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dharam_ver9
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Hydraulic Pressure Calculation

05/01/2012 10:47 AM

Dear friends,

I have 125 mm inside diameter hydraulic cylinder for lifting 1000kg weight. what should be the pressure of oil to lift the weight. can any body give me calculation of force which are apply there.
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PWSlack
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#1

Re: hydraulic pressure calculation

05/01/2012 10:49 AM

Is the weight suspended from the piston or pushed up by it? If the former, what is the diameter of the suspending shaft?

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dharam_ver9
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#4
In reply to #1

Re: hydraulic pressure calculation

05/01/2012 11:59 AM

it is piston dia of direct lift.
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PWSlack
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#5
In reply to #4

Re: hydraulic pressure calculation

05/01/2012 12:10 PM

OK. Back to the Physics class: "Show that the minimum pressure needed on the underside of the piston is a little under 8e5N/m2 (10 marks)."

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lyn
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#6
In reply to #4

Re: hydraulic pressure calculation

05/01/2012 12:24 PM

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phoenix911
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#2

Re: Hydraulic Pressure Calculation

05/01/2012 11:23 AM

you'll need need more information than whats currently asked, is it a direct lift, or is the cylinder on a scissors or some type of linkage lift?

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RVZ717
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#3

Re: Hydraulic Pressure Calculation

05/01/2012 11:39 AM

Force = Pressure X Area

Pressure = Force / Area

You need to account for the rod diameter.

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Tornado
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#7

Re: Hydraulic Pressure Calculation

05/01/2012 7:56 PM

Using some consistent units, the area under the piston is ~123cm2; 1000kg/123cm2 ≈ 8.1 kg/cm2 pressure. You may convert to other units if desired.

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jerrys
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#10
In reply to #7

Re: Hydraulic Pressure Calculation

05/01/2012 11:08 PM

123 is the diameter, not the area
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Tornado
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#11
In reply to #10

Re: Hydraulic Pressure Calculation

05/01/2012 11:25 PM

Sorry; you are wrong both times.

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IdeaSmith
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#8

Re: Hydraulic Pressure Calculation

05/01/2012 9:29 PM

While you doing this homework please also think about if it would be different with Water, Butan, Methan and Air.

It is 24 deg C outside and the rest is up to you!

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jerrys
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#9

Re: Hydraulic Pressure Calculation

05/01/2012 10:52 PM

12.5 cm area = pi * r * r say 39 cm-squared. 1000 kg/39 cm-squared. a pressure greater than 25 kg/cm-squared would be required just to "hold it." This is assuming no leverage is involved.
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dhayanandhan
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#12

Re: Hydraulic Pressure Calculation

05/02/2012 12:06 AM

Dear Mr. dharam ver9,

What is the diametre of the Shaft on which the Ram or Piston is mounted.?

The area of the shaft will NOT BE AVAILABLE for providing the lifting Force.

125 MM Dia of Cylinder is equal to 12.5 CM.

Tthe Pressure required will be

P x A = 1000, where P=oil pressure in Kg/CM^2,

A= NETT area or Effective Area calculated from (3.14/4)x (12.5^2 - d^2) and once you substitute d and get the NETT area, you can calculate the oil Pressure required.

DHAYANANDHAN.S
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Mikerho
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#13

Re: Hydraulic Pressure Calculation

05/02/2012 2:01 AM

Well, first off, you need to include the weight of the piston and connecting hardware to the 1000kg weight to determine the actual force you will need:

mT = mW + mP

The force required to lift must be greater than the mass of what you are lifting:

F > mT

The pressure required is the force required divided by the area it is acting on, in this case the face of the piston:

P = F/A

Remember to keep consistent units when doing the final calculation.

Determine the extra weight involved (piston, etc.), do the calculations and come back with an answer. We'll check it for you.

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kevin sharp
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#14

Re: Hydraulic Pressure Calculation

05/02/2012 2:31 AM

force(1000kg) / eff area (3.14159 x 6.25cm(r) x 6.25cm(r) = 1000kg / 122.71835cm2

=8.1487405kg/cm2.

we manufacture pressure gauges and re-range them to suit tons/tonne/kn every day this is the calculation that would be used, tornado is correct.
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edo
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#15

Re: Hydraulic Pressure Calculation

05/02/2012 3:59 AM

Try with 8.2 kg/ cm2 (theoretical value)

Because friction, specially at the start the pressure must be hihger,

10 kg/cm2 should be enough, when there are no special mechanical

systems that request again more force

edo
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capri
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#16

Re: Hydraulic Pressure Calculation

05/02/2012 6:27 AM

Tornado is absolutely right. However, the pressure mentioned by him is just enough to overcome the dead weight of 1000Kgs. Any addition to pressure beyond 8.15Kg/cm2 will start moving it. The speed of lift will depend on how quickly (LPM) you are able to pump.

But My dear, this is all elementary.

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cingold
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#17

Re: Hydraulic Pressure Calculation

05/02/2012 8:56 AM

Isn't using CR4 a way of using the internet?

O well, I gave you a GA anyway because this shouldn't have made it to CR4...and it certainly didn't merit so much argument.
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phoenix911
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#18
In reply to #17

Re: Hydraulic Pressure Calculation

05/02/2012 9:35 AM

GO AWAY, STOP BOTHERING ME.

nice observation!

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Users who posted comments:

capri (1); cingold (1); dharam_ver9 (1); dhayanandhan (1); edo (1); IdeaSmith (1); jerrys (2); kevin sharp (1); lyn (1); Mikerho (1); phoenix911 (2); PWSlack (2); RVZ717 (1); Tornado (2)

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