(reveiw) Hydraulic System with tandem center solinoid for control

[Talo]

hi i am fairly new to the hydraulic business and need to create a hydraulic lift that has warm up loop that also raises the lift at the speed i choose based on the power given to the pump. and lowers slowly with a regulator.


i made a schematic of the way i think it is supposed to be done.

here's the visio project in office 2007

http://files.engineering.com/getfil...8-a70e-2f9c8249e12a&file=Hydraulic_System.vsd

also attached is the image of the same schematic.

 

[Talo]

that way the pipe won't burst if i have the counterbalance on the manifold.

 

[budt]

I've seen 6" Shedule 160 pipe broken more than once on a 2,500 Ton press and steel tubing split and fittings come apart several times.

If the Counter Balance valve is not bolted directly to the cylinder there will be a cylinder that falls unexpectadly sooner or later. Just pray no one gets hurt or killed.

It's your call though if you are the circut designer.


Bud Trinkel, Fluid Power Consultant
HYDRA-PNEU CONSULTING

 

[hydtools]

Like Bud says, 'Your choice.' That's the cool thing about being the designer, you get to choose.

And be responsible.

Ted

 

[Talo]

yes i don't think that a 750lb lift would have a pipe burst.

 

[stroupaloop]

Well that is a question of your dynamic hydraulic system conditions. A 750 lbf load could create such issues in a system due to dynamic fluid changes. One such change is a water hammer effect. You must also consider any vibratorial issues that may occur due to natural frequencies. These issues can effect and cause lines to break in even the smallest systems.

 

[budt]

stroupaloup;
Talo is like so many persons on the Forums who say they are looking for help when the actually mean "APPROVE MY CIRCUIT AS DESIGNED" or I will not be happy no matter how much experience is behind any of the answers.

That is what happens with a System that is not recognized by most users as a discipline that needs TRAINED/DEDIACTED persons to apply the equipment in an efficient and safe manner.

I seldom see these kinds of questions on the Electrical and Mechanical Engineering Forums.

Oh well Someday, Maybe.


Bud Trinkel, Fluid Power Consultant
HYDRA-PNEU CONSULTING

 

[Talo]

true its probably a lot different because in the electrical area there are a larger amount of people that would understand. for instance the frequency of the voltage also affects the type of cable and sheilding needed for the voltage. so in a system where there are high voltages and low voltages if the hight gauge and low gauge cable are close to each other in a way the the wires cross 180 degrees to the other they create a bidirectional freqincey loop that causes the wires to have electrical noise on them. rather than the proper way of haveing a 90 degree parralell crossing of the high and low voltages.





but i am trying to look for a alternative to the cbv problem. cause unless i have a bottom port routed to the top of the cylinder before i add the cbv then i would have room to place it directly onto the port. becuase i don't have the room for it in the design of the cylinder's hole in the ground.

 

[budt]

but i am trying to look for a alternative to the cbv problem. cause unless i have a bottom port routed to the top of the cylinder before i add the cbv then i would have room to place it directly onto the port. becuase i don't have the room for it in the design of the cylinder's hole in the ground.

One way to overcome the running away problem, when a line fails, is to orifice the port to slow the cylinders decent and use some sort of mechanical retardation to catch the falling load when a line fails.

Also, designing a circuit that is free from shock will reduce the chance of line failure.


Bud Trinkel, Fluid Power Consultant
HYDRA-PNEU CONSULTING

 

[Talo]

i know im looking for a cylinder that has the bottom port and top port on the top of the cylinder so that it will be accessible for service instead of the port being in the groubnd where i won't be able to service it or the cbv.

 

[budt]

With 750# on top of the cylinder you could make it a Single Acting Ram and just let the weight return it by allowing oil back to tank.
Then you would only need one port.


Bud Trinkel, Fluid Power Consultant
HYDRA-PNEU CONSULTING

 

[Talo]

i want to make it as elevator but without the floor controls or excessive safty. it is a remotly operated elevator wich only goes up and down when needed (maybe twce every month) but when controled know one is near it or around it. only when it is stoped.

now what i need is a piston like that of an elevator , custom or ready mae options welcome

 

[Talo]

i want to make it as elevator but without the floor controls or excessive safty. it is a remotly operated elevator wich only goes up and down when needed (maybe twce every month) but when controled know one is near it or around it. only when it is stoped.

now what i need is a piston like that of an elevator , custom or ready made options welcome

 

[Talo]

it only needs to be 1 tonn cylinder diametre 4" and double acting.
that is at least 4000 psi

80" stroke.