Hydraulic pumps are an incredibly important component within hydraulic systems. IFP Automation offers a variety of pump and hydraulic system products that deliver exceptional functionality and durability. Our partner Parker’s extensive line of hydraulic pumps deliver ideal performance in even the most demanding industrial and mobile applications. In this post, we are going to spend time discussing pressure compensated and load sensing hydraulic pumps.

First – the simple purpose of a pump is to provide the flow needed to transmit power from a prime mover to a hydraulic actuator.

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Variable Volume Pressure Compensated Piston Pumpimage3

  • Pressure Compensated: Self Adjusting Based on Pressure
  • Attempts to Maintain a Maximum Pressure Setting by Providing Flow
  • Pump Reduces Flow (Compensates) Once Maximum Pressure Setting is Achieved
  • Maintains Max Pressure with System “Deadheaded” while Providing Internal System Leakage Flow Rate
  • Works Well in Systems Where Functions Require ABOUT the Same Pressure

 

How Does it Work?

  • When the pressure at the outlet port reaches the compensator setting then the compensator spool moves over against the spring force.
  • This allows the pump outlet pressure to have a path to the internal servo piston.
  • Do to the surface area of the servo piston and the pressure exerted on that area, a force is generated that pushes the swash plate of the pump to a lower degree of stroke angle.
  • Causing the piston travel in the rotating group to be reduced, thus a lower flow rate of fluid is produced at the outlet port of the pump.
  • Once the pressure in the system drops below the compensator setting, the compensator spool is forced back the other direction via the spring force.
  • This allows the oil in the servo piston chamber to exhaust into the case of the pump, where it is returned to tank via a case drain line.
  • The servo piston force that was holding the swash plate at a low angle is now reduced and the bias spring pushes the swash plate back on stroke at full angle and flow
  • The pump tries to maintain compensator setting pressure, and will provide whatever flow (up to it’s maximum flow rate) that is necessary to reach that pressure setting.

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Load Sense Pump Control

  • Load Pressure Difference AFTER a Flow Restriction Controls When the Pump Will Compensate (Reduce Flow)
  • Pump Produces Flow Trying to Balance Load Pressure + Differential Spring Against Pump Outlet Pressure
  • Load Pressure + Differential Pressure will Equal Pump Outlet Pressure
  • Thus, Flow Through System Orifice Stays Constant Even as Load Pressure Changes
  • If the load sense signal is 0 psi, then the pump will compensate at low pressure standby, which is the differential setting on the pump compensator.

 

For more information on how you can make use of hydraulic pump technology in your applications, please contact us here to receive a personalized contact by an IFP Application Engineer:

About IFP Automation

IFP Automation supplies innovative technology and design solutions to the automation and mobile marketplaces.  Our firm is a technology supplier specializing in the design and supply of automation and motion control products to OEM, integrator, and end user customers. Companies partner with IFP because they like the depth of our product and application knowledge and our commitment to outstanding customer service.

 

 

 

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