Tag Archive: valve

Open/Closed center circuits


  • Open/Closed center circuits – what does it mean?
  • Which one I use?
  • What can happen if I connect my system to wrong center circuit?

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There are two types of valve circuits can be used to control your system: “Open center circuit” and “Close center circuit”.

Proportional valve control calculation. Part 1.

Part 1. Proportional control of double acting hydraulic cylinder.

See also:
Part 2. Proportional control in the regeneration mode
Online calculator for cylinder proportional control.

Fig.1. Double acting cylinder control.

Fig.1. Double acting cylinder control.

The goal of this calculation is a definition of a cylinder velocity at any percent of the operating control signal at the valve’s solenoid (voltage or amperage).
For calculations we need to know: cylinder and valve parameters (take them from manufacturer catalog), values of forces at the cylinder rod (load), and pressure drop at the return line (can be assumed as zero if unknown).

1.1. Hydraulic cylinder extension calculation.
1.1.1. Spool lands ratio.
1.1.2. Pressure drops at the spool lands
1.1.3. Balance of forces at the cylinder.
1.1.4. System pressure calculation.
1.1.5. Flow through spool lands: max. and at current voltage.
1.2. Hydraulic cylinder retraction calculation.
1.3. Full stroke time calculation.

Hydraulic Load Sensing design FAQ

By subscriptions I have received the separate links to “Load-Sensing Systems FAQ” from different suppliers. To read them you need to click the links below, fill the forms and download the PDF files with FAQ:

Of course, it’s free. Next questions are discussed there:

  • How can load sensing be beneficial to a hydraulic system?
  • What is the typical efficiency of a hydraulic system?
  • What are the problems when flow is fixed?
  • How is load sensing technology energy effective?
  • etc.