Proper hydraulic component selection

18th Dec 2016

We receive emails and phone calls daily from customers asking us why their hydraulic system doesn't work. Most of the time, the customer has selected component A from a surplus outlet, component B from an auction website  and component C from company XYZ on the internet. The common problem that we see is that the components are not matched to do the task.

Perhaps they purchased a valve with a 12 gallons per minute flow rate, an actuator that requires 20 gallons per minute to cycle in the time needed to accomplish the work and a 50 gallons per minute pump to supply flow to the valve and actuator. Bottom line is that it just will not work.

Hydraulic systems should be designed from the point of work backwards to the pump. First, determine how much force or torque is required to perform the work. Second, select the actuator that will accomplish that work based on the amount of force or torque required, either a cylinder or motor. Next, select a valve that will supply the flow rate needed to accomplish the task. Finally, select the pump that will provide the correct amount of flow to accomplish the task.

After the key components in the system have been properly sized and selected for the application, the other components can be selected to complete the system. Other components to complete the system will be the reservoir, filtration, secondary valving like flow controls, relief valves, check valves, hose & fittings,etc.

Customers can save themselves time, money and frustration by assembling the proper components at the beginning of the project. Consulting with a knowledgeable fluid power distributor is a good starting place. Most fluid power distributors now have competent engineers or certified fluid power specialists on staff to assist customers with projects. 

Bad things can happen if hydraulic components are not properly selected or applied correctly. Ruptured hoses and leaking seals are minor when it comes to hydraulic component failure. Personally, we have seen cylinder pistons and rods become flying high speed projectiles. Over pressurized cast iron pumps or valves are turned into shrapnel.

Take the time and do it right. If you are not sure if it is right, ask for help.