Does Diameter Reduction After Pump Cause Impeller Overexertion?

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Discussion Overview

The discussion revolves around the potential effects of diameter reduction on the pressure side of a pump and whether it induces overexertion of the impeller. Participants explore the implications of this setup in a mid-scale mining operation, focusing on the mechanical behavior of the pump under specific conditions.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions whether the term "overexertion" is appropriate and suggests that the pump may be cavitating, prompting a request for flow and pressure readings and pump curve analysis.
  • Another participant speculates that the proximity of the diameter reduction to the pump could cause excessive pressure, leading to backward thrust on the impeller.
  • A suggestion is made to install a pressure regulator linked to the engine throttle to mitigate potential issues, with a warning that cavitation could damage the pump if not addressed.
  • There is a request for additional information, such as a sketch of the setup and the height of the pump above the inlet, to facilitate better speculation on the issue.

Areas of Agreement / Disagreement

Participants express differing views on the cause of the pump's issues, with some suggesting cavitation while others propose that pressure dynamics due to diameter reduction may be at play. The discussion remains unresolved with multiple competing hypotheses.

Contextual Notes

Participants note the rudimentary nature of the mining operation and the presence of monitoring appendages, which may influence the interpretation of the pump's performance and the conditions leading to vibration.

Who May Find This Useful

Individuals interested in pump mechanics, fluid dynamics, and those involved in mining operations may find the discussion relevant.

sword
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Does diameter reduction on the pressure side shortly after the pump induces overexertion of the impeller?
This is the setup: suction line: 8" - length: 20' ; high pressure centrifugal pump powered by a engine at approx. 2000 rpm ; pressure line: 6" at a length of 18" directly followed by a manifold of 2x 4". Pump distance after this is approx. 200 m. Pump medium: water.
The experience is that the pump intermittently vibrates heavily. Could this be overexertion of the pump impeller?
 
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sword said:
Does diameter reduction on the pressure side shortly after the pump induces overexertion of the impeller?
This is the setup: suction line: 8" - length: 20' ; high pressure centrifugal pump powered by a engine at approx. 2000 rpm ; pressure line: 6" at a length of 18" directly followed by a manifold of 2x 4". Pump distance after this is approx. 200 m. Pump medium: water.
The experience is that the pump intermittently vibrates heavily. Could this be overexertion of the pump impeller?
Moving to mechanical engineering...

I don't know what "overexertion" means in this context, but it doesn't sound right. Do you have flow and pressure readings before and after the pump? Have you checked the pump curve and npsh? My first guess would be that it is cavitating.
 
No, there are monitoring appendages on the setup. Since this is a mid scale mining operation, about everything happens very rudimentary. I guessed that since the manifold or in other words the diameter reduction is so close to the pump, the pressure gets to high in that area causing some kind of backward thrust towards the impeller. Does that make any sense?
 
sword said:
No, there are monitoring appendages on the setup. Since this is a mid scale mining operation, about everything happens very rudimentary. I guessed that since the manifold or in other words the diameter reduction is so close to the pump, the pressure gets to high in that area causing some kind of backward thrust towards the impeller. Does that make any sense?
Think about this, install a pressure regulator w/gauge on the pressure side, tie it to the engine throttle so that if the pressure reaches a set point the engine throttles back reducing the flow, this should be done for safety reasons anyway. I agree that it sounds like cavitation, if not fixed it will ruin the pump
 
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If you give us a sketch of the setup, we may be able to speculate better. What is the height of the pump above the inlet? Pump make/model?
 

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