Category Archives: Hydraulic Institute

Horizontal Vertical Pumps VFD Performance

How will pump efficiency be affected with variable speed drives?

By Hydraulic Institute

Q How much will pump efficiency be affected with the addition of a variable speed drive?

A It is a misconception that adding a variable speed drive (VSD) to a pump will increase its efficiency. When considering the wire-to-water efficiency of the pump, motor and VSD, each component that is added lowers the wire-to-water efficiency at a respective flow rate because each component has losses associated with it. Image 1 illustrates this concept showing the pump efficiency being the greatest, then the wire-to-water efficiency decreasing at the respective flow rate when the motor and VSD are added to the extended pump product.

Standards for Fossil Power Plant Pumps

The advantage that the VSD brings to the picture is that it can control the speed of the pump to meet the requirements of the system, which can reduce power consumed by less efficient controls that is not an essential requirement of the process. Additionally, the VSD can be used with on-off controls so the pump operates at a minimum speed where the specific energy consumption is optimized. Based on this, the VSD potentially increases the entire pump system efficiency by eliminating wasted head across control valves and wanted flow through bypass vales, and in some instances allows the pump to operate closer to its best efficiency point (BEP).

Horizontal Vertical Pumps VFD Performance

Image 2 illustrates two examples where the gray box represents power that is essential to the system and the orange box represents power that is not essential to the system. The orange box shows how much energy is wasted by throttling control in the first image or bypass control in the second image. In each case, the reduced speed pump curve can satisfy the operating flow without the orange wasted control power. The wasted control power typically outweighs the slight decrease in wire-to-water efficiency of the extended product. The two examples in Image 2 show systems with all friction head, and it is understood that the potential variable speed energy savings will decrease when static head is introduced to the system curve.

For more information on variable speed pumping and the application and efficiency considerations, refer to Hi’s Application Guideline for Variable Speed Pumping at pumps.org. ■

Link to original article in PUMPS & SYSTEMS Magazine Dec 2018.

Centrifugal pump selection guide 3

HI Pump FAQs® is produced by the Hydraulic Institute as a service to pump users, contractors, distributors, reps and OEMs. For more information, visit pumps.org.


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A Complete Line of Pumps for Industry

Vertiflo Pump Company’s Vertical Sump Centrifugal Pumps, Horizontal End Suction Centrifugal Pumps and self-priming pumps are delivered fast, usually in half the typical lead time. Vertiflo’s vertical sump pump line offers up to 3000 GPM, 250′ Heads and 26′ depth. The horizontal end suction pump line offers up to 3000 GPM and 300’ Heads.

Vertiflo pumps are designed for nonresidential applications and currently over 20,000 are operating successfully worldwide. Vertiflo is recognized as a quality manufacturer of dependable pumps, and continues to grow and encompass new applications in the pump industry.

Centrifugal pump selection guide 3

Standards for Fossil Power Plant Pumps

By Hydraulic Institute

Q What standards are applied to fossil power plant pumps?

A Specifications for power plant pumps will invoke many standards and requirements that will vary based on the specifier. A specific design standard is not applied.

Pump manufacturers that supply to this industry have developed product lines designed to internal standards to meet the reliability and pricing requirements that the market demands. Sometimes American Petroleum Institute (API) design standards are applied or pumps complying with API standards are specified in the power gen industry.

Regarding the performance, testing and application of the pumps, Hydraulic Institute (HI) standards and , Hydraulic Institute (HI) standards and guidebooks can also be applied as follows:

• Important application considerations, pump types and typical materials of construction that are used in typical fossil power plant pump applications can be found in HI’s Pump Application Guidebook for Power Plant Pumps.

• Guidelines for the measurement of airborne sound can be found in ANSI/ HI 9.1-9.5 Pumps – General Guidelines.

• Guidelines on the application of net positive suction head (NPSH) margin and the preferred and allowable operating region can be found in ANSI/HI 9.6.1 Rotodynamic Pumps – Guideline for NPSH Margin and ANSI/HI 9.6.3 Rotodyanmic Pumps – Guideline for Operating Regions.

• Vibration acceptance testing of the pumps should be per ANSI/HI 9.6.4 Rotodynamic Pumps – Vibration Measurements and Allowable Values.

• Recommendations on the condition monitoring of the installed pump can be found in ANSI/HI 9.6.5 Rotodynamic Pumps – Guideline for Condition Monitoring.

• Important system components like piping connecting to the pump and free surface intakes should be designed to ANSI/HI 9.6.6 Rotodynamic Pumps for Pump Piping and ANSI/HI 9.8 Rotodynamic Pumps for Intake Design, respectively.

• Guidelines for dynamic analysis that should be conducted can be found in ANSI/HI 9.6.8 Rotodynamic Pumps – Guidelines for Condition Monitoring.

• Hydraulic performance, NPSH3, and hydrostatic acceptance testing of the pump should be per ANSI/HI 14.6 Rotodynamic Pumps for Hydraulic Performance Acceptance Tests.

View the original article publication at PUMPS & SYSTEMS Dec 2018 issue.

Centrifugal pump selection guide 3

HI Pump FAQs® is produced by the Hydraulic Institute as a service to pump users, contractors, distributors, reps and OEMs. For more information, visit pumps.org.


Industry News from the Hydraulic Institute

2019 HI Conference Retrospective – Pump Engineer Magazine

Hydraulic Institute Announces Board of Directors for 2019-2020

2019 HI Annual Awards News Release


A Complete Line of Pumps for Industry

Vertiflo Pump Company’s Vertical Sump Centrifugal Pumps, Horizontal End Suction Centrifugal Pumps and self-priming pumps are delivered fast, usually in half the typical lead time. Vertiflo’s vertical sump pump line offers up to 3000 GPM, 250′ Heads and 26′ depth. The horizontal end suction pump line offers up to 3000 GPM and 300’ Heads.

Vertiflo pumps are designed for nonresidential applications and currently over 20,000 are operating successfully worldwide. Vertiflo is recognized as a quality manufacturer of dependable pumps, and continues to grow and encompass new applications in the pump industry.

Flexible Couplings Alignment & Pumps in Explosive Atmospheres

Q: Is there a simple way to check the alignment of flexible couplings on a pump?

A: Laser alignment systems are used to determine the extent of shaft misalignment by measuring the movement of a laser beam across the surface of a detector plate as the shafts are rotated.

Horizontal Centrifugal Pump Alignment
Horizontal Centrifugal Pump Alignment

Many laser alignment systems are available, and the procedure for alignment is provided by the laser system’s producer. They are capable of aligning couplings with and without spacers and are most commonly used for precision alignments. Image 1 shows an example of a laser alignment system setup on a pump and motor shaft.  By following the instructions of the laser system, the computer will output adjustment requirements to align the shafts.

In the absence of a laser alignment system, users can check the alignment with some simple tools. The necessary tools used for checking the alignment of a flexible coupling are a straightedge and a taper gauge or a set of feeler gauges, or by use of dial indicators.

Vertical Sump Pump Alignment
Vertical Sump Pump Alignment

A rough check for angular alignment is made by inserting the taper gauge or feelers between the coupling faces at 90 degree intervals (see Image 2). Checks for angular and parallel alignment by this method can only be done if the face and outside diameters of the coupling halves are square and concentric with the coupling bores. A rough check for parallel alignment is made by placing a straightedge across both coupling rims at the top, bottom and at both sides (see Image 3). After rough alignment, fasten the indicator to the pump half of the coupling, with the indicator button resting on the other half coupling periphery (see Image 4). Set the dial to zero, and mark the coupling half beside where the button rests. Rotate both shafts by the same amount, i.e., all readings on the dial must be made with the button beside the mark. The dial readings will indicate whether the driver has to be raised, lowered or moved to either side.

After each adjustment, recheck both parallel and angular alignments. Accurate alignment of shaft centers can be obtained with the dial indicator method — even where faces or outside diameters of the coupling halves are not square or concentric with the bores—provided all measurements for angular alignment are made between the same two points on the outside diameters. For angular alignment, change the indicator so it bears against the face of the same coupling half and proceed as described for parallel alignment.

There are additional techniques not described in this answer that are required for proper pump alignment, such as correcting for indicator sag or compensating for cold aligning a hot pump system. Please reference industry standards and the pump and coupling manufacturer’s instructions as well.

For more information about coupling alignment for rotodynamic pumps, including additional considerations, see the American National Standard ANSI/HI 14.4 Rotodynamic Pumps for Manuals Describing Installation, Operation, and Maintenance at pumps.org.


Q: What is meant by the temperature class for my pumps that are rated for explosive atmospheres?

A: Pumps installed in potentially explosive atmospheres must be designed and operated in a way to limit their surface temperature based on the type of potentially explosive atmosphere. 

Explosive Centrifugal Pump Applications
Explosive Centrifugal Pump Applications

A reference for the requirements of electrical and nonelectrical equipment is the European Union (EU) ATEX Directive 2014/34/EU (Ex). Within this directive, one requirement is that pumps have a temperature class as stated in the explosion (Ex) rating on the nameplate. These are based on a maximum ambient temperature of 40 C (104 F). Refer to the manufacturer for higher ambient temperatures.

The surface temperature on the pump is influenced by the liquid handled. The maximum permissible liquid temperature depends on the temperature class and must not exceed the values in Image 5. The temperature rise at the seals and bearings due to the minimum permitted fl ow rate is taken into account in the temperatures stated. Note that the plant operator is responsible for compliance with the specified maximum liquid temperature. Surface temperatures above 54 C (130 F) can cause irreversible skin damage and, therefore, require insulation to ensure personnel protection. For more information about the manuals describing the installation, operation and maintenance of rotodynamic pumps, refer to ANSI/HI 14.4 Rotodynamic Pumps for Manuals Describing Installation, Operation, and Maintenance at pumps.org.

Centrifugal pump selection guide 3

HI Pump FAQs® is produced by the Hydraulic Institute as a service to pump users, contractors, distributors, reps and OEMs. For more information, visit pumps.org.


Industry News from the Hydraulic Institute

2019 HI Conference Retrospective – Pump Engineer Magazine

Hydraulic Institute Announces Board of Directors for 2019-2020

2019 HI Annual Awards News Release


A Complete Line of Pumps for Industry

Vertiflo Pump Company’s Vertical Sump Centrifugal Pumps, Horizontal End Suction Centrifugal Pumps and self-priming pumps are delivered fast, usually in half the typical lead time. Vertiflo’s vertical sump pump line offers up to 3000 GPM, 250′ Heads and 26′ depth. The horizontal end suction pump line offers up to 3000 GPM and 300’ Heads.

Vertiflo pumps are designed for nonresidential applications and currently over 20,000 are operating successfully worldwide. Vertiflo is recognized as a quality manufacturer of dependable pumps, and continues to grow and encompass new applications in the pump industry.

Horizontal Centrifugal Pump

What is a centrifugal pump?

What is the Difference Between Centrifugal & Rotodynamic Pumps

Rotodynamic pumps include centrifugal, mixed and axial flow pumps.
by Hydraulic Institute, February 27, 2019

Q: I am used to hearing the term “centrifugal” pump, but sometimes hear them referred to as “rotodynamic” pumps. Can these terms be used synonymously?

A: Rotodynamic pumps are kinetic machines in which energy is continuously imparted to the pumped fluid by means of a rotating impeller, propeller or rotor. These pumps transfer mechanical energy to the fluid primarily by increasing the fluid kinetic energy. Kinetic energy is then converted into potential energy (pressure) in the discharge collector. The most common types of rotodynamic pumps are radial (centrifugal), mixed flow and axial flow (propeller) pumps, including pumps historically referred to as vertical turbine pumps. Radial, mixed and axial flow impellers are shown in Image 1.

Centrifugal pump

Image 1. Radial (centrifugal), mixed and axial flow impellers (Images courtesy of the Hydraulic Institute)

As seen from the definition of a rotodynamic pump and Image 1, it is a term used to describe a larger group of pumps that includes centrifugal (radial flow) pumps, but also includes mixed and axial flow pumps and some other unique constructions. Centrifugal pumps are the most common type and the term is synonymous with radial flow impellers where the flow enters the impeller in line with the pump shaft, but discharges the impeller perpendicular to the pump shaft.

Centrifugal pump

Image 2. Rotodynamic pump types by classification

Rotodynamic pump types are also commonly described by their general mechanical configuration. To answer the question directly, a centrifugal pump is a type rotodynamic pump, and not all rotodynamic pumps are centrifugal pumps.

Centrifugal pump selection guide 3

For more information, refer to ANSI/HI 14.1-14.2 rotodynamic pumps for nomenclature and definitions, and ANSI/HI 14.3 rotodynamic pumps for design and application at www.pumps.org.

Centrifugal pump selection guide 3

Pump Bearings & Housing Seal Lubrication – By Hydraulic Institute

What types of lubrication can be used for pump bearings?

March 2019 Pumps & Systems Magazine

There are many bearing types, which require different lubrication methods. This response focuses on the most common methods for lubricating rolling element bearings in horizontal process pumps and their application considerations include:

• Grease lubrication:
An advantage of grease lubrication is simplified maintenance, and some disadvantages are over-pressurization and limited heat dissipation. The use of grease is primarily limited to lower speed and horsepower pumps.
• Oil splash:
Some advantages of oil bath/splash lubrication are a wider range of speeds than grease and visual verification of oil level is possible, and some disadvantages are sensitivity to oil level and contaminants remaining in the oil bath. Oil splash lubrication can be achieved by the bearing being in direct contact with the oil, oil rings contacting the lubricant and splashing it throughout the bearing housing, or slinger disks that splash the lubricant throughout the bearing housing.
• Pure oil mist:
Some advantages of pure oil mist lubrication are lower operation temperature compared to oil bath, wear particles are not recirculated and lower oil consumption. Some disadvantages are that it requires higher level of application knowledge and higher initial costs compared to oil bath. The basic concept of oil mist lubrication system is dispersion of an oil aerosol into the bearing housing. There is no reservoir of oil in the housing, and oil rings are not used. The oil is atomized and airflow transports the small oil particles through a piping system into the pump bearing housing.
Horizontal & vertical centrifugal pump seals
What methods can be used to maintain lubrication oil quantity and quality?
For oil bath lubrication, quantity of oil can always be adjusted by adding oil to maintain the manufacturer’s recommended level. However, another approach to maintain the proper quantity of oil is with bearing housing seals. When properly applied, bearing seals can eliminate lubrication leaks from the housing and help maintain recommended oil levels.
Examples are lip seals, labyrinth isolators and magnetic face seals shown in Image 1. These mentioned seals  are also useful in the reduction of oil contamination to maintain the quality of the oil.
Particle contamination can be avoided with consideration of materials, design and maintenance of lubricant containers, seals and bearing isolators. When selecting gaskets and seals, materials should be compatible with the lubricant.
When filling the bearing housing, the fill port should be cleaned prior to opening, the lubricant container should be closed until filling, and care should be taken to prevent atmospheric contaminants from entering the fill port during the fill process.
In addition to preventing lubricant leakage, bearing housing seals also serve to prevent contaminant ingress.
Focusing on isolator technology, labyrinth and magnetic face-type bearing isolators are widely used on pumps. Bearing isolators allow increased pressure created in the bearing housing by normal pump operation to vent through the isolator and have proven to be effective at reducing, and sometimes eliminating, contaminant ingress. The face design and the labyrinth design allow for the venting to occur while in operation.
Horizontal & vertical centrifugal pump seals
The face design of the magnetic isolator protects the bearings against contaminants while the pump is shut off or in standby using the contacting faces.
Labyrinth isolators may use shut-off features to provide ingress protection when the equipment stops rotating, as shown in Image 2.
These shut-off devices are designed to prevent moisture from penetrating the bearing chamber when the equipment shuts down and air is drawn into the housing.
When properly specified, bearing housing lubrication quality­enhancing components-including oilers, bearing protection devices and vents-can be effective in maintaining the quality of bearing lubricants.
For more information about proper bearing lubrication and maintaining the quality of the lubrication, download HI’s new free white paper “Proper Lubrication Methods for Bearings” at pumps.org/lubrication. ■
Centrifugal pump selection guide 3
HI Pump FAQs” is produced by the Hydraulic Institute as a service to pump users, contractors, distributors, reps and OEMs. For more information, visit pumps.org.

Vertiflo Pump Company – A Complete Line of Pumps for Industry

Vertiflo Pump Company’s vertical, horizontal and self-priming pumps are delivered fast, usually in half the typical lead time! Vertiflo’s vertical sump pump line offers up to 3000 GPM, 250′ Heads and 26′ depth. The horizontal end suction pump line offers up to 3000 GPM and 300’ Heads.

Vertiflo Pump Company, Inc. was established in 1979 to design, sell and build packaged lift stations. Since 1981, Vertiflo has concentrated on manufacturing vertical process pumps, sump pumps, end suction pumps and self-priming pumps in cast iron, stainless steel and special alloys.

Vertiflo pumps are designed for nonresidential applications and currently over 20,000 are operating successfully worldwide. Vertiflo is recognized as a quality manufacturer of dependable pumps, and continues to grow and encompass new applications in the pump industry.

Vertiflo Pump Company, Dept. I, 7807 Redsky Drive, Cincinnati, OH 45249 • 513-530-0888 • www.vertiflopump.com[email protected]