What If I ran a 540 RMP pump @ 1100 RPM?

[SPYDERLK]

PD = Positive displacement pump. If this type of pump is speed-ed up the increased volume flow resistance will increase the output pressure on an ongoing basis.

On a centrifugal pump this pressure will increase to a certain degree but stop increasing when the pressure limits of the vanes or stages are met.

I see what youre saying. Friction in the faster flowing fluid will be greater, causing pressure against the pump to be higher based on how much pressure it takes to flow the greater amount to and thru the relief valve. Looked at another way tho, the PD pump does not require much speed to develop its full rated pressure, and only a little more to break it unless its relieved. On the other hand, non PD pumps rely on speed to develop their pressure. Speeding them up is the only way to get more pressure from them. As you say, this only works within a limited range - altho often a fairly broad limit if your not expecting linear increases.
Iplayfarmer, what kind of pump are you talking about??
larry

 

[Iplayfarmer]

Iplayfarmer, what kind of pump are you talking about??
larry

I don't know.

I'm just asking the question hypothetically. I figured (correctly) that there'd be something to learn from it.

I saw that there were different speed pumps on Surplus Center and wondered what the difference was.

 

[Egon]

Thats said a lot better than my version SPYDERLK!

 

[Soundguy]

I agree with the cavitation and grenade scenerio mentioned when you run an implement at 2x it's rated speed.

soundguy

 

[Brad_Blazer]

If the pump requires a lot less horsepower than your engine produces you can use the high speed PTO setting with the engine RPM proportionally reduced. Maybe a good option for running something stationary like a log splitter. I agree that overspeeding the pump is not a good idea.

Pump info:
Pump Types Menu -* Engineers Edge

 

[SPYDERLK]

I don't know.

I'm just asking the question hypothetically. I figured (correctly) that there'd be something to learn from it.

I saw that there were different speed pumps on Surplus Center and wondered what the difference was.

OK. Hyd pumps are usually rated at 2-3krpm. Much higher than your pto,but perhaps some are supplied with integral gearboxes for pto use. In such cases, if you want to fully use the pump you will have to do some research to do it safely. You need to know its spec and the gear ratio used to drive it. If you push its spec you must have a good unimpeded suction supply at or with positive elevation wrt the pump. Limit overspeed severely. Short term and never more than 10%. If your new speed is significantly greater than the rpm set up as supplied, you will need to verify that the relief valve can handle the added flow. That will take a pressure gauge at an appropriate point and an understanding of what the reading means under various modes of operation.

If youre talking roller pumps youre safer. There is more forgiveness and less $. These are notably more efficient when run faster, especially after they have worn some. Most are speced at 850 or above. I would avoid running them above 1000. Have a good suction supply and a good relief.

For centrifugal pumps you may be pumping air or liquid and the added variable makes it even harder to make informed generalizations. Particularly on a large pump dont overspeed much. Relief valves may or may not be needed.

Become informed enuf in any specific case so that you can vet advice given w/o detailed knowledge of your specific case.

larry​

 

[shaley]

Prince brand PTO Pumps are rated for 10% overspeed and that's it.

Cut from the Prince manual
SHAFT SPEEDS
Prince PTO pumps are designed to operate at up to
110% of standard PTO shaft speeds. Standard speeds
are 540 rpm for the 6 tooth shaft and 1000 rpm for the
21 tooth shaft.

 

[Wayne County Hose]

Okay now, rather than all the mathematical calculations and theories, just install the thing. Please have a high speed camera mounted on a tripod aimed at the pump. I would love to see the carnage. Let's take an airplane with a fuselage rated for 200 mph, and install an engine and try to do 400 mph. It will never make it. Take a tire with an 85 mph speed rating and try to do 170 mph. This pump is designed to pump fluid most efficiently at 540 rpm. Increasing the speed will not give more pressure, it will give more flow. Increased pressure will be a by-product of the increased flow. Pumps do not make pressure, they make flow. Spin ANYTHING at double it's designed rpm and I hope you have safety gear on.

 

[sandman2234]

What did they call those blankets we used to put over the clutch discs on cars when we souped them up? (Scatter blankets?)Might be a good use for one of them!
David from jax

 

[Soundguy]

Blast shield?

Soundguy