Pump capabilities

[Superfly257]

Hello all,

I am very new to this and I am trying to wrap my head around what it is that pumps can and can't do, as well as what exactly all the information listed in pump brochures means.

For instance, I am looking at a pump here:

http://vikingpump.com/en/documents/Brochures/500_ProductSelectionGuide_en.pdf

on page 18 ( the iron external gear pump)for a certain application. I need to purchase a pump that can pump 15W40 engine oil in a temperature range from -25 C (where it has a viscosity of 7000 cP)up to 200 C. The flow rates I need to hit are 0.5 to 5 GPM and I need a pressure of about 60 PSI.
I see that these pumps can get up to 1,000,000 cSt... does that mean they can pump any oil up to 1,000,000 cSt?
Also, looking on the right at, say, pump SG-0519 it looks like it can pump at my desired flow rates, but would it be able to pump an oil at 1,000,000 cSt at those flow rates?
In other words, can it pump minimum and maximum listed flow rates (and everything in between) for the entire viscosity range it has listed (1 to 1,000,000 cSt)?
Also, if I get a device to control and regulate the flow and pressure of the pump, will I be able to pump any given flow rate at any pressure, or does the pump need a specific pressure to hit a specific flow rate?
(i.e. can I pump 5 GPM at 40 psi, 60 psi, 100 psi, etc.?)

Again, I am very new to all this, and how all these things correlate to one another and work together is proving tough to understand, so any light you could shed on the situation would be greatly appreciated!

Thanks!

 

[BigInch]

Looks like it will do it.

The pump, being a positive displacement gear pump, will pretty much reach any pressure required to move your fluid UP TO THE POINT that either it runs out of the power required to do so, breaks down, explodes, or blows up your piping. It is rated for continuous duty up to 500 psi, so as long as your piping system does not have a pressure loss of around 500 psi at your required flowrate, it will get it on.

Highly viscous oils are likely to be somewhat non-Newtonian and may require a high pressure to get moving with a lower pressure required afterwards to keep it moving, or if you keep the same high pressure, your flowrate will increase, and this pump will reach much higher pressures for short spikes, so there is also some good capacity for that if needed, once again, provided your pipe is rated for those pressure spikes too. I didn't notice if it has an internal pressure relief valve, so be sure your piping is protected from possible overpressures that may develope, should some downstream valve become closed, or flow otherwise gumed up.

http://virtualpipeline.spaces.live.com

 

[BigInch]

The pressure required to move your fluid depends on the resistance of your piping. Smaller diameter, longer pipe, partially closed valves, more fittings and higher viscosities will all conspire to require higher pressure at whatever speed you select to get your desired flowrate. A low flowrate in large diameter pipe will most likely require little pressure, but a high flowrate through a very small diameter, long pipe, with a viscous fluid could cause this pump to reach very high pressures, which it will be happy to try to do up to the point where things go "bang" or a pressure relief valve opens.

http://virtualpipeline.spaces.live.com

 

[TenPenny]

You've just raised about a month's worth of questions.

To simply greatly, a gear pump will pump a particular volume at a particular speed; the discharge pressure will be whatever is required to move that volume through the piping. The pump is going to keep trying to push that volume until it moves or something breaks. So, in order to vary the flow rate over such a side range, the speed will likely have to be varied.

Viscosity will have a definite effect on the pump, though; to some extent, the lower the viscosity, the more 'slip' you will get (leakage back to suction around the gears). So the higher the viscosity, the less slippage, although this tends to be a fairly small figure.