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Construction Equipment Tech Hydraulics, Electronics, General Engineering, ect in constr equip |
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#1
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2 questions
My first question: Does the regular magom hydraulic elbow keep the hose attached to it, or do I need something to keep the pressure from kicking the hose off? Because I've seen a lot of people's hydraulics with just the hose attached directly to the elbow with nothing on it. Can I do that without the hose flying off?
My second question: Would I be able to increase the pressure on my centrifugal pump by putting a higher rpm/kv motor on it? Thanks |
#2
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Re: 2 questions
Quote:
Not sure about the motor change, i'm still using the stock
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Giving up is not an option!!! Rob |
#3
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Re: 2 questions
Hydraulic pressure is a function of close-fit of pump internal parts (pump efficiency) and the resistance in the system. A good hydraulic pump will build pressure regardless of flow (volume) in the system. Increasing pump speed will increase volume of oil and therefore, speed of the actuators, but pressure is still determined by pump efficiency.
You might see a small increase in pressure with higher RPM but it will not be much, and as the pump wears, that pressure will drop off. Have you adjusted the pressure relief valve to see if the pump can produce more pressure? That might give you some extra power, but have to watch for additional heat build-up in the system. Ken
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#4
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Re: 2 questions
Thanks guys!
I read somewhere that having smaller pipes/ports will increase the psi? Is that true? |
#5
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Re: 2 questions
No. Your psi is whatever your relief valve is set to. Smaller piping & fittings will just restrict flow to create slower speed of cyl movement.
Want more power, use bigger bore cyls, more surface piston area. Soft flexible rubber hyd hose, don't exceed 20bar. Stiffer neoprene hyd hose might be good to 40bar.
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Sharing knowledge is one thing that defies basic arithmetic logic --- the more you share, the more you get! Joe |
#6
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Re: 2 questions
Wow ok thanks!
I know it's annoying, and I am listening but; how do I increase the pump efficiency to make it stronger? I have 150 psi now with my little water pump, but I would like 200 or even 170. If I made the pump cavity smaller (the impeller closer to the wall of the casing) would that work? Also; what if I made the impeller bigger? |
#7
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Re: 2 questions
What are you using for a pump?
__________________
Sharing knowledge is one thing that defies basic arithmetic logic --- the more you share, the more you get! Joe |
#8
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Re: 2 questions
It's a little bayite 12 volt water pump rated at 150 psi (10
Bar). I just would like 170 cause that's what the wedico 966g is rated at and it seems fine |
#9
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Re: 2 questions
Bump
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#10
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Re: 2 questions
Closed systems (like equipment hydraulics) use positive displacement pumps such as gear and piston types. Positive displacement means when the pump turns, fluid is moved, without much power loss, due to the tight fitment of internal parts. Pressure relief valves are required to prevent over-pressure and pump damage.
Water pumps are typically non-positive displacement pumps, using an open impeller, that is not very efficient for high pressures, and don't use pressure regulating valves. Impeller pumps usually cannot be modified to increase pressure output very much. Even if you do get the pressure you want from this pump, as the system works at its upper pressure limits, you will increase heat buildup because of the fluid "slippage" (low efficiency) of impeller pumps. If you want higher pressures, I'd recommend considering a gear-type pump designed for hydraulics. Ken
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Big iron is awesome! |
#11
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Re: 2 questions
Yep. That makes sense. Well back to the drawing board lol
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#12
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Re: 2 questions
Hey, another question (sorry): so I'm going to get the pump but I'm making my own valves using brass pipe nipples. Does the neutral port on the valve have to be covered up before the outflow port can be used, or can the back to tank (neutral) port still be open a little when one of the other ports is accessed?
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#13
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Re: 2 questions
You are describing an open-center system - pump discharge goes through the valve & back to tank in the "off" or neutral valve position. As you open a valve to direct oil to a cylinder, the return-to-tank port is proportionally closed. At full -open to cylinder, the return port should be fully closed. This allows max cylinder speed and the pump can provide max pressure, which is now regulated by the system pressure relief valve. If the tank port is open at valve full-open, you will reduce flow to the cylinder and the pump will have to overcome flow loss and pressure reduction. Remember that flow goes to the path of least resistance, so any passage to tank will happen first and system pressure will be limited to whatever can be produced with the tank port open. This can work, if the pump has some extra flow capacity.
Ken
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Big iron is awesome! |
#14
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Re: 2 questions
Well put! That answers my question, thanks!
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