Pumps, flow and restrictions.....

   / Pumps, flow and restrictions..... #31  
You dont list the pressure capacity of the pump so an absolute answer cannot be given. The flow will either stay the same or decrease to zero as the pump blows up due the added pressure needed to maintain the positive displacement 10 gpm flow. At 500psi to drive 10gpm thru a 1/2sqin orifice we are talking some pretty viscous fluid. ... thats like -- 3/4" dia :eek:
larry

Sorry larry, you are making this more complicated than it is....you do not even have to think about fitting sizes....OK...any pressure can be considered way below your "pump capacity"....
In that case you have the answer. I just covered both possibilities. Sorry for the confusion.

The fitting/orifice size does not affect the answer. It was just a comment on the boundary conditions. You must be pumping molasses in January.
larry
 
   / Pumps, flow and restrictions.....
  • Thread Starter
#32  
In that case you have the answer. I just covered both possibilities. Sorry for the confusion.

The fitting/orifice size does not affect the answer. It was just a comment on the boundary conditions. You must be pumping molasses in January.
larry

You were fine Larry!:thumbsup:
 
   / Pumps, flow and restrictions..... #33  
Here's a look see at these wonderful things we call "Flow Meters".....simple yes, but they do the trick.....notice they all have some sort of load valve...

Funny how most all of the posts here on TBN mention using pressure guages to troubleshoot but, hardly ever hear of a Flow/Pressure Test being done.....Best way to see AKKAMAN's reasoning's for this thread without all the Engineering/Mathematical Analysis .....(Not that it's not important:thumbsup:)
 

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   / Pumps, flow and restrictions..... #36  
Here's a look see at these wonderful things we call "Flow Meters".....simple yes, but they do the trick.....notice they all have some sort of load valve...

Funny how most all of the posts here on TBN mention using pressure guages to troubleshoot but, hardly ever hear of a Flow/Pressure Test being done.....Best way to see AKKAMAN's reasoning's for this thread without all the Engineering/Mathematical Analysis .....(Not that it's not important:thumbsup:)

Nice setup!

I think the reason (mine anyway) that you don't hear mention of them here on TBN is simple, Pressure gauges are cheap-you can get a 0-3000 PSI gauge, short piece of hose, and a QD nipple to plug into a existing port on the tractor for $30 to $40 and virtually anyone with basic mechanical skills can use it accurately and effectively.

As you well know, flow gauges are expensive (cheapest I have seen is $150 and up), and you must plumb it in to the system, often requiring many fitting and/or adapters-plus a set of manuals to tell where the test ports are if there even is any.

The average backyard mechanic can test for pressure, and even adjust PRV's with very basic skills and tools, but to test for flow is a whole 'nother story!
 
   / Pumps, flow and restrictions..... #37  
So, now the question becomes ... What is the pressure needed to drive that same flow thru an orifice having half the area?
larry
 
   / Pumps, flow and restrictions.....
  • Thread Starter
#38  
So, now the question becomes ... What is the pressure needed to drive that same flow thru an orifice having half the area?
larry

becuz pump keep delivering the same flow
 
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   / Pumps, flow and restrictions..... #39  
Something is still not right here. With a constant rpm, on a gear type pump, the volume through a tube will be the GPM's for the pump, with no or little pressure. If you start decreasing the output of the hose/line, with smaller orifice, the pressure will increase, and the velocity through the orifice will increase. The smaller the orifice, more pressure is developed, until you close it off completely, and the pump develops burst pressure. Is this correct?
 
   / Pumps, flow and restrictions..... #40  
Something is still not right here. With a constant rpm, on a gear type pump, the volume through a tube will be the GPM's for the pump, with no or little pressure. If you start decreasing the output of the hose/line, with smaller orifice, the pressure will increase, and the velocity through the orifice will increase. The smaller the orifice, more pressure is developed, until you close it off completely, and the pump develops burst pressure. Is this correct?

Yes.:)

Also in a closed loop system as the aperture gets smaller the fluid may heat up, change characteristics, and result in a loss of NPSH to the point no fluid is being pumped.:thumbsup:
 

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