Dynamics of a Load Sense System Adjustment

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We've done several videos about load sense so far. In this video, we'll take another approach to looking at the way load sense pumps work. We study the behaviour in schematic form, and watch how the system responds when we make changes to the rate of flow, the resistance to flow, and the compensator setting. You'll see a wide range of dynamic load sense behaviour, which should help you better understand how load sensing pumps work. But don't stop here - be sure to watch all our other load sense videos: • Load Sense

Опубликовано:

3 окт 2024

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Комментарии : 23

@steveh9106 7 лет назад

Another great video, thanks so much for these videos they really are a help in my line of work.

@alexalex2397 6 лет назад

Thank You so much for Your channel. The quality of videos is AMAZING

@hoinguyendang4249 7 лет назад

Thank you so much

@subhonia_entertatinment Год назад

what is the name of this software?

@brianmartineau5945 2 года назад

Thanks for all these great lessons in hydraulics, very interesting and well done. I've got a Volvo ec60e excavator that uses a open center negative control hyd system that I would be very interested in how it functions compared to the closed center load sense system.. From what I understand it senses off the carry over flow from the open center and de strokes the pump as this carry over flow increases. Thanks so much Carl! Regards , Brian

@ChandanKumar-ux3jz 9 месяцев назад

Very good sir ji

@lovrorb 7 лет назад

Great video, but there is one thing bugging me here! Once you start varying load, in your animation swash plate angle increases, which leads to increased displacement and considering motor speed is unchanged, the result is higher flow! Is this correct? You still have exactly the same pressure drop over the needle valve (~20 Bar) which is controlled by flow compensator, and orifice pass is unchanged. So the flow should remain the same, right? Isn't this the whole point of load independent flow/speed control? Actually, as load increases in reality, it will make an actuator a bit slower, since the compensator in pressure compensated flow controller is not perfect, as you nicely explained in previous video

@lunchboxsessions 7 лет назад

Carl here. Sorry for the delay. Travel schedule is hectic right now, but I'll try to keep up. Here's a paste of an answer I offered to a similar question by Ahmed Z. on our video What is a Load Sensing Pump ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-PbXB2VnhpXw.html Don't forget that as pump outlet pressure rises, the amount of internal pump leakage increases, and is seen on the case drain line, if (when) a flow meter is present. Also, bulk modulus (compressibility of the fluid) means that very sudden increases in load (shock) pressure at the cylinder can cancel the pressure differential across the flow controlling valve, if only for a very short amount of time (perhaps less than one second), meaning that even a fixed swash plate angle cannot guarantee steady flow under all circumstances. Lovro, our swash plate angle corrections are at times, a bit exaggerated so that the learner can see them occurring. You would be right that at times these angle changes are very small.

@lovrorb 7 лет назад

Hey, no hurries! It was just something I mentioned to Ivan btw! :) Thanks a lot. This is what I actually had in mind, but, still, it seemed like a too much of an increase in wasted flow somehow.

@ashutoshsingh1137 Год назад

Orifice control pressure or flow .. please recommend. Study material about it.

@ashutoshsingh1137 Год назад

As soon as possible

@smindustries8847 Год назад

How come having a higher margin pressure is better for systems where the load pressure can rise or drop off sharply. I have an issue where the load van change rapidly and this seems to result in the motor stalling. LS pressure is set to 18 bar

@오일파워 6 лет назад

Great Video, It help me to study hydraulic system.I can't understand Flow control valve's move.delta P is fixed (150 bar or 200bar in the video), How does flow control valve is moved? although same delta PPleas answer

@antt5112 7 лет назад

These are great, I know a load sense relief can be used to limit system pressure but what would a margin relief be used for, is it to drop pump pressure off quickly when you drop off the load sense signal??

@lunchboxsessions 7 лет назад

Great observation Ant T! Yes, the load sense compensator (if that's what you meant by margin relief) drops the pump down to near zero flow, and at low pressure when flow is not required (flow/directional valves closed, load sense signal line bled down) . If a pump only has a pressure compensator, then when flow or DCV valves closed, pump produces near zero flow, but at high pressure. This is not as good for energy/heat savings. But the other aspect of load sense, is that the pump outlet pressure is constantly kept at a level just slightly higher than what the load needs. We'll do more videos on this topic soon.

@robmom1993 5 лет назад

Hey Carl, thanks for the video. I've got one small comment on the pilot line of the pressure compensator. In your animation, this spool is piloted by the control pressure, but normally it will be piloted by the tank pressure right? After all, it should open when the discharge pressure gets to 1500 PSI, not the difference between the discharge and the control pressure. Additionally, is there anything you can explain about the two relief valves that connect the control piston to the tank line? It is my understanding that this changes the dynamic behaviour of the swash mechanism quite a bit.

@tusharsharma8666 3 года назад

Please clear How many conditions the pressure compensator work?

@samadhanpatil6612 4 года назад

Thanks...Informative Video..

@aidwilli 3 года назад

lmao this music

@tommcloughlin6149 Год назад

Hi I have a problem with a variable displacement pump can your email so I cam send you some photos and questions thanks

@ИльяРадзивинович 6 лет назад

Thank for your video, but I think there is one mistake or my misunderstanding. The adj. spring side of the pressure compensator must NOT be connected with pump pressure (when flow compensator working and pump pressure passing through to pressure comp. and piston), it must be vented to the pump case or tank.

@lunchboxsessions 6 лет назад

Hmm I am not sure exactly what you mean. There are constant tiny control piston position changes being made. Can you tell me what time (0:00) in the video you mean? I'll then have another look. - Carl

@ИльяРадзивинович 6 лет назад

Look at this drive.google.com/file/d/1wO4coU6xJ2Ep6LFdhXEjolg-Cm6iGF-E/view?usp=sharing I mean usually the spring side cavity of the pressure compensator connects to the pump case (drain). I drew it with a red line on my pic. If not, I think system pressure can exceed 1500 psi in case of clogged orifice (marked with red circle on my pic) for example. I saw such a problems in DFR ragulators not once, i mean orifice (exactly this orifice that I'm talking about) clogged with rubber or another contaminations.