13/13 I would like to reiterate the fact that THERE IS NO HEAVY TECHNICAL VOCABULARY! It is refreshing to watch an engineering video that is straightforward and visually aiding.
@@martynasvizbaras1180 basically everything is built into the closed loop system . enough room for oil and the control valves. seems like the open system is more user friendly. easier to repair.
I also taught hyd and some folks just never really unstand how it works 😊 No matter how you explain it to them 😢 I loved working but had to retire at 68
Good presentation. In summary from my past experience as an ex hydraulic engineer. Closed loop systems primarily used in mobile applications where a compact design is needed and a direct, dual direction connection is required between a single pump and motor or motors. Advantages: compact design due to smaller tank, smaller hydraulic pipes, less valves. Disadvantages: expensive components, often variable dual direction pumps and/or motors, design limitations in adding additional end uses, unequal displacement end users users (such as standard cylinders). Open loop systems primarily used in static industrial systems. Advantages: lower component costs and unlimited design options, multi independent actuators from a single system. Disadvantages: bigger tank capacity required, bigger pipes on the return side, separate valves.
@Ask APT No, moved out of the field 21 years ago. Still very passionate about all hydraulic. While mechanically I would imagine the systems remained similar, I am sure on the control side, there have been good developments over the past 20 years. All the best.
I gathered this from my basic knowledge of hydraulics. I'm learning mobile can be a be a little more complicated because of the size constraints. But they can have many configurations and is important to know what your working on before your working on it.
Very helpful and informative! I loved the way you demonstrated your point: by sequentially adding parts and explaining the differences in the state of the loop as you went.
But here is a flaw concerning the open loop system. Directional control valves are usually proportional. You can control the speed with the lever pretty well. You don't normally need any flow control valve that increases unneccessary pressure, energy consumption, heating and wear on the pump.
On every tractor, loader, excavator etc with a fixed displacement pump for the working functions you control the hydraulic cylinders and even motors by the levers on the control valve and rarely any flow control valve is used. Controlling the speed of a cylinder is pretty much like controlling the speed of a motor.
@@ontheroadagain4773 Exactly. In most cases, you don't need a flow valve when you have a control valve that will do the same. The systems with solenoid control valves you do if you don't want full flow on part of the circuit.
closed loop is used in transmissions in just about every construction, forestry and farming machines these days, open loop is for hydraulic cylinders where the oil needs to be returned to a tank as the oil amount varies to and from the hydraulic rams/cylinders.
On a car, the open loop system is the better choice for a lot of reasons! The variable speed ability is taken over by the engine, and gives you the ability to use sliding vane or gerotor pumps for simplicity and longevity. An example is a power-steering assembly. These systems pump fluid through an a little hole (called an orifice). At low engine speed, the orifice is too big to be a restriction, and the car is likely parked or has low duty requirements, so drag isn't a problem. You can turn your power steering pump with your hand! Pressure gain has exponential characteristics. Doubling engine speed will quadruple the pressure, and the engine often goes over 10-times the idle speed. Any shock loads against these systems are typically resolved with the tremendous amounts of momentum in the engine. For an Electric motor that rotates at a fixed frequency (60hz, geared down to whatever suits your nominal shaft torque requirements and pump speeds), the closed loop system makes sense, but has its own sacrifices. For example, we might need a sudden burst of speed. The motor often can't cope with this, or becomes a reactive load for the power source. The work-around is to have a huge flywheel on the motor. If you're dealing with shock loading, the flywheel will give you all of the load you could ever want, but the shock loads can trigger your safety valves, causing the system to go backwards.
Automatic transmissions have open-loop systems that are optimized for the duty at hand. You have control over engine speed and should be mature enough to know what kind of gear shifting duty the transmission would ever need to do. Given that information, an open loop system can be made, such that its mode of failure is known and forced to happen for safety reasons.
@@BigCroca still would need a valve to change direction and control speed what is driving each pump? and on a high cycle time machine you would need coolers on each one, a normal valve is in no way complicated to understand
Really many many thanks for your your existence, and the videos you upload. I've been trying to understand the hydraulic system on the bulk carrier ships i work and you are definitely helping.
A very good video. Very well explained with the help of equipment. There are no clutters in the explanation and hence easy to understand. Thanks very much...
Great video mate very descriptive. My favourite part was how you drew the hoses on the white board demostrating whats happening then showing us physically afterwards. Thank you for the content
Awesome video. I learned practical things that i did not fully understand due to the limitation that i studied it through books only. Thanks. Keep it up please
Very well done. I am fluid power certified hydraulic mechanic with 40 yrs. Exp. Best video i have seen. Here in the US we say Open Center and Closed Center. But great job
Just watched your Great video, very well done!. I learnt hydraulics 35 years ago, as a mechanical fitter working on presses and factory equipment, just a mention that the swash plate in a axial piston pump changing positions may not just change displacement volume, but also can change its relative position to the inlet and outlet ports on certain pumps!. What amazes me is the service life of some equipment may have been from WW2.😂 All gone now I imagine!
I just bought tons of hydraulic Pistons, a pump, line and valves, also a big ram with absolutely no clear understanding of how to make them work or what to do with them... 😄😄😄😄 UA-cam to the rescue AGAIN.😎💯👍
Good explanation . Closed loop systems would generally have some kind of top up or boost pump incorperated to keep a contant gpm. also without a top up a possibility of cavitation could occur. If there was some kind of drag/force holding the wheel then pressure would build up thats why a PRV would be installed to divert back to tank. hense the reason for a boost pump to keep the fliud topped up. and hense the reason the tank is still there.
Great video , can you make a video on how to correctly add a oil cooler , return side , with all the components and options like how much oil to put through the cooler , GPM flow etc . Cheers
Very cool I am watching this and all of a sudden a light comes on and this is my John Deere transmission driving lawn mower I rebuilt, basically I changed about 40 Orings & a couple of shaft seals they wanted a thousand dollars for a new one I bought a rebuild kit for 80 dollars I must of fixed it still working after two years !! LOL
This guy really knows how to teach. But I would suggest for a more tidy environment especially since its a video presentation. One can easily be distracted. Also I suggest that different colour hoses be used for 'send' and return lines. But I really like how he teaches. keep it up. What textbooks are recommended for the study of hydraulics installation and repair?
LegendLength the problem with open loop is the valves themselves, you got priority, boom over bucket etc etc, on a skid steer that would look like, boom up, nearly no more traction, by the hydrostatic system, each pump only has one motor to actuate therefore, you can control each pump to have the same power even if you lift the boom or bucket, because the hydrostatic pump doesn’t provide oil for the boom up, so you can drive, turn and lift boom all at the same time. If you do boom up and bucket at the same time, you will have to balance your actions because if you go 100% boom up, there will be no oil for the bucket.
LegendLength Skid steer loaders generally have a tandem closed loop transmission pump for drive. The two pump elements are of equal displacement and each unit feeds a drive motor for the wheels on the left or the right. this means that if each pump is on maximum displacement the vehicle travels in a straight line. If the operator reduces displacement on one of the pumps its corresponding motor will slow down and the vehicle will start to turn. If the operator has one pump on maximum forward displacement and the other pump on maximum reverse displacement the vehicle will spin on the spot.
But this isn't how an open loop system works in practice. Directional control valves are usually proportional. You can control the speed with the lever pretty well. You don't normally need any flow control valve that increases unneccessary pressure, energy consumption, heating and wear on the pump. But in systems with solenoid control (on-off function) valves you need flow control valves if you don't want full flow on part of the circuit.
I think all you've taught me are the two names. I've driven a few machines that use both for the drive wheels. Hands up all those who want Lego to make a new range of ADULT LEGO with hydraulic parts including pumps driven by 3 phase motors - yeah !
thank you for your videos they have been very useful , i have a morgan giles motor cruiser from the 1970s with Hydraulic drive based on a perkins 4108 diesel engine attached to a Hydraulic pump in an open system that has a motor driving the propeller, i am looking at adding a hydraulic generator into to system and restoring its original functionality. i am wondering if you can explain remotes on this system, my boat has the mechanical direction and speed controls in the engine bay but also another set that look electrical on the helm that are supposed to be controlling the direction and speed when its all working .
But here is a flaw concerning the open loop system. Directional control valves are usually proportional. You can control the speed with the lever pretty well. You don't normally need any flow control valve that increases unneccessary pressure, energy consumption, heating and wear on the pump.
On every tractor, loader, excavator etc with a fixed displacement pump for the working functions you control the hydraulic cylinders and even motors by the levers on the control valve and rarely any flow control valve is used. Controlling the speed of a cylinder is pretty much like controlling the speed of a motor.
Positive with open loop system is low cost components and simple, if using propotional spool you have good control of the wheel. Closed loop wirh varible pumps requires super clean oil and pump costs 10 times more. So type of system to choose depends on machine and application.
Right. To be more exact, this system is called "closed loop hydrostatic". I have a playlist on my channel named "hydraulic learning". There you can find 2 videos where this system is explained in detail. The system is in principle a stepless gear box with its variable bidirectional displacement pump - and in more advanced systems even a variable displacement motor. Less oil flow means less speed and more torque while more oil flow means more speed and less torque. The simpliest example of this system is on lawn movers But a precise hydrostatic drive can also work with an open loop system as well as with a closed loop system. The difference is that a valve is needed to change the direction of the oil flow, because the pump can't be bi-directional. Most bigger modern excavators use the open loop system. They usually have 2 variable displacement unidirectional pumps that drive both the tracks and the digging equipments controlled by valves.
I am guessing on the open loop, when the directional values are in neutral, then the oil makes a loop from the pump through the directional valve and back into the tank. otherwise it would dead-end.
That's how all open loop systems that use fixed displacement pump work. These valves, in opposite to the closed center valve in this video, are open center valves. And proportional directional control valves are used, which means you can control the speed by the lever on the valve and no flow control valve is needed. This guy doesn't seem to know much about hydraulics.
But this isn't how an open loop system works in practice. Directional control valves are usually proportional. You can control the speed with the lever pretty well. You don't normally need any flow control valve that increases unneccessary pressure, energy consumption, heating and wear on the pump. But in systems with solenoid control (on-off function) valves you need flow control valves if you don't want full flow on part of the circuit.
Two questions: In closed loop, how does fluid from the tank get in/out of the system with variable volume applications, like cylinders? And on the open loop, can't the actuator adjust speed by diverting more/less fluid to the working loop vs the return?
There is a huge flaw in this. Also in an open loop system you normally control the flow by the control lever and you don't use any flow control unit that rises the pressure and causes overloading and heating up the oil. When no oil pressure is needed the oil has free passage through the pump. A very little power is needed for this. Almost every excavator, loader and agricultural machine uses the open loop system for digging and loading. The closed loop system is mostly used to move the whole machine, because the variable displacement pump works like a stepless automatic gear box: Less volume (speed) means more pressure (torque). In an open loop system you don't have more pressure at less flow. I can't understand how an obviously educated person can spread disinformation like in this video. I've been working with hydraulics for decades and I haven't seen any special flow control valve used for this purpose. It's only used for safety reasons to put a limit to the maximum oil flow.
If the motor is running the oil goes like this: Tank > pump > directional control valve > motor > directional control valve > tank. This valve has a pump port (P), a tank port (T) and two output ports (A and B) for a motor or a cylinder. In neutral position, where the motor isn't running, the oil flow goes directly from port P to port T. Notice that I didn't mention the flow control valve. A directional control valve is almost always proportional which means you can control the speed well enough with it. You don't normally need any flow control valve that increases unneccessary pressure, energy consumption, heating and wear on the pump. A flow control valve should only be used in combination with a flow compensated variable displacement pump. Not with a fixed displacement pump like this. "Specialists" have their limits too....:)
Well done. So closed loop is direct control of the plate and amount of fluid pumped. Open pumps same amount always and you control where it goes or how much bypasses.
Very informative. I know this was 7 years ago, but I have a question. In the closed loop you don't have an oil tank? If so, would you service the hydraulic oil in the pump itself? Thanks and again, great video.
Closed loop still uses a tank, just a lot smaller in size (which is one of the benefits of closed loop). Servicing the oil in a closed loop system is the same - change the oil and filters like a normal system.
Great video, it visualization gave me a better understanding with its explanation of course but als intrigued me. Like how fixed is the motor as it’s closed off and does the restriction valve boost the power too besides restrictions the pump?
From his explanation, open loop system is better in the sense that we can add a pressure relief valve once the pressure in the system is built up. This is to protect the pump from overheating. But whereas closed loop system cannot do it. Is my observation correct?
Almost certainly - the helicopter swash plate allows the pitch of the rotor blades to change depending on where they are in the rotation (The cyclic pitch), to allow roll and pitch to be controlled. It works the same way as the pump shown except instead of moving pistons as the pump turns relative to the swash plate, the angle of attack (pitch) of the rotor blades is adjusted by the swash plate.
A very well presented video, with clear uncomplicated use of English Language, and obviously well-prepared visual aids.
10/10 for this one!
9/9 how do you fill the closed loop system with oil without tank, thats what i missed the most :(
Brian Gillis Baie has
13/13 I would like to reiterate the fact that THERE IS NO HEAVY TECHNICAL VOCABULARY! It is refreshing to watch an engineering video that is straightforward and visually aiding.
@@martynasvizbaras1180 basically everything is built into the closed loop system . enough room for oil and the control valves. seems like the open system is more user friendly. easier to repair.
I taught hydraulics for John Deere techs at a Technical College. This presentation is SUPER GOOD. Every Tech should see this one. Great Job!!!
I also taught hyd and some folks just never really unstand how it works 😊
No matter how you explain it to them 😢
I loved working but had to retire at 68
This is the best, simple, practical explaination I have seen on youtube for this subject matter.
Well stated👍
I don't think it is the best simple practical explanation but it's not bad for a beginner.
Good explanation how the hydraulic pump works.This gentleman makes it easy to understand
Good presentation. In summary from my past experience as an ex hydraulic engineer. Closed loop systems primarily used in mobile applications where a compact design is needed and a direct, dual direction connection is required between a single pump and motor or motors. Advantages: compact design due to smaller tank, smaller hydraulic pipes, less valves. Disadvantages: expensive components, often variable dual direction pumps and/or motors, design limitations in adding additional end uses, unequal displacement end users users (such as standard cylinders). Open loop systems primarily used in static industrial systems. Advantages: lower component costs and unlimited design options, multi independent actuators from a single system. Disadvantages: bigger tank capacity required, bigger pipes on the return side, separate valves.
@Ask APT No, moved out of the field 21 years ago. Still very passionate about all hydraulic. While mechanically I would imagine the systems remained similar, I am sure on the control side, there have been good developments over the past 20 years. All the best.
I gathered this from my basic knowledge of hydraulics. I'm learning mobile can be a be a little more complicated because of the size constraints. But they can have many configurations and is important to know what your working on before your working on it.
The best demonstration I found so far, it is really best to explain while showing the actual system work at the same time.
Super nice presentation. Good understandable language, no dumb loud music.
Thank you and keep up the good work
The yeare is 2024 and this video is helping me with my A&P hydraulics class better than my instructor! Thank you so much for the amazing video!!!
You the best hydraulics tutor on UA-cam right now,Respect🙇🏽♂️
This is the best and most clearly explanation of closed and open loop systems I’ve ever seen. Thank you for the post!!
The most excellent presentation ever.
I've understood the concepts I've been missing for year.
I like what you have prepared. It was a great explanation. I really liked seeing inside the pump.
Best explanation of this I've ever seen.
Well done and thank you.
Visual learning is way better than theory training. Great job! Keep the vids coming.
The hydrostatic tractor i use to cut the yard.
One pedal is forward and the other is for reverse.
A great explanation!!
This guy explains things so well. Natural teacher.
Excellent demonstration. Thanks for taking the time to do this.
Very helpful and informative! I loved the way you demonstrated your point: by sequentially adding parts and explaining the differences in the state of the loop as you went.
But here is a flaw concerning the open loop system. Directional control valves are usually proportional. You can control the speed with the lever pretty well. You don't normally need any flow control valve that increases unneccessary pressure, energy consumption, heating and wear on the pump.
On every tractor, loader, excavator etc with a fixed displacement pump for the working functions you control the hydraulic cylinders and even motors by the levers on the control valve and rarely any flow control valve is used. Controlling the speed of a cylinder is pretty much like controlling the speed of a motor.
@@ontheroadagain4773 Exactly. In most cases, you don't need a flow valve when you have a control valve that will do the same.
The systems with solenoid control valves you do if you don't want full flow on part of the circuit.
closed loop is used in transmissions in just about every construction, forestry and farming machines these days, open loop is for hydraulic cylinders where the oil needs to be returned to a tank as the oil amount varies to and from the hydraulic rams/cylinders.
Why are they not used in cars: Is there torque multiplication, Can they be used for high speed?
Wait why not use a closed loop since then you just have a pump on every ram instead of one with a complicated valve system?
On a car, the open loop system is the better choice for a lot of reasons!
The variable speed ability is taken over by the engine, and gives you the ability to use sliding vane or gerotor pumps for simplicity and longevity. An example is a power-steering assembly. These systems pump fluid through an a little hole (called an orifice). At low engine speed, the orifice is too big to be a restriction, and the car is likely parked or has low duty requirements, so drag isn't a problem. You can turn your power steering pump with your hand! Pressure gain has exponential characteristics. Doubling engine speed will quadruple the pressure, and the engine often goes over 10-times the idle speed. Any shock loads against these systems are typically resolved with the tremendous amounts of momentum in the engine.
For an Electric motor that rotates at a fixed frequency (60hz, geared down to whatever suits your nominal shaft torque requirements and pump speeds), the closed loop system makes sense, but has its own sacrifices. For example, we might need a sudden burst of speed. The motor often can't cope with this, or becomes a reactive load for the power source. The work-around is to have a huge flywheel on the motor. If you're dealing with shock loading, the flywheel will give you all of the load you could ever want, but the shock loads can trigger your safety valves, causing the system to go backwards.
Automatic transmissions have open-loop systems that are optimized for the duty at hand. You have control over engine speed and should be mature enough to know what kind of gear shifting duty the transmission would ever need to do. Given that information, an open loop system can be made, such that its mode of failure is known and forced to happen for safety reasons.
@@BigCroca still would need a valve to change direction and control speed what is driving each pump? and on a high cycle time machine you would need coolers on each one, a normal valve is in no way complicated to understand
A very excellent video presentation- clear, simple, and succinct. Many Thanks for this, really really appreciate it!
Fantastic explanation,even a layman can understand ❤
Really many many thanks for your your existence, and the videos you upload. I've been trying to understand the hydraulic system on the bulk carrier ships i work and you are definitely helping.
A very good video. Very well explained with the help of equipment. There are no clutters in the explanation and hence easy to understand. Thanks very much...
this was honestly a well made video. straight to the point. I learnt something today thanks.
Great video mate very descriptive. My favourite part was how you drew the hoses on the white board demostrating whats happening then showing us physically afterwards. Thank you for the content
Thanks for the great video,,,like everyone said, very clear with vocabulary and visual aids and no annoying music
Awesome video. I learned practical things that i did not fully understand due to the limitation that i studied it through books only. Thanks. Keep it up please
Very informative. Thanks for sharing. I just bought my first tractor and this will help me comprehend how to hydraulic systems work on it. God Bless.
Very well done. I am fluid power certified hydraulic mechanic with 40 yrs. Exp. Best video i have seen. Here in the US we say Open Center and Closed Center. But great job
Just watched your Great video, very well done!. I learnt hydraulics 35 years ago, as a mechanical fitter working on presses and factory equipment, just a mention that the swash plate in a axial piston pump changing positions may not just change displacement volume, but also can change its relative position to the inlet and outlet ports on certain pumps!. What amazes me is the service life of some equipment may have been from WW2.😂 All gone now I imagine!
It was clear, simple, and viable. Thank you so much.
wow i got this i thought it was going to trigger headache but the explanation has gone so well and i really enjoyed it thank you so much
the best illustration of open and closed systems. thanks sir
There should be oil cooler in closed hydraulic system..
As the hydraulic oil on heating reduces the efficiency..
3:52 "I've now connected my hydraulic directional control valve into my open-loop system I'll remove my"
You've done far more than that mate !
I just bought tons of hydraulic Pistons, a pump, line and valves, also a big ram with absolutely no clear understanding of how to make them work or what to do with them... 😄😄😄😄 UA-cam to the rescue AGAIN.😎💯👍
a discussion about balanced close system and therefore very little heat could be included. Nice presentation.
the best video on this topic, we learned so much
Good explanation .
Closed loop systems would generally have some kind of top up or boost pump incorperated to keep a contant gpm. also without a top up a possibility of cavitation could occur.
If there was some kind of drag/force holding the wheel then pressure would build up thats why a PRV would be installed to divert back to tank. hense the reason for a boost pump to keep the fliud topped up. and hense the reason the tank is still there.
Absolutely clear and concise. Brilliant. Thanks!
I learned in this 10 minutes more than those hours in the class!
This Piston pump is very interesting, as it can develop even more pressure with small tilt or volume. Effizient as you say. Cool.
Great video , can you make a video on how to correctly add a oil cooler , return side , with all the components and options like how much oil to put through the cooler , GPM flow etc . Cheers
Good clear and simple explanation. Top marks
Good explanation of the main two kinds of hydraulic system differences.
Very cool I am watching this and all of a sudden a light comes on and this is my John Deere transmission driving lawn mower I rebuilt, basically I changed about 40 Orings & a couple of shaft seals they wanted a thousand dollars for a new one I bought a rebuild kit for 80 dollars I must of fixed it still working after two years !! LOL
Excellent presentation bro. I really appreciate the good explanation.
This guy really knows how to teach. But I would suggest for a more tidy environment especially since its a video presentation. One can easily be distracted. Also I suggest that different colour hoses be used for 'send' and return lines. But I really like how he teaches. keep it up. What textbooks are recommended for the study of hydraulics installation and repair?
This was helpful, nice and simple presentation, thank you so much bro
On a skid steer you have two closed loop systems and one open loop system.
LegendLength the problem with open loop is the valves themselves, you got priority, boom over bucket etc etc, on a skid steer that would look like, boom up, nearly no more traction, by the hydrostatic system, each pump only has one motor to actuate therefore, you can control each pump to have the same power even if you lift the boom or bucket, because the hydrostatic pump doesn’t provide oil for the boom up, so you can drive, turn and lift boom all at the same time.
If you do boom up and bucket at the same time, you will have to balance your actions because if you go 100% boom up, there will be no oil for the bucket.
LegendLength Skid steer loaders generally have a tandem closed loop transmission pump for drive. The two pump elements are of equal displacement and each unit feeds a drive motor for the wheels on the left or the right. this means that if each pump is on maximum displacement the vehicle travels in a straight line. If the operator reduces displacement on one of the pumps its corresponding motor will slow down and the vehicle will start to turn. If the operator has one pump on maximum forward displacement and the other pump on maximum reverse displacement the vehicle will spin on the spot.
@ John Ayres why don't bulldozers use the same system? It would save alot of cost with their large transmission sizes.
David Vermillion I am not familiar with Bull Dozer circuits but hydrostatic transmissions are more efficient than valve controlled motors.
No what I meant was taking the system skid steer bobcats use and scaling it up.
You are a great “precision” based teacher
Very good explanation. Great job. Thank you
omg thank you so much for sharing such a awesome video. It is very understandable and easy for beginner.
But this isn't how an open loop system works in practice. Directional control valves are usually proportional. You can control the speed with the lever pretty well. You don't normally need any flow control valve that increases unneccessary pressure, energy consumption, heating and wear on the pump.
But in systems with solenoid control (on-off function) valves you need flow control valves if you don't want full flow on part of the circuit.
I think all you've taught me are the two names. I've driven a few machines that use both for the drive wheels.
Hands up all those who want Lego to make a new range of ADULT LEGO with hydraulic parts including pumps driven by 3 phase motors - yeah !
thank you for your videos they have been very useful , i have a morgan giles motor cruiser from the 1970s with Hydraulic drive based on a perkins 4108 diesel engine attached to a Hydraulic pump in an open system that has a motor driving the propeller, i am looking at adding a hydraulic generator into to system and restoring its original functionality. i am wondering if you can explain remotes on this system, my boat has the mechanical direction and speed controls in the engine bay but also another set that look electrical on the helm that are supposed to be controlling the direction and speed when its all working .
Great simplified lecture
But here is a flaw concerning the open loop system. Directional control valves are usually proportional. You can control the speed with the lever pretty well. You don't normally need any flow control valve that increases unneccessary pressure, energy consumption, heating and wear on the pump.
On every tractor, loader, excavator etc with a fixed displacement pump for the working functions you control the hydraulic cylinders and even motors by the levers on the control valve and rarely any flow control valve is used. Controlling the speed of a cylinder is pretty much like controlling the speed of a motor.
Positive with open loop system is low cost components and simple, if using propotional spool you have good control of the wheel.
Closed loop wirh varible pumps requires super clean oil and pump costs 10 times more.
So type of system to choose depends on machine and application.
Thank you for the great explanation!
What is the type of the motor on the closed loop system?
This lad will go far. Thx
It clears the concept of open & closed loop pump
Brilliantly presented. Thanks!
Awesome demonstration! Great job explaining this
wonderful accesible cogent clarity!
Correct me if i'm wrong, but my understanding from the video the close system is like a servo motor. To get a precise movement of the actuator, right?
Right. To be more exact, this system is called "closed loop hydrostatic". I have a playlist on my channel named "hydraulic learning". There you can find 2 videos where this system is explained in detail.
The system is in principle a stepless gear box with its variable bidirectional displacement pump - and in more advanced systems even a variable displacement motor. Less oil flow means less speed and more torque while more oil flow means more speed and less torque. The simpliest example of this system is on lawn movers
But a precise hydrostatic drive can also work with an open loop system as well as with a closed loop system. The difference is that a valve is needed to change the direction of the oil flow, because the pump can't be bi-directional. Most bigger modern excavators use the open loop system. They usually have 2 variable displacement unidirectional pumps that drive both the tracks and the digging equipments controlled by valves.
Really well put together! learned loads! thanks dude!
Could you do a video on an orbital unit please.
When should you use an oil cooler and where should it be located ?
I am guessing on the open loop, when the directional values are in neutral, then the oil makes a loop from the pump through the directional valve and back into the tank. otherwise it would dead-end.
That's how all open loop systems that use fixed displacement pump work. These valves, in opposite to the closed center valve in this video, are open center valves. And proportional directional control valves are used, which means you can control the speed by the lever on the valve and no flow control valve is needed.
This guy doesn't seem to know much about hydraulics.
this is soo cool and makes it simple to understand i had to download it
But this isn't how an open loop system works in practice. Directional control valves are usually proportional. You can control the speed with the lever pretty well. You don't normally need any flow control valve that increases unneccessary pressure, energy consumption, heating and wear on the pump.
But in systems with solenoid control (on-off function) valves you need flow control valves if you don't want full flow on part of the circuit.
You can also have open/closed loop as in Parker Gold cup “D” version
Great video, I will definitely recommend this training to others.
Excellent explanation. Thank you for this!
Two questions: In closed loop, how does fluid from the tank get in/out of the system with variable volume applications, like cylinders? And on the open loop, can't the actuator adjust speed by diverting more/less fluid to the working loop vs the return?
excellent presentation. easy to understand. if you teach to small kids. i guarantee you that they will understand it.
There is a huge flaw in this. Also in an open loop system you normally control the flow by the control lever and you don't use any flow control unit that rises the pressure and causes overloading and heating up the oil. When no oil pressure is needed the oil has free passage through the pump. A very little power is needed for this. Almost every excavator, loader and agricultural machine uses the open loop system for digging and loading.
The closed loop system is mostly used to move the whole machine, because the variable displacement pump works like a stepless automatic gear box: Less volume (speed) means more pressure (torque). In an open loop system you don't have more pressure at less flow.
I can't understand how an obviously educated person can spread disinformation like in this video. I've been working with hydraulics for decades and I haven't seen any special flow control valve used for this purpose. It's only used for safety reasons to put a limit to the maximum oil flow.
You don't limit the speed with a restrictor before the valve in a open loop system. Best way is to limit movement och spool
yes terrible device before the pressure relief
Nice class!! My old tractor vs my new zero turn mower, Now I get it :) Thanks!!
So when I'm right. From 6:00 - 6:40 min. is the oil going from the valve directly back to the tank?
If the motor is running the oil goes like this: Tank > pump > directional control valve > motor > directional control valve > tank. This valve has a pump port (P), a tank port (T) and two output ports (A and B) for a motor or a cylinder. In neutral position, where the motor isn't running, the oil flow goes directly from port P to port T.
Notice that I didn't mention the flow control valve. A directional control valve is almost always proportional which means you can control the speed well enough with it. You don't normally need any flow control valve that increases unneccessary pressure, energy consumption, heating and wear on the pump. A flow control valve should only be used in combination with a flow compensated variable displacement pump. Not with a fixed displacement pump like this.
"Specialists" have their limits too....:)
A very well presented good job and thanks for the great information
Well done. So closed loop is direct control of the plate and amount of fluid pumped. Open pumps same amount always and you control where it goes or how much bypasses.
Great job. I feel these would be awesome in cars and trucks
Without the tank aren't you removing the cooling aspect for the oil as well as giving up the opportunity for any dirt to drop out?
4:35 One way you can control its speed - just go easy on the lever ! It's infinitely variable between stopped and max.
Very informative. I know this was 7 years ago, but I have a question. In the closed loop you don't have an oil tank? If so, would you service the hydraulic oil in the pump itself? Thanks and again, great video.
Closed loop still uses a tank, just a lot smaller in size (which is one of the benefits of closed loop). Servicing the oil in a closed loop system is the same - change the oil and filters like a normal system.
@@CustomHydraulics awesome! Thanks for the reply.
Great video, it visualization gave me a better understanding with its explanation of course but als intrigued me. Like how fixed is the motor as it’s closed off and does the restriction valve boost the power too besides restrictions the pump?
Do you have a video on explaining the Hydraulics for a Tractor? I need to install hydraulics for a external motor with a valve.
From his explanation, open loop system is better in the sense that we can add a pressure relief valve once the pressure in the system is built up. This is to protect the pump from overheating. But whereas closed loop system cannot do it. Is my observation correct?
Thank you for the well informed video. Came out great.
thanks bro , it was easy to understand basics of hydraulics. Keep it up
thanks for video but what if we want to add a small reservoir for in case of leakage? Where should we connect?
Is there a video on how to design which size motors and pumps and hoses and tanks and so on.
Can you show me how the swash plate pump is used in positioning the rudder angle in the ship?
Thanks for the video.... very well made! Easy to understand the basics!
very simplified & helpful vdo, plz make more vdos like this. thank u
Absolutely perfect presentation!
Brilliant clear concise video. Thanks
Best explanation so far!!! How do I learn more? where? And thank you for sharing this!
Fantastically simple explanation. Thank you very much for posting this video.
I wonder if the swash plate is related to the swash plate used to control the direction of a helicopter
probably,
Yes
Almost certainly - the helicopter swash plate allows the pitch of the rotor blades to change depending on where they are in the rotation (The cyclic pitch), to allow roll and pitch to be controlled. It works the same way as the pump shown except instead of moving pistons as the pump turns relative to the swash plate, the angle of attack (pitch) of the rotor blades is adjusted by the swash plate.
Thankyou soo much.very easy and simple way of teaching.I really appreciated.
Best explanation ever, Thank you.
Heat is a killer of the system and keeping it cool is very very important