Assistance with locating a hydraulic flow divider

In summary, the conversation discusses troubleshooting an old 2-post automotive lift from the 70's that has unevenly rising and lowering arms. The solution being sought is a flow divider that can adjust the flow to each piston, with options for different split ratios. The ideal divider should be accurate and insensitive to pressure differences. A gear-based rotary flow divider is recommended, and a mechanical solution involving wire cables and pulleys is also suggested. A pressure regulator could also be used to adjust the pressure and ensure equal performance. The discussion also touches on potential issues such as unequal hydraulic cylinder sections and the need for proper bleeding.
  • #1
B. Elliott
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At my shop we recently acquired an old 2-post automotive lift from the 70's. The lift has two cylinders, one for each post. The hydraulic lines were a bit hacked up when we got it and we're now in the process of trying to get it up and running again. We have it operational, but the arms are rising and lowering unevenly.

We're looking for some type of flow divider where we can adjust the amount of flow that is fed to either piston with 1-in and 2-out. For example, a 20/80 split, 50/50, or a 75/25. Something where we can fine tune it so that they will rise and lower at equal speeds.

~3000-3500 psi
3/8th NPT

We're having trouble sifting through all the available types on the market. Most of what we have found are priority-type, but that's not what we're looking for.

Any assistance would be greatly appreciated!
 
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  • #2
Your hydraulic cylinders should be of equal section. That will require exactly equal volumes of fluid pass to, or from each side. Because the mass distribution being lifted or lowered will not always be symmetrical, the pressure to the two sides of the lift may be significantly different.

So what you need is an accurate equal flow divider that is quite insensitive to pressure difference. Gear based, rotary flow dividers are maybe 3% accurate, so that should do the job OK. The differential pressure between the two sides will be countered by the torque difference on the gears in the flow divider.
http://www.salami.it/public/articoli/pdf/1608_1_Technical%20catalogue%202DRE.pdf

A mechanical solution could be to run a single loop of wire cable up, down and between both legs. That will need 6 pulleys. By clamping the lift points to the appropriate cable you can mechanically balance the pressure and the position on the two sides, the cylinder pressures can then be equal and so will work together. In that situation the actuator cylinder sections do not have to be identical.
 
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  • #3
Thank you very much Baluncore. That information is exactly what we were looking for!

Cheers!
 
  • #4
A pressure regulator could be used 1 in 2 out adjusting the pressures to get both rams to work together. also can check the distances between both pipes, also have found if the rams are not bled properly and have small amount of air inside could be an issue. On one instance I found that the I/d of pipes where different thus giving different pressures. Thus a pressure regulator would be best option giving pressure equally if a load is put on.
 
  • #5


I would recommend looking for a flow divider with a proportional flow control valve. This type of valve allows for precise control of the flow rate to each cylinder, allowing for fine-tuning and equal speeds for the arms of the lift. Additionally, make sure to check the maximum pressure rating and fitting sizes to ensure compatibility with your system. It may also be helpful to consult with a hydraulic specialist or engineer for further guidance and recommendations.
 

1. What is a hydraulic flow divider?

A hydraulic flow divider is a device that divides a single hydraulic flow into multiple streams of equal or proportional flow. It is commonly used in hydraulic systems to distribute a single input flow to multiple outputs, allowing for precise control and efficient operation.

2. When do I need assistance with locating a hydraulic flow divider?

You may need assistance with locating a hydraulic flow divider if you are designing or modifying a hydraulic system and require a specific flow distribution, or if you are experiencing issues with uneven flow distribution in your current system.

3. How do I choose the right hydraulic flow divider for my application?

Choosing the right hydraulic flow divider depends on several factors, including the required flow rates, pressure ratings, and the type of fluid being used. It is important to consult with a hydraulic expert to determine the best type and size of flow divider for your specific application.

4. Can a hydraulic flow divider be customized?

Yes, hydraulic flow dividers can be customized to meet specific requirements. This may include modifying the flow ratio, pressure ratings, and materials of construction. A hydraulic expert can assist with designing and manufacturing a custom flow divider for your application.

5. How can I troubleshoot issues with my hydraulic flow divider?

If you are experiencing issues with your hydraulic flow divider, it is important to first check for any leaks, blockages, or other mechanical issues. If the issue persists, it is best to consult with a hydraulic expert who can diagnose and resolve the problem. Regular maintenance and proper installation can also help prevent issues with flow dividers.

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