Tech Article

One of the largest issue we have seen with our engineered pump systems over the last few years is nozzle, or flange, loading of the pumps. While not something people normally look at, it can cause huge issues with the pumps themselves.

Nozzle loads are the net forces and moments exerted on equipment nozzles. In pump systems, excessive nozzle loading occurs when forces and moments acting on the inlet and discharge ports of a pump combine to overcome a certain limit. The loads exerted are predominantly affected by how the connected equipment and piping are supported, misalignment in the system, and thermal expansion of piping material.

Causes and Issues:

• Thermal Expansion – Change in the length of a particular metal because of a change in temperature of that Hot fluid systems can cause pipework to expand with temperature. The expansion intensifies nozzle loading on all three axes.
• Nozzle loads can create torsional stresses across pipework, pumps and supports. For example, in external gear pumps, torsional stresses often lead to uneven gear wear and in severe cases contacting of the pump housing with gears.
• In less severe cases irregular wear will affect tight clearances designed to cater for shaft deflection, therefore slip occurs and the pump needs to run faster to maintain the required flow.
• Excessive nozzle loading can also lead to increased vibrations throughout the pumping This can have a dramatic effect on residual out of balance forces, exacerbating existing nozzle load issues and possible catastrophic pump failure.
• Misalignment is another cause. Connecting fixed pipework to smaller pumps can increase the chance of misalignment as well as sagging from the intrinsic self-weight of piping plus the weight of the fluids.

Solutions and Prevention:

• To minimize nozzle loading, all pipework should be externally supported on both inlet and discharge sides of the Where possible all pipes should be supported at the same level as the pump to reduce the number of bends and potential loading sites in the system.
• The pumping system should be designed with sufficient flexibility to withstand thermal expansion without creating excess forces at the flanges.
• Inlet piping should be free from any flow distributing fittings for a given minimum length to reduce potential pressure spikes.
• Devices that can aid in reducing moments and forces on the inlet condition are a flexible link, hose or bellows.

Victor Pumps has decided to invest in environmental protection and end-user safety by designing a new type of stainless-steel casings for its self-priming centrifugal pumps with semi-open impellers for corrosive, aggressive, and contaminant-laden dirty waters containing suspended solids. The new casings feature a reduced number of covers and openings, which are potential points of leakage or accidental spillage due to improper cover handling by an operator. The pumps affected by this modification are the 1½” S 41+50, S 49+50, and the 2″ S 51+50, S 62+50 models, covering a flow range from 20 to 200 gpm and a suction head of up to -26 ft w.c.

The continuous updating of CF-8M stainless steel castings such as impellers, casings, volutes, and other components is made possible by the innovative casting method starting from 3D prints, overseen firsthand by qualified technical staff of Victor Pumps’ engineering department.

GreenPumps is still expanding their offering in the magnetic drive pump market. A new addition to the GPM series is the GPM 40.2, which has a 2” flanged connection and a low NPSH option offering for the low feed head applications. This new pump is still going to be constructed in the GPM standard 316SS and will be available in the north American market with the NEMA

C-faced motor adapter. Contact us for more information.

Who is on Top?

The year finished off strong for all our distribution, and for that we are forever grateful, and look forward to great things in 2024. We have established a forecast for each of the territories with a solid growth plan. Our Top Ten for 2023 (again in no particular order):

Texas Steam, Houston, Tx

Cardinal Pump-St. Louis, MO

Hugh M. Cunningham, Carrolton, TX

James, Cooke, and Hobson, Phoenix, AZ

Mechanical Equipment Co, Matthews, NC

RE Merrell,

Pumps and Systems, Dearborn Heights, MI

Wichita Burner, Wichita, KS

PREMCO, New York City, NY

Boiler Supply, Nashville, TN

Training:

We apologize for the issues with the March Training class, which have all been resolved. We will be redoing the Victor Training class shortly and get the invitation out to all our distribution partners.

The Future:

We are looking forward to the online training this year. If you want to schedule special training for either your employees or a special customer, please let us know.

We are all looking forward to continuing a great 2024.

Best Regards, 

Greg, Dan, Tom, Debbie, Scott, Tristan, Samatha, Drew, Joey, Dee, David, and Paul: “The GPM Team!!”