Making the right pump selection is very important; the right choice can reduce energy costs and provide decades of strong service. The wrong choice could dramatically increase operation and maintenance costs, and limit the life of the pump.
This reminder of what to check comes from Cornell Pump’s Hydraulic Seminar workbook. The information is a reminder of lessons about calculating Total Dynamic Head (TDH). Participants at Cornell’s Virtual Pump School 2020, will not only get this handy workbook, but also get numerous presentations (e.g. NPSH, TDH, pump sizing, etc.) that lead to this very topic (Pump Selection) being covered in detail on day three of the school. Plus, you’ll get the Condensed Hydraulic Databook, along with many other reference materials.
Right now, cost for general admission to the school is only $79 USD. But hurry – It goes up to $99 this weekend. Learn more about Virtual Pump School 2020. The school runs September 15 through 17, 2020, with ten sessions total offered per day; five each in Basic and Advanced tracks.
How To Select a Centrifugal Pump
The pump is selected after all the system data has been gathered and computed. The system TOTAL CAPACITY in gallons per minute and TOTAL DYNAMIC HEAD in feet must be determined. You should consider suction submergence, NPSHr and NPSHa, various speeds, other drives (engine, motor, etc.) and all system conditions to optimize the selection.
Typical Pump Installation
TOTAL DYNAMIC HEAD is the SUM of the following:
Suction pipe friction (see Condensed Hydraulic Data Book).
Suction lift (vertical distance, in feet, from lowest expected water surface to center of pump inlet).
Suction entrance loss (usually figured at one velocity head plus foot valve losses
Discharge pipe friction (Condensed Hydraulic Data Book).
Discharge lift (vertical distance, in feet from pump to high point in system).
Pressure, in feet, for service intended (pressure, in P.S.I., x 2.31 equals feet of head).
Miscellaneous losses, in feet (for valves, elbow, and all other fittings, see Condensed Hydraulic Data Book).
For capacity of 320 GPM, total head in feet is determined as follows:
28’ Suction friction (6” steel pipe, 20’ long – 1.39’/c x 20’)
5’ Suction lift
3’ est. Suction entrance loss (1’ vel. Head + 0.49’ + screen loss)
14’ Discharge friction (6” steel pipe,1000’ long – 1.39’/c x 1000’)
15’ Discharge lift
100’ System pressure (43 P.S.I. x 2.31)
10’ Miscellaneous losses (Use your own safety factor here)
147’ total head (Approx.)
For capacity of 600 GPM, total head in feet is determined as follows:
.89’ Suction friction (6” steel pipe, 20’ long – 4.46’/c x 20’)
5’ Suction lift
5’ est. Suction entrance loss (1’ vel. Head + 1.6’ + screen loss)
Cornell Pump’s design for double volutes can help keep radial forces from snapping a shaft, while increasing wear life.
The Double Volute System enables Cornell single stage, end-suction centrifugal pumps to easily handle large volume and high-pressure jobs.
As the impeller adds energy to the fluids, pressure increases around the periphery of the volute. On single volute pumps, the increasing pressure acts against the impeller area and creates unbalanced radial forces. By contrast, the Double Volute System effectively balances these forces around the impeller to reduce shaft flexure and fatigue.
Cornell’s “DVS” design helps keep shafts from breaking, extends the life of packing and mechanical seals, wear rings, and bearings – maintaining high hydraulic efficiency.
This diagram comes from page 3 of Cornell’s Hydraulic & PumpsSeminar workbook, which will feature prominently at our Virtual Pump School. Every attendee gets a print copy of the book, along with other printed materials, and even a Maglite® flashlight. Sign up now—the regular rate ends soon! Only $79 for three great days of learning, resources, and networking!
Cornell is excited to announce the winners of our 5K followers drawing!
When we hit 5,000 followers on LinkedIn, we told those that had followed us, and any that followed us with the next week, they would be entered into a drawing for some Cornell swag. The prizes and winners include:
Cornell Yeti Rambler
Kevin Paczwa at Rexnard Corporation
Daniel Trujillo at Rain for Rent
Cornell MagLite Flashlight and Leatherman Knife Combo
Shelley Hadaway at RWN Pump and Fabrication
Rod Smith, CPA, CMA at Ship Repair and Construction
Cornell North Face Jacket
Michael Hill at Sunbelt Rentals
Richard Hurst at Cargill
And you can get a Cornell MagLite flashlight if you attend our virtual pump school. As part of the mailed packet, we’ll send you a flashlight! Register for Virtual Pump School now – early bird pricing ends on August 15!
Hundreds of people have taken advantage of the early-bird pricing on virtual pump school. At $59 for three days of classes, that is less than $4.00 an hour for industry-leading instruction!
But, the early-bird pricing is ending on Saturday, August 15. Register now for the lowest price.
Virtual Pump School runs Tuesday, September 15 through Thursday, September 17, 2020. Classes are live from 8:30 a.m. until 1:20 P.M. PDT, run 50 minutes, and include a short break between sessions. Extensive daily agenda and class choices are available on the registration website.
The Cornell 2020 Virtual Pump School has two tracks, a basic track and an advanced track, and over 26 different subjects, so the school is applicable for both those new to the pump industry, as well as seasoned pump professionals.
The early-bird registration special of $59 gets you access to all three days of live seminars, the mailed packet, and to the recorded sessions afterward. Attendees also receive a certificate of attendance, and corresponding hours engaged for CEU/TCU credits after the school is finished. Sign up now , the early bird pricing ends on Saturday!
Packing is often used as a sealing method for general purpose and agricultural pumps. For the packing to be effective, and not be overheated by the shaft rotation, there must be a consistent drip of liquid, about one drip per second.
Running clearance on most new general purpose water pumps is about .010 inch on a side. (check with the factory for specifications on for your model). If wear increases this to .032 inch, the wear ring should be replaced and the impeller repaired or replaced. Wear may be caused by abrasives in the pumpage, unsupported piping loads, or other causes.
Tighten the gland nuts 1/4 turn every ten minutes until a leakage of only 40–60 drops per minutes is achieved. If the packing must be replaced, a packing puller may be needed.
The diagram is from Cornell Pump’s Installation and Care book; a workbook that provides great ideas and reminders for pump set-up and operation. Every registrant to our Virtual Pump School will not only get this workbook, but also our Pump Seminar workbook and Condensed Hydraulic Data Book, along with (most importantly) more than 15 hours of pump and hydraulic instruction. Learn more about Virtual Pump School.
Cornell has been innovative and efficient for nearly 75 years. This page from one of our brochures, circa 1955, shows off a feature you still find on our pumps; the ability to mount in many different configurations. Cutting edge in the 50’s, it still gives our customers the flexibility to use our pumps in a multitude of ways.
Watch this video done in 2017 to promote Pump School, to get a sense of the factory. We’ll not only be showing pre-recorded components of the factory, but we’ll also have machinery operators available to answer any of your questions, live. And we’ll be doing the same for test lab—one of the largest pump testing facilities west of the Mississippi!
You can sign up for Cornell Pumps Virtual Pump School 2020 now, for only $59; where we offer three days of industry-leading hydraulic instruction. That’s less than twenty bucks a day, an unbeatable price for accredited classes. Hurry, early bird pricing ending soon.
Cornell Pump reached a milestone on LinkedIn last week, topping 5,000 followers. We started our LinkedIn page in December 2011, and for many years had only a few hundred followers. It wasn’t until last year that we broke 3,000 followers. Through promoting blog posts, videos, tips, and more, we’ve been able to steadily grow.
And, we are ever-so-close to having 1,000 YouTube subscribers as well! A couple of years ago, we had fewer than 150 subscribers to the channel.
Thank you if you have followed us already. If you have not, we encourage you to do so on our linkedIn page.
And as an added incentive, we’ll be pulling a few names for some Cornell swag, such as Cornell logoed NorthFace® jackets , Yeti® ramblers, or Maglite® knife/flashlight combos! Great stuff as a thank you! Anyone who has been a follower or follows by July 28, 2020 could be drawn for one of these prizes.
And, a second chance to win; if we can get our YouTube channel subscribers to 1,000 (we need 67 more to reach that level), we’ll offer up more swag to the drawing.