Pump dynamics definiton

[pehl]

I have an issue with the definition of the "pump dynamics".
Can somebody explain to me what it means exactly?
Thank you!

Peter H.

 

[lookintomyeyes]

Can you give an example of the context in which the term is used?
"Pump dynamics" at its simplest level could refer to the general nature of how pumps function, and I'm not sure that's the definition you're looking for.

 

[BigInch]

To me it would mean the torque acting on the pump and fluid inside it and the generated pressure acting on the fluid in the pipe, as it overcomes impeller and fluid inertia when accelerating the impeller to angular velocity and the fluid to pipeline velocity. It may also be a loose reference to the effects of any imbalanced forces that tend to cause vibrations.

Going the Big Inch!

http://virtualpipeline.spaces.msn.com

 

[pehl]

Hello,
it should be related to the ability of a pump to deliver required volume of liquid in very short time after start pumping or, control valve opening.

I have developed a hydraulic system for direct injection of herbicides, which includes a gear pump, pressure relief valve and a PWM proportional solenoid valve placed upstream of the injection point. The flow rate is controlled by using this PWM valve.

The issue is when I fully open the PWM valve, the pressure in the pipe drop down immediatelly. Than it takes a long time to get the right pressure again and hence the required flow rate.

I guess, the problem must in the pump used. If there will be a "stronger" pump (pump with a better dymanics) the pressure increase would be much more faster.

Now, I don't how to define or describe this situation. How is the relation between the flow rate, revolutions, pressure and time. Eventually how to choose the right pump.

Thank you
Peter H.

 

[25362]

FWIW, a gear pump is not a dynamic machine, it is a displacement type of tool.

In dynamic machines the energy is used to impart a high velocity to the fluid converted to developed pressure within the pump and piping later on.

Displacement machines apply energy to the fluids by enclosing them in moving volume boundaries; the pressure increases up to the value required to move the fluid through the discharge system.

 

[BigInch]

You might be overpressuring your tubing before opening the valve. It might cause a lot of immediate flow, and perhaps some vapor space, then the pump has a bit of a difficult time building flow again. Just guessing here, but does it sound like its a possibility?

Going the Big Inch!

http://virtualpipeline.spaces.msn.com

 

[pmover]

sounds like the piping system + associated equipment/controls needs to be slightly modified to maintain a relatively constant pressure within the piping system; such that when the solenoid valve is open, the pressure within the piping system does not drop too much. my SWAG is that the volume of piping system MAY be undersized such that when solenoid valve is open and flow is established, the "pressure control system" is not responding adequately or teh system resistance MAY be excessive. another possibility is a slightly undersized pump for the desired process conditions (i.e. flow and/or pressure). it is difficult to tell with more information.

meanwhile, i hope this helps with the situation.

good luck!
-pmover

 

[Artisi]

Where has the term come from - where is it being used? this might help to define the usage. As you can see from the answers posted so far, everyone has their own idea as to what it might mean.

A dictionary definition in this case is also vague.

Naresuan University
Phitsanulok
Thailand