The Little Things That Make a Big Difference in Your Pump Station Design

Note: The following catalog of content covered in this webinar is time stamped to allow you to follow along or skip to sections of the video that are relevant to your questions. You can also search for content on this page using the FIND command in your browser (CTRL + F in Windows, Command + F in Mac OS.)

• Intro/TOC
• Pump Styles
• Minimum Flows
• Single or Multiple VFDs
• Enclosures
• Vertical Turbine Seals
• Pressure Tanks

0:00 – 2:45: Intro/TOC

2:46 –8:05: Pump Styles

Horizontal and vertical multi-stage centrifugal pumps (2:46)

Horizontal centrifugal pump pros (2:59)

Horizontal centrifugal pump cons (3:38)

Vertical centrifugal pump pros (3:50)

Vertical centrifugal pump pros (4:16)

Horizontal centrifugal design (4:48)

• Most widely applied pumps for the irrigation industry
• Lifts water or boosts water, based on the application
• Efficiency is moderate based on the pump selection
• Cost effective and easy maintenance

Vertical multi-stage pumps (5:17)

• Highly efficient pumps capable of high pressure and high flows
• Higher R&M cost
• Excellent pump for surface water applications that require high flows and pressures

Takeaways (6:07)

• Multiple pump styles can often accomplish the same job
• Need to determine the tradeoffs that matter most
• Common tradeoffs to consider:
• Efficiency
• Longevity
• Ease of service
• Cost

8:06 – 12:38: Minimum Flows

Chart: pump performance and efficiency at high and low flows (9:06)

Takeaways (11:22)

• Provide minimum flows along with the maximum flows
• Minimum flows can have significant impact on design
• There may be benefits to using multiple pumps – potential increase in cost vs. longevity and reduced maintenance

12:39 – 23:07: Single or Multiple VFDs

Takeaways (16:25)

• Several control scenarios are possible
• Most VFDs offer flexibility and added efficiency
• Must understand power availability at site
• Control scenario will affect cost – up-front costs vs. total cost of ownership

Cycle stops (17:52)

Variable frequency drives vs. flow control valves for controlling PSI and flow (19:35)

Vertical turbine pumps (20:26)

23:08 –27:52: Enclosures

Examples of enclosures (26:10)

Takeaways (26:45)

• Convey all environmental information
• Discuss any special appearance needs
• Temperature control and sound attenuation can be addressed, but must be known

27:53 –36:27: Vertical Turbine Seals

Packing seals (aka stuffing boxes) (28:25)

Mechanical seals (29:10)

Takeaways (32:18)

• Very important to include information about water quality and content
• Either packing or a mechanical seal can be the right seal – it depends on the application
• Retrofits may be able to take advantage of changing the seal
• Mechanical seals bring a potential increase in cost vs. longevity and reduced maintenance – total cost of ownership

Packing vs. mechanical seal cost comparison (33:41)

Discussion on seals for horizontal centrifugal pumps (35:05)

36:28 – end: Pressure Tanks

Why are pressure tanks used for pump stations?

• Short cycling
• Expansion (heat)
• Water hammer

Pressure tank application and size variation: chart (38:02)

Other necessary devices to include in a pump station (41:53)

Recommended percentage of maximum flow as a minimum flow to avoid larger cost impacts (15 to 20 percent) (46:37)

Discussion of irrigation master valves used with pump stations (47:34)

The possibility of having two different pressure settings on the VFD: low PSI to run drip zones, and then high PSI to run rotors, i.e., set points on the VFD (yes, this is possible) (48:37)

Running one duty pump with a jockey pump, vs. running two duty pumps that share duty alternately (48:43)

Description of Munro Pumps (48:43)