worry about the control being "twitchy" and/or "slamming" due to high flow rate.

I know there are needle valves for this which allow me to "fine tune", but wondering if there are cheaper alternatives, such as flow limiter, orifice fittings or like that. Besides being expensive(ish) it is not clear the needle valves will hold setting under use, vibration, etc.
If you decide on the orifice route then you could buy small and then open up the orifice with a drill bit. But you must take into consideration that the area of a round orifice will increase with the square of the diameter. So double the diameter will result in 4 times the area. I don't know what the orifices look like but recently i was presented with a bucket loader problem on one of my sons friend's small dozers. The blade would move fine in one direction but would move erratically in the other. One side was obviously suffering from some sort of restriction. After pulling hoses I determined that there was rubber in the crimp restricting fluid flow. I ran a drill bit by hand to cut out the bulging rubber and the blade now works perfectly. The restriction looked small but made a big difference. That area thing. In any case, if you can drill out the orifice, and have the drills, the math is easy to use to figure out how much more fluid will go through the orifice when enlarged. But really, if you have a good selection of number, letter, and fractional drill bits you can do this empirically. Try one orifice diameter. If good then leave it alone. If not then try the next size larger drill bit. And so on. Remembering that every increase in size will be magnified by the square of the difference.
 
   / Ways to limit flow for small cylinders? #7  
Thanks for the replies. Yes, it is for the B21 and happens to be the Kubota cylinders, glad it was still available.

Good idea to try it out first of course and be very careful first try. May not be till spring the way things are going.
Here is what I supply for the T&T sets that I sell.
2" dia cylinders get .030 orifice.
2 1/2" dia cylinders get .045 orifice.
3" dia cylinders get .060 orifice.

In theory you should only need one on the rod end port, but for whatever reason I have found the one at each port has eliminated any issues.

This seems to work well for 99.9% of my customers.

You should have 2" cylinders, so .030 orifice should work well for you. (y)
 
   / Ways to limit flow for small cylinders? #8  
Probably lots of threads on this but did not find any. I'm collecting parts to hook up a top and tilt kit. Got an 11gpm joystick valve coming which appears correct, from what I've read, as the tractor has an 8.5gpm pump and "they say" valves should be 25% greater capacity. So about right.

But, the cylinders are quite small, the tilt being not much larger than a soda can or one of those "monster" energy drink cans. So, I worry about the control being "twitchy" and/or "slamming" due to high flow rate.

I know there are needle valves for this which allow me to "fine tune", but wondering if there are cheaper alternatives, such as flow limiter, orifice fittings or like that. Besides being expensive(ish) it is not clear the needle valves will hold setting under use, vibration, etc.
Needle valve been holding 30 years here but I don't know how long the duration of your intentions are.
 
   / Ways to limit flow for small cylinders?
  • Thread Starter
#9  
You'll need a "Check Valve" to hold a setting. I have a needle valve it work great on slowing things down to get the top and side link exactly where you want it.
The valve is said to have "internal checks" on each spool. Summit Hydraulics. Similar valves much cheaper from the universal Asian valve company, but with a hodgepodge of port types. And generally no PB adapter to be found.
 
   / Ways to limit flow for small cylinders?
  • Thread Starter
#10  
Here is what I supply for the T&T sets that I sell.
2" dia cylinders get .030 orifice.
2 1/2" dia cylinders get .045 orifice.
3" dia cylinders get .060 orifice.

In theory you should only need one on the rod end port, but for whatever reason I have found the one at each port has eliminated any issues.

This seems to work well for 99.9% of my customers.

You should have 2" cylinders, so .030 orifice should work well for you. (y)

Thanks, good starting points. Where do you get, or sell the adapters? Various fitting connection types?

For TnT I'd rather have "too slow" than "too fast". Speaking as Capt. Obvious.
 

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