Pick Your Pump
How to Select, Operate and Maintain a Centrifugal Pump
By Pam Kleineke Apr 12, 2013
When heading to the jobsite, a typical equipment checklist wrangles in the big guys —excavators, wheel loaders, backhoes — but what about the supporting cast of machines? Crews dealing with excavation or any other sort of utility work can encounter groundwater that impedes progress. This obstacle calls for the use of a pump to transport it and get the ball rolling for work to begin.
“Before any excavation, trenching or grading can begin on a construction project, such as laying or relining pipelines, groundwater must be removed,” explains Kirsten Stroud, marketing manager for Thompson Pump. “Too much moisture in the material will slow or prevent construction operations and will leave the project site without the necessary preparation for further building or compaction.”
When water does becomes an issue — whether it’s to supply water to a project or dewater a jobsite — a centrifugal pump is a popular choice for utility construction work. This type of pump is ideal because it’s very durable and offers an efficient method for moving water.
“Pumps are popular because they are a necessary evil of the construction industry, says Thomas Aldridge Jr., sales engineer for Griffin Dewatering. “They are one of the most widely used tools because nature keeps producing water and in order to perform most construction, that water has to be moved.”
A centrifugal pump is a simple rotary machine consisting of an impeller that rotates inside a stationary volute casing. Hansen Webel, manager of Centrifugal Pumps for Gorman-Rupp, further explains: “When the impeller rotates in the volute, velocity energy is imparted on the fluid as it moves from the center eye of the impeller to the impeller vane tips. The increased pressure of the fluid causes it to flow, rise to a higher level, or do both, while simultaneously reducing pressure at the impeller eye and allowing more liquid to enter the pump.”
Typically in the utility construction market, a pump must be paired with a priming system. This addition will help to rapidly create the low pressure area, as well as to handle the air that is a by-product in the system — enabling a crew to move water more efficiently.
Before You Buy
After deciding that a pump is the right fit for your job, the next step is finding a reliable manufacturer and dealer for the purchase. There’s a variety of manufacturers to from which to choose. These companies typically offer a diverse selection of centrifugal pumps and priming systems ideal for utility work.
When choosing a manufacturer, Stroud recommends doing your homework and picking one with pump-specific, knowledgeable employees. This core group will be able to address any concerns you may have and help you select the right pump for your needs.
“Be sure to choose a manufacturer that is a member of the Contractor’s Pump Bureau [CPB] with the Association of Equipment Manufacturers [AEM],” she adds. “This certifies that the pump has been designed and manufactured in conformance with CPB pump standards.”
After-sale support is also important to consider when making a pump purchase. Webel suggests that buyers should inquire how long a company has been in business and ask for references from past customers. These can be an indication of how much factory support is available in terms of expertise, education, manufacturing capabilities and repair parts availability.
“If the user has issues or questions down the road, there is no substitute for partnering with a quality world-class pump company,” says Webel. “Saving a few dollars on the front end of a pump purchase by ignoring this advice will often end up costing the equipment owner much more down the road. The old adage that ‘You get what you pay for’ is certainly true when purchasing a pump.”
Although finding a pump system can seem overwhelming, the biggest consideration to take into account is the application it’s expected to perform in and the desired outcome of its use. This requires looking at the liquid the pump will encounter and matching a unit accordingly. Aldridge points out that when purchasing a pump, it is important to know what the requirements for the equipment will be from both a performance and operational standpoint.
“Performance should be defined based on how much fluid needs to be moved, where it is being moved from and to, and the resistance it has to overcome for that,” says Aldridge. “It should also be determined what is being pumped. From an operational standpoint, it is important to look at ease of maintenance, transportation, set-up and general usability.”
To help simplify the purchasing process, Stroud offers several questions to address with an equipment dealer:
1. What do you need to accomplish with the pump?
2. What type of liquid will you be pumping?
3. Is there any solid matter in the liquid you’re pumping?
4. What is the distance the fluid will be pumped.
5. How quickly does the liquid need to be moved?
6. Is noise an issue where you will be working?
7. What type of hose will be used?
Protecting Your Investment
After selecting a pump, understanding how to properly use and maintain it is essential to be productive on the job. To achieve this, Stroud says it’s imperative that only trained and qualified personnel be allowed to transport, set-up, operate and maintain the pump. Crews should always wear and use appropriate Personal Protective Equipment (PPE) and be acquainted with the pump’s operator’s manual, as well as any safety, health and environmental instructions provided with the pump. Additional training outlets are also a great way to become accustomed to the machinery.
“All users of the pump should thoroughly verse themselves with all safety recommendations from the manufacturer and should be familiar with all precautions and operational procedures as outlined in the operator’s manual for the equipment,” says Webel. “End-users should take advantage of any hands-on training classes offered by the manufacturer of the equipment, and should never operate a pump without proper training.”
Like with any piece of machinery with moving parts, maintenance is necessary to keep a pump running in tip-top shape. Since centrifugal pumps are very durable pieces of equipment, they should not require excessive amounts of maintenance as long as they are sized and used properly.
Routine preventative maintenance should be performed after every eight hours of operation and include a thorough check of the engine fluid levels and the fuel system, says Stroud. Prior to performing maintenance, it’s important to always shut down the unit and allow it to cool.
Webel adds, “When performing maintenance on a pump, the user should ensure that new seals and gaskets are installed as required, and that any regular maintenance items such as wear rings or bearing oil chambers have been properly inspected and serviced as necessary.”
According to a recommended 250-hour maintenance schedule, pumps should undergo several advanced assessments, replacements and lubrications. Although the pump requires minimal maintenance, Stroud mentions that the use of the pump in dusty, dirty, wet or otherwise adverse conditions may require more frequent inspection and maintenance.
Pam Kleineke is a contributing editor for Trenchless Technology.