Series and Parallel Hydraulic Circuits (Full Lecture)

[@brianwaterman8185]

Thanks for the lesson. Explains some of the issues im having with 2 cylinders in series.

[@johnc4352]

Hi Jim. After observing the double acting cylinders in series, I realized there is no direct path from pump to tank in a circuit with a hydraulic cylinder, unlike a circuit with a hydraulic motor. The double acting hydraulic cylinder is very similar in action to a capacitor in DC electricity. It allows a finite amount of flow, from the positive terminal to negative terminal or pump to tank, without having an actual direct path from one to the other. And flow ceases when the charge on the capacitor is equal to source voltage or when the cylinder is either fully extended or retracted.

[@bigbadtech]

+John C Charging and discharging of accumulators is also another great analogy for capacitor circuits since flow rate will initially be quite high during the start of the charge and then level out as the accumulator approaches full charge (i(t)= (V/R) e^(-t/tau)). I've got an accumulator lecture in the works right now and I'm hoping to get to capacitors this spring/summer(?).

[@nescrapper4023]

Awesome video!

[@FluidTekPH]

Great!

[@sjefbeekmans314]

Excellent video. In scissor car lifts, I often see double acting cylinder setup, controlled by a synching valve. I am still not sure how this actually works. Clients call with problems of the lift not being in sync going down. Other then bringing both cylinders to maximum extension to remove any air, I have yet to figure out how exactly that sync valve functions and how to trouble shoot it.Hopefully I find the answer in your other videos. Non synching lifts is the most common problem in this field.

[@Nudnik1]

Some telescopic cranes had a small gear rotor which would flow divide differential volumes per each cylinder for equal extension retraction of multiple cylinders of different sizes. Two or three gear rotors of different flow per revolution to match flow to match volume in each cylinder. I think Prince made them for Grove cranes. Shalom

[@AmosMosesJr]

I've worked on series hydraulic systems but never had to bleed the hose between the cylinders. It seems to self bleed but that part I don't understand.

[@alexc5369]

Hi there, in your first example,but if you had several in series, would the rods progressively retract slower and slower due to the rod end taking up space? Edit: sorry I think you are explaining it later in the video.

[@morninghater3831]

Hi Jim; excellent video. My unique doubt is: abouyt the series connected cylinders with same stroke and different diameter (to obtain perfect synchro) what about the force of each cylinder, if both cylinder rods are lifting the same load mass? I expect cylinder Y is having an intensified force, while cylinder X is acting with a small force (pressure x rod area only); do you agree? sorry for not perfect english, I'm Italian.

[@Eplemos4Life]

Hello, Jim. @31:50 could you not just put the valve to the clamp cylinder into closed center possition to trap the hydraulic pressure. Then when it is closed you could activate the bend cylinder so that its hydraulic needs would not affect the other cylinder? This way you would not need accumulators and it would make more economic sense. Thanx great videos!

[@bigbadtech]

Yes, that would totally work, however, one can also create an even better circuit for a clamp and bend system that uses a single DCV and a pressure control valve called a pressure reducing valve. kzbin.info/www/bejne/a6fXn4KCrsaqhsk

[@nishka1264]

Great video .. can u teach how one cylinder goes up when other goes down ? ...

[@bigbadtech]

Super easy quasi series relationship .... cylinder A starts retracted, cylinder B starts extended, rod end of A goes to rod end of B, pressurized flow enters cap end of A, A extends and rod output of A is rod input of B, cap of B dumped to tank, B retracts. Reverse flow to perform A retract/B extend. Big thing to realize fluid in the rod ends of A and B doesn't circulate or get filtered or replenished. This trapped fluid would necessitate regular maintenance and/or a "makeup" input.

[@nishka1264]

@@bigbadtech I want to use it in concrete pump .. and we can use hydraulic accumulator also .. so is there a circuit diagram ? I understand system but exact I am unable to apply

[@nishka1264]

@@bigbadtech I want to use it in Concrete pump application

[@hydraulichero9399]

@@nishka1264 kzbin.info/www/bejne/g5zWfH2OeK2al6M. Watch this for concrete pump circuit

[@utubedaveg]

@@bigbadtech I have a ojd 140 ditch witch backhoe. it has two short double acting cylinders with one valve to swing side to side. Each cylinder has what they call swing control valves. They are shot and leak. Also no longer available. I understand your above post to an extent. If rod a pushes on rod b and fluid from valve pushes on cap a or b how is there any oil in the rod ends. hope I explained this right. this is a small hoe and not used except around the farm. thanks.

[@superxtroid5712]

@10:33 how did you get the values of Arod??

[@bigbadtech]

Everything you need and more: kzbin.info/www/bejne/hHXVkqiNl7qgfNk

[@scottcarullo4757]

Great video thanks for sharing and for your time. In the series portion you mentioned a few ways to overcome the different travel speeds etc or two rams, like a double ram (I think thats what you called it) since then the volumes would be the same for the cap and rod ends of both cylinders. I wanted to ask your opinion on an even simpler solution... Having two cylinders with the same physical connection types (rod and cap ends) couldn't you just install one upside down such that the outflow of the rod end on one side enters the rod end of the other ram so the volumes are the same? The pressures should remain the same across both in series and they should also remain synchronized...

[@bigbadtech]

That's a totally workable solution, however, as one extends (exhausting rod volume) the other would retract (filling rod volume).

[@TTTT-yd6qe]

78