Hydraulic gear pump vs axial piston pump.

[Davidov]

@Mobiltech I don't think that they have brakes,written on this pdf link ,it say that they only have pressure relief valve (without pressure boost facility).Also 1 speed.

 

[Tones]

I've seen high pressure accumulators, just have to buy the right specs

It was the best Stauff had from a very reputable company.

 

[cfherrman]

What was the max psi rating? How much nitrogen was in the bladder?

 

[davejo]

How is the speed of the drum being monitored or estimated? Some sort of tachometer or by ear?

Perhaps the pressure gauge display used on a skidsteer rotary mower is there to inversely correlate rotor rpm?

The HP calculators described in this thread put the currently installed 107cc gear pump at 120-135hp consumption. We want to dump another 60hp (+50%) into the flail so can't we try a 150cc gear pump to see what happens? We are using salvaged parts so perhaps some trial and error is in order.

 

[Davidov]

Hello.I thought at first u ask about project screw type wood chipper xd,was confused little...
No problem,anyway yes,those guys,mechanics,that worked with me used tachometer to check speed of rotor with no load.I do plan to add pressure gauge on pressure line towards motors just to monitor at what pressure are they working while mulching.
Pump is 133cc on loader right now,low pressure type,gear,2300psi.
107cc are hydraulic motors,piston type,fixed displacement,2 of them.
I do plan to search for either gear pump +-200-240cc,lower pressure ,or piston pump +-130-150cc higher pressure.I mean maximum power output of both pumps would be more or less same.

 

[Welder Dave]

You need to read the rules concerning advertising.

 

[Shimmy1]

You need to read the rules concerning advertising.

Everyone gets one freebie.

 

[IceHole]

An engine for a gear pump system has to be sized for maximum flow and pressure. Flow X Pressure/1714 X Efficiency% = HP.

An engine for a variable displacement piston pump can be sized a bit smaller since the pump provides high flow at low pressures and low flow at high pressures. Add in HP limiting controls to the pump and engine size can be further reduced.

IME, (43 years with excavators), 170 HP with gear pumps gave considerably less performance than 170 HP with variable displacement piston pumps with HP limiting.

Interesting.

I run a 40gpm pump off a 30hp Kubota. Relief is 3000psi.

According to that equation, I'd need like 60hp.

 

[cfherrman]

You are not getting 40 gpm at 3000 psi, probably 10 at 3000 if your lucky

 

[56wrench]

When i used to check flow and pressure, max flow is at low pressure and dropped off the closer to relief pressure. At relief pressure the flow will be zero.

 

[IceHole]

You are not getting 40 gpm at 3000 psi, probably 10 at 3000 if you're lucky

The pump definitely doesn't bypass that much!

 

[cfherrman]

At 3000 psi I'm sure it can plus it's not bypassing it's also compressing fluid

 

[56wrench]

Uh, fluid doesn’t compress

 

[IceHole]

At 3000 psi I'm sure it can plus it's not bypassing it's also compressing fluid

No, it doesn't.

Just need to keep in mind of the pressure of normal operation, might be a few hundred psi, and not factor relief pressure.

 

[TishaDele]

From my experience, piston pumps generally do require less power to run than gear pumps, but the difference isn’t huge. Piston pumps tend to be more efficient, so they can achieve the same output with less energy, which can make a difference when you're looking at long-term use. But if you have a gear pump and piston pump with the same power output, they should both work with similar engine sizes.

 

[TishaDele]

From my experience, piston pumps generally do require less power to run than gear pumps, but the difference isn’t huge. Piston pumps tend to be more efficient, so they can achieve the same output with less energy, which can make a difference when you're looking at long-term use. But if you have a gear pump and piston pump with the same power output, they should both work with similar engine sizes. For a 100 kW pump, you’d typically need a diesel engine around 110-130 kW, depending on the system’s efficiency and load. I’ve used gear pumps in the past, and Northern Hydraulics always had great options to choose from when I needed to replace or upgrade my pumps.

 

[Vetech63]

From my experience, piston pumps generally do require less power to run than gear pumps, but the difference isn’t huge. Piston pumps tend to be more efficient, so they can achieve the same output with less energy, which can make a difference when you're looking at long-term use. But if you have a gear pump and piston pump with the same power output, they should both work with similar engine sizes. For a 100 kW pump, you’d typically need a diesel engine around 110-130 kW, depending on the system’s efficiency and load. I’ve used gear pumps in the past, and Northern Hydraulics always had great options to choose from when I needed to replace or upgrade my pumps.

What are you wearing?

 

[bayslasha190819]

G’day boys . So I have bought this Mulcher for my 2017 Hyundai 14 tonner. I began testing it and it’s making a horrible noise when it winds down . What’s causing it any ideas ? Cheers Morty

 

[funwithfuel]

I am unfamiliar with your attachment but pics and description are terrific. You say the horrible noise starts when you stop the implement. Without hearing it. I would guess the rotating mass continues after you close the flow. In the motor, should be an anti-cavitation valve. This keeps the motor from becoming a pump and blowing itself up. It takes oil from the B port and directs it to the A port. It does this through a restricted passage to help slow the implement without a sudden stop which break all the expensive things.
Again this is based on NOT HEARING WHAT YOU'RE DESCRIBING. But to be safe, I'd advise a filter service on your hydro circuit and to inspect the filter media . Make sure you have no debris and no sparkly bits. Also , very important, make sure that the case drain line is clear and smooth with no kinks or obstructions.
Good luck

 

[bayslasha190819]

I am unfamiliar with your attachment but pics and description are terrific. You say the horrible noise starts when you stop the implement. Without hearing it. I would guess the rotating mass continues after you close the flow. In the motor, should be an anti-cavitation valve. This keeps the motor from becoming a pump and blowing itself up. It takes oil from the B port and directs it to the A port. It does this through a restricted passage to help slow the implement without a sudden stop which break all the expensive things.
Again this is based on NOT HEARING WHAT YOU'RE DESCRIBING. But to be safe, I'd advise a filter service on your hydro circuit and to inspect the filter media . Make sure you have no debris and no sparkly bits. Also , very important, make sure that the case drain line is clear and smooth with no kinks or obstructions.
Good luck

Thanks heaps mate. Spoke with diesal Hydraulic mate he said undo the case drain hose ( into a bucket or something) spin it up and see if it still does it disconnected from the circuit. And if there’s tons of oil pump is rogered! Would a pump like that be easy to replace ? Rob