Pumps are among the oldest machines ever invented by mankind. All the way back in 2000 BC, the Egyptians invented a device for raising water called a shadoof, a long, suspended rod with a bucket at one end and a weight on the other. And we’ve been using pumps to move water from one place to another, in one way or another, ever since.
Anyone working in irrigation should have some basic understanding of pumps— when they’re needed and how they work. Although not all irrigation systems have pumps, they’re often found on irrigation systems. Pumps are also needed when water must be pushed uphill.
Types of pumps
There are many different types of pumps on the market today; however, for landscape irrigation purposes, there are just a few basic types that are commonly used.
The centrifugal pump is the most common type, either in a horizontal or a vertical configuration. They’re used to either boost existing pressure, or to suction water from a pond or lake, as long as the lift length is less than 15 feet. Submersible pumps are also used to lift water up, but only while completely submerged. They can pump water from a great depth, as in deep-well applications, or from bodies of water.
There are two other types of pumps that are commonly used: vertical turbine and vertical multistage. These are generally used in larger irrigation systems. The large-landscape markets and golf courses rely heavily on vertical turbines, as they’re the most energy-efficient.
Vertical multistage pumps are more complicated; however, they can deliver high pressure in a small, compact footprint. They do have higher upfront costs than horizontal end-suction units, but they pay for themselves with higher energy efficiency.
“We’re seeing more vertical multistage pumps in landscape applications now, where they are going up against horizontal end-suction units,” says H. Rex Hansen, pump station sales manager at Rain Bird Corporation.
Smaller pumps, such as the ones used on backyard ponds or water features, often come prepackaged from the factory with motors already attached. “When you start to get above 5 to 7.5 hp, however, you’re going to buy pump ends and motors separately, to match what you need to do the job,” said Kurt K. Thompson, director of irrigation at Massey Services, Inc., Orlando, Florida.
A pump station can be delivered as a complete, fabricated package, custom-built and sized specifically to the needs of a particular irrigation system. It will include the pump(s), the motor, the control panel, the manifold piping and the enclosure, mounted on a skid. All a contractor has to do is hook up the intake and output, and tie it into the electrical power.
Or, a contractor can configure and assemble a pump station ‘from scratch.’ “With the big pump stations, you have to match everything; you’ll pick not only the pump end and the motor, but the panel, the starter, the variable frequency drive (VFD), and all the capacitors,” says Thompson.
Troy Owen, project manager at LSP Nursery, Inc., in Palm Bay, Florida, has built many pump stations from the ground up. “Usually, we’ll get the pump from a separate manufacturer,” he says. “But everything from there on out will usually be from the same company.” Getting everything from the same company makes life much easier when it comes to installation, maintenance and repairs, especially when you’re not certain which part is malfunctioning. Calling one technical-support hotline is simpler than calling five of them!
Submersibles are a little different from land-based pumps. They may need to be ‘primed’ before they’ll start working. “Usually, once you put a submersible in the water, it’s ready to go,” said Andy Schoenberger, portfolio manager at Fort Wayne, Indiana-based Franklin Electric.