can anyone help me with providing me with links and videos to be a ware of and understand how exactly the hydraulic pump work? and to recognize the hole parts of the pump? and how they works?

thanks for all
regards

powereng

You can find just about everything on YouTube.
http://www.youtube.com/watch?v...next_from=PL&index=7
You didn't say what kind of pump so I grabbed the first one.

quote:

Originally posted by Peter Nachtwey:
You can find just about everything on YouTube.
http://www.youtube.com/watch?v...next_from=PL&index=7
You didn't say what kind of pump so I grabbed the first one.

thanks for your attention
but what i want the bent axis hydraulic pumps ( used in heavy equipments ) i actually understand the principle of many of hydraulic pumps but as i say its out of principles i want professional explanation for the pent axis pump used in heavy equipments . and how we can control and adjust it ?

thanks so much

regards
powereng

quote:

Originally posted by powereng:

quote:

Originally posted by Peter Nachtwey:
You can find just about everything on YouTube.
http://www.youtube.com/watch?v...next_from=PL&index=7
You didn't say what kind of pump so I grabbed the first one.

thanks for your attention
but what i want the bent axis hydraulic pumps ( used in heavy equipments ) i actually understand the principle of many of hydraulic pumps but as i say its out of principles i want professional explanation for the pent axis pump used in heavy equipments . and how we can control and adjust it ?

thanks so much

regards
powereng

There are two types of pumps.....
"Positive" pumps...."forces" or displaces the fluid forward...
"Negative" pumps...."throws" the fluid forward...(there is a negative pump in the torque converter in your cars automatic transmission)

Pumps in the movie Peter showed is concidered negative pumps or centrifugal pumps....
They convert mechanical/rotational power into hydraulic power, and the hydraulic power is a product of the mass and velocity of the fluid...Negative pumps usually need to be primed (prefilled with fluid) because they are not sealed or "tight" between suction side and pressure side. There fore they also have low volumetric efficiancy. They also usually work without a pressure releif valve.

Positive pumps displace the fluid forward and convert mechanical/rotational power into hydraulic power, and the hydraulic power is a product of pressure and flow....

There are many types and varieties of positive pumps....
Most common are the...
Gearpumps....
Pistonpumps....
Vanepumps....
Gerotorpumps...

Google or Youtube them....

Size/capacity of positive pumps is a product of displacement(volume per revulotion) and speed (revolutions per time unit, rpm or rps)

Positive pumps can be grouped into....
Fixed displacement pumps....are usually used in open center systems...they need pressure control via relief valve

and

Variable displacement pumps...usually radial or axial pistonpumps are used in closed center systems...can be pressure controlled via relief valve, but also via displacement control by limiting the stroke of the pistons....

In a bent axis piston pump, this is done via a servo attachment that make the bent axle(axis) almost straight...and pump will rotate with no stroke (zero displacement) on the pistons...

see
http://www.animatedsoftware.com/pumpglos/bentaxis.htm


Also to be Googled and Youtube'd

Note: Open center or closed center is about how the control valve's neutral position (no actuating)let fluid bypass to tank or not....

Now it's your turn to work.....

Good luck!

quote:

i want professional explanation for the pent axis pump used in heavy equipments

I assume your asking about bent axis pump used mainly on excavators? The two most common are Hitachi HPV series and Rexroth or Uchida A8V (a twin version of a A7V). Uchida, the Japanese version of Rexroth, is almost the same, with some slight differences.

You can find general information as to how a bent axis pump functions, however the controllers are a different story. The controller usually combines several functions and usually has lens plate position feedback, making it a servo controller.

They often combine negative control pressure, horsepower limiting, summation, and swing circuit sensing functions. What you need to do is find the service manual for the particular machine you are interested in as there are a lot of varieties.

This message has been edited. Last edited by: Doug Hanson,

quote:

Rexroth or Uchida A11V (a twin version of a A7V)

Sorry, that should read Rexroth or Uchida A8V (a twin version of a A7V).
A11V is a swash plate design.

thanks for all
thanks for your attentions

but that what i dont want . exactly i am an mechanical power engineer graduated in this year June 2009 and i know all the pumps principles because i studied a hydraulic machine course containing hydraulic pumps . But now i want the explanation of excavator hydraulic pumps and its LS as well as reducing valves installed on pumps . i want some videos of learning me much more a bout excavators from the point of hyadraulic circiut designs . and parts maintanace .

thanks for all

regards

quote:

Originally posted by powereng:
thanks for all
thanks for your attentions

but that what i dont want . exactly i am an mechanical power engineer graduated in this year June 2009 and i know all the pumps principles because i studied a hydraulic machine course containing hydraulic pumps . But now i want the explanation of excavator hydraulic pumps and its LS as well as reducing valves installed on pumps . i want some videos of learning me much more a bout excavators from the point of hyadraulic circiut designs . and parts maintanace .

thanks for all

regards

Thats very high demands for a young(?) student! With only 3!! post on this forum.
What make you so sure someone wants to spoon feed you from a silverplate here on the forum.....and probobly also, chew the food so well for you, so you dont have to digest it????

Go and make some research (Google, Wikipedia etc)
about CF systems, CP systems, CPU systems, and LS Systems, open loop systems and closed loop systems, open center systems, closed center systems etc etc....


Learn about delta P, stand-by pressure, signal, compensator, load pressure etc etc....and PLEASE be welcome come back with a more discussion like query....and maybe you learned something to share, that others dont know...:-)

BTW if you as a young fresh student cant find a video animation of this pump, how do you think old retards (grey haired 56) like me (and some others) can find them for you???

Here is a bone for you.....chew it!

http://www.designworldonline.c...draulic-Systems.aspx

Parker-Hannifin have a lot of experience of mobile hydraulics....

Also check out Olsberg Hydraulics from Sweden....their control valves are on every HIAB truck crane out there...

Real animation, a few out of nearly 300, you can watch at

www.hydrocad.blogspot.com

A little distored due to conversion. Original are as Animated GIF

Nahum

quote:

Originally posted by AKKAMAAN:

quote:

Originally posted by powereng:
thanks for all
thanks for your attentions

but that what i dont want . exactly i am an mechanical power engineer graduated in this year June 2009 and i know all the pumps principles because i studied a hydraulic machine course containing hydraulic pumps . But now i want the explanation of excavator hydraulic pumps and its LS as well as reducing valves installed on pumps . i want some videos of learning me much more a bout excavators from the point of hyadraulic circiut designs . and parts maintanace .

thanks for all

regards

Thats very high demands for a young(?) student! With only 3!! post on this forum.
What make you so sure someone wants to spoon feed you from a silverplate here on the forum.....and probobly also, chew the food so well for you, so you dont have to digest it????

Go and make some research (Google, Wikipedia etc)
about CF systems, CP systems, CPU systems, and LS Systems, open loop systems and closed loop systems, open center systems, closed center systems etc etc....


Learn about delta P, stand-by pressure, signal, compensator, load pressure etc etc....and PLEASE be welcome come back with a more discussion like query....and maybe you learned something to share, that others dont know...:-)

BTW if you as a young fresh student cant find a video animation of this pump, how do you think old retards (grey haired 56) like me (and some others) can find them for you???

Here is a bone for you.....chew it!

http://www.designworldonline.c...draulic-Systems.aspx

Parker-Hannifin have a lot of experience of mobile hydraulics....

Also check out Olsberg Hydraulics from Sweden....their control valves are on every HIAB truck crane out there...

thanks so much

but i am an engineer not an a student
what i a sked not involved in my studied and i dont know the key of search but you had opend the way for me

thanks again
and thanks for the site

quote:

thanks so much

but i am an engineer not an a student
what i a sked not involved in my studied and i dont know the key of search but you had opend the way for me

thanks again
and thanks for the site

You are welcome!!

Be patient mr. Powereng. There are a lot of LS topic in this forum. There is also a LS system set up for fix displacement pump by manipulating the relief valving system.

The cheapest way to learn it is for you to buy hydraulic book/s(I recommend rexroth). You can also buy CD/DVD if there is available(possibly very expensive/and or exclusive). There are also other training materials available, but try to search for it.

To give you a little headstart, an LS is a way of trying to utilize the load pressure feedback so as to reduce the amount of power losses in the system.

In variable pump application(usually for rotary actuator applications), the load pressure is being feedbacked to the pump load sensing port so that the amount of output energy is almost equal to the input energy(disregarding some losses and inefficiencies).

I can not tell you exactly what is happening inside the pump controls because each and every brand has different type of contrlling method bur I am sure they follow the same principles. The control process can only be learned if a pump expert is willing to tell/teach you the nitty-gritty of it. Or if you can analyze the "pumps circuitry". Most hydraulic people can tell you that after the load pressure is overcame by the main system pressure, the pump will destroke until the output energy equalizes with the input energy(assuming 100% eff). But still, there are small very important things that need to be stufied to really understand how the mechanism operates/functions and why? The pump circuitry can tell, if you know how to analyze it, but I believe that a basic knowledge is not enough... Some topics on Bud T ebook may be of help, but I doubt if there is a complete explanation.

But since you are an engineer, if you really have the desire to learn it, read about hydraulics... It is very interesting.

Powereng said he is interested in controllers used on excavators. Excavators rarely use load sense systems. They are multi function servo controllers. Here is an example.

They generally tend to use a negative control pressure arrangement, which could almost be considered the opposite of a load sense system. I would love to go into the theory and opperation of such controllers, but it would be pretty time consuming and difficult to do without a lot of illustrations, the best thing to do is get a service manual for the machine you are interested in. Jhon Deere and Cat manuals usually have 'theory of operation' descriptions.

pump.pdf (32 KB, 33 downloads) Pump Diag

quote:

Originally posted by maglub:
Be patient mr. Powereng. There are a lot of LS topic in this forum. There is also a LS system set up for fix displacement pump by manipulating the relief valving system.

The cheapest way to learn it is for you to buy hydraulic book/s(I recommend rexroth). You can also buy CD/DVD if there is available(possibly very expensive/and or exclusive). There are also other training materials available, but try to search for it.

To give you a little headstart, an LS is a way of trying to utilize the load pressure feedback so as to reduce the amount of power losses in the system.

In variable pump application(usually for rotary actuator applications), the load pressure is being feedbacked to the pump load sensing port so that the amount of output energy is almost equal to the input energy(disregarding some losses and inefficiencies).

I can not tell you exactly what is happening inside the pump controls because each and every brand has different type of contrlling method bur I am sure they follow the same principles. The control process can only be learned if a pump expert is willing to tell/teach you the nitty-gritty of it. Or if you can analyze the "pumps circuitry". Most hydraulic people can tell you that after the load pressure is overcame by the main system pressure, the pump will destroke until the output energy equalizes with the input energy(assuming 100% eff). But still, there are small very important things that need to be stufied to really understand how the mechanism operates/functions and why? The pump circuitry can tell, if you know how to analyze it, but I believe that a basic knowledge is not enough... Some topics on Bud T ebook may be of help, but I doubt if there is a complete explanation.

But since you are an engineer, if you really have the desire to learn it, read about hydraulics... It is very interesting.

deer MR.Eng.Maglub

i dont know how to thank you
but rally i had the main idea very well .

thanks a gain

quote:

Originally posted by Doug Hanson:
Powereng said he is interested in controllers used on excavators. Excavators rarely use load sense systems. They are multi function servo controllers. Here is an example.

They generally tend to use a negative control pressure arrangement, which could almost be considered the opposite of a load sense system. I would love to go into the theory and opperation of such controllers, but it would be pretty time consuming and difficult to do without a lot of illustrations, the best thing to do is get a service manual for the machine you are interested in. Jhon Deere and Cat manuals usually have 'theory of operation' descriptions.

thanks so much

but i think that pump diag that you had loaded is a part of acomplete diagram please could you load it and if you have another hydraulic circuits for heavy equipment applications load it

thank