0:08

So quick review, first of all we've talked about a lot of different components, and

we started off talking about hydraulic cylinders, where we have a cap and

a rod side also called a base.

And we realize that there's a different area on the cap and the rod side.

And we then use that to calculate what the force of the actuator would create for

a given pressure.

We then also talked about hydraulic pumps, such as this gear pump.

And many different architectures of pumps.

And we focused primarily on positive displacement pumps.

Because these are the ones that are used in high pressure hydraulic systems.

0:36

We then moved into talking about a couple of different kinds of valves.

Directional control valves, check valves, needle valves.

And really we just scratched the surface of all the different types of valves

that you will see in fluid power systems, but hopefully gave you enough

tools that you'll be able to decipher how other valves will function as well.

We talked a little bit about fluid power conduits, anything from a T, to a hose,

to a rigid hard line, and then we also talked about the energy storage vice,

device for hydraulic systems, the hydraulic accumulator.

This one right here happens to be a bladder style accumulator, and

recall that these are filled with a compressible gas, typically nitrogen, and

then as we pump oil into this, we use the gas as a spring to store the energy.

Now we talked about all of these components, but

as we were talking about them we introduced a lot of different concepts.

And really the first concept was,

we just need a way to talk about hydraulic systems.

So we introduced the variables and

units that we used, both in the SI and the U.S. customary system.

And then we went into talking about force amplification, and

this was primarily in the area of the cylinder.

Where we're using Pascal's Law to say we've got a,

a uniform pressure everywhere, and from that we can calculate forces.

And then we went into a mass conservation discussion, where we said,

if the hydraulic fluid is relatively incompressible,

then I can take one step further and say that my volume is conserved, and therefore

we can calculate the summation of flows going through some sort of, junction.

1:58

Then we took another step and said,

all right, how about a pressure flow relationship across different components?

Well, we started to treat our valves as orifices, and we started looking at

pressure drop through hydraulic lines, and we also started looking at leakage.

We looked at a piston cylinder example, but it really applies to

any place where we have flow between a parallel plate type of architecture.

2:19

We then talk about fluid properties.

And we said that like other,

other systems we really have resistance, compressibility and inertial effects.

So the resistance is the fluid viscosity, where this creates a,

a drag force in the fluid.

It's also what prevents leakage in the tight clearage that we see in

hydraulic systems.

The fluid is slightly compressible, and

this leads to challenges when we get to very high frequency response.

We can get in to resonance of their systems.

And it also makes it challenging to have very precise control.

But this is one of the strengths of hydraulic systems.

We have very, very, relatively incompressible fluids.

And then also we looked at what happens when we have a reasonable amount of

inertia in our fluid, and the water hammer effects that we see.

And if you recall, that was related to the length divided by

the area of the pipe that we had.

3:25

So then we used, the applications of these components, and

looked at a variety of systems to show you how some of these applications can be,

realized in real life products.

So for example, we took you to Toro company, where we went through one of

their large mowing machines to show you about schematic diagrams, and to show

how these abstract schematic diagrams, in fact are realized in actual systems.

4:47

And we also took you out to the Eaton Corporation, and used that as an example

of a hydraulic hybrid vehicle, hybrid forklift truck that you see here.

Stores energy, releases energy and that one is a great example of

both an cumulator use, but also how you can simulate complex systems.

>> Mm-hm.

>> And then finally to show the power of an cumulator, we took you to an amusement

park where Jim and I took a ride on a pneumatically driven swing,

that largely uses the principals of release of energy from an accumulator to

give you that thrill as you're going up a couple hundred feet in the air.

5:27

Your learning shouldn't stop here in this course, and there are a variety of

resources that you can use to continue your education in fluid power.

And one of the easiest way to do that is through books.

So we've just got a,

a small selection of some of the favorite books that Jim and I use.

But there's a number of others out there.

One that we use in a textbook for the Fluid Power course at the University of

Minnesota, in Minneapolis is the Eden Book on Industrial Hydraulics Manual.

And this is kind of a nice mix between fluid power principles, and

some really hands on types of information, all written on a very practical basis.

So this is a good one, for you to look at.

6:08

The book titled Hydraulic Control Systems by Merritt,

is a classic that is on pretty much every shelf of academic,

professors who are teaching or doing research in fluid power.

It was written in 1967, but has, it's a wonderful background on both how to

model and analyze systems and how to control systems.

And then a few years ago, there's a terrific update, written by Noah Manring,

which has the same title Hydraulic Control Systems and, and kind of takes

the information that was in the Merritt book and, brings it more up to date.

So this is another, really good one for

you to take a look at if you want to get more into hydraulic control systems.

Then the last one we have on the desk is one of a number of specialty books, and

this one is if you really want to get into the details of modeling complex systems.

It takes you kind of down into the, the depths of how you

think about mathematical models, and how you simulate complex fluid power systems.

>> Mm-hm.

So in addition to these texts books, some other resources is simply conferences.

There are a number of fluid power conferences throughout the world.

And I, I have a list of, of some of the, the more popular ones here.

But obviously it's quite, quite challenging when we

have people all over the world saying this is the conference you should go to.

And so with that said, there is a calendar that's quite,

kept quite up to date that is listed right here at this website.

So I'd suggest that if you're interested in attending a Fluid Power conference,

go to this calendar and see what is close to you, and, and, what dates would,

would work with your schedule.

Now, in addition to the conference proceedings that come out of that and,

and some great papers that are presented.

You can also look at, at, some scientific journals.

And there's a number of, of different journals where you see

fluid power articles but the, the primary one that is carrying the majority of the,

the content and is specialized for fluid power is,

The International Journal of Fluid Power, which I have the, the masthead here.

And in addition to this, there are a few, trade publications such as I listed,

Fluid Power Journal and Hydraulics and Pneumatics.

There's a few others as well but these are really the, the most dominant ones.

But just a place where you can go and get more information about fluid power.

8:14

Now, if you want to extend your learning a little bit further,

there are a lot of hands-on applications or, or opportunities for, for fluid power.

One option is to go to a fluid power company and

see if they have in-house classes.

Now here in Minnesota we know that Eaton Corporation,

that we visited during this class, has in house classes that they give, where

they introduce either their customers or interested users, they introduce them to

all the different components that we've seen in the classroom.

But you actually get hands on experience with them.

A lot of college, colleges also offer, fluid power, either through the,

their extensions, or through their, their classes.

And, one of the, the most well known in the,

the neighboring area to where we are is, Milwaukee School of Engineering, and

they have a, a great fluid power program, and do a lot of, hands on training.

Also, community college is a great place to get,

technical information about fluid power and again, close to Minnesota we

have Hennepin Technical College that trains a lot of fluid power technicians.

In addition to that, you really don't have to go too far throughout the world to

find some great research going on in fluid power and so, graduate research is a way

to really do a deep dive into fluid power and get great, practical, experience.

9:31

>> Well we've come to the end of the course and what we need to do is just

thank some people because Jim and I could not have done this course, by ourselves.

>> Mm-hm. >> And so

are out there on the site visit at Eaton Corporation, Rod Erickson Tim Meehan,

Michael Olson.

At MTS Systems, Paul Carroll, Mike Graikowski, Dave Holub, Walter Kan,

Pat Kimball, and Nick Undis.

At the Science Museum of Minnesota, J.

Newlin was a great help.

Toro Company, John Heckel.

At Valleyfair, Mike Frahm, Matt Hehl, Lyle Jaeger, and Robin Stinnett.

And at Ziegler Cat, Corey Kettner and Myron Muehlbauer.

So thank you to all.

Then of course the people of MathWorks,

who made the availability to Sim Hydraulics.

So John Kotwicki, Michael Reardon, Sebastian Castro, and Ken Cleveland.

And thanks to all those for

providing the software, and for hopping on the forums to help out with questions.

And then finally, here at the University of Minnesota,

Annette McNamara, David Lindeman, Kris Gorman, and Everett Wenzel.

So thank you to all of you who really made this course easy for us.

>> Yes, yes.

And, thank you as well.

Thank you very much for attending this class, we hope that you've found it

informative and entertaining to a certain extent, and that you have

a better appreciation for what fluid power can do and the applications of it.

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