Vertical Pumps are Great Pumps!

Recently, I read a publication that talked about the reliability of vertical pumps and almost recommended not to use them. This really bothered me a lot because it is false and wrong. I, although today I work independently, I can tell you that I spent thirty years in the design, manufacture, installation, operation and commissioning of this type of pumps and there is nothing further from reality. To know about these pumps you have to have a deep contact with them, and really know them from the strainer to the head shaft. I wrote a?book ?about ?vertical pumps almost 20 year ago, which has helped thousands of users to know and operate these pumps satisfactorily.

There are a few things that can make your vertical pump last for many years of uninterrupted service, such as:

• Construction of all its elements with concentricity and parallelism values of 0.002".
• Leveling of the pump from 0.002" per foot of base to a maximum of 0.006".
• Shafts with ?a maximum run out of 0.002" mils.
• Pump alignment with values that does not exceeding 0.002".
• Application of correct bolt torque between bowls and also columns
• Correct material selection, especially for bearings and shafts.
• Operation of the pump within the preferred range, i.e. between 80% and 110% of BEP
• Use of a combination valve immediately after the check valve.
• Ratchet anti-reverse!
• Provide correct submergence!
• Place a casing around the pump if it is exposed to the current of a fluid such as in a river or on a dock in the sea.

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These are fundamental things that will make your pump last for many years in a satisfactory manner, and I am referring to 7 or 8 years of continuous operation before the first maintenance, and in some cases much longer. I once removed a 120-meter-long vertical pump in a municipal service that had been operating for 15 years without any previous intervention and was able to reuse the same shafts, columns, bearing retainer, and bowl assembly. We only changed the wear rings and bearings, which is completely normal, isn't it?

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There are applications where the only pump that can be installed is a VS6 or VS7, and where horizontal pumps no matter how good they are, do not have the capacity to operate. If you don't have enough NPSHA, even if you hate vertical pumps, you will have to install a VS6 or VS7 pump. I agree that vertical pumps have weaknesses and perhaps one of the biggest is that the bearings are exposed to the pumped fluid, but it is also true that there are options so that even in that condition the pump can operate well, either using an "Enclosed line Shaft" design, Rifle Drilling, or my favorite, using materials that are resistant to erosion and wear. I have seen pumps with tungsten carbide coated bearings and shaft contact area that operated for 7 years, pumping crude ?oil with high sand content, 350F, 1800 RPM, working 24/7 and with power ratings in excess of 1000 HP.

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If the pump selection is done properly, using the right materials, with a construction that meets the concentricity and parallelism values, and most importantly, assembling it as it should be done and installing and operating it correctly, then your VS pump will last for many years, many, many years.

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Now, what we have said here is not far from the care you must take when using an OH pump or a BB pump. In my long career, I have seen many people say things and demand others, but at the time of installing, operating, or repairing equipment, they do not follow the applicable standards and practices. Of course, if you installed a VS pump wrong or repaired it wrong, it will fail, but the same will happen to a Horizontal pump. Won't it? You cannot expect the pump to absorb your bad operating and assembly practices, or your operating practices. Those of us who study engineering, and are in this field, must do things right ALWAYS.

Thousands of vertical pumps operate in conditions that no horizontal equipment could do. Look at the pumps installed in barges in Chile, Peru, Argentina where no horizontal pump can do what these animals do. To say they are less reliable is easy if their operation, repair, and maintenance practices are poor. All seawater intakes are done with vertical pumps because you can't submerge an OH or BB pump. So, let's not create a false matrix to people new to pumps because perception or what you read in a paper said otherwise. Look for the root cause of the failure and you will see that it is not the pump. I assure you. You will find that someone did something wrong. For example, if you change the pump bearing material from bronze to rubber and do not do a critical speed study, you have most likely turned a perfect design into a pump that will be a bad actor but this is not the pump's fault, it is the fault of the person who dared to make modifications without the proper knowledge.

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If you do not properly level a pump, the few thousandths you measure at the base of the head, can easily be more than 1 inch at the bottom end of the pump, and that will cause premature wear, vibration and of course pump shutdown. But here again the pump experienced the failure of something someone did wrong.

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If you want to know about it, do your research, read the manuals, check API 686 when you install a vertical pump, follow the recommendations of experts in the field and not in the library. Get the right advice, consult. Do not do things without having the required experience and then go out and say that the equipment is bad. This professional network is very good, powerful, but it is also a lethal weapon if what is said in it is not analyzed in depth. Don't believe them all and do your research. Not everything is on the Internet. Use the experience that is the most valuable tool.