Subject:
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Re: pneumatic cylinder: why not hydraulic ??
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Newsgroups:
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lugnet.technic
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Date:
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Thu, 8 Apr 2004 08:44:57 GMT
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Viewed:
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2293 times
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Not alone thinked about it a while back,currently studing fliud power and in
the fluid power industry
> I' ve read a long time ago something like this: LEGO pneumatic cylinder cannot
> be use as hydraulic cylinder.
Lego pneumatic cannot be used for hydraulic's period!
Nor will there be such a thing put out by lego there in the toy industry not
heavy machinary industry!
1.Pneumatic & hydraulic systems use fluid power, this is the transmission of
power using flowing fluids under pressure e.g fram equip, continuous miner
longwall roof supports, aircraft.
2. hydraulics medium (normal minerial oil) is liquid and is used as the flowing
medium
3. pneumatics medium (air or "some type of gas eg dry nitrogen since it is an
unreative gas"meaning it reduces the risk of fire or explosion good for
undergound mining) gas is the flowing medium
So knowing this one can find the advantages and disadvantages of each
hydraulics
-infinite control of speed. lego, it's a childs plaything not a motor
car
-infinite control of pressure. read it here childs fngner cutoff with new
powerful lego system, not a good read
Above Transmits large forces.
-instant change of direction. child will slow reaction time gets hit in
head
-components are big and heavy Tank, filters, motor, pump,
-leaks are easy to detect Systems leak
-Systems run at higher running temperatures not only the system but this
heat can move to where you don't want it to e.g. the lego frame holding the oil
tank starts to melt or a plastic ram doing the same, they would all have to be
metal I'm sorry
-Thicker hoses are needed and how big are you going to going 1/8in 1/4in 3/8in 1in 2in and not as easy to bend
-What type of Threads are you going to use JIC,UNO,BSPT,BSPF,NPT or Quick
release??
-how are the fittings going to fit on the hose? Are they crimped like in
industry,are the hoses made to lenght by lego or do you buy the crimper to
or do you use screw on fitting?
-The cost can hit hundred of dollars easy
and I can good on and on
So to sum up The reason there is no lego hydro system is,
1. Problems over coming heat,yes a cooler or heat exchange could be used but
thats just more crap to buy installand and so on.
2. The power hydro systems have is alot more then pneumatics.
3. A degree of knowledge and understanding is needed to understand what is
happening in a system and how a hydro circuit works then compaired to
pneumatics.
3. cost to you , you think lego costs lots!!
4. Cost to make these small components and make all your lego in to say
anodized metal pieces, not to day.
Pneumatics
- the equipment is light by it's nature. great don't need a crane to help me
-Does not need any return to tank lines as it can just vent to atomsphere
also not storage facilities therefore needed. Thank you cause I have a problem
cleaning up after myself
-Fluid medium Doesn't make a mess and as a result no mess to the environment
asa a result of no heavy fluid in system. Great because I'm a Greeny
-High speeds can be achieved without the high pressures needed for hydro
systems. Lovely it's not going to crush me.
-Components are cheap to mass produce good for lego good for me.
-low working temps in fact systems can have the opposite problem to hydro
systems and can actually freeze up eg pneumatic drill or grinder.
So really it's a win win situation you get a model that moves or does
something wacky and lego give you the system to do it.
But on that note I do have to say that they do lack in the types of component
available currently (like everything else in there range at the monent)
> Is anybody can explain me why ?? May be we can' t use water with cylinder (may
> be cause of corrosion) but what about silicone oil ?? or something like that..
..Say you got a cube that has a volume of 10cc and you put air into that 10cc
cube,then you put a lid on it and squashed it down to say 1cc what you have done
is made 10cc fit into 1cc and therefore compressed it or given it pressure, you
know this Because when you take your hand s away the lid pops off
Now try it with water, no doesn't work, well that because water cannot be
compressed like oil or air so you can't make 10cc of water fit down to 1cc. That
is why you Will not come across it to ofton as a flowing medium.
cc being cubiecentmetre
This therefore rules out water unless you some how live in the reaissance and
the industial era is still 300-40yrs away then by all means try it for yourself.
Also l think water and electric don't mix esp with kids.
If you are very interested in fluid power one can talk to there local tech
college about enrolling in a class or point you in the right direction with
technical book on the subject as they are not the type of book you can get from
just any bookshop
Regards Eli
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Message is in Reply To:
 | | pneumatic cylinder: why not hydraulic ??
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| Hi everybody, I' ve read a long time ago something like this: LEGO pneumatic cylinder cannot be use as hydraulic cylinder. Is anybody can explain me why ?? May be we can' t use water with cylinder (may be cause of corrosion) but what about silicone (...) (20 years ago, 6-Apr-04, to lugnet.technic)
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