Low Cost Counterbalance Valve 1

[winchengr]

Looking for a manifold mount valve (motor mounted) to operate at 2500 psi max and 15 gpm max using hydraulic fluid. Used for speed control. Cost needs to be less than $35.

Can be either bi-directional or uni-directional.

 

[hydromech]

winchengr...

1) You can't rely on a counter balance to regulate speed.

2) Bi-directional is uni-directional. In any case a counter balance valve will only work in one direction. To control a bi-directional motor you will require a double overcentre valve and manifold.

3) If you want to use a valve to control the speed of a motor you can use a flow control valve. Although the motor operation could be a bit crappy.

4) If you want to hold a motor still, use an overcentre valve. An overcentre valve is the same as a counterbalance valve but it has a pilot function to help it open.

5) A counterbalance valve or overcentre valve cannot hold a motor still if the motor is under load. Internal leaks within the motor will allow it to turn. If you are going to use the motor on a winch, as your name suggests, you will be better using a mechanical brake.

The valves you are looking for can be found at sunhydraulics.com integratedhydraulics.com or hydraforce.com

Regards

Hydromech
Hydraulic Systems Engineer

 

[winchengr]

Hydromech,

I would like to respond to some of your points:

1) A counterbalance valve can be used for load control or speed control. Without it, the load would overspeed on lowering.

2) A counterbalance valve can have one or two cartridges, thus the description. If the valve has two cartridges, it will work in both directions.

4) If you are referring to a closed center (cylinder spool) control valve, it is not the same as a counterbalance valve in this application. An open center control valve must be used in order to release the brake.

5) The counterbalance valve is used in conjunction with a static brake. The brake holds the load when stopped, the counterbalance controls the load on lowering. The valve has a brake release port. This combination has been used successfully for many years.

I am familiar with the companies mentioned, but was looking for lower-cost counterbalance valve alternatives or a lower-cost way to control the load in conjunction with a static brake.

Regards,
winchengr

 

[PNachtwey]

"1) A counterbalance valve can be used for load control or speed control. Without it, the load would overspeed on lowering."

How can a counterbalance valve be used for speed control?
I haven't seen a counterbalance balance with a position or speed feedback.

 

[winchengr]

PNachtwey,
You are correct that the counterbalance valve cannot be adjusted to regulate the speed, but it will reduce the lowering speed of the load.

 

[hydromech]

As with all hydraulic systems it is possible to get what you want many different ways, but if you use a counter balance valve or an overcentre valves to control the speed of an actuator, you will leave youself open to trouble.

I think we are talking about the same valves...it's just the terminology that gets in the way.

Please dont take offence at the way the responses are written...its easier to assume that the people asking for help know very little.

Regards

Hydromech
Hydraulic Systems Engineer

 

[budt]

A Counter Balnace Valve is a PRESSURE CONTROL VALVE. It opens when the pressure it is set for is reached and only opens enough to let any excess fluid out that would try to raise pressure above its set pressure.

In essence, it is a Relief Valve used to retard a running away load from any type actuator and will stop and hold that actuator in position as long as the actuator and/or Counter Balance construction cannot bypass fluid.

The only way it can successfully control speed is by retarding the actuator movement when more or less flow is fed into it. This could be with a Meter In FLow Control, Dual Pump setup or a Proportional or Servo valve.


Bud Trinkel CFPE
HYDRA-PNEU CONSULTING, INC.
fluidpower1 @ hotmail.com

http://www.fluidpower1.us

 

[kcj]

If I were designing winches, I would not be looking to save 20 bucks in the lowering controls. The liabilty prosecuting attorney would take that as a golden gift.

kcj

 

[winchengr]

kcj,
I was looking for technical info rather than legal info.

Most companies nowdays who want to stay in business have ongoing cost reduction programs and realize that any replacement critical component must be qualified by testing. The most expensive isn't always the best.

 

[budt]

Try

http://www.hydraulicspneumatics.com

and look in the "Designers Guide" under "Valves Pressure Control" and then "Valves, pressure control" and see the many manufacturers oof all types of pressure controls.

A lot of the mobile equipment manufacturers have inexpensive valves in a screw-in cartridge design. Try Command Controls, Fluid Power Systems, Gresen, and Delta to name a few.

The list at the above web site is impressive.


Bud Trinkel CFPE
HYDRA-PNEU CONSULTING, INC.
fluidpower1 @ hotmail.com

http://www.fluidpower1.us

 

[kcj]

Sorry if my short post offended you. If you are new to the board, you don’t have the history of past discussions. I will elaborate on what I meant.

I am not saying cost is no object. We are all under that pressure.

Since most of the major brands I see (Sun, Hydraforce, Sterling, SauerDanfoss, Integrated) are close to your $35 target, I assume you are trying to save money not just on the cartridge cost but by combining functions of speed and load control into one valve.

Many knowledgeable people here are willing to help, and several have pointed out that POCB is a pressure/load control device, not a flow/speed control device. Properly applied, the counterbalance can do both. Control valves of whatever type after all are simply variable orifices controlled by some sort of pilot pressure signals. With some innovation, and balancing of pilot ratios, spring pressures, and damping orifices the circuit could work great.

However, many people on this board deal frequently with circuits that are too slow, overheat, chatter, leak, or otherwise misbehave. Usually they were put together by someone without quite enough knowledge for the task they took on. (After all, it’s only plumbing. . . There is another quite lengthy thread on this topic.)

IMO, if your background is not strong in hydraulics, a safety critical circuit should be reviewed by a very experienced person who can see the application and the entire circuit. Any unusual circuit involves nuances and factors that cannot be conveyed in a forum like this. Even then, testing and data acquisition will likely reveal some unplanned things that need to be fine tuned.

Best wishes in your project.

kcj