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
Getting A Submersible Pump’s Rotation Right
I spent the better part of 25 years attending hundreds of submersible pumps’ start-ups, and the single most common error I had to correct prior to commissioning was the pump’s rotation. The majority of Hevvy/Toyo submersible pumps sold feature an agitator. With the agitator or cutter fan clearly visible when the pump is viewed from below, observing rotation during a … Read More
Cleaning Carbon Tanks In Carbon in Leach And Carbon in Pulp Processes
The two gold extraction processes CIL (Carbon in Leach) and CIP (Carbon in Pulp) are quite similar, both using granulated activated carbon to extract the gold from the solution. For the extraction processes to function efficiently a specific carbon granule size must be maintained. It is therefore critical to handle the fragile carbon particles in a manner that does not … Read More
Understanding How Static And Dynamic Balancing Affect Cantilever Pumps
I was recently asked to investigate a vibration in a vertical cantilever pump. The client had recently rebuilt the pump and was wondering what he had missed or done wrong. In the absence of any vibration monitoring equipment, we resorted to physical checks. With the pump out of the sump, we carefully rotated the shaft and there was no evidence … Read More
What exactly is an impeller’s “tip speed” and how do you calculate it?
Establishing an impeller’s “Tip Speed” is very useful when selecting the best pump for your application, but what exactly is tip speed and how do you calculate it? The tip speed is simply the distance that any selected point on the peripheral of the impeller travels in a set time. In other words the “speed” of that point. To calculate … Read More
Differences Between Flush and Quench In Slurry Pump Seal Support Plans
When discussing slurry pump seal support plans it seems that the terms “Flush” and “Quench” are often confused and or misused. With the concept being slightly different for mechanical seal boxes vs packed seal boxes I will separate these, discussing each in turn. Mechanical Seal The basic mechanical seal flush plan is very simple. It calls for a clear/clean liquid, … Read More
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