restrictors for hydraulic hoses

[davidseaquist]

I have an attachment with a hydraulic cylander that closes too quickly. If I move the control foreward slowly I can control the flow to the cylander. But if I just push the cylander control forward the cylander slams the attachment shut. I use 1/2" hydraulic hoses and the flow is about 13 gpm I need to reduce the flow so the attachment does not close so fast. I am looking for restrictor washers I can put in the hoses or fittings. I have not been able to locate them. Thanks David.

 

[stevenf]

David, I'm by no means qualified to answer your question but I'll give you my findings that are way simplified the smaller the hose the less volume of hydraulic fluid is allowed to flow use smaller hose for instance I've got a HTL on my 90hp tractor can't remember the gpm of the pump but the hoses to the cylinder are 1/4" id it makes the cylinder very useable when accuracy is critical as it slows my implements movement a lot, but yet just as strong since the pressure is still there just not the volume. Reduce your hose sizes its a quick, cheap fix and what has been reccomended on this site many times for the troubles your describing.
Steve

 

[MadReferee]

You can either go to TSC and buy a restrictor fitting or switch to smaller diameter hoses. I almost always go to 1/4" hoses for working hydraulic cylinders on attachments and HTLs. The flow is restricted enough to allow fine feathering of the cylinder in either direction.

If you don't have anyone nearby who can supply hose then go to http://www.discounthydraulichose.com and order some 2 wire hose with the proper swivel fittings. You may need an adapter fitting to go from the cylinder to the hose but DHH has them too. Plenty of us here have used them and we are very satisfied.

 

[mchasal]

What about a flow restrictor like this: http://surpluscenter.com/item.asp?UID=2006063013055256&item=9-5300-50&catname=hydraulic
Probably more money that what you describe, but it's adjustable and only restricts flow in one direction, which may be beneficial.

They also have some non-adjustable ones that are much cheaper: http://surpluscenter.com/item.asp?UID=2006063013055256&item=9-1208&catname=hydraulic


Mike

 

[norton]

An adjustable flow control like mchasal described is the way to go. However,if you want your cylinders to exdend and retract at the same speed,you will need 2. One for each port on the valve. Because cylinders extend slower than they retract given the same flow rate. This is also why they meter oil only in one direction. Norton

 

[PineRidge]

I added a 4 dollar restrictor from TSC and the grapple is now just right for feathering.

 

[ccsial]

I have bought them at my local New Holland and Kubota dealers. They were in stock and I got them right away.

 

[davidseaquist]

Thanks for all of the replys. I will check with my local Tractor dealers. I will see if the washer style or some inexpensive restrictor is available if not I will buy smaller hoses. I hate to purchace new hoses at 15 to 30 dollars apice when my hoses are new. David

 

[PineRidge]

Dave you don't need to go to the added expense to replace your existing hoses. When my grapple was installed it too was way to fast acting with 3/8" hoses. There was no way to feather the joystick so I went to TSC and purchased one 4 dollar restrictor, you can install it on either hydraulic hose. Once installed the grapple slowed to a point where it could easily be feathered.

The recommendation for smaller hydraulic hoses is valid if you hadn't already made your hose purchase. Since you already have the larger hoses use the cheap fix and get-r-done.

 

[turnkey4099]

Thanks for all of the replys. I will check with my local Tractor dealers. I will see if the washer style or some inexpensive restrictor is available if not I will buy smaller hoses. I hate to purchace new hoses at 15 to 30 dollars apice when my hoses are new. David

In addition to the other things mentioned, you can get restrictor fittings to replace the ones on the cylinder. They come with small holes. If it is too slow, you can just drill them out a size or two.

Harry K

 

[norton]

Heck,I didnt know you wanted to do this as cheap as possible. You could just take a small pair of vise grips( you probably have sone lying around)and clamp them on a hose. At least this way cylinder speed is still adjustable. Norton

 

[jinman]

An adjustable flow control like mchasal described is the way to go. However,if you want your cylinders to exdend and retract at the same speed,you will need 2. One for each port on the valve. Because cylinders extend slower than they retract given the same flow rate. This is also why they meter oil only in one direction. Norton

Norton, I know you mean well, but your advice is "junk science." If you put a restrictor into one line, all the fluid that flows thru it has to flow thru the other line too. It doesn't matter whether you are extending or retracting the cylinder. All flow has to go thru a single restrictor. If you add a second restrictor (one in both lines) then all the fluid ALWAYS flows thru both of them; no difference.

Of course, if you are driving around with a half-dozen "adjustable" vise grip restrictors hanging off all your hydraulic lines, then this won't make any difference to you.

 

[norton]

Gee Jinman,I would think before you post a reply,you would at least look at the adjustable flow control Mchasal described and see how it operates. If you notice it has an internal check valve that allows full flow in one direction, and meters oil in the other. Therefore it only is a "restrictor" in one direction. By using 2 of these you can adjust cylinder speed independly in both directions. Its not junk science,its hydraulics. Norton

 

[john_bud]

norton said "Its not junk science, its hydraulics. Norton"


He he he -- good one!

jb

 

[jinman]

Gee Jinman,I would think before you post a reply,you would at least look at the adjustable flow control Mchasal described and see how it operates. If you notice it has an internal check valve that allows full flow in one direction, and meters oil in the other. Therefore it only is a "restrictor" in one direction. By using 2 of these you can adjust cylinder speed independly in both directions. Its not junk science,its hydraulics. Norton

Norton, your responses are neither good hydraulics nor economics. You are suggesting spending about $75 for two adjustable valves and then with the adapters you have to add to get them into the lines, you're up to at least $100.

Now, where are you going to put them? Are you going to mount them inline on the hoses at the quick connects? Do you have room? Are you going to build a mounting bracket for them in the operator's platform and then have to plumb in the lines? Talk about expensive.... I can easily see your "hydraulics" costing more than the cylinders you are trying to control. Let's say you have both TnT and a grapple like I have. Now you are up to six of these little "jewels" in your system.

But wait.... We could use the non-adjustable type, right? Well, not really. Did YOU read the specs? The minimum flow for the non-adjustable type is 4.5 gpm. Heck, that's half my maximum flow rate. I gain NOTHING by putting one, two, or more inline. They're $8 each plus shipping for no gain whatsoever.

So yes, Norton, you could put these into your system and you'd have one big overbuilt waste of money system with possibly a plumbing spiderweb to boot. These valves were never meant to be used for tractors. They are for critical control of systems far more complex than a grapple or TnT. To use them on a tractor is a kludge.

You suggested I had not read the specs for the valve from Surplus Center. In fact, I've read the specs of these valves many times before and also the valves available from Bailey (www.baileynet.com). I also have many of the $4.95 orifices in my tractor's hydraulics system and they work beautifully. So I'm not just aware of what is available, I'm also a seasoned veteran of many hours of use.

When I used the word "restrictor" in my reply to you, I did not say "adjustable valve" because I was not talking about an adjustable valve. A single $4.95 ristrictor can do exactly what you need and my comments about the flow having to go thru the orifice in both directions is true. There is no checkvalve in a restrictor.

The reason I first responded to you was your flippant statement that you could use a set of vise grip pliers to control flow if you wanted cheap. When was the last time you bought a pair of vise grips? Were they less than $4.95? Please take the "vise grips" off your opinion and listen to the many folks here who have lots of experience. Please don't belittle what is good and well thought-out advice.

 

[ccsial]

You could put a servo valve in there and then program an embedded micro-controller to run it. A digital keypad and display could allow the operator to enter the desired rate in either direction in inchs per minute. It could automatically correct for the difference in cyclinder displacement in both directions too. Heck, add a thermistor and we can correct for the temperature so the motion rate is the same at any temperature. Add a linear transducer and we could position it too.

But, I used the resistrictors on my tractors. Sorry, I couldn't resist, this is too much fun.

 

[norton]

I see,beacause you dont understand it,it must be wrong. Norton

 

[TwinWillows]

My dealer put restrictors in my TNT lines. He used hoses that ended w/a fitting that had a short bent metal tube between the hose & the fitting nut. He said this type of fitting was needed near the restrictor because they concentrated the hydraylic flow into a small streem that'd cut thru a rubber hose. Don't know if this is ssscience or fiction but my hoses don't have any holes!