How to model ball vavle sealing at both ends of travel limits

I am working to replicate a physical hydraulic system where a sliding ball seals on a conical surface at each ends of its travel. The system has no springs. The Ball Valve block is convinent for this but only seals at 0 (ie one end of travel) and i'm unable to look under the mask to understand how this block is built in order to build my own. Any recommendation is appreciated to model this system, I have tried many many different methods with no luck. I have tried both Hydraulic Cartridge Valve Actuator and Hydraulic Double-Acting Vavle Actuator with 0 spring rate and near 0 spring preload to provide S. Of these, the Hydra Cartridge Vavle Actuator was nice because signal was always positive; however, I dont require 3 hydraulic inputs. Either of these actuators can likely be made to work but how to seal at the far end of the travel limit is the issue. thank you!

[Joris Naudin]

Maybe you can try to use two check valves opposed with an offset ?

Answer 1

[Jocie Kluger]

Hi Michael,

I recommend using Physical Signal blocks like PS Abs to transform the control signal that's fed into the Ball Valve. The valve area closes (saturates at the leakage area) when the input signal equals -x0. x0 is the "Ball displacement offset" parameter in the dialog box. This doc page has more information on the equations. Hope this helps.

Regards,

Jocie