## Understanding how pump curves are generated

Industrial pump manufacturers always have available pump curves for fixed-speed pumps with full-size impellers, but what if you want to run the pump at a different RPM or use a trimmed impeller?  Well, the manufacturer should be able to provide you with a modified curve but if that is not easily obtainable just use affinity laws to modify the manufacturer’s … Read More

## What’s the Difference Between Water Pressure & Water Head

In a previous blog, I quoted the number 2.31 when discussing the relationship between water pressure  & water head.  Since then I have had a request to elaborate on the number 2.31 and where it comes from.  Frankly, with many gauges still calibrated in PSI  I still relate to the US system of measure. The quoted factor therefore only applies … Read More

## Let’s Explain the Confusing Term: Bulk Density Ratio

A couple of months ago I used the term “Bulk Density Ratio” and said that it was a subject for another day. So today is the day. The term bulk density ratio describes the relationship of a material or substance mass as found in a particular sample vs its theoretical mass, assuming “complete compactness” and no voids of any type. … Read More

## Understanding the Effects of Specific Gravity on Centrifugal Pumps’ Head and Pressure

It is very important when working with centrifugal pumps that there is a clear understanding of how specific gravity, commonly abbreviated to just  SG, affects or doesn’t affect pump output in terms of head and or pressure. Let’s first define SG. The dictionary definition is simply “ the ratio of the density of a substance to that of water”.   As shown below one … Read More

## Differences Between Cutter Fan Agitators and Shaft-Connected Inducers

I  was recently in a discussion with an engineer regarding the use of a cutter fan to supply agitation. I was very surprised to find that the engineer, although having some pump experience did not understand the difference between the title objects. Not only could this lead to backward rotation and subsequent damage to a pump but the lack of … Read More

## There Is No Such A Thing As A Bad Pump Only A Misapplied Pump!

No manufacturer that has been around for any length of time makes a bad pump. The bad press that follows an early pump failure is generally the result of a misapplied pump. Unfortunately, it is often the pump’s reputation that takes the rap and not the circumstances that lead to the installation of the “wrong pump”. Any reputable supplier will … Read More

## 6 Parameters Maximizing A Mechanical Seal’s Performance And Longevity

Pumps fail for a host of reasons, but as the chart below depicts, more than two-thirds of the failures relate to sealing device issues. With the movement to conserve water and minimize the quantity of waste liquids requiring treatment, the industry is relying more and more on mechanical seals. As the installed population grows so does the percentage of pump … Read More

## When Hevvy/Toyo’s “Biggest Sand Pump” Rescues A Billion Dollar Drill Rig

Over the holidays my son asked me if I had ever been on an oil drill rig. In enlightening him as to what his old man did in the 80s I realized the story might me interesting to others, so here goes. It started with a telephone call from a purchasing engineer with the Gulf Canada Resources. He was interested … Read More