Tag Archives: Horizontal Centrifugal Pump

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.


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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.

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.

Horizontal Centrifugal Pump

Horizontal Vortex Pump, Provides Unrestricted Flow, Impeller Not In Contact with Solids Being Pumped

Vertiflo Pump Company offers a rugged, dependable Series 1600 Industrial Horizontal Centrifugal Pump Vortex Sump for service in industrial and municipal applications. Fully recessed vortex impeller design provides an unrestricted flow since the impeller is not normally in contact with the solids being pumped. Industrial process applications include slurries, fragile food processing solids, pulpy solids, oils, pollution control and wastewater treatment. Solids handling up to 4” diameter spheres. 

The Series 1600 is designed for long life in severe services with heads to 170 feet, temperatures to 250° F with flows to 1600 GPM. Construction options include cast iron, 316 stainless steel fitted, all 316 stainless steel, Alloy 20 and CD4MC. Model 1620 has a 0.875” shaft diameter with 1.25” sleeve, Model 1626 has a 1.25” shaft diameter with a 1.625 diameter sleeve. Positively driven and gasketed, protecting motor shaft from liquid being pumped.

Use any NEMA Standard JP Shaft Motor, standard JP shaft extension allows for easy interchangability to packing, standard mechanical seal or optional single or double mechanical seals of various designs and materials of construction. All pumps are designed with back pull-out feature which allows for removal of all pump rotating components without disturbing the piping connections.

All suction and discharge openings are flanged for installation ease and integrity. All impellers have wiping vanes which reduce axial loading and prevent dirt from entering the sealing area. Impeller is keyed to shaft, and an impeller locking screw assures positive attachment. Vortex-type concentric design casing has extra heavy wall thick-ness for corrosion allowance. Three brackets fit all pump sizes.

All Vertiflo pumps are delivered fast, usually shipped in one-half the typical lead time. 

Vertiflo Pump Company, 513-530-0888, www.vertiflopump.com