Hello,

I have seen many design criteria in design of hydraulic reservoir for industrial hydraulic systems. I am curious to know, in the case of mobile hydraulic systems, which design criteria we should consider. Is there any good reference to help us in designing of hydraulic reservoir for mobile systems?
Thanks for your help

Try to locatea Eaton/Vickers "Mobile Hydraulics Manual" to see a good writeup on Mobile equipment Reservoire (Tanks.) The First Edition has a date of 1998.

It covers the subjest vey well and should answer all your questions and concerns.

thank you very much for your reply.

I have no access to this book and would appreciate if you let me know about other
materials,especially those that can be reached via internet.

I'm not aware of any Mobile Training book except the Vickers offering. You could do a Google serch for Mobile+Hydraulics+Training to see if there is anything on the web.

Here are some things to consider:

-size: Ideally, you want a reservoir sized 2 to 3 times the pump flow(i.e., if your pump flows 10 gpm, you should have a 20-30 gallon reservoir) for ideal cooling effect. This isn't always practical with mobile hydraulics, so basically make it as big as possible within your limitations. If you have an extremely low duty cycle (like on a tow truck), you just need a reservoir sized large enough to fill all the cylinders without pump starvation.

-filtration: Because mobile systems are in inherently dirty environments, proper filtration is very important. A high quality filter/breather cap with a fill strainer, a large, fine-mesh suction strainer, and a high quality return-line filter.

-a clean out panel would also be ideal. As hard as you try, you're going to get plenty of contamination in your mobile system, so being able to access the inside of the reservoir for a good cleaning every once in a while would help.

-a baffle plate to prevent "rivering" of hydraulic fluid from the return line back into the suction line.

-a level/temp guage to keep an eye on fluid condition, especially if your reservoir is undersized.

In calculation of Tank volume ( as we interest to be as minimum as possible) should we consider differential volume of hydraulic cylinders or total volume of cylinders when all of them extended.
thanks.

Just the differential volume, as the rest of the fluid volume will be contained in the conduits, valve and the rod end of the cylinder. If your duty cycle is low, then reservoir volume can be also...

Could you please give me the definition for duty cycle ( better to say low duty cycle)? is there any specific definition?
thanks

Duty cycle is the amount of time the machine is on as a percentage of the amount of time the machine is off. If a machine is on for 10 seconds and off for 90 seconds, that's a 10% duty cycle.

a Google search came up with this .pdf file:
http://www.idcmotion.com/pdf/9007.pdf

Many machines I have worked on had reservoirs that were only about 1/3 of the pump flow. The big thing is keeping the air out.

Another issue that seems to crop up every so often is oil coming out of the breather. This is due to a combination of 1) air being displaced due to a cylinder collapsing and 2)vehicle dynamics causing the oil to slosh in the tank. For a start try to keep the breather outlet in the middle of the reservoir. A larger diameter line will also keep the air velocity down, reducing the tendency of the escaping air to carry oil. As a last resort an expansion chamber in the breather line may help.

ISZ

Another item often applied to Tanks that are undersized is some type of Diffuser to reduce fluid velocity into an undersized.

There is a Demo of this feature with a plastic window tank a couple of years back on Jack Johnsons web site, http://www.idaseng.com/Videos.htm You can get a copy here.

What a coincidence that you would bring that video up Bud, I was telling my hydraulic design engineer about it last week!

ISZ

ISZ;
If you don't mind, would you please explain (currently) behind your Location?

Born and schooled in Wisconsin.
5yrs in Chicago
4yrs in Twin Cities
4yrs in Portland, Or
2+yrs in Milwaukee
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