It is the middle of the night and you get a call that a process pump in your system went down. This halts the entire production floor, which causes hurried calls to on-site maintenance workers, distributors and/or pump repair shops looking to expedite a fix. You have the pump tag and serial information, motor information and pipe size but nothing else, and there are no repair parts in the crib! The distributor that sold the pump tells you there is an eight-week lead time for a replacement pump, which is not acceptable. Not only that, but they also don’t have the impeller trim information or the system head curve to properly size a new pump.
Reactive actions cause every level of the supply chain, from the manufacturer to end user, to become less efficient. This could include time-consuming phone calls to find a sufficient replacement or hasty repairs that end in more shutdowns. These problems can be easily avoided with proactive pump fundamentals that need to occur at the time of the pump purchase.
The intent of this article is to shed light on simple pump sizing fundamentals that distributors should provide, and what end users should request, to reduce the overall inefficiencies that plague the process pump industry.
Beyond application data
Let us backtrack to the beginning: your application required proper sizing for the process pump, which would be specific to your needs and take into account all of your requirements. You or your local pump specialist makes sure that the pump selection will meets all your needs. That includes flow, pressure, temperature, pH and net positive suction head available (NPSHa) requirements, as well as elastomeric and metallurgic compatibility — if it is for continuous or intermittent duty — and correct voltage, phase and controls to fit your needs. You find the right pump that fits your current or new application and you order it; installation has already been completed and the pump is in full operation. What steps are we missing?
We could successfully leave after the sale/purchase and install, however, that leaves the plant susceptible to potential loss in uptime and costly temporary fixes. For anyone trying to find a solution for a breakdown, it is like having a ring of keys and the clock is loudly ticking while you try multiple keys to unlock the solution, feeling the pressure rise with each failed attempt.
Like with most large purchases, you would receive a manual, receipt and warranty information. For process pumps, the problem is simple if you only have the IOM (installation, operation, maintenance) manual, in which case you are NOT setting yourself (or the purchaser) up to be a proactive success. To answer the above question of what steps are we missing, see the following:
- Application data (this includes the inputs used to size the pump)
- Pump curve
- System head curve
- Warranty information
- Data system to manage the data for different lines, applications, plants and locations
Why do you need all this information? You need it if your intent is to become proactively efficient. Whether you are the end user, distributor or direct manufacturer, this information is used only if there is a problem. Using these proactive fundamentals increases your reliability and, in turn, your retention as a transparent solution provider.
When a new pump is sold (or purchased if you are the end user), make note of all the pump system inputs you used to size and select the pump. This includes:
- What fluid or material is being pumped (if the pump is being used with multiple liquids, notate this as well)
- Operating temperature at point of install
- Specific gravity
- Size/Amount of any particulates
- SDS (Safety Data Sheet/Formerly MSDS)
- Discharge and suction conditions (piping)
- Elastomeric and metallurgic compatibility
- Schedule of operation (i.e., continuous duty)
- Electrical (voltage, phase)
If you have multiple pumps or collected other data that were used to size and select a pump, make note of that, and keep it in a place that is accessible. Making detailed drawings of the system piping with fittings to see the full process is particularly useful, should a part of the process or piping be changed later, causing the system to potentially change. These can be engineered drawings signed off by the purchaser to verify that the system that is being installed is to their specification.
It may seem strange to focus on including a pump curve — however, would you know what the potential output for the pump should be without it? Having a pump curve would allow you to develop a baseline if system issues arise. For instance, if you are wanting to increase the flow or pressure output from your pump, you can check the pump’s capacity based on the pump curve. For centrifugal pumps, if you aren’t at the full diameter trim for the impeller, you could purchase a new impeller without having to replace the pump (dependent of output increase), and be sure to verify that a larger impeller does not overload the existing motor.
Be sure to include the NPSHr (Net positive suction head required) along with the pump curve from the selected pump and be sure that your NPSHa (available) is greater than your NPSHr (required). This information is typically located on or below the curve and it should be noted what the corresponding requirement is for the selected pump; if it is not there, the pump manufacturer should be able to provide it.
System head curve
While a system head curve sounds similar to a pump curve, it is not the same thing. A system head curve is the combination of the pump’s performance curve and the total dynamic head (TDH). When this is overlaid on top of the pump performance curve for the pump, it will show where the pump will be performing on the curve. This accounts for the system head, friction loss (piping length, piping size, fittings, radius of bends, etc.) and difference in elevation between the suction and discharge. This is, in fact, one of the most overlooked components of proper pump sizing and application, and is something that is critical to the life and operation of the pump. This is a larger topic, however, for the purpose of this article, it should be mentioned that it is an important fundamental step in operating process pumps.
Warranty information seems simple enough, but how many times do you see the warranty information listed with purchase order, serial number, date of order, date the pump was received, install date and who installed the pump? These are fine details that can be asked should a warranty issue present itself. Most distributors have records going back on purchase orders — however, having a redundant system in place can save you time and money should a catastrophic failure happen to the initial record. It is a huge time-saving step if a failure occurs.
Managed pump system data
The article has been building up to this section so far with what records should be kept for a pump (or any equipment asset for that matter). How do you currently store your data? Bar napkin? Folders filled with papers that have been stapled too many times? For those who remember filing away project files, there wasn’t an easy process to filter your results. It involved foraging through each file trying to find what you were looking for. All kidding aside, having a redundant or cloud-based data management system is crucial in quickly producing mass amounts of on-demand data. Saving large project files per each pump project isn’t so bad. Consider though, if you are a vendor who has a customer with multiple lines, applications and locations, and they call asking for specific information. The same goes for an end user — trying to find information on a specific asset may be cumbersome if you have a large-scale operation with many pump assets. Depending on your operation or customer base, find a scheme that works best to establish an organized view of all facets of your new data management system. Including pictures of the pump when it ships/arrives, its storage area location and installation location are also helpful ways to protect your pump asset.
Breakdowns are never good for anyone. Fundamental practices that anyone from an end user to a distributor should take away from this article are 1) record the steps and data used in selection and ordering, and 2) provide an efficient process to make breakdowns, repairs and replacements less of a hassle.
Tavis McVey has worked in the process pumps industry for six years with Motion Industries. He is currently a graphic and communications manager with a focus on technical product marketing. For more information, visit motionindustries.com/processing or Mi’s Process Pumps Specialist page: https://tinyurl.com/n5s2qwr.