Radial Thrust vs. Flowrate or Volute Diameter 2

[Mark0420]

I realize that there are many, many geometries of pumps and volutes so a general or rule-of-thumb type white paper may not exist for what I'm looking for.

Has anyone seen some type of graph or chart that shows how radial thrusts increase with either increasing flow rate or increasing volute diameter in a general way?

Another general type graph that would be helpful is radial thrust vs. bearing life. In other words, as radial thrusts increase, at what point does it really start to matter?

 

[Artisi]

The answer is far too complex to answer here in one or 2 paragraphs.
A good starting point -

http://www.mcnallyinstitute.com/13-html/13-02.htm

 

[Mark0420]

I actually found that same paper on Google, but it doesn't include diameter (let alone area) or flow rate. I'm assuming that some of the other variables in his equations include diameter, pressure or flow rate, but I can't get that specific on every pump I look at. I'm not designing them . . . I'm selecting them! I don't really even need to see numbers. The shape of a generic graph would tell me a lot. Some rules of thumb would be nice . . . like "consider double suction pumps at flow rates over . . .". Ever heard of anything like that?

 

[Artisi]

The rule of thumb is to operate within the bounds set by the manufacturer, if this is not marked up on the pump performance curve - ask them.

A very rough rule is, do not operate below 80% of BEP flow or more than 120% - however, this rule is broken everyday and usually without any major concerns or problems.

Pump selection should be based on sound engineering considerations which includes many factors not just radial thrust.

 

[BigInch]

Mark0420,

It certainly does include flowrate. Look at the term K then look at what the Q values represent.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[electricpete]

Two more articles gives cover roughly the same info in a little more detail I think:

http://www.pump-zone.com/articles/22.pdf

http://www.pump-zone.com/articles/15.pdf

Is it standard terminology to use the term "radial thrust"? I realize there are radial and axial forces. I always thought the term "thrust" was reserved for axial..apparenlty not?

=====================================
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[BigInch]

SOP

Here's the reliability chart, attached.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[Mark0420]

Electricpete and BigInch,

Thank you both for the information. It was very helpful!