I have a question - for the single direction hydraulic motor brake at 23:00, did you need to use a sequence valve with an external drain and integrated check? Could you use a regular relief valve and drain to tank (if tank pressure is at atmosphere)? I thought the check valve on the opposite port of the pump addressed the potential suction/cavitation issue. Thanks for the excellent videos!!!
Yes, for a single direction application the check valve bypass on the sequence valve would be kind of useless ... however ... as you pointed out you might want a make up check valve on the other side to prevent cavitation. Check out the "Vented and Remotely Controlled Pressure Relief Valves" at: th-cam.com/video/zWRFibp6WnU/w-d-xo.html for an alternate method.
Jim, please don't be annoyed by this observation rather interpret it as a student starting to grasp your material. At 27:00 you say the Clamp Seq Valve will hold the part in place until the bend cylinder reaches its upward limit. Correct me if I'm wrong, but although the clamp will not actually move up, it won't truly have pressure on the part as the now output side (top) of the cylinder sees tank pressure, not system pressure. Last item, I realize you must keep the component count to a minimum in these illustrations lest they become WAY to complex and the the explanations wander off. One last last item, thanks again for the amazing content!
Yes, during retraction at ~17:00 you're correct that the cap end of the clamp cylinder would be at tank pressure, however, the rod end is effectively blocked. Given a liquid is being used rather than a compressible gas, the clamp cylinder will not freely retract. Yes, we'll examine more sophisticated electrically sequenced systems in later lectures.
Hello Jim, first I want to say good job !!! I have a question regarding sequence valve, have you ever seen normally open sequence valve to be used in hydraulic circuits? if you did, can you please say in what application ? I have trouble with old hydraulic machine which was two normally open sequence valves on a manifold block and I m trying to drawn hydraulic schematic but I can't quite figure it out. Thank you in advance. Best R N
Oh you are opening a can of worms .... yes quite like NC and NO switches manufacturers do offer different styles of valves. I could imagine the schematic symbol for a NO sequence valve looking exactly like a NO pressure reducing valve th-cam.com/video/5vtnOLyawPg/w-d-xo.html only it's sensory pilot line (the dashed line) pointing at the input (or remote) rather than the output.
question,when the sequence valve receives enough pressure to over come the internal spring and send fluid to the 2nd cylinder,does the fact that the 2nd cylinder is now moving freely with no initial resistance until it touches the plate mean that the pressure the spring is seeing in the sequence valve also reduces thus causing a juddering effect?
You're describing a "kick down" style sequence valve. These type of valves don't maintain pressure in the primary circuit where as a normal sequence valve does. Kick down style sequence valves are very application specific.
hello Jim, thank you so much for the videos you have provided all of them are really helpful. i am wondering in case you have a video on the topic " hydraulic cartridge logic valve"
Nothing on the topic yet. I'm still involved with finishing the basic electronics series, however, I do wish to return to advanced fluid power applications in the future. Stay in touch.
Hi Jim can you let me know how do you run four hydraulic motors in sequence? The external load might very motor to motor. All the motors must have the same rotation. You know what I mean. The oil supply is from one pump.
I don't see a clear difference between the sequence valve and the counterbalance valve. Is the counterbalance valve simply a sequence valve without an external drain?
They're remarkably similar (aside from the drain) however sequence valves are ordinarily located on the "input" of an actuator whereas counterbalance valves are ordinarily located on the "output" of an actuator.
@@bigbadtech I just saw the crossectional view of both of them and now I can understand it better why one is better for input and the other is better for output. i think you should mention that in your video so anyone can understand it better too... btw thank you for your very good content, I'm currently working on refurbishing a coiled tubing unit in which a hydrolic plays a very important role, watching ur video helped me a lot to finish this project...
So good. All the information and theory without the usual fluff and sham wow plugs. Thank you for the great videos!
this video was very helpful and how to differentiate between the pressure control valves is very important
Cant tell you how much this has helped me out. Thank you
I have a question - for the single direction hydraulic motor brake at 23:00, did you need to use a sequence valve with an external drain and integrated check? Could you use a regular relief valve and drain to tank (if tank pressure is at atmosphere)? I thought the check valve on the opposite port of the pump addressed the potential suction/cavitation issue.
Thanks for the excellent videos!!!
Yes, for a single direction application the check valve bypass on the sequence valve would be kind of useless ... however ... as you pointed out you might want a make up check valve on the other side to prevent cavitation. Check out the "Vented and Remotely Controlled Pressure Relief Valves" at: th-cam.com/video/zWRFibp6WnU/w-d-xo.html for an alternate method.
Jim, please don't be annoyed by this observation rather interpret it as a student starting to grasp your material. At 27:00 you say the Clamp Seq Valve will hold the part in place until the bend cylinder reaches its upward limit. Correct me if I'm wrong, but although the clamp will not actually move up, it won't truly have pressure on the part as the now output side (top) of the cylinder sees tank pressure, not system pressure. Last item, I realize you must keep the component count to a minimum in these illustrations lest they become WAY to complex and the the explanations wander off. One last last item, thanks again for the amazing content!
Yes, during retraction at ~17:00 you're correct that the cap end of the clamp cylinder would be at tank pressure, however, the rod end is effectively blocked. Given a liquid is being used rather than a compressible gas, the clamp cylinder will not freely retract. Yes, we'll examine more sophisticated electrically sequenced systems in later lectures.
Hello Jim u are wonderful in hydraulics.plz add some trouble shooting videos.
Hello Jim, first I want to say good job !!!
I have a question regarding sequence valve, have you ever seen normally open sequence valve to be used in hydraulic circuits? if you did, can you please say in what application ? I have trouble with old hydraulic machine which was two normally open sequence valves on a manifold block and I m trying to drawn hydraulic schematic but I can't quite figure it out.
Thank you in advance.
Best R
N
Oh you are opening a can of worms .... yes quite like NC and NO switches manufacturers do offer different styles of valves. I could imagine the schematic symbol for a NO sequence valve looking exactly like a NO pressure reducing valve th-cam.com/video/5vtnOLyawPg/w-d-xo.html only it's sensory pilot line (the dashed line) pointing at the input (or remote) rather than the output.
question,when the sequence valve receives enough pressure to over come the internal spring and send fluid to the 2nd cylinder,does the fact that the 2nd cylinder is now moving freely with no initial resistance until it touches the plate mean that the pressure the spring is seeing in the sequence valve also reduces thus causing a juddering effect?
You're describing a "kick down" style sequence valve. These type of valves don't maintain pressure in the primary circuit where as a normal sequence valve does. Kick down style sequence valves are very application specific.
hello Jim, thank you so much for the videos you have provided all of them are really helpful. i am wondering in case you have a video on the topic " hydraulic cartridge logic valve"
Nothing on the topic yet. I'm still involved with finishing the basic electronics series, however, I do wish to return to advanced fluid power applications in the future. Stay in touch.
Hi Jim can you let me know how do you run four hydraulic motors in sequence? The external load might very motor to motor. All the motors must have the same rotation. You know what I mean. The oil supply is from one pump.
Check out this lecture on the HydraForce HTD 10-40 Hydraulic Torque Divider: th-cam.com/video/6VkH_rBQ6Ec/w-d-xo.html
I don't see a clear difference between the sequence valve and the counterbalance valve. Is the counterbalance valve simply a sequence valve without an external drain?
They're remarkably similar (aside from the drain) however sequence valves are ordinarily located on the "input" of an actuator whereas counterbalance valves are ordinarily located on the "output" of an actuator.
@@bigbadtech I just saw the crossectional view of both of them and now I can understand it better why one is better for input and the other is better for output. i think you should mention that in your video so anyone can understand it better too... btw thank you for your very good content, I'm currently working on refurbishing a coiled tubing unit in which a hydrolic plays a very important role, watching ur video helped me a lot to finish this project...
Imagine how much money you could make, if you can remember half of this🤑
Please talk slowly because that very hard on the other nationalities