Piston dimensioning

[ramesse87]

Hello everyone

a double effect piston of the diameter of 399 mm and height 99 mm, does it exist?
if you for which applications is used?

from its function, my goal is
- dimensional the piston (just obtain the values of 399mm and 99 mm)
- by calculations on operating conditions, to establish that the piston must be made of spheroidal cast iron

(in a nutshell I have to go on "back")

who can help me in design?

I don't know where to go since I have a few oleodynamic knowledge

---Images of the piece---

[La prossima volta cerca di NON linkare ad altri siti che rimandano a pubblicità!
Leggiti BENE le regole del forum.
Per ora ho sistemato così.
Grazie.
gerod]

 

[mariom]

a double effect piston?? ? ? ? ?
If you're referring to the photos attached to me, it looks like an actuator's plunger.
If so you have to determine how much force you need, to do this, use the following formula f=p*a where:
f= force
p= pressure applied to the plunger (mpa)
a= plunger area (mm2)
to calculate the area of the plunger you get the formula:
a=f/p

 

[mariom]

I didn't see that the subject had already dealt with it in another discussion.

 

[Er Presidente]

Hello everyone

a double effect piston of the diameter of 399 mm and height 99 mm, does it exist?
if you for which applications is used?

from its function, my goal is
- dimensional the piston (just obtain the values of 399mm and 99 mm)
- by calculations on operating conditions, to establish that the piston must be made of spheroidal cast iron

(in a nutshell I have to go on "back")

who can help me in design?

I don't know where to go since I have a few oleodynamic knowledge

---Images of the piece---

the images attach them to the message with the dedicated command "allegati" (the attache icon).
I think you've already been told.

 

[MBT]

Hello everyone

a double effect piston of the diameter of 399 mm and height 99 mm, does it exist?
if you for which applications is used?

by trade no, definitely not.
but beyond this, even assuming to do it in drawing, if I were your "project" and I see a design of a cylinder alesaggio 399 and run 99 I would place you an obsessive so that you fall from the chair!!!
possible that you can not use one with 400 alesaggio and 100 ?????

That we are doing "philosophy", but to make it out of a calculation as value 399 I know of heresy.. .

 

[cacciatorino]

It can be a cylinder for servovalve in which a thread between d400 and d399 piston is allowed. for the height of the psitone h=99 actually the thing is strange.

the use of cast iron instead of steel could be due to a production to be made in series, then piece obtained by fusion instead of for mechanical processing.

the spheroidal cast iron is more resistant than the normal cast iron as the carbon is placed in small spheres that decrease the carving effect than the traditional cast iron.

 

[gerod]

the images attach them to the message with the dedicated command "allegati" (the attache icon).
I think you've already been told.

Here is the
next time pay more attention to the attachments.
I solved this...
Greetings.

 

[zeigs]

a doubt arises me looking at the section of the caves, considering also the comments to the other discussion: Isn't it a compressor piston? Maybe a first stage
this because on diameters so wide and considering that they are 3 caves, I do not think that rubber seals are mounted that crawl directly on the shirt, rather in teflon, but there is no room for the or that makes the seal
then it would also explain the 399 diameter: for so low pressures (the butt there, 5-6 bar at most, depends what is attached) you can think of keeping a 1 mm piston/camicile game (yes, even in my opinion it is an exaggeration, if it were aluminum to contain the weights I could understand it, when it comes to 100-150° it spreads a bit...) and having a nominal diameter of 400

 

[ramesse87]

thank you guys for the answers, and apologize for the wrong "link"

Okay, now I'd like to ask you two more questions.
- if the piston has to endure a force of 180 or 200 tons, with an area of 0.125 m(quadri), like the piston of my case, then the pressure is about 15 mpa.
what sense does it have, then, to do it in spheroidal cast iron gs700 that has a yielding load of 400mpa (in safety about 133mpa)?

- How does oil temperature vary with pressure? I mean, what do I do?

 

[Fulvio Romano]

thank you guys for the answers, and apologize for the wrong "link"

Okay, now I'd like to ask you two more questions.
- if the piston has to endure a force of 180 or 200 tons, with an area of 0.125 m(quadri), like the piston of my case, then the pressure is about 15 mpa.
what sense does it have, then, to do it in spheroidal cast iron gs700 that has a yielding load of 400mpa (in safety about 133mpa)?

What are you a student of?

Have you ever seen a hydraulic cylinder whose piston yields for crushing?

do not think there are other reasons for collapse like:
- shirt failure?
- but before that, surrender of the estates?
- but before that, point load on the auction?

- How does oil temperature vary with pressure? I mean, what do I do?

For what matters, you can consider it constant.

 

[ramesse87]

thank you guys for the answers, and apologize for the wrong "link"

Okay, now I'd like to ask you two more questions.
- if the piston has to endure a force of 180 or 200 tons, with an area of 0.125 m(quadri), like the piston of my case, then the pressure is about 15 mpa.
what sense does it have, then, to do it in spheroidal cast iron gs700 that has a yielding load of 400mpa (in safety about 133mpa)?

What are you a student of?

Have you ever seen a hydraulic cylinder whose piston yields for crushing?

do not think there are other reasons for collapse like:
- shirt failure?
- but before that, surrender of the estates?
- but before that, point load on the auction?

Can you explain yourself better? I don't know.

 

[Fulvio Romano]

Can you explain yourself better? I don't know.

Yes, I noticed. :wink:

However, to know more precisely what to explain and also how, I would like to understand what studies.
Are you at middle school? A high school? a technical institute? University? a phd?

 

[ramesse87]

I study at university, but I have no notion of oleodynamics and design of hydraulic hammers.

in practice, I have to justify the use of the spheroid cast iron for the realization of a piston of diameter 400mm(approximately) and height 100mm(approximately)
if the spheroidal cast iron gs700-2 has yield of 400mpa, making f=p*a
Do I get the load that this pencil can bear? It seems a little unlikely.

what depends on the choice of this particular type of cast iron? what variables do I have to take into account? and what do I do?

 

[Fulvio Romano]

the use of cast iron instead of steel could be due to a production to be made in series, then piece obtained by fusion instead of for mechanical processing.

This could be a motivation.

I would not raise structural issues, the seals would start drawing well before a plastic piston deformation.

However, in order to assess well you should be told also what this cylinder serves, in what conditions it works, at what temperatures and for what type of service.

Maybe pump acid, and cast iron resists better than steel to corrosion...(it was a joke!)

 

[Fulvio Romano]

I now reread your desire to "procede back".
It's not that simple. .not all choices are made for precise design choices, sometimes they are company standards to optimize production batches, other times we do so "because we always did so". .

They are not questions that should be asked to students. . .

 

[ramesse87]

Okay, I understand. .
but according to you:

if the application for which the piston serves raises a load of 400 t
and I take charge of snervam=4000000/0,125=32mpa

(*0,125 square meters is the piston air of 199,5 mm square radius)

the yielding load is much lower than that of the cast iron which is 400mpa

to this I deduce that: or I have wronged my calculation and it is not at all reasoned.
or there are other motivations, design, etc. etc. according to which the choice can fall on the cast iron for production.

 

[cacciatorino]

Okay, I understand. .
but according to you:

if the application for which the piston serves raises a load of 400 t
and I take charge of snervam=4000000/0,125=32mpa

(*0,125 square meters is the piston air of 199,5 mm square radius)

the yielding load is much lower than that of the cast iron which is 400mpa

to this I deduce that: or I have wronged my calculation and it is not at all reasoned.
or there are other motivations, design, etc. etc. according to which the choice can fall on the cast iron for production.

I'm sorry, you're an engineering student, have you ever heard of evenly paid load and momentum? or, complicating things a little bit, under pressure plates?

is a uniformly distributed load beam subject to a max sigma equal to the pressure generated by the distributed load? Think about this, and then go back to your piston.

 

[Fulvio Romano]

Okay, I understand. .
but according to you:

if the application for which the piston serves raises a load of 400 t
and I take charge of snervam=4000000/0,125=32mpa

(*0,125 square meters is the piston air of 199,5 mm square radius)

the yielding load is much lower than that of the cast iron which is 400mpa

to this I deduce that: or I have wronged my calculation and it is not at all reasoned.
or there are other motivations, design, etc. etc. according to which the choice can fall on the cast iron for production.

the air of a piston... which has radius of 199.5mm paintings.. .
must be a hypercylinder, whose volume is six-dimensional. to solve it you must first anti-transform according to laplace and bring it back in a canonical Euclidean space...or perhaps approach the problem with string theory. . .
vabbé, just taken for the cu@o... :angry:

 

[cacciatorino]

I took advantage of it to pick up salome and aster after a long time. rigorously linear analysis with very big mesh.

 

[stevie]

Are you sure that piston model is serious?
I ask you both because the odds 399 and 99 mm know how to grip me for the bottoms, and because by personal experience I tell you that I have never seen a hydraulic piston so done. . .
what leaves me perplexed are the 3 caves that so to the eye seem identical; Typically in a double effect cylinder piston you have a central guide ring whose quarry has a higher width than the side seals, or you use a central bidirectional seal with 2 side guide rings, but never saw 3 identical cables
then the fact that it uses spheroidal cast iron. . .