Pressure in Parallel Circuits

The path of least resistance - you've probably heard of this concept, and you probably know how it works. But what happens to a system when the hoses are undersized? Does oil just flow through the one path with the least load? Watch the the video, and tell us in the comments what you thought was going to happen.
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[@coolkid9770]

The clearest demonstration ive come across, thank you!

[@larsvbundli1740]

This might be the best channel on youtube!

[@helicopterpeace7434]

I am very impressed. I love the way you explain this and your voice is conducive for effective teaching. Thank you. Anastasia

[@romanibukharst9517]

Thank you. Really informative explained in a easy way.

[@roberthopkins7984]

Thank you for your invaluable tuition. I have learnt a lot in a short time. I am currently learning to drive excavators, and rather than just drive them I with to have a better understanding of how they operate. And I have also done engineering many years ago at college, and watching these videos has helped answer a few questions; not just in hydraulics but in electronics also.

[@snazakat9211]

I’ve only learned from this channel of nice devoted engineers. Seen these videos several times. Thank you thank you

[@c.nagchowdhury6412]

Nicely explained👍

[@odungbedavid1193]

fantastic lecture

[@hydengineersmz3475]

Thank u very much . They said fluid power is not complicated but sophisticated Eng. salim from Iraq. Baghdad

[@akyl_tech]

such a good video material thanks a lot

[@hatimosman896]

Thank you guys your vidoes are the best realy great explanation and informative way of represnting that system wish you all the best and keep up the good work me as a fresh mechanical engineer find these videos so helpful just please dont ever stop

[@juseongseok8008]

Many thanks keep it up.

[@islamtaha6414]

Think you so much

[@troubledsole9104]

I had a system with parallel circuits for cooling. I added throttle valves for each leg to balance the flow in the branches.

[@cck0728]

As usual excellent video. You are explaining complicated things in a very easy way . Thanks for your excellent work. I have two queries: 1) For the first case, Why the (200*300: 500) psi pressure is not reflected on the gauge as this pressure would be present on the junction of the two lines? 2) Is there any general formula to calculate for any pipe, @ which maximum flow the pipe will start choking/restricting the flow? Thanking you for sparing your valuable time.

[@tankyouaa8714]

thank you this is Hassan from Eritrea

[@ajinkyasutar5376]

It's just amazing

[@mostafahemati5345]

Excellent

[@SampaioRoan]

i love technology, thank you sir

[@bertusvandewetering3015]

Very cool video with a great explanation of the concept! Does anyone know any open-source software that is able to create circuits similar to those in these videos, where you can play around with fluid flow, resistances, tube sizing and other potential circuit components? Thanks in advance!

[@henrykraft3646]

I'm interested in the dynamics of a unified lifting system of say, four parallel circuits. It seems that when a single load is evenly distributed amongst the four cylinders, the cylinders will act in unison. However, in real world circumstances, rarely are the loads equal. How do I lift an uneven load at a uniform rate? The "path of least resistance" doctrine seems to indicate that when using the parallel circuit from a common manifold, I will lift the lightest loads first. Imagine uniformly lifting a baseball bat laying horizontally using four cylinders spread somewhat equidistant. Thank you! This is a fascinating series.

[@KevinNguyen79]

Great example! In the case where the tube was undersized for the pump, which allowed a circuit pressure to open the 200 psi check, is there a heat concern in those applications? Is there a way to calculate the amount of heat that would be created due to the extra friction?

[@mangie2178]

Interested to see how this would change when regulating gas, rather than liquid

[@VivekAnandJ]

Wonderful video. Thank you so much. I however have a doubt. When larger pump is used and 279 PSI pressure is in system what happens on the output side? Since both lines join at one junction, won't the output from 200 psi line build back pressure on the 100 psi one effectively shutting it? Or since path of least resistance is towards the tank both lines will merge?

[@user-bc6kc2ff4s]

I have a question..if we install smaller diameter pipes, would not that mean that the velocity of the oil would be increased in order to maintain the flow?

[@oliverdiaz5122]

Fuel lines going to the engine normally has inline filter with pressure gauges upstream and downstream. What does it indicate if both pressure readings are equal?

[@santoshupashi1857]

hi sir.. please explain one complete industrial applications

[@fionatirmizi4446]

How do you connect in parallel when you want to operate multiple functions at once? a Crane for example. I want to lift and extend a boom at the same time. which valve will be used and how will the cnnections be made?

[@msm8212]

Thanks for your videos. @5.43, is the pressure reading is 279 or 379 PSI?

[@engindeniz1175]

What if we install shut off ball valve just before the 100psi c/v and not fully open it, but open it like %30. Would the system pressure increase? I am curious, if we do it for the initial scenario, would we reach higher pressures?

[@lovrorb]

In real life system you usually have a main valve (electro-proportional directional direct acting or pilot operated) with several sections. On every section max flow can be adjusted by means of precise pressure drop adjustment which limits out the flow on maximal spool displacement (biggest orifice opening) by pressure drop to flow equation. That way, flow can be varied by differeny current signal to the solenoid. If total maximum flow of all movents is lower than maximum flow that pump can give, all movements can be operated at max speed simultaneously. If not, what I usually do is implementation of MULTI OPEARATION function in the PLC which limits some current signals and/or prioritazing some movements. Otherwise, flow will go to movement that reqires most pressure first...and so on, total chaos :) Of course, it's not that simple, you must account for pressure drops generated only by flow through the component itself, like hydraulic motor, which completely unloaded spends more pressure on higher flow/speeds. If the pump is LS compensated variable displaced, idle pressure setting (the one which it'll maintain when no movements are initiated, and/or add up to the highest combined LS signal from "heaviest" movement) must be set higher than flow adjustment valve. Different flow rates can be acquired in many ways, depending on the producer, another way would be different/unevenly machined orifices

[@lunchboxsessions]

Wow that's a super fantastic explanation. Thanks for sharing Lovro.

[@lovrorb]

And thank you Carl (I guess) for this great animations. I've seen most of your videos, and although I understand the topic quite well already, I enjoy in this visualizations. As a electrical/controll engineer starting to work as a commissioning engineer for complex offshore cranes about a year ago, I didn't know anything about hydraulics and I had to learn a lot the hard way. If only I found this channel sooner :) However, there is is still one more (basic) thing that is bugging me, I found it important for understanding, not really for practice. I'm sure that the explanation is simple though. I would be very thankful if you could give me an answer, or even better, if you make a video about it. I will c/p the question I made some time ago on one forum. There was a huge interest in topic, I got a lot of people to think, but nobody could give me an actual answer! I'm sure many people here would be interested as well :) Here's the c/p "Hi everyone, I have some uncertainties in understanding the orifice pressure drop equation. First of all, I perfectly understand why do we have a certain pressure drop across the orifice, speed increases on the cost of the pressure drop according to formula (In ideal situations with no turbulence/viscosity factor Cd would be 1), but after the normal flow area is restored and velocity returns to original value, shouldn't the pressure increase (at the cost of kinematic energy) and end up restored by the very same formula again? (In ideal conditions, I understand there are certain losses). Does the pressure restore after it passes the orifice, and if not, why not? I'm sure I'm missing something here. I try to google for this but didn't find the info I need. Is the only pressure drop here related to losses? If so, I don't see the formula formulated in that way, it is based on pressure drop across the orifice because of gain in speed. Following that logic, after the speed is back to pre-orifice one, shouldn't the pressure be restored (minus the losses)? What would be the formula if the system is ideal (no losses)? p1=p2? Again, there must be some simple thing I'm missing here but if someone could give me an explanation of this, it would be great :) p.s. the source I found mentioning this pressure restoration, but then not including it or saying anything about it in their formulas! neutrium.net/fluid_flow/calculation-of-flow-through-nozzles-and-orifices/ Thanks in advance, L"

[@lunchboxsessions]

Well this is a deep subject. I'll just tackle a little bit of your question for now. After the orifice, one in a series of resistances is now behind the flowing hydraulic fluid molecules. The fluid is on it's way back to tank (atmospheric pressure usually, and also a low potential), and so maximum circuit pressure (potential energy) is highest at the pump outlet (for many/most systems, when functioning normally) and all other orifices are pressure drops, as fluid moves back towards the tank. This is very much the same as for voltage. Potential energy (voltage) in an electrical circuit is highest before electrons flow through a resistance on their way to the neutral/ground pole. Energy losses are permanent in a hydraulic system if heat was created/radiated outward, due to friction. The only time that I am aware of, that pressure is the same after an orifice as before, is when no flow is occurring (Pascal's law). I am speaking in general terms around your complex question. So I will give it more thought yet, especially where you are comparing only pressure to speed.

[@lunchboxsessions]

- Carl

[@lovrorb]

Thanks again! I get the general idea and I understand the concept in case you have only a pump and an orifice. You need some pressure/force to squeze the fluid through the small opening but on the orifice outlet you have tank connection. It gets a bit fuzzier when you have more complex system, like flow-metered directional valve and an actuator/load after it. Of course, it's understandable how the pressure drops are pressure losses, which translates to energy losses in form of heat. The funny thing is that I understand intuitivly these pressure drops accross the orifice (it makes sense), but the way most sources are explaining why do we have pressure drops is Bernoulli equation, and Bernoulli equation also mandates that after passing through the narrower are, the pressure will rise once again, but it doesn't, it is converted into heat. Simple question that kinda gets you thinking :) We have 2 full time hydraulic designers in our office. I asked them both the same question, and surprisingly, nobody could give me an answer. They told me I got them thinking now. When they were learning about this in their study days, they simply excepted the common explanation, without thinking too much deeper. Would be great if you could make a video about it one day!

[@friraider4]

Can aplicating in high pressure washer?

[@dpbq]

what software do you use to simulate this? thanks!!

[@lunchboxsessions]

Each simulation is built from scratch, using our own specialized tools built on standard web technologies (SVG and JavaScript). Our animators draw out all the shapes, and then write custom code to animate them. I hope that answers your question!

[@KalShaen]

The spring loaded valves in the first two should be open when the pressure of the system exceeds their rating :p

[@elouaer3abdallah826]

sir please with which program you create the hydraulic simulation

[@blmaan9299]

Sir according to ypu is ni back press then pressure would be zero but if i cut pipe just after valve there would be pressure so how this is hapening. In daily use positive displacement pump after valve we still get pressure same like if wu squze the pipe we get more pressure outside????

[@vanillapapaya9938]

What softwere do you use for simulation?

[@scass1100]

Seeing these videos makes me release how shit my education was

[@braveecologic2030]

Hopefully someone will answer accurately: if I put a 600 resistance in the single line after the the 3 parallel loads, would that allow all loads to open? And the total supply pressure in the single line before the loads would be 1200? Further, if I put a restricter of 200 after the 100 load and a restricter of 100 after the 200 load, would that also give me flow through all lines? If so, is that more efficient or less efficient way than undersizing pipes?

[@michaelfinck4994]

To your first question, no. The 600 would be in series with the check valves above so would add to the upstream pressure. Ie with both taps open, pressure at gauge would be 700psi. With both taps closed, gauge would show 900. Second question, yes that would mean all valves open and flow splits evenly between the 3 lines.

[@learnmechatronics2545]

can i download lunchbox software ,if yes ,how ?

[@Ronak.Purohit]

What is the equation to determine the percentage of the flow sharing?

[@dreamshop6916]

Sir please explain wagon tippler ckt

[@dakshsoni]

I want to simulate circuits like this can you suggests some software

[@Mech.Masters]

Pressure Gauges used in Hydraulic Machines have got a small hole of 1 mm dia, How does the gauge shows the correct value of pressure in system, there should be a pressure drop as it is also similar to orifice?

[@mattw1393]

Mech E no because there is no flow through the gauge.

[@insideengineering2490]

Sir Can you guide me which software you are using to design hydraulic system

[@imoath_s5302]

Hello! What is the program used

[@lettoalex1316]

what software that you used for design that schematics ?

[@lunchboxsessions]

See here: www.lunchboxsessions.com/help/what-software-do-you-use-to-make-the-simulations

[@user-vv9ud1ry9j]

i need any simulating program for hydraulic system,,, need a help

[@maxz3809]

According to Bernoulli's principle, when you increase the pipe diamter, shouldn't the pressure increase instead of dropping??

[@KalShaen]

That could be correct depending on the system, but generally no it's not correct unless your volumetric flow rate is increased by a larger amount than the ratio of your pressure to your flow in your equation... (not sure if I explained that well)

[@nageshalla5852]

Can any one answer please From a compressed air tank 4 pipes all of different diameters are emerging and what will be the pressure ,flow rate ,velocity from each pipe

[@midwest9757]

It will be 5 12 9 and 33

[@danielbuckner2167]

@@midwest9757 😆

[@michaelzajac5284]

How to Download it? I want to study and I watch at your movie.

[@lunchboxsessions]

Hi Michael. We don't have any way to download these videos, but there are lots of "youtube downloader" websites. Good luck!

[@michaelzajac5284]

Aw...

[@multiforc271]

please fix the mic noise ! your content is amazing and useful, but the constant noise is killing me and won't let me focus !

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[@shengjingbo8725]

I am the first

[@mmb811]

drop the background NOISE (music) it makes the video almost UNWATCHABLE, hence the DOWN THUMB