Hydraulic lines (3/8 vs 1/2) when to choose one over the other??

[pharmvet]

I am at the end of a disk restoration (JD 225 8' offset) The old hydraulic lines were 3/8. The swivel type of connection I wanted to use to connect to the cylinder was only available at my tractor dealor in 1/2" line size so I had them make me 1/2 inch lines to replace the 3/8" lines that were origionally on the disk. Then I started thinking about the differences and wondered if there is any reason I shouls not do this. The lines are definately more "bulky" and upon examination of my tractor, I noteded all the lines to my FEL are 3/8". What is your opinion? When would you want to use a 1/2 rather than a 3/8 and vice versa??? thanks

 

[J_J]

It has been recommended to increase the size of QD's one level up, so as not to restrict any flow. The reason that most people don't do it is cost. If the cost difference is minimal, then do it.

 

[pharmvet]

Sounds good. What is QD ? sorry for my ignorance

 

[Heavy Metal Doctor]

Quick Disconnect

 

[cowski]

production ,bigger lines faster pick up at the ends turning around.

 

[pharmvet]

So it looks like my switch is mostly a good thing? Regarding pressure, someone mentioned the smaller line was rated for more pressure. I dont suppose the weight of my 8 ft. disk could induce more pressure than 1/2" line will handle????

 

[2458n]

I do not belive this to be true. I mean the part about smaller lines being capable of greater pressure.

 

[J_J]

The pressure has to do with surface area. A smaller hose will handle larger pressures. A lot of the rams use 10,000 psi hoses. I don't think you will see that in a 1 in hose.

If you look through the hyd hose catalog, you will see the difference, providing everything is the same type hose.

http://www.gates.com/brochure.cfm?brochure=916&location_id=535

 

[cowski]

my tractors operate with less than 3000 psi at the coupler . some of my hoses are bigger than a inch .the hoses i buy are rated for the same pressure whether it is 3/8 0r 1 in.it is stamped on the hose. bigger hoses = faster pick up.

 

[boggen]

it deals with fluid dynamics. larger size inside diameter hose = less friction loss, along with capacity.

a larger size hose that is rated at same max psi pressure, will be more expensive, but can provide better performance for say using hyd motors. were fluid is constantly being pumped through the lines.

when it comes to hyd cylinders, larger size hose rated at same max psi. = quicker fully extending / contracting. will you notice the difference, to many variables. perhaps when the tractor is barely able to lift a 3pt hitch. and that tractor is struggling, you might notice a difference

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note i mentioned inside diameter. outside diameter, does not matter.

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just remember though larger size rubber hoses. as they age. could collapse and have more fluxtations. for example going down a bumpy road. with a heavy 3pt implement. may cause larger diameter hose to collaspe before a smaller diameter hose. when you go over a bump and all the weight of imlement plus the moment plunges downwards. and if not collaspe may allow the 3pt implement to bounce more. causing a rougher ride or perhaps slower driving to keep things safe. reason being is rubber hoses are just that rubber and they can expand / contract some. a solid rigid metal pipe will not flex. (well they can, but when they do, you normally have to replace them *doh*)