Piston Velocity for Hydraulic Cylinder

It can be 0 or which ever value imposed by the pump flow. Pressure has no meaning for speed. The limit depends on the seals as type and compound. You can even have sealless cylinders for very high speeds.

So that in fact your question shows that you better try to get an even short tuition in hydraulics.

The speed of the Cylinder will depend on along with few other factors

a) The quantity of fluid you can pump in

b) The sealing system and the maximum velocity the seals can handle.

c) The cushioning system in the stroke end.

d) The mechanical design to handle the acceleration and deceleration (especially the thrust loads)

As per NFPA T3.6.64 clause 4.3 : usual velocity is maintained between 0.3 to 0.9m/s (however upto 3m/sec has been achieved)

But this is the factor for the designers of the cylinder. for you it depends on the cylinder you have (or you are going to have)

speed of hydraulic cylinder =?

ans:we can use the formula to calculate the piston speed as below

Rse = Qx231/720 X Ae feet/sec.

Q = pump flow in GPM(gallon per mints) given in pump capacity on name plate of pump.

Ae = cap. end piston area in square inches you can calculate with the help of formula=22/7 x r2

you can use above and get ans.

rcmandal

C.E.(INDIA)

sir, thank you for your information. please help me, i need cylinders with speeds upto 2-2.5 m/s. i am interested in converting linear reciprocating motion of these into rotary motion.

Paramveer,

Contact a reputable vendor to help you out. You don't seem real interested in giving all the information needed to complete any sort of calculations for you to use, so you must have a process that you are trying to protect. Your vendor should be able to be trusted, or he is in the wrong business. Everyone's equipment is different, and your situation is all we have to work with.

Have you thought about a motor to create your rotary motion (probably so)? Have you thought about a pneumatic ROTARY Actuator???? They come in pretty small packages and have a lot of options.

Your vendor can do more for you than you are giving us to work with...

Frank is right, get a reputable cylinder manufacturer,. Ask him to provide a cylinder with the speed that you need and also ask him to provide the requirements for the power-pack to drive the cylinder.

For specific applications we usually go in collaboration with the vendors to develope. We don't have to give too much information to them, only the minimum they need and that solves the problem.

sir, i am a graduating student and is working on my project which is to develope a hydraulic engine(using 3 or 4 hydraulic cylinders in place of pistons in the engine to rotate the crankshaft). i am also new to this forum so please keep me guiding where ever you feel that i am wrong.

1- you should have written it from the start

2-my recommendation is still valid : have a look at a book about hydraulics we cannot teach you all what you need.

3- make a trial as you think it and present it I am sure many will make corrections but 1st you must do your work. The principle at CR4 is to help but NOT to do the student work since it is not in his own interest to get things done by others, he has to learn and understand this is his goal as a student.

4- basically if you use cyliders then you should coordinate the flows in and out with the crankshat movement so think how you imagine to do that.

5- to get an idea look at hydraulic motor manufacturers how they solve the problem.

Good luck and be sure if you do your preparatory wprk help will be here.

Contact the manufacturer of the equipment you have the question about.

There's not enough here to give intelligent response.

We can give you the speed of your piston provided you give us two missing parameters.

1) The actual, working diameter of your piston (or cylinder,) in cm or mm.

2) The output (actual working discharge) of your pump in liters per minute.

A_cylinder/Q, in consistent units of your choice.

You've got it all wrong. Velocity of a cylinder is dependant upon flowrate of fluid into the cylinder. For instance, a fixed displacement pump may only pump 50 cc's per minute into a cylinder, and if the volume of the fully stroked cylinder is 50 cc's, it will take one minute. Pressure is important in regards to force, not speed.

Hi. As one can see, there is no response from our dear Mr. paramveer. So one can reasonably ask why did he pose his absurd question at all. Was it to test our responses... or to make fun of us? This is just not serious !!!

What is the flow rate and the both sizes of the piston (full face size and back size with ram diameter) of the cylinder?

As everyone knows the velocity means distance traveled/ time. here the time taken by cylinder to travel the distance of 60-70mm is not given. 20 bar pressure acting on it does not make any sence here. if the cylinder does not move with 20 bar pressure due to external load, than the velocity become zero. is it your real problem? it does not make any movement even it connected to a high flow power source. the pump capacity or flow requirement can be calculated if the pressure is suffient to move the cylinder load. Paramveer have to clarify, is the cylinder moving at all or not.

From Tim Hawley Master Mech.

Hello Paramveer,

WOW, I have so my questions to ask you I don't know where to start...

Need more information!

Tim

Or use a stop watch, in which case V = L/t.

All above are also forgetting loss in velocity due to line loss in hydraulic/pneumatic lines feeding the cylinders as well as line sizes, orifice sizes, fitting configurations, pressure (only to the extent it can move the air in the lines), etc., etc.

As a couple have already stated: If this question is being asked because there is a critical design at stake, the original author is in over his head and he needs to defer to an expert in the field and NOT try to do this himself. We here may be experts and may be willing to share our knowledge, but we don't hold up in court, nor can we read minds. Garbage information in means garbage data out.

If it is merely for "nice to know" information, the best bet is to use as large a ports on the cylinder as available, use as large a valve as practicable (affordable), and install flow (yes - speed regulation as opposed to pressure regulation) regulators (also known as speed controls) on the lines just prior to the cylinder. They restrict flow OUT of the cylinder so you will need to adjust the one that is exhausting to adjust the flow speed. You can then time the action or adjust by eyesight/feel afterward. If you are doing a large quantity of this exact set-up, do this on the prototype and skip it afterward, sizing the future valves/lines accordingly and/or use an orifice to "fix" the speed at the cylinder.

There are many other games you can play to accomplish what you are looking for out of the action of the cylinder, but they should be left in the qualified hands of those who obviously know better. Consult a Fluid Power Engineer. Your vendor can also be a wealth of information regarding your needs and/or questions. The good ones are, since many of their customers do not get this education in school, but on-the-job as poor designs fail and they lean on the vendors to "get them through". A good fluid power engineer will be of advanced age - there is no substitution for experience in the design of fluid power systems.

Yes - I do have some grey in my beard, but I also have some good vendors I lean on from time-to-time. I also do not wish to upset all the young-uns who have paid good money for their educations. I understand that some of you have, and you may be very capable, but if you are honest with yourself, you will also admit that there is something to be learned every day. The more of those days that go by, the more likely it is that you can design the "perfect" system. Good luck with that - I haven't done it yet. I like to think I get close, though, from time to time.

The maximum speed possible is flow/area - irrespective of the unit you choose. The pressure drops, internal leaks, inertia will reduce the value. Normally it is 90% of the theoretical maximum