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Rotary Hydraulic To Electric Power Generation

03/20/2017 4:38 PM

Let say I have a large and available force that I want to convert to electrical power.

Let's say I can couple two rotary actuators and that most of the time both actuators will be driven slowly back and fourth anywhere from a few degrees to as much as 90.

My experience with hydraulics is limited to gate operators that I have completely completely disassembled and reassembled for service/repair. Most were linear, but a few were in ground rotary units.

I could use linear hydraulics, but rotary seems like a better fit for this application.

In the end, I'm not quite sure what I'd need in terms of accumulator, motor, generator, and bypass valves, etc.. but I'm gathering information.

I'll be heading away from the grid for a few so I'm just putting this out there to simmer.

I've been around the google-sphere a bit on this topic, but I'm looking for some sources of knowledge. If you know any that would help? please provide a source.

In terms of the amount of force available in the rotary action?

anything from 100 to 100K lbs of force should be achievable.

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#1

Re: rotary hydraulic to electric power generation

03/20/2017 5:03 PM

Us knowing the source of the power/forces to run the overall system would be helpful.

I for one can't think of too many sources of mechanical force that would give such ranges of movement other than wave action working on huge pontoon rigs floating in a big body of water.

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#3
In reply to #1

Re: rotary hydraulic to electric power generation

03/20/2017 5:42 PM

Is this power from a tornado watersport based self powering based implosion engine?

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#4
In reply to #1

Re: rotary hydraulic to electric power generation

03/20/2017 5:58 PM

That would be ideal for certain. Disclosure wouldn't be in the spirit of development. For you I'd extend a disclosure, but there's no huge hurry.. as I said, I'll be off line soon enough.

And while it's difficult to fathom such energy. It's here and there.. besides all of that. I'm just picking the brain for the day in the future when the next prototype can come to life. ...100klbs of force would require a very large prototype, but one with a force of several hundred pounds or more should be doable with a relatively small material and time investment.

I'm interested in knowing the smallest and lowest cost configuration for the hydraulic and related components. I've built a version that doesn't convert to power some time ago and have had the urge to move forward sometime.

If I can get the unit opertional it will be able to operate without supervision and for extended periods considering the low maintenance and long life of the components. Scaling up wouldn't be an issue and I would expect the efficiency to go up with size of the components.

The number of partial rotations and the force applied would be variable. Expect several motions per minute.

Is all of this vague enough?

Sorry about that.

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#2

Re: rotary hydraulic to electric power generation

03/20/2017 5:42 PM

The amount of energy available is force x displacement and the amount of power is force x speed. In rotary terms this would be Energy = torque x angle (in radians) and Power would be torque x rotation speed (in radians per second).

I would figure out how much energy and power you can get first to see if its worth the trouble.

1 pound x 1 ft/sec = 1.36 watts. (linear)

1 lb-ft x 1 RPM = 0.142 watts. (rotary)

On top of this, you have to figure that the efficiency won't be 100 percent.

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#6
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Re: rotary hydraulic to electric power generation

03/20/2017 6:06 PM

That looks like rotary is 10x less efficient? Am I missing something? .. if I move a linear piston (or grouping) 1' with 1klbs I would have ~1.3kw at 100% efficiency? I can do that.. minus the 100% efficiency.

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#7
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Re: rotary hydraulic to electric power generation

03/20/2017 6:42 PM

Yes you are missing something. Factor out the radial velocity of the mass at one foot distance to a linear motion equivalent velocity and see what you end up with comparatively.

Personally I like to think of these little variations on how something is factored out to be sort of like easter egg landmines. If and how you deal with one determines the outcome and how those who know what it is will see you afterwards.

Right now I'm thinking you just got your hand blown off by what could have been a Hershey's kiss.

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#8
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Re: rotary hydraulic to electric power generation

03/20/2017 7:04 PM

I'm over thinking this.. there's a single linear piston version I can employ. I'm mobile. Do people diy hydraulics with pvc? It would be a good way to prototype. I could use a garden hose variety hydro generator. I just need to figure out the size of the piston required and go from there.

Nothing ventured.. anyhow.. just another iron in the fire. .. a side idea. Fun type project. And no. This has nothing to do with tornado implosion.

I think I can get a single piston operational / proof of concept for next to nothing.

.. keep things interesting

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#10
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Re: rotary hydraulic to electric power generation

03/20/2017 7:40 PM

Actually yes you can make fairly reliable low pressure water based hydraulic cylinders with common PVC pipe, flat stock, fittings and what not.

You'll need at minimum a basic lathe of sorts to make the more specialty parts like the piston and any O rings or seal related modifications to certain pieces though.

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#11
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Re: rotary hydraulic to electric power generation

03/20/2017 8:24 PM

Nice to know. I can probably co2 laser up some gaskets and even pistons in a laminated fashion.

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#12
In reply to #6

Re: rotary hydraulic to electric power generation

03/20/2017 9:12 PM

1 RPM = 2pi rad/min=2pi/60 rad/sec, about .1 radian/sec or about .1 ft/sec at a radius of 1 foot where the force is 1 pound.

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#5

Re: rotary hydraulic to electric power generation

03/20/2017 6:05 PM

Well if you have a back and forth motion you could go direct drive....

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#9
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Re: rotary hydraulic to electric power generation

03/20/2017 7:05 PM

The length of the stroke will vary.

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#13

Re: Rotary Hydraulic To Electric Power Generation

03/20/2017 11:08 PM

I suspect something similar has been done before a long time ago. Driving your two pistons in apposition was one of the basic mechanisms known as a balanced beam engine. One of its features is that it can convert rotary motion to reciprocating motion, or reciprocating motion to rotary motion, depending upon the timing of the valving.

Your high pressure accumulator/low pressure reservoir are similar to the basic functionality of James Watt's original steam engine. Your system uses compact hydraulics instead of the reciprocating balanced beam, with the check valves essentially ensuring that the fluid flow is unidirectional as it enters the hydraulic motor.

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#14
In reply to #13

Re: Rotary Hydraulic To Electric Power Generation

03/20/2017 11:43 PM

You can turn this in either direction and the drive system engages in only one direction, and you can switch the direction...

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#16
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Re: Rotary Hydraulic To Electric Power Generation

03/21/2017 1:54 AM
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#15

Re: Rotary Hydraulic To Electric Power Generation

03/21/2017 1:24 AM

Hmmm. Could this be an attemp to generate power from the relative motion between dock and ship?

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#17

Re: Rotary Hydraulic To Electric Power Generation

03/21/2017 11:28 AM

Start with the power your new digs will need. A residence will hardly need 100,000 pound actuators.

Let us say you need an average of 2000 watts 24 hours per day with a peak of 5000 watts.

That means your generator needs 2000 watts to start, plus extra to deal with peaks.

You can then build a 2500 watt system and add a Tesla battery to deal with peaks, and have it shut off when zero power is needed.

The conversion factors of watts to hydraulic power are well known and are about 50-60% efficient in small operations.(large ones can be up to 95% efficient)

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#18
In reply to #17

Re: Rotary Hydraulic To Electric Power Generation

03/21/2017 1:50 PM

All things considered, one has to factor in the realistic cost of setup and operation which, for any off grid power systems, I would be weighting that cost against already well established off grid power systems like wind/solar/micro hydro/battery combo systems already in existence.

What's the point of burning up a huge amount of money, time, and effort to end up with a poorly functioning high appertaining cost system that can be bested by any decent existing mid range RE power system?

Contrary to what so many seem to think, if nature has something that can be tapped into for power, someone has already proven whether or not it's practical to work with. Not only that, but more than likely the overall concept of how to tap into that power source as cheaply and efficiently as can be with present technology has already also been largely refined as well.

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#19
In reply to #18

Re: Rotary Hydraulic To Electric Power Generation

03/21/2017 2:04 PM

Yes, many people have unwise expectations about energy. A friend of mine buys into free energy from 3 phase motors with some funny scheme or other, like this crap.

https://www.youtube.com/watch?v=OtH2BbrD9FY&index=9&list=PL7ND5F3QU-MU8qCznX0-o8VSYmYwny-Xp

https://www.youtube.com/watch?v=fIrBYMHtq3M

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#21
In reply to #18

Re: Rotary Hydraulic To Electric Power Generation

03/26/2017 1:12 PM

Can't argue with that. In fact this source is tapped. All around the world. Just another way to skin the cat. There is no such thing as wasted time and money in a pursuit of enjoyment. You could say I waste away the summer gardening, but I really like getting up before the sun and heading out with a cup of coffee to check the harvest and pull weeds. For breakfast I like to chop steel and fabricate. For lunch I enjoy a little drafting followed by a light dinner of woodwork and projects.

When I was a young man I thought it had all been done and discovered too.. what a setback.

This odd idea is what led me to CR4 years ago. It was the subject of my second post here and I've not wasted a nickel or a minute on it. It's been pure enjoyment.

And no.. I'm not harnessing a ship at dock.

In terms of expenses of the system? It's mostly mass needed to operate and keep the system from tearing itself to bits.

Yes there are new ideas under the sun.

There are times this system would be idle. It's not magic.

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#20

Re: Rotary Hydraulic To Electric Power Generation

03/21/2017 3:51 PM

The hydraulic circuit shown in your post does not work!!! Without non return valves the oil will just flow in and out of the reservoir as that is the easiest path. Add non return valves that allows oil to flow into the cylinders from the reservoir as they extend and non return valves to allow oil to flow out of the cylinders to to the accumulator replacing valves 1 & 2 as they retract. If you are reusing rotary actuators, these are normally double acting cylinders so the same arrangement of non return valves on the annular end of the cylinders allows you to extract power from the return stroke. So for every cycle you get the area of the full bore end times the stroke plus the area of the annular end times the stroke. For rack and pinion type actuators this doubles you flow rate.

If the total power output is going to be above a few kilowatts you will need a cooling circuit in the oil reservoir. Assuming that your efficiency is 50% (you should be so lucky) then the other 50% ends up as heat in your oil unless you build in a way of dissipating it.

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